Tag Archives: racing

Kernel 4.17 released

Post Syndicated from corbet original https://lwn.net/Articles/756373/rss

Linus has released the 4.17 kernel, which
will indeed be called “4.17”.
No, I didn’t call it 5.0, even though all the git object count
numerology was in place for that. It will happen in the not _too_
distant future, and I’m told all the release scripts on kernel.org are
ready for it, but I didn’t feel there was any real reason for it.

Headline features in this release include
improved load estimation in the CPU
scheduler,
raw
BPF tracepoints
,
lazytime support in the XFS filesystem,
full in-kernel TLS protocol support,
histogram triggers for tracing,
mitigations for the latest Spectre variants,
and, of course, the removal of support for eight unloved processor
architectures.

All Systems Go! 2018 CfP Open

Post Syndicated from Lennart Poettering original http://0pointer.net/blog/all-systems-go-2018-cfp-open.html

The All Systems Go! 2018 Call for Participation is Now Open!

The Call for Participation (CFP) for All Systems Go!
2018
is now open. We’d like to invite you
to submit your proposals for consideration to the CFP submission
site
.

ASG image

The CFP will close on July 30th. Notification of acceptance and
non-acceptance will go out within 7 days of the closing of the CFP.

All topics relevant to foundational open-source Linux technologies are
welcome. In particular, however, we are looking for proposals
including, but not limited to, the following topics:

  • Low-level container executors and infrastructure
  • IoT and embedded OS infrastructure
  • BPF and eBPF filtering
  • OS, container, IoT image delivery and updating
  • Building Linux devices and applications
  • Low-level desktop technologies
  • Networking
  • System and service management
  • Tracing and performance measuring
  • IPC and RPC systems
  • Security and Sandboxing

While our focus is definitely more on the user-space side of things,
talks about kernel projects are welcome, as long as they have a clear
and direct relevance for user-space.

For more information please visit our conference
website
!

[$] Using user-space tracepoints with BPF

Post Syndicated from corbet original https://lwn.net/Articles/753601/rss

Much has been written on LWN about dynamically instrumenting kernel
code. These features are also available to user-space code with a
special kind of probe known as a User Statically-Defined Tracing
(USDT) probe. These probes provide a low-overhead way of
instrumenting user-space code and provide a convenient way to debug applications
running in production. In this final article of the BPF and BCC series
we’ll look at where USDT probes come from and how you can use them to
understand the behavior of your own applications.

How AWS Meets a Physical Separation Requirement with a Logical Separation Approach

Post Syndicated from Min Hyun original https://aws.amazon.com/blogs/security/how-aws-meets-a-physical-separation-requirement-with-a-logical-separation-approach/

We have a new resource available to help you meet a requirement for physically-separated infrastructure using logical separation in the AWS cloud. Our latest guide, Logical Separation: An Evaluation of the U.S. Department of Defense Cloud Security Requirements for Sensitive Workloads outlines how AWS meets the U.S. Department of Defense’s (DoD) stringent physical separation requirement by pioneering a three-pronged logical separation approach that leverages virtualization, encryption, and deploying compute to dedicated hardware.

This guide will help you understand logical separation in the cloud and demonstrates its advantages over a traditional physical separation model. Embracing this approach can help organizations confidently meet or exceed security requirements found in traditional on-premises environments, while also providing increased security control and flexibility.

Logical Separation is the second guide in the AWS Government Handbook Series, which examines cybersecurity policy initiatives and identifies best practices.

If you have questions or want to learn more, contact your account executive or AWS Support.

10 visualizations to try in Amazon QuickSight with sample data

Post Syndicated from Karthik Kumar Odapally original https://aws.amazon.com/blogs/big-data/10-visualizations-to-try-in-amazon-quicksight-with-sample-data/

If you’re not already familiar with building visualizations for quick access to business insights using Amazon QuickSight, consider this your introduction. In this post, we’ll walk through some common scenarios with sample datasets to provide an overview of how you can connect yuor data, perform advanced analysis and access the results from any web browser or mobile device.

The following visualizations are built from the public datasets available in the links below. Before we jump into that, let’s take a look at the supported data sources, file formats and a typical QuickSight workflow to build any visualization.

Which data sources does Amazon QuickSight support?

At the time of publication, you can use the following data methods:

  • Connect to AWS data sources, including:
    • Amazon RDS
    • Amazon Aurora
    • Amazon Redshift
    • Amazon Athena
    • Amazon S3
  • Upload Excel spreadsheets or flat files (CSV, TSV, CLF, and ELF)
  • Connect to on-premises databases like Teradata, SQL Server, MySQL, and PostgreSQL
  • Import data from SaaS applications like Salesforce and Snowflake
  • Use big data processing engines like Spark and Presto

This list is constantly growing. For more information, see Supported Data Sources.

Answers in instants

SPICE is the Amazon QuickSight super-fast, parallel, in-memory calculation engine, designed specifically for ad hoc data visualization. SPICE stores your data in a system architected for high availability, where it is saved until you choose to delete it. Improve the performance of database datasets by importing the data into SPICE instead of using a direct database query. To calculate how much SPICE capacity your dataset needs, see Managing SPICE Capacity.

Typical Amazon QuickSight workflow

When you create an analysis, the typical workflow is as follows:

  1. Connect to a data source, and then create a new dataset or choose an existing dataset.
  2. (Optional) If you created a new dataset, prepare the data (for example, by changing field names or data types).
  3. Create a new analysis.
  4. Add a visual to the analysis by choosing the fields to visualize. Choose a specific visual type, or use AutoGraph and let Amazon QuickSight choose the most appropriate visual type, based on the number and data types of the fields that you select.
  5. (Optional) Modify the visual to meet your requirements (for example, by adding a filter or changing the visual type).
  6. (Optional) Add more visuals to the analysis.
  7. (Optional) Add scenes to the default story to provide a narrative about some aspect of the analysis data.
  8. (Optional) Publish the analysis as a dashboard to share insights with other users.

The following graphic illustrates a typical Amazon QuickSight workflow.

Visualizations created in Amazon QuickSight with sample datasets

Visualizations for a data analyst

Source:  https://data.worldbank.org/

Download and Resources:  https://datacatalog.worldbank.org/dataset/world-development-indicators

Data catalog:  The World Bank invests into multiple development projects at the national, regional, and global levels. It’s a great source of information for data analysts.

The following graph shows the percentage of the population that has access to electricity (rural and urban) during 2000 in Asia, Africa, the Middle East, and Latin America.

The following graph shows the share of healthcare costs that are paid out-of-pocket (private vs. public). Also, you can maneuver over the graph to get detailed statistics at a glance.

Visualizations for a trading analyst

Source:  Deutsche Börse Public Dataset (DBG PDS)

Download and resources:  https://aws.amazon.com/public-datasets/deutsche-boerse-pds/

Data catalog:  The DBG PDS project makes real-time data derived from Deutsche Börse’s trading market systems available to the public for free. This is the first time that such detailed financial market data has been shared freely and continually from the source provider.

The following graph shows the market trend of max trade volume for different EU banks. It builds on the data available on XETRA engines, which is made up of a variety of equities, funds, and derivative securities. This graph can be scrolled to visualize trade for a period of an hour or more.

The following graph shows the common stock beating the rest of the maximum trade volume over a period of time, grouped by security type.

Visualizations for a data scientist

Source:  https://catalog.data.gov/

Download and resources:  https://catalog.data.gov/dataset/road-weather-information-stations-788f8

Data catalog:  Data derived from different sensor stations placed on the city bridges and surface streets are a core information source. The road weather information station has a temperature sensor that measures the temperature of the street surface. It also has a sensor that measures the ambient air temperature at the station each second.

The following graph shows the present max air temperature in Seattle from different RWI station sensors.

The following graph shows the minimum temperature of the road surface at different times, which helps predicts road conditions at a particular time of the year.

Visualizations for a data engineer

Source:  https://www.kaggle.com/

Download and resources:  https://www.kaggle.com/datasnaek/youtube-new/data

Data catalog:  Kaggle has come up with a platform where people can donate open datasets. Data engineers and other community members can have open access to these datasets and can contribute to the open data movement. They have more than 350 datasets in total, with more than 200 as featured datasets. It has a few interesting datasets on the platform that are not present at other places, and it’s a platform to connect with other data enthusiasts.

The following graph shows the trending YouTube videos and presents the max likes for the top 20 channels. This is one of the most popular datasets for data engineers.

The following graph shows the YouTube daily statistics for the max views of video titles published during a specific time period.

Visualizations for a business user

Source:  New York Taxi Data

Download and resources:  https://data.cityofnewyork.us/Transportation/2016-Green-Taxi-Trip-Data/hvrh-b6nb

Data catalog: NYC Open data hosts some very popular open data sets for all New Yorkers. This platform allows you to get involved in dive deep into the data set to pull some useful visualizations. 2016 Green taxi trip dataset includes trip records from all trips completed in green taxis in NYC in 2016. Records include fields capturing pick-up and drop-off dates/times, pick-up and drop-off locations, trip distances, itemized fares, rate types, payment types, and driver-reported passenger counts.

The following graph presents maximum fare amount grouped by the passenger count during a period of time during a day. This can be further expanded to follow through different day of the month based on the business need.

The following graph shows the NewYork taxi data from January 2016, showing the dip in the number of taxis ridden on January 23, 2016 across all types of taxis.

A quick search for that date and location shows you the following news report:

Summary

Using Amazon QuickSight, you can see patterns across a time-series data by building visualizations, performing ad hoc analysis, and quickly generating insights. We hope you’ll give it a try today!

 


Additional Reading

If you found this post useful, be sure to check out Amazon QuickSight Adds Support for Combo Charts and Row-Level Security and Visualize AWS Cloudtrail Logs Using AWS Glue and Amazon QuickSight.


Karthik Odapally is a Sr. Solutions Architect in AWS. His passion is to build cost effective and highly scalable solutions on the cloud. In his spare time, he bakes cookies and cupcakes for family and friends here in the PNW. He loves vintage racing cars.

 

 

 

Pranabesh Mandal is a Solutions Architect in AWS. He has over a decade of IT experience. He is passionate about cloud technology and focuses on Analytics. In his spare time, he likes to hike and explore the beautiful nature and wild life of most divine national parks around the United States alongside his wife.

 

 

 

 

Confused About the Hybrid Cloud? You’re Not Alone

Post Syndicated from Roderick Bauer original https://www.backblaze.com/blog/confused-about-the-hybrid-cloud-youre-not-alone/

Hybrid Cloud. What is it?

Do you have a clear understanding of the hybrid cloud? If you don’t, it’s not surprising.

Hybrid cloud has been applied to a greater and more varied number of IT solutions than almost any other recent data management term. About the only thing that’s clear about the hybrid cloud is that the term hybrid cloud wasn’t invented by customers, but by vendors who wanted to hawk whatever solution du jour they happened to be pushing.

Let’s be honest. We’re in an industry that loves hype. We can’t resist grafting hyper, multi, ultra, and super and other prefixes onto the beginnings of words to entice customers with something new and shiny. The alphabet soup of cloud-related terms can include various options for where the cloud is located (on-premises, off-premises), whether the resources are private or shared in some degree (private, community, public), what type of services are offered (storage, computing), and what type of orchestrating software is used to manage the workflow and the resources. With so many moving parts, it’s no wonder potential users are confused.

Let’s take a step back, try to clear up the misconceptions, and come up with a basic understanding of what the hybrid cloud is. To be clear, this is our viewpoint. Others are free to do what they like, so bear that in mind.

So, What is the Hybrid Cloud?

The hybrid cloud refers to a cloud environment made up of a mixture of on-premises private cloud resources combined with third-party public cloud resources that use some kind of orchestration between them.

To get beyond the hype, let’s start with Forrester Research‘s idea of the hybrid cloud: “One or more public clouds connected to something in my data center. That thing could be a private cloud; that thing could just be traditional data center infrastructure.”

To put it simply, a hybrid cloud is a mash-up of on-premises and off-premises IT resources.

To expand on that a bit, we can say that the hybrid cloud refers to a cloud environment made up of a mixture of on-premises private cloud[1] resources combined with third-party public cloud resources that use some kind of orchestration[2] between them. The advantage of the hybrid cloud model is that it allows workloads and data to move between private and public clouds in a flexible way as demands, needs, and costs change, giving businesses greater flexibility and more options for data deployment and use.

In other words, if you have some IT resources in-house that you are replicating or augmenting with an external vendor, congrats, you have a hybrid cloud!

Private Cloud vs. Public Cloud

The cloud is really just a collection of purpose built servers. In a private cloud, the servers are dedicated to a single tenant or a group of related tenants. In a public cloud, the servers are shared between multiple unrelated tenants (customers). A public cloud is off-site, while a private cloud can be on-site or off-site — or on-prem or off-prem.

As an example, let’s look at a hybrid cloud meant for data storage, a hybrid data cloud. A company might set up a rule that says all accounting files that have not been touched in the last year are automatically moved off-prem to cloud storage to save cost and reduce the amount of storage needed on-site. The files are still available; they are just no longer stored on your local systems. The rules can be defined to fit an organization’s workflow and data retention policies.

The hybrid cloud concept also contains cloud computing. For example, at the end of the quarter, order processing application instances can be spun up off-premises in a hybrid computing cloud as needed to add to on-premises capacity.

Hybrid Cloud Benefits

If we accept that the hybrid cloud combines the best elements of private and public clouds, then the benefits of hybrid cloud solutions are clear, and we can identify the primary two benefits that result from the blending of private and public clouds.

Diagram of the Components of the Hybrid Cloud

Benefit 1: Flexibility and Scalability

Undoubtedly, the primary advantage of the hybrid cloud is its flexibility. It takes time and money to manage in-house IT infrastructure and adding capacity requires advance planning.

The cloud is ready and able to provide IT resources whenever needed on short notice. The term cloud bursting refers to the on-demand and temporary use of the public cloud when demand exceeds resources available in the private cloud. For example, some businesses experience seasonal spikes that can put an extra burden on private clouds. These spikes can be taken up by a public cloud. Demand also can vary with geographic location, events, or other variables. The public cloud provides the elasticity to deal with these and other anticipated and unanticipated IT loads. The alternative would be fixed cost investments in on-premises IT resources that might not be efficiently utilized.

For a data storage user, the on-premises private cloud storage provides, among other benefits, the highest speed access. For data that is not frequently accessed, or needed with the absolute lowest levels of latency, it makes sense for the organization to move it to a location that is secure, but less expensive. The data is still readily available, and the public cloud provides a better platform for sharing the data with specific clients, users, or with the general public.

Benefit 2: Cost Savings

The public cloud component of the hybrid cloud provides cost-effective IT resources without incurring capital expenses and labor costs. IT professionals can determine the best configuration, service provider, and location for each service, thereby cutting costs by matching the resource with the task best suited to it. Services can be easily scaled, redeployed, or reduced when necessary, saving costs through increased efficiency and avoiding unnecessary expenses.

Comparing Private vs Hybrid Cloud Storage Costs

To get an idea of the difference in storage costs between a purely on-premises solutions and one that uses a hybrid of private and public storage, we’ll present two scenarios. For each scenario we’ll use data storage amounts of 100 terabytes, 1 petabyte, and 2 petabytes. Each table is the same format, all we’ve done is change how the data is distributed: private (on-premises) cloud or public (off-premises) cloud. We are using the costs for our own B2 Cloud Storage in this example. The math can be adapted for any set of numbers you wish to use.

Scenario 1    100% of data on-premises storage

Data Stored
Data stored On-Premises: 100%100 TB1,000 TB2,000 TB
On-premises cost rangeMonthly Cost
Low — $12/TB/Month$1,200$12,000$24,000
High — $20/TB/Month$2,000$20,000$40,000

Scenario 2    20% of data on-premises with 80% public cloud storage (B2)

Data Stored
Data stored On-Premises: 20%20 TB200 TB400 TB
Data stored in Cloud: 80%80 TB800 TB1,600 TB
On-premises cost rangeMonthly Cost
Low — $12/TB/Month$240$2,400$4,800
High — $20/TB/Month$400$4,000$8,000
Public cloud cost rangeMonthly Cost
Low — $5/TB/Month (B2)$400$4,000$8,000
High — $20/TB/Month$1,600$16,000$32,000
On-premises + public cloud cost rangeMonthly Cost
Low$640$6,400$12,800
High$2,000$20,000$40,000

As can be seen in the numbers above, using a hybrid cloud solution and storing 80% of the data in the cloud with a provider such as Backblaze B2 can result in significant savings over storing only on-premises. For other cost scenarios, see the B2 Cost Calculator.

When Hybrid Might Not Always Be the Right Fit

There are circumstances where the hybrid cloud might not be the best solution. Smaller organizations operating on a tight IT budget might best be served by a purely public cloud solution. The cost of setting up and running private servers is substantial.

An application that requires the highest possible speed might not be suitable for hybrid, depending on the specific cloud implementation. While latency does play a factor in data storage for some users, it is less of a factor for uploading and downloading data than it is for organizations using the hybrid cloud for computing. Because Backblaze recognized the importance of speed and low-latency for customers wishing to use computing on data stored in B2, we directly connected our data centers with those of our computing partners, ensuring that latency would not be an issue even for a hybrid cloud computing solution.

It is essential to have a good understanding of workloads and their essential characteristics in order to make the hybrid cloud work well for you. Each application needs to be examined for the right mix of private cloud, public cloud, and traditional IT resources that fit the particular workload in order to benefit most from a hybrid cloud architecture.

The Hybrid Cloud Can Be a Win-Win Solution

From the high altitude perspective, any solution that enables an organization to respond in a flexible manner to IT demands is a win. Avoiding big upfront capital expenses for in-house IT infrastructure will appeal to the CFO. Being able to quickly spin up IT resources as they’re needed will appeal to the CTO and VP of Operations.

Should You Go Hybrid?

We’ve arrived at the bottom line and the question is, should you or your organization embrace hybrid cloud infrastructures?

According to 451 Research, by 2019, 69% of companies will operate in hybrid cloud environments, and 60% of workloads will be running in some form of hosted cloud service (up from 45% in 2017). That indicates that the benefits of the hybrid cloud appeal to a broad range of companies.

In Two Years, More Than Half of Workloads Will Run in Cloud

Clearly, depending on an organization’s needs, there are advantages to a hybrid solution. While it might have been possible to dismiss the hybrid cloud in the early days of the cloud as nothing more than a buzzword, that’s no longer true. The hybrid cloud has evolved beyond the marketing hype to offer real solutions for an increasingly complex and challenging IT environment.

If an organization approaches the hybrid cloud with sufficient planning and a structured approach, a hybrid cloud can deliver on-demand flexibility, empower legacy systems and applications with new capabilities, and become a catalyst for digital transformation. The result can be an elastic and responsive infrastructure that has the ability to quickly respond to changing demands of the business.

As data management professionals increasingly recognize the advantages of the hybrid cloud, we can expect more and more of them to embrace it as an essential part of their IT strategy.

Tell Us What You’re Doing with the Hybrid Cloud

Are you currently embracing the hybrid cloud, or are you still uncertain or hanging back because you’re satisfied with how things are currently? Maybe you’ve gone totally hybrid. We’d love to hear your comments below on how you’re dealing with the hybrid cloud.


[1] Private cloud can be on-premises or a dedicated off-premises facility.

[2] Hybrid cloud orchestration solutions are often proprietary, vertical, and task dependent.

The post Confused About the Hybrid Cloud? You’re Not Alone appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Facebook and Cambridge Analytica

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/03/facebook_and_ca.html

In the wake of the Cambridge Analytica scandal, news articles and commentators have focused on what Facebook knows about us. A lot, it turns out. It collects data from our posts, our likes, our photos, things we type and delete without posting, and things we do while not on Facebook and even when we’re offline. It buys data about us from others. And it can infer even more: our sexual orientation, political beliefs, relationship status, drug use, and other personality traits — even if we didn’t take the personality test that Cambridge Analytica developed.

But for every article about Facebook’s creepy stalker behavior, thousands of other companies are breathing a collective sigh of relief that it’s Facebook and not them in the spotlight. Because while Facebook is one of the biggest players in this space, there are thousands of other companies that spy on and manipulate us for profit.

Harvard Business School professor Shoshana Zuboff calls it “surveillance capitalism.” And as creepy as Facebook is turning out to be, the entire industry is far creepier. It has existed in secret far too long, and it’s up to lawmakers to force these companies into the public spotlight, where we can all decide if this is how we want society to operate and — if not — what to do about it.

There are 2,500 to 4,000 data brokers in the United States whose business is buying and selling our personal data. Last year, Equifax was in the news when hackers stole personal information on 150 million people, including Social Security numbers, birth dates, addresses, and driver’s license numbers.

You certainly didn’t give it permission to collect any of that information. Equifax is one of those thousands of data brokers, most of them you’ve never heard of, selling your personal information without your knowledge or consent to pretty much anyone who will pay for it.

Surveillance capitalism takes this one step further. Companies like Facebook and Google offer you free services in exchange for your data. Google’s surveillance isn’t in the news, but it’s startlingly intimate. We never lie to our search engines. Our interests and curiosities, hopes and fears, desires and sexual proclivities, are all collected and saved. Add to that the websites we visit that Google tracks through its advertising network, our Gmail accounts, our movements via Google Maps, and what it can collect from our smartphones.

That phone is probably the most intimate surveillance device ever invented. It tracks our location continuously, so it knows where we live, where we work, and where we spend our time. It’s the first and last thing we check in a day, so it knows when we wake up and when we go to sleep. We all have one, so it knows who we sleep with. Uber used just some of that information to detect one-night stands; your smartphone provider and any app you allow to collect location data knows a lot more.

Surveillance capitalism drives much of the internet. It’s behind most of the “free” services, and many of the paid ones as well. Its goal is psychological manipulation, in the form of personalized advertising to persuade you to buy something or do something, like vote for a candidate. And while the individualized profile-driven manipulation exposed by Cambridge Analytica feels abhorrent, it’s really no different from what every company wants in the end. This is why all your personal information is collected, and this is why it is so valuable. Companies that can understand it can use it against you.

None of this is new. The media has been reporting on surveillance capitalism for years. In 2015, I wrote a book about it. Back in 2010, the Wall Street Journal published an award-winning two-year series about how people are tracked both online and offline, titled “What They Know.”

Surveillance capitalism is deeply embedded in our increasingly computerized society, and if the extent of it came to light there would be broad demands for limits and regulation. But because this industry can largely operate in secret, only occasionally exposed after a data breach or investigative report, we remain mostly ignorant of its reach.

This might change soon. In 2016, the European Union passed the comprehensive General Data Protection Regulation, or GDPR. The details of the law are far too complex to explain here, but some of the things it mandates are that personal data of EU citizens can only be collected and saved for “specific, explicit, and legitimate purposes,” and only with explicit consent of the user. Consent can’t be buried in the terms and conditions, nor can it be assumed unless the user opts in. This law will take effect in May, and companies worldwide are bracing for its enforcement.

Because pretty much all surveillance capitalism companies collect data on Europeans, this will expose the industry like nothing else. Here’s just one example. In preparation for this law, PayPal quietly published a list of over 600 companies it might share your personal data with. What will it be like when every company has to publish this sort of information, and explicitly explain how it’s using your personal data? We’re about to find out.

In the wake of this scandal, even Mark Zuckerberg said that his industry probably should be regulated, although he’s certainly not wishing for the sorts of comprehensive regulation the GDPR is bringing to Europe.

He’s right. Surveillance capitalism has operated without constraints for far too long. And advances in both big data analysis and artificial intelligence will make tomorrow’s applications far creepier than today’s. Regulation is the only answer.

The first step to any regulation is transparency. Who has our data? Is it accurate? What are they doing with it? Who are they selling it to? How are they securing it? Can we delete it? I don’t see any hope of Congress passing a GDPR-like data protection law anytime soon, but it’s not too far-fetched to demand laws requiring these companies to be more transparent in what they’re doing.

One of the responses to the Cambridge Analytica scandal is that people are deleting their Facebook accounts. It’s hard to do right, and doesn’t do anything about the data that Facebook collects about people who don’t use Facebook. But it’s a start. The market can put pressure on these companies to reduce their spying on us, but it can only do that if we force the industry out of its secret shadows.

This essay previously appeared on CNN.com.

EDITED TO ADD (4/2): Slashdot thread.

Tracing Stolen Bitcoin

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/03/tracing_stolen_.html

Ross Anderson has a really interesting paper on tracing stolen bitcoin. From a blog post:

Previous attempts to track tainted coins had used either the “poison” or the “haircut” method. Suppose I open a new address and pay into it three stolen bitcoin followed by seven freshly-mined ones. Then under poison, the output is ten stolen bitcoin, while under haircut it’s ten bitcoin that are marked 30% stolen. After thousands of blocks, poison tainting will blacklist millions of addresses, while with haircut the taint gets diffused, so neither is very effective at tracking stolen property. Bitcoin due-diligence services supplant haircut taint tracking with AI/ML, but the results are still not satisfactory.

We discovered that, back in 1816, the High Court had to tackle this problem in Clayton’s case, which involved the assets and liabilities of a bank that had gone bust. The court ruled that money must be tracked through accounts on the basis of first-in, first out (FIFO); the first penny into an account goes to satisfy the first withdrawal, and so on.

Ilia Shumailov has written software that applies FIFO tainting to the blockchain and the results are impressive, with a massive improvement in precision. What’s more, FIFO taint tracking is lossless, unlike haircut; so in addition to tracking a stolen coin forward to find where it’s gone, you can start with any UTXO and trace it backwards to see its entire ancestry. It’s not just good law; it’s good computer science too.

Needed: Sales Development Representative!

Post Syndicated from Yev original https://www.backblaze.com/blog/needed-sales-development-representative/

At inception, Backblaze was a consumer company. Thousands upon thousands of individuals came to our website and gave us $5/mo to keep their data safe. But, we didn’t sell business solutions. It took us years before we had a sales team. In the last couple of years, we’ve released products that businesses of all sizes love: Backblaze B2 Cloud Storage and Backblaze for Business Computer Backup. Those businesses want to integrate Backblaze into their infrastructure, so it’s time to expand our sales team and hire our first dedicated outbound Sales Development Representative!

Company Description:
Founded in 2007, Backblaze started with a mission to make backup software elegant and provide complete peace of mind. Over the course of almost a decade, we have become a pioneer in robust, scalable low cost cloud backup. Recently, we launched B2 — robust and reliable object storage at just $0.005/gb/mo. Part of our differentiation is being able to offer the lowest price of any of the big players while still being profitable.

We’ve managed to nurture a team oriented culture with amazingly low turnover. We value our people and their families. Don’t forget to check out our “About Us” page to learn more about the people and some of our perks.

We have built a profitable, high growth business. While we love our investors, we have maintained control over the business. That means our corporate goals are simple — grow sustainably and profitably.

Some Backblaze Perks:

  • Competitive healthcare plans
  • Competitive compensation and 401k
  • All employees receive option grants
  • Unlimited vacation days
  • Strong coffee
  • Fully stocked Micro kitchen
  • Catered breakfast and lunches
  • Awesome people who work on awesome projects
  • New Parent Childcare bonus
  • Normal work hours
  • Get to bring your pets into the office
  • San Mateo Office — located near Caltrain and Highways 101 & 280

As our first Sales Development Representative (SDR), we are looking for someone who is organized, has high-energy and strong interpersonal communication skills. The ideal person will have a passion for sales, love to cold call and figure out new ways to get potential customers. Ideally the SDR will have 1-2 years experience working in a fast paced sales environment. We are looking for someone who knows how to manage their time and has top class communication skills. It’s critical that our SDR is able to learn quickly when using new tools.

Additional Responsibilities Include:

  • Generate qualified leads, set up demos and outbound opportunities by phone and email.
  • Work with our account managers to pass qualified leads and track in salesforce.com.
  • Report internally on prospecting performance and identify potential optimizations.
  • Continuously fine tune outbound messaging – both email and cold calls to drive results.
  • Update and leverage salesforce.com and other sales tools to better track business and drive efficiencies.

Qualifications:

  • Bachelor’s degree (B.A.)
  • Minimum of 1-2 years of sales experience.
  • Excellent written and verbal communication skills.
  • Proven ability to work in a fast-paced, dynamic and goal-oriented environment.
  • Maintain a high sense of urgency and entrepreneurial work ethic that is required to drive business outcomes, with exceptional attention to detail.
  • Positive“can do” attitude, passionate and able to show commitment.
  • Fearless yet cordial personality- not afraid to make cold calls and introductions yet personable enough to connect with potential Backblaze customers.
  • Articulate and good listening skills.
  • Ability to set and manage multiple priorities.

What’s it like working with the Sales team?

The Backblaze sales team collaborates. We help each other out by sharing ideas, templates, and our customer’s experiences. When we talk about our accomplishments, there is no “I did this,” only “we.” We are truly a team.

We are honest to each other and our customers and communicate openly. We aim to have fun by embracing crazy ideas and creative solutions. We try to think not outside the box, but with no boxes at all. Customers are the driving force behind the success of the company and we care deeply about their success.

If this all sounds like you:

  1. Send an email to jobscontact@backblaze.com with the position in the subject line.
  2. Tell us a bit about your sales experience.
  3. Include your resume.

The post Needed: Sales Development Representative! appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

[$] Dynamic function tracing events

Post Syndicated from corbet original https://lwn.net/Articles/747256/rss

For as long as the kernel has included tracepoints, developers have argued
over whether those tracepoints are part of the kernel’s ABI. Tracepoint
changes have had to be reverted in the past because they broke existing
user-space programs that had come to depend on them; meanwhile, fears of
setting internal code in stone have made it difficult to add tracepoints to
a number of kernel subsystems. Now, a new tracing functionality is being
proposed as a way to circumvent all of those problems.

Wielaard: dtrace for linux; Oracle does the right thing

Post Syndicated from corbet original https://lwn.net/Articles/747260/rss

Mark Wielaard writes
about
the recently discovered relicensing of the dtrace dynamic tracing
subsystem under the GPL. “Thank you Oracle for making everyone’s
life easier by waving your magic relicensing wand!

Now there is lots of hard work to do to actually properly integrate this. And I am sure there are a lot of technical hurdles when trying to get this upstreamed into the mainline kernel. But that is just hard work. Which we can now start collaborating on in earnest.”

Sharing Secrets with AWS Lambda Using AWS Systems Manager Parameter Store

Post Syndicated from Chris Munns original https://aws.amazon.com/blogs/compute/sharing-secrets-with-aws-lambda-using-aws-systems-manager-parameter-store/

This post courtesy of Roberto Iturralde, Sr. Application Developer- AWS Professional Services

Application architects are faced with key decisions throughout the process of designing and implementing their systems. One decision common to nearly all solutions is how to manage the storage and access rights of application configuration. Shared configuration should be stored centrally and securely with each system component having access only to the properties that it needs for functioning.

With AWS Systems Manager Parameter Store, developers have access to central, secure, durable, and highly available storage for application configuration and secrets. Parameter Store also integrates with AWS Identity and Access Management (IAM), allowing fine-grained access control to individual parameters or branches of a hierarchical tree.

This post demonstrates how to create and access shared configurations in Parameter Store from AWS Lambda. Both encrypted and plaintext parameter values are stored with only the Lambda function having permissions to decrypt the secrets. You also use AWS X-Ray to profile the function.

Solution overview

This example is made up of the following components:

  • An AWS SAM template that defines:
    • A Lambda function and its permissions
    • An unencrypted Parameter Store parameter that the Lambda function loads
    • A KMS key that only the Lambda function can access. You use this key to create an encrypted parameter later.
  • Lambda function code in Python 3.6 that demonstrates how to load values from Parameter Store at function initialization for reuse across invocations.

Launch the AWS SAM template

To create the resources shown in this post, you can download the SAM template or choose the button to launch the stack. The template requires one parameter, an IAM user name, which is the name of the IAM user to be the admin of the KMS key that you create. In order to perform the steps listed in this post, this IAM user will need permissions to execute Lambda functions, create Parameter Store parameters, administer keys in KMS, and view the X-Ray console. If you have these privileges in your IAM user account you can use your own account to complete the walkthrough. You can not use the root user to administer the KMS keys.

SAM template resources

The following sections show the code for the resources defined in the template.
Lambda function

ParameterStoreBlogFunctionDev:
    Type: 'AWS::Serverless::Function'
    Properties:
      FunctionName: 'ParameterStoreBlogFunctionDev'
      Description: 'Integrating lambda with Parameter Store'
      Handler: 'lambda_function.lambda_handler'
      Role: !GetAtt ParameterStoreBlogFunctionRoleDev.Arn
      CodeUri: './code'
      Environment:
        Variables:
          ENV: 'dev'
          APP_CONFIG_PATH: 'parameterStoreBlog'
          AWS_XRAY_TRACING_NAME: 'ParameterStoreBlogFunctionDev'
      Runtime: 'python3.6'
      Timeout: 5
      Tracing: 'Active'

  ParameterStoreBlogFunctionRoleDev:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          -
            Effect: Allow
            Principal:
              Service:
                - 'lambda.amazonaws.com'
            Action:
              - 'sts:AssumeRole'
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole'
      Policies:
        -
          PolicyName: 'ParameterStoreBlogDevParameterAccess'
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              -
                Effect: Allow
                Action:
                  - 'ssm:GetParameter*'
                Resource: !Sub 'arn:aws:ssm:${AWS::Region}:${AWS::AccountId}:parameter/dev/parameterStoreBlog*'
        -
          PolicyName: 'ParameterStoreBlogDevXRayAccess'
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              -
                Effect: Allow
                Action:
                  - 'xray:PutTraceSegments'
                  - 'xray:PutTelemetryRecords'
                Resource: '*'

In this YAML code, you define a Lambda function named ParameterStoreBlogFunctionDev using the SAM AWS::Serverless::Function type. The environment variables for this function include the ENV (dev) and the APP_CONFIG_PATH where you find the configuration for this app in Parameter Store. X-Ray tracing is also enabled for profiling later.

The IAM role for this function extends the AWSLambdaBasicExecutionRole by adding IAM policies that grant the function permissions to write to X-Ray and get parameters from Parameter Store, limited to paths under /dev/parameterStoreBlog*.
Parameter Store parameter

SimpleParameter:
    Type: AWS::SSM::Parameter
    Properties:
      Name: '/dev/parameterStoreBlog/appConfig'
      Description: 'Sample dev config values for my app'
      Type: String
      Value: '{"key1": "value1","key2": "value2","key3": "value3"}'

This YAML code creates a plaintext string parameter in Parameter Store in a path that your Lambda function can access.
KMS encryption key

ParameterStoreBlogDevEncryptionKeyAlias:
    Type: AWS::KMS::Alias
    Properties:
      AliasName: 'alias/ParameterStoreBlogKeyDev'
      TargetKeyId: !Ref ParameterStoreBlogDevEncryptionKey

  ParameterStoreBlogDevEncryptionKey:
    Type: AWS::KMS::Key
    Properties:
      Description: 'Encryption key for secret config values for the Parameter Store blog post'
      Enabled: True
      EnableKeyRotation: False
      KeyPolicy:
        Version: '2012-10-17'
        Id: 'key-default-1'
        Statement:
          -
            Sid: 'Allow administration of the key & encryption of new values'
            Effect: Allow
            Principal:
              AWS:
                - !Sub 'arn:aws:iam::${AWS::AccountId}:user/${IAMUsername}'
            Action:
              - 'kms:Create*'
              - 'kms:Encrypt'
              - 'kms:Describe*'
              - 'kms:Enable*'
              - 'kms:List*'
              - 'kms:Put*'
              - 'kms:Update*'
              - 'kms:Revoke*'
              - 'kms:Disable*'
              - 'kms:Get*'
              - 'kms:Delete*'
              - 'kms:ScheduleKeyDeletion'
              - 'kms:CancelKeyDeletion'
            Resource: '*'
          -
            Sid: 'Allow use of the key'
            Effect: Allow
            Principal:
              AWS: !GetAtt ParameterStoreBlogFunctionRoleDev.Arn
            Action:
              - 'kms:Encrypt'
              - 'kms:Decrypt'
              - 'kms:ReEncrypt*'
              - 'kms:GenerateDataKey*'
              - 'kms:DescribeKey'
            Resource: '*'

This YAML code creates an encryption key with a key policy with two statements.

The first statement allows a given user (${IAMUsername}) to administer the key. Importantly, this includes the ability to encrypt values using this key and disable or delete this key, but does not allow the administrator to decrypt values that were encrypted with this key.

The second statement grants your Lambda function permission to encrypt and decrypt values using this key. The alias for this key in KMS is ParameterStoreBlogKeyDev, which is how you reference it later.

Lambda function

Here I walk you through the Lambda function code.

import os, traceback, json, configparser, boto3
from aws_xray_sdk.core import patch_all
patch_all()

# Initialize boto3 client at global scope for connection reuse
client = boto3.client('ssm')
env = os.environ['ENV']
app_config_path = os.environ['APP_CONFIG_PATH']
full_config_path = '/' + env + '/' + app_config_path
# Initialize app at global scope for reuse across invocations
app = None

class MyApp:
    def __init__(self, config):
        """
        Construct new MyApp with configuration
        :param config: application configuration
        """
        self.config = config

    def get_config(self):
        return self.config

def load_config(ssm_parameter_path):
    """
    Load configparser from config stored in SSM Parameter Store
    :param ssm_parameter_path: Path to app config in SSM Parameter Store
    :return: ConfigParser holding loaded config
    """
    configuration = configparser.ConfigParser()
    try:
        # Get all parameters for this app
        param_details = client.get_parameters_by_path(
            Path=ssm_parameter_path,
            Recursive=False,
            WithDecryption=True
        )

        # Loop through the returned parameters and populate the ConfigParser
        if 'Parameters' in param_details and len(param_details.get('Parameters')) > 0:
            for param in param_details.get('Parameters'):
                param_path_array = param.get('Name').split("/")
                section_position = len(param_path_array) - 1
                section_name = param_path_array[section_position]
                config_values = json.loads(param.get('Value'))
                config_dict = {section_name: config_values}
                print("Found configuration: " + str(config_dict))
                configuration.read_dict(config_dict)

    except:
        print("Encountered an error loading config from SSM.")
        traceback.print_exc()
    finally:
        return configuration

def lambda_handler(event, context):
    global app
    # Initialize app if it doesn't yet exist
    if app is None:
        print("Loading config and creating new MyApp...")
        config = load_config(full_config_path)
        app = MyApp(config)

    return "MyApp config is " + str(app.get_config()._sections)

Beneath the import statements, you import the patch_all function from the AWS X-Ray library, which you use to patch boto3 to create X-Ray segments for all your boto3 operations.

Next, you create a boto3 SSM client at the global scope for reuse across function invocations, following Lambda best practices. Using the function environment variables, you assemble the path where you expect to find your configuration in Parameter Store. The class MyApp is meant to serve as an example of an application that would need its configuration injected at construction. In this example, you create an instance of ConfigParser, a class in Python’s standard library for handling basic configurations, to give to MyApp.

The load_config function loads the all the parameters from Parameter Store at the level immediately beneath the path provided in the Lambda function environment variables. Each parameter found is put into a new section in ConfigParser. The name of the section is the name of the parameter, less the base path. In this example, the full parameter name is /dev/parameterStoreBlog/appConfig, which is put in a section named appConfig.

Finally, the lambda_handler function initializes an instance of MyApp if it doesn’t already exist, constructing it with the loaded configuration from Parameter Store. Then it simply returns the currently loaded configuration in MyApp. The impact of this design is that the configuration is only loaded from Parameter Store the first time that the Lambda function execution environment is initialized. Subsequent invocations reuse the existing instance of MyApp, resulting in improved performance. You see this in the X-Ray traces later in this post. For more advanced use cases where configuration changes need to be received immediately, you could implement an expiry policy for your configuration entries or push notifications to your function.

To confirm that everything was created successfully, test the function in the Lambda console.

  1. Open the Lambda console.
  2. In the navigation pane, choose Functions.
  3. In the Functions pane, filter to ParameterStoreBlogFunctionDev to find the function created by the SAM template earlier. Open the function name to view its details.
  4. On the top right of the function detail page, choose Test. You may need to create a new test event. The input JSON doesn’t matter as this function ignores the input.

After running the test, you should see output similar to the following. This demonstrates that the function successfully fetched the unencrypted configuration from Parameter Store.

Create an encrypted parameter

You currently have a simple, unencrypted parameter and a Lambda function that can access it.

Next, you create an encrypted parameter that only your Lambda function has permission to use for decryption. This limits read access for this parameter to only this Lambda function.

To follow along with this section, deploy the SAM template for this post in your account and make your IAM user name the KMS key admin mentioned earlier.

  1. In the Systems Manager console, under Shared Resources, choose Parameter Store.
  2. Choose Create Parameter.
    • For Name, enter /dev/parameterStoreBlog/appSecrets.
    • For Type, select Secure String.
    • For KMS Key ID, choose alias/ParameterStoreBlogKeyDev, which is the key that your SAM template created.
    • For Value, enter {"secretKey": "secretValue"}.
    • Choose Create Parameter.
  3. If you now try to view the value of this parameter by choosing the name of the parameter in the parameters list and then choosing Show next to the Value field, you won’t see the value appear. This is because, even though you have permission to encrypt values using this KMS key, you do not have permissions to decrypt values.
  4. In the Lambda console, run another test of your function. You now also see the secret parameter that you created and its decrypted value.

If you do not see the new parameter in the Lambda output, this may be because the Lambda execution environment is still warm from the previous test. Because the parameters are loaded at Lambda startup, you need a fresh execution environment to refresh the values.

Adjust the function timeout to a different value in the Advanced Settings at the bottom of the Lambda Configuration tab. Choose Save and test to trigger the creation of a new Lambda execution environment.

Profiling the impact of querying Parameter Store using AWS X-Ray

By using the AWS X-Ray SDK to patch boto3 in your Lambda function code, each invocation of the function creates traces in X-Ray. In this example, you can use these traces to validate the performance impact of your design decision to only load configuration from Parameter Store on the first invocation of the function in a new execution environment.

From the Lambda function details page where you tested the function earlier, under the function name, choose Monitoring. Choose View traces in X-Ray.

This opens the X-Ray console in a new window filtered to your function. Be aware of the time range field next to the search bar if you don’t see any search results.
In this screenshot, I’ve invoked the Lambda function twice, one time 10.3 minutes ago with a response time of 1.1 seconds and again 9.8 minutes ago with a response time of 8 milliseconds.

Looking at the details of the longer running trace by clicking the trace ID, you can see that the Lambda function spent the first ~350 ms of the full 1.1 sec routing the request through Lambda and creating a new execution environment for this function, as this was the first invocation with this code. This is the portion of time before the initialization subsegment.

Next, it took 725 ms to initialize the function, which includes executing the code at the global scope (including creating the boto3 client). This is also a one-time cost for a fresh execution environment.

Finally, the function executed for 65 ms, of which 63.5 ms was the GetParametersByPath call to Parameter Store.

Looking at the trace for the second, much faster function invocation, you see that the majority of the 8 ms execution time was Lambda routing the request to the function and returning the response. Only 1 ms of the overall execution time was attributed to the execution of the function, which makes sense given that after the first invocation you’re simply returning the config stored in MyApp.

While the Traces screen allows you to view the details of individual traces, the X-Ray Service Map screen allows you to view aggregate performance data for all traced services over a period of time.

In the X-Ray console navigation pane, choose Service map. Selecting a service node shows the metrics for node-specific requests. Selecting an edge between two nodes shows the metrics for requests that traveled that connection. Again, be aware of the time range field next to the search bar if you don’t see any search results.

After invoking your Lambda function several more times by testing it from the Lambda console, you can view some aggregate performance metrics. Look at the following:

  • From the client perspective, requests to the Lambda service for the function are taking an average of 50 ms to respond. The function is generating ~1 trace per minute.
  • The function itself is responding in an average of 3 ms. In the following screenshot, I’ve clicked on this node, which reveals a latency histogram of the traced requests showing that over 95% of requests return in under 5 ms.
  • Parameter Store is responding to requests in an average of 64 ms, but note the much lower trace rate in the node. This is because you only fetch data from Parameter Store on the initialization of the Lambda execution environment.

Conclusion

Deduplication, encryption, and restricted access to shared configuration and secrets is a key component to any mature architecture. Serverless architectures designed using event-driven, on-demand, compute services like Lambda are no different.

In this post, I walked you through a sample application accessing unencrypted and encrypted values in Parameter Store. These values were created in a hierarchy by application environment and component name, with the permissions to decrypt secret values restricted to only the function needing access. The techniques used here can become the foundation of secure, robust configuration management in your enterprise serverless applications.

HackSpace magazine 3: Scrap Heap Hacking

Post Syndicated from Andrew Gregory original https://www.raspberrypi.org/blog/hackspace-magazine-3-scrap-heap-hacking/

We’re making with a purpose in issue 3 of HackSpace magazine. Not only are we discovering ways in which 3D printing is helping to save resources — and in some case lives — in the developing world, we’re also going all out with recycling. While others might be content with separating their glass and plastic waste, we’re going much, much further by making useful things out of discarded old bits of rubbish you can find at your local scrapyard.

Hackspaces

We’re going to Cheltenham Hackspace to learn how to make a leather belt, to Liverpool to discover the ways in which an open-source design and some bits and bobs from IKEA are protecting our food supply, and we also take a peek through the doors of Nottingham Hackspace.

Tutorials

The new issue also has the most tutorials you’ll have seen anywhere since…well, since HackSpace magazine issue 2! Guides to 3D-printing on fabric, Arduino programming, and ESP8266 hacking are all to be found in issue 3. Plus, we’ve come up with yet another way to pipe numbers from the internet into big, red, glowing boxes — it’s what LEDs were made for.



With the addition of racing drones, an angry reindeer, and an intelligent toaster, we think we’ve definitely put together an issue you’ll enjoy.

Get your copy

The physical copy of HackSpace magazine is available at all good UK newsagents today, and you can order it online from the Raspberry Pi Press store wherever you are based. Moreover, you can download the free PDF version from our website. And if you’ve read our first two issues and enjoyed what you’ve seen, be sure to subscribe!

Write for us

Are you working on a cool project? Do you want to share your skills with the world, inspire others, and maybe show off a little? HackSpace magazine wants your article! Send an outline of your piece to us, and we’ll get back to you about including it in a future issue.

The post HackSpace magazine 3: Scrap Heap Hacking appeared first on Raspberry Pi.

Strawberry Jam 2 🍓

Post Syndicated from Eevee original https://eev.ee/release/2018/01/24/strawberry-jam-2/

🔗 Strawberry Jam 2 on itch

I’m running a game jam, and this announcement is before the jam starts! What a concept!

The idea is simple: you have all of February to make a horny game.

(This jam is, as you may have guessed, NSFW. 🔞)


I think there’s a lot of interesting potential at the intersection of sex and games, but we see very little exploration of it — in large part because mega-platforms like Steam (and its predecessor, Walmart) have historically been really squeamish about anything sexual. Unless it’s scantily-clad women draped over everything, that’s fine. But un-clad women are right out. Also gratuitous high-definition gore is cool. But no nipples!!

The result is a paltry cultural volume of games about sex, but as boundaries continue to be pushed without really being broken, we get more and more blockbuster games with sex awkwardly tacked on top as lazy titillation. “Ah, it’s a story-driven role-playing shooter, but in this one part you can have sex, which will affect nothing and never come up again, but you can see a butt!” Truly revolutionary.

The opposite end of the spectrum also exists, in the form of porn games where the game part is tacked on to make something interactive — you know, click really fast to make clothes fall off or whatever. It’s not especially engaging, but it’s more compelling than staring at a JPEG.

So my secret motive here is to encourage people to explore the vast gulf in the middle — to make games that are interesting as games and that feature sexuality as a fundamental part of the game. Something where both parts could stand alone, yet are so intertwined as to be inseparable.

The one genre that is seeing a lot of experimentation is the raunchy visual novel, which is a great example: they tend to tell stories where sexuality plays a heavy part, but they’re still compelling interactive stories and hold up on those grounds just as well. What, I wonder, would this same sort of harmony look like for other genres, other kinds of interaction? What does a horny racing game look like, or a horny inventory-horror game, or a horny brawler? Hell, why are there no horny co-op games to speak of? That seems obvious, right?

I haven’t said all this on the jam page because it would add half a dozen paragraphs to what is already a lengthy document. I also suspect that I’ll sound like I’m suggesting “a racing game but all the cars are dicks,” which isn’t quite right, and I’d need to blather even more to clarify. Anyway, it seems vaguely improper as the jam organizer to be telling people what kind of games not to make; last year I just tried to lead by example by making fox flux.


If exploring this design space seems interesting to you, please do join in! If you’ve never made a game before, this might be a great opportunity to give it a try — everything is going to be embarrassing and personal regardless. Maybe hop on Discord if you need help or want a teammate. Feel free to flip through last year’s entries, too, or my (super nsfw) thread where I played some and talked about them. Some of them are even open source, cough, cough.

Previously:

[$] BPFd: Running BCC tools remotely across systems and architectures

Post Syndicated from corbet original https://lwn.net/Articles/744522/rss

BPF is an increasingly capable tool for instrumenting and tracing the
operation of the kernel; it has enabled the creation of the growing set of
BCC tools. Unfortunately, BCC has no support for a cross-development
workflow where the development machine and the target machine running the
developed code are different. Cross-development is favored by
embedded-systems kernel developers who tend to develop on an x86 host and
then flash and test their code on SoCs (System on Chips) based on the ARM
architecture. In this article, I introduce BPFd, a project to enable cross
development using BPF and BCC.

Raspbery Pi-newood Derby

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/pinewood-derby/

Andre Miron’s Pinewood Derby Instant Replay System (sorry, not sorry for the pun in the title) uses a Raspberry Pi to monitor the finishing line and play back a slow-motion instant replay, putting an end to “No, I won!” squabbles once and for all.

Raspberry Pi Based Pinewood Derby Instant Replay Demo

This is the same system I demo in this video (https://youtu.be/-QyMxKfBaAE), but on our actual track with real pinewood derby cars. Glad to report that it works great!

Pinewood Derby

For those unfamiliar with the term, the Pinewood Derby is a racing event for Cub Scouts in the USA. Cub Scouts, often with the help of a guardian, build race cars out of wood according to rules regarding weight, size, materials, etc.

Pinewood derby race car

The Cubs then race their cars in heats, with the winners advancing to district and council races.

Who won?

Andre’s Instant Replay System registers the race cars as they cross the finishing line, and it plays back slow-motion video of the crossing on a monitor. As he explains on YouTube:

The Pi is recording a constant stream of video, and when the replay is triggered, it records another half-second of video, then takes the last second and a half and saves it in slow motion (recording is done at 90 fps), before replaying.

The build also uses an attached Arduino, connected to GPIO pin 5, to trigger the recording and playback as it registers the passing cars via a voltage splitter. Additionally, the system announces the finishing places on a rather attractive-looking display above the finishing line.

Pinewood derby race car Raspberry Pi

The result? No more debate about whose car crossed the line first in neck-and-neck races.

Build your own

Andre takes us through the physical setup of the build in the video below, and you’ll find the complete code pasted in the description of the video here. Thanks, Andre!

Raspberry Pi based Pinewood Derby Instant Replay System

See the system on our actual track here: https://youtu.be/B3lcQHWGq88 Raspberry Pi based instant replay system, triggered by Arduino Pinewood Derby Timer. The Pi uses GPIO pin 5 attached to a voltage splitter on Arduino output 11 (and ground-ground) to detect when a car crosses the finish line, which triggers the replay.

Digital making in your club

If you’re a member of an various after-school association such as the Scouts or Guides, then using the Raspberry Pi and our free project resources, or visiting a Code Club or CoderDojo, are excellent ways to work towards various badges and awards. So talk to your club leader to discover all the ways in which you can incorporate digital making into your club!

The post Raspbery Pi-newood Derby appeared first on Raspberry Pi.

Wanted: Sales Engineer

Post Syndicated from Yev original https://www.backblaze.com/blog/wanted-sales-engineer/

At inception, Backblaze was a consumer company. Thousands upon thousands of individuals came to our website and gave us $5/mo to keep their data safe. But, we didn’t sell business solutions. It took us years before we had a sales team. In the last couple of years, we’ve released products that businesses of all sizes love: Backblaze B2 Cloud Storage and Backblaze for Business Computer Backup. Those businesses want to integrate Backblaze deeply into their infrastructure, so it’s time to hire our first Sales Engineer!

Company Description:
Founded in 2007, Backblaze started with a mission to make backup software elegant and provide complete peace of mind. Over the course of almost a decade, we have become a pioneer in robust, scalable low cost cloud backup. Recently, we launched B2 – robust and reliable object storage at just $0.005/gb/mo. Part of our differentiation is being able to offer the lowest price of any of the big players while still being profitable.

We’ve managed to nurture a team oriented culture with amazingly low turnover. We value our people and their families. Don’t forget to check out our “About Us” page to learn more about the people and some of our perks.

We have built a profitable, high growth business. While we love our investors, we have maintained control over the business. That means our corporate goals are simple – grow sustainably and profitably.

Some Backblaze Perks:

  • Competitive healthcare plans
  • Competitive compensation and 401k
  • All employees receive Option grants
  • Unlimited vacation days
  • Strong coffee
  • Fully stocked Micro kitchen
  • Catered breakfast and lunches
  • Awesome people who work on awesome projects
  • Childcare bonus
  • Normal work hours
  • Get to bring your pets into the office
  • San Mateo Office – located near Caltrain and Highways 101 & 280.

Backblaze B2 cloud storage is a building block for almost any computing service that requires storage. Customers need our help integrating B2 into iOS apps to Docker containers. Some customers integrate directly to the API using the programming language of their choice, others want to solve a specific problem using ready made software, already integrated with B2.

At the same time, our computer backup product is deepening it’s integration into enterprise IT systems. We are commonly asked for how to set Windows policies, integrate with Active Directory, and install the client via remote management tools.

We are looking for a sales engineer who can help our customers navigate the integration of Backblaze into their technical environments.

Are you 1/2” deep into many different technologies, and unafraid to dive deeper?

Can you confidently talk with customers about their technology, even if you have to look up all the acronyms right after the call?

Are you excited to setup complicated software in a lab and write knowledge base articles about your work?

Then Backblaze is the place for you!

Enough about Backblaze already, what’s in it for me?
In this role, you will be given the opportunity to learn about the technologies that drive innovation today; diverse technologies that customers are using day in and out. And more importantly, you’ll learn how to learn new technologies.

Just as an example, in the past 12 months, we’ve had the opportunity to learn and become experts in these diverse technologies:

  • How to setup VM servers for lab environments, both on-prem and using cloud services.
  • Create an automatically “resetting” demo environment for the sales team.
  • Setup Microsoft Domain Controllers with Active Directory and AD Federation Services.
  • Learn the basics of OAUTH and web single sign on (SSO).
  • Archive video workflows from camera to media asset management systems.
  • How upload/download files from Javascript by enabling CORS.
  • How to install and monitor online backup installations using RMM tools, like JAMF.
  • Tape (LTO) systems. (Yes – people still use tape for storage!)

How can I know if I’ll succeed in this role?

You have:

  • Confidence. Be able to ask customers questions about their environments and convey to them your technical acumen.
  • Curiosity. Always want to learn about customers’ situations, how they got there and what problems they are trying to solve.
  • Organization. You’ll work with customers, integration partners, and Backblaze team members on projects of various lengths. You can context switch and either have a great memory or keep copious notes. Your checklists have their own checklists.

You are versed in:

  • The fundamentals of Windows, Linux and Mac OS X operating systems. You shouldn’t be afraid to use a command line.
  • Building, installing, integrating and configuring applications on any operating system.
  • Debugging failures – reading logs, monitoring usage, effective google searching to fix problems excites you.
  • The basics of TCP/IP networking and the HTTP protocol.
  • Novice development skills in any programming/scripting language. Have basic understanding of data structures and program flow.
  • Your background contains:

  • Bachelor’s degree in computer science or the equivalent.
  • 2+ years of experience as a pre or post-sales engineer.
  • The right extra credit:
    There are literally hundreds of previous experiences you can have had that would make you perfect for this job. Some experiences that we know would be helpful for us are below, but make sure you tell us your stories!

  • Experience using or programming against Amazon S3.
  • Experience with large on-prem storage – NAS, SAN, Object. And backing up data on such storage with tools like Veeam, Veritas and others.
  • Experience with photo or video media. Media archiving is a key market for Backblaze B2.
  • Program arduinos to automatically feed your dog.
  • Experience programming against web or REST APIs. (Point us towards your projects, if they are open source and available to link to.)
  • Experience with sales tools like Salesforce.
  • 3D print door stops.
  • Experience with Windows Servers, Active Directory, Group policies and the like.
  • What’s it like working with the Sales team?
    The Backblaze sales team collaborates. We help each other out by sharing ideas, templates, and our customer’s experiences. When we talk about our accomplishments, there is no “I did this,” only “we”. We are truly a team.

    We are honest to each other and our customers and communicate openly. We aim to have fun by embracing crazy ideas and creative solutions. We try to think not outside the box, but with no boxes at all. Customers are the driving force behind the success of the company and we care deeply about their success.

    If this all sounds like you:

    1. Send an email to [email protected] with the position in the subject line.
    2. Tell us a bit about your Sales Engineering experience.
    3. Include your resume.

    The post Wanted: Sales Engineer appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

    Physics cheats

    Post Syndicated from Eevee original https://eev.ee/blog/2018/01/06/physics-cheats/

    Anonymous asks:

    something about how we tweak physics to “work” better in games?

    Ho ho! Work. Get it? Like in physics…?

    Hitboxes

    Hitbox” is perhaps not the most accurate term, since the shape used for colliding with the environment and the shape used for detecting damage might be totally different. They’re usually the same in simple platformers, though, and that’s what most of my games have been.

    The hitbox is the biggest physics fudge by far, and it exists because of a single massive approximation that (most) games make: you’re controlling a single entity in the abstract, not a physical body in great detail.

    That is: when you walk with your real-world meat shell, you perform a complex dance of putting one foot in front of the other, a motion you spent years perfecting. When you walk in a video game, you press a single “walk” button. Your avatar may play an animation that moves its legs back and forth, but since you’re not actually controlling the legs independently (and since simulating them is way harder), the game just treats you like a simple shape. Fairly often, this is a box, or something very box-like.

    An Eevee sprite standing on faux ground; the size of the underlying image and the hitbox are outlined

    Since the player has no direct control over the exact placement of their limbs, it would be slightly frustrating to have them collide with the world. This is especially true in cases like the above, where the tail and left ear protrude significantly out from the main body. If that Eevee wanted to stand against a real-world wall, she would simply tilt her ear or tail out of the way, so there’s no reason for the ear to block her from standing against a game wall. To compensate for this, the ear and tail are left out of the collision box entirely and will simply jut into a wall if necessary — a goofy affordance that’s so common it doesn’t even register as unusual. As a bonus (assuming this same box is used for combat), she won’t take damage from projectiles that merely graze past an ear.

    (One extra consideration for sprite games in particular: the hitbox ought to be horizontally symmetric around the sprite’s pivot — i.e. the point where the entity is truly considered to be standing — so that the hitbox doesn’t abruptly move when the entity turns around!)

    Corners

    Treating the player (and indeed most objects) as a box has one annoying side effect: boxes have corners. Corners can catch on other corners, even by a single pixel. Real-world bodies tend to be a bit rounder and squishier and this can tolerate grazing a corner; even real-world boxes will simply rotate a bit.

    Ah, but in our faux physics world, we generally don’t want conscious actors (such as the player) to rotate, even with a realistic physics simulator! Real-world bodies are made of parts that will generally try to keep you upright, after all; you don’t tilt back and forth much.

    One way to handle corners is to simply remove them from conscious actors. A hitbox doesn’t have to be a literal box, after all. A popular alternative — especially in Unity where it’s a standard asset — is the pill-shaped capsule, which has semicircles/hemispheres on the top and bottom and a cylindrical body in 3D. No corners, no problem.

    Of course, that introduces a new problem: now the player can’t balance precariously on edges without their rounded bottom sliding them off. Alas.

    If you’re stuck with corners, then, you may want to use a corner bump, a term I just made up. If the player would collide with a corner, but the collision is only by a few pixels, just nudge them to the side a bit and carry on.

    An Eevee sprite trying to move sideways into a shallow ledge; the game bumps her upwards slightly, so she steps onto it instead

    When the corner is horizontal, this creates stairs! This is, more or less kinda, how steps work in Doom: when the player tries to cross from one sector into another, if the height difference is 24 units or less, the game simply bumps them upwards to the height of the new floor and lets them continue on.

    Implementing this in a game without Doom’s notion of sectors is a little trickier. In fact, I still haven’t done it. Collision detection based on rejection gets it for free, kinda, but it’s not very deterministic and it breaks other things. But that’s a whole other post.

    Gravity

    Gravity is pretty easy. Everything accelerates downwards all the time. What’s interesting are the exceptions.

    Jumping

    Jumping is a giant hack.

    Think about how actual jumping works: you tense your legs, which generally involves bending your knees first, and then spring upwards. In a platformer, you can just leap whenever you feel like it, which is nonsense. Also you go like twenty feet into the air?

    Worse, most platformers allow variable-height jumping, where your jump is lower if you let go of the jump button while you’re in the air. Normally, one would expect to have to decide how much force to put into the jump beforehand.

    But of course this is about convenience of controls: when jumping is your primary action, you want to be able to do it immediately, without any windup for how high you want to jump.

    (And then there’s double jumping? Come on.)

    Air control is a similar phenomenon: usually you’d jump in a particular direction by controlling how you push off the ground with your feet, but in a video game, you don’t have feet! You only have the box. The compromise is to let you control your horizontal movement to a limit degree in midair, even though that doesn’t make any sense. (It’s way more fun, though, and overall gives you more movement options, which are good to have in an interactive medium.)

    Air control also exposes an obvious place that game physics collide with the realistic model of serious physics engines. I’ve mentioned this before, but: if you use Real Physics™ and air control yourself into a wall, you might find that you’ll simply stick to the wall until you let go of the movement buttons. Why? Remember, player movement acts as though an external force were pushing you around (and from the perspective of a Real™ physics engine, this is exactly how you’d implement it) — so air-controlling into a wall is equivalent to pushing a book against a wall with your hand, and the friction with the wall holds you in place. Oops.

    Ground sticking

    Another place game physics conflict with physics engines is with running to the top of a slope. On a real hill, of course, you land on top of the slope and are probably glad of it; slopes are hard to climb!

    An Eevee moves to the top of a slope, and rather than step onto the flat top, she goes flying off into the air

    In a video game, you go flying. Because you’re a box. With momentum. So you hit the peak and keep going in the same direction. Which is diagonally upwards.

    Projectiles

    To make them more predictable, projectiles generally aren’t subject to gravity, at least as far as I’ve seen. The real world does not have such an exemption. The real world imposes gravity even on sniper rifles, which in a video game are often implemented as an instant trace unaffected by anything in the world because the bullet never actually exists in the world.

    Resistance

    Ah. Welcome to hell.

    Water

    Water is an interesting case, and offhand I don’t know the gritty details of how games implement it. In the real world, water applies a resistant drag force to movement — and that force is proportional to the square of velocity, which I’d completely forgotten until right now. I am almost positive that no game handles that correctly. But then, in real-world water, you can push against the water itself for movement, and games don’t simulate that either. What’s the rough equivalent?

    The Sonic Physics Guide suggests that Sonic handles it by basically halving everything: acceleration, max speed, friction, etc. When Sonic enters water, his speed is cut; when Sonic exits water, his speed is increased.

    That last bit feels validating — I could swear Metroid Prime did the same thing, and built my own solution around it, but couldn’t remember for sure. It makes no sense, of course, for a jump to become faster just because you happened to break the surface of the water, but it feels fantastic.

    The thing I did was similar, except that I didn’t want to add a multiplier in a dozen places when you happen to be underwater (and remember which ones need it to be squared, etc.). So instead, I calculate everything completely as normal, so velocity is exactly the same as it would be on dry land — but the distance you would move gets halved. The effect seems to be pretty similar to most platformers with water, at least as far as I can tell. It hasn’t shown up in a published game and I only added this fairly recently, so I might be overlooking some reason this is a bad idea.

    (One reason that comes to mind is that velocity is now a little white lie while underwater, so anything relying on velocity for interesting effects might be thrown off. Or maybe that’s correct, because velocity thresholds should be halved underwater too? Hm!)

    Notably, air is also a fluid, so it should behave the same way (just with different constants). I definitely don’t think any games apply air drag that’s proportional to the square of velocity.

    Friction

    Friction is, in my experience, a little handwaved. Probably because real-world friction is so darn complicated.

    Consider that in the real world, we want very high friction on the surfaces we walk on — shoes and tires are explicitly designed to increase it, even. We move by bracing a back foot against the ground and using that to push ourselves forward, so we want the ground to resist our push as much as possible.

    In a game world, we are a box. We move by being pushed by some invisible outside force, so if the friction between ourselves and the ground is too high, we won’t be able to move at all! That’s complete nonsense physically, but it turns out to be handy in some cases — for example, highish friction can simulate walking through deep mud, which should be difficult due to fluid drag and low friction.

    But the best-known example of the fakeness of game friction is video game ice. Walking on real-world ice is difficult because the low friction means low grip; your feet are likely to slip out from under you, and you’ll simply fall down and have trouble moving at all. In a video game, you can’t fall down, so you have the opposite experience: you spend most of your time sliding around uncontrollably. Yet ice is so common in video games (and perhaps so uncommon in places I’ve lived) that I, at least, had never really thought about this disparity until an hour or so ago.

    Game friction vs real-world friction

    Real-world friction is a force. It’s the normal force (which is the force exerted by the object on the surface) times some constant that depends on how the two materials interact.

    Force is mass times acceleration, and platformers often ignore mass, so friction ought to be an acceleration — applied against the object’s movement, but never enough to push it backwards.

    I haven’t made any games where variable friction plays a significant role, but my gut instinct is that low friction should mean the player accelerates more slowly but has a higher max speed, and high friction should mean the opposite. I see from my own source code that I didn’t even do what I just said, so let’s defer to some better-made and well-documented games: Sonic and Doom.

    In Sonic, friction is a fixed value subtracted from the player’s velocity (regardless of direction) each tic. Sonic has a fixed framerate, so the units are really pixels per tic squared (i.e. acceleration), multiplied by an implicit 1 tic per tic. So far, so good.

    But Sonic’s friction only applies if the player isn’t pressing or . Hang on, that isn’t friction at all; that’s just deceleration! That’s equivalent to jogging to a stop. If friction were lower, Sonic would take longer to stop, but otherwise this is only tangentially related to friction.

    (In fairness, this approach would decently emulate friction for non-conscious sliding objects, which are never going to be pressing movement buttons. Also, we don’t have the Sonic source code, and the name “friction” is a fan invention; the Sonic Physics Guide already uses “deceleration” to describe the player’s acceleration when turning around.)

    Okay, let’s try Doom. In Doom, the default friction is 90.625%.

    Hang on, what?

    Yes, in Doom, friction is a multiplier applied every tic. Doom runs at 35 tics per second, so this is a multiplier of 0.032 per second. Yikes!

    This isn’t anything remotely like real friction, but it’s much easier to implement. With friction as acceleration, the game has to know both the direction of movement (so it can apply friction in the opposite direction) and the magnitude (so it doesn’t overshoot and launch the object in the other direction). That means taking a semi-costly square root and also writing extra code to cap the amount of friction. With a multiplier, neither is necessary; just multiply the whole velocity vector and you’re done.

    There are some downsides. One is that objects will never actually stop, since multiplying by 3% repeatedly will never produce a result of zero — though eventually the speed will become small enough to either slip below a “minimum speed” threshold or simply no longer fit in a float representation. Another is that the units are fairly meaningless: with Doom’s default friction of 90.625%, about how long does it take for the player to stop? I have no idea, partly because “stop” is ambiguous here! If friction were an acceleration, I could divide it into the player’s max speed to get a time.

    All that aside, what are the actual effects of changing Doom’s friction? What an excellent question that’s surprisingly tricky to answer. (Note that friction can’t be changed in original Doom, only in the Boom port and its derivatives.) Here’s what I’ve pieced together.

    Doom’s “friction” is really two values. “Friction” itself is a multiplier applied to moving objects on every tic, but there’s also a move factor which defaults to \(\frac{1}{32} = 0.03125\) and is derived from friction for custom values.

    Every tic, the player’s velocity is multiplied by friction, and then increased by their speed times the move factor.

    $$
    v(n) = v(n – 1) \times friction + speed \times move factor
    $$

    Eventually, the reduction from friction will balance out the speed boost. That happens when \(v(n) = v(n – 1)\), so we can rearrange it to find the player’s effective max speed:

    $$
    v = v \times friction + speed \times move factor \\
    v – v \times friction = speed \times move factor \\
    v = speed \times \frac{move factor}{1 – friction}
    $$

    For vanilla Doom’s move factor of 0.03125 and friction of 0.90625, that becomes:

    $$
    v = speed \times \frac{\frac{1}{32}}{1 – \frac{29}{32}} = speed \times \frac{\frac{1}{32}}{\frac{3}{32}} = \frac{1}{3} \times speed
    $$

    Curiously, “speed” is three times the maximum speed an actor can actually move. Doomguy’s run speed is 50, so in practice he moves a third of that, or 16⅔ units per tic. (Of course, this isn’t counting SR40, a bug that lets Doomguy run ~40% faster than intended diagonally.)

    So now, what if you change friction? Even more curiously, the move factor is calculated completely differently depending on whether friction is higher or lower than the default Doom amount:

    $$
    move factor = \begin{cases}
    \frac{133 – 128 \times friction}{544} &≈ 0.244 – 0.235 \times friction & \text{ if } friction \ge \frac{29}{32} \\
    \frac{81920 \times friction – 70145}{1048576} &≈ 0.078 \times friction – 0.067 & \text{ otherwise }
    \end{cases}
    $$

    That’s pretty weird? Complicating things further is that low friction (which means muddy terrain, remember) has an extra multiplier on its move factor, depending on how fast you’re already going — the idea is apparently that you have a hard time getting going, but it gets easier as you find your footing. The extra multiplier maxes out at 8, which makes the two halves of that function meet at the vanilla Doom value.

    A graph of the relationship between friction and move factor

    That very top point corresponds to the move factor from the original game. So no matter what you do to friction, the move factor becomes lower. At 0.85 and change, you can no longer move at all; below that, you move backwards.

    From the formula above, it’s easy to see what changes to friction and move factor will do to Doomguy’s stable velocity. Move factor is in the numerator, so increasing it will increase stable velocity — but it can’t increase, so stable velocity can only ever decrease. Friction is in the denominator, but it’s subtracted from 1, so increasing friction will make the denominator a smaller value less than 1, i.e. increase stable velocity. Combined, we get this relationship between friction and stable velocity.

    A graph showing stable velocity shooting up dramatically as friction increases

    As friction approaches 1, stable velocity grows without bound. This makes sense, given the definition of \(v(n)\) — if friction is 1, the velocity from the previous tic isn’t reduced at all, so we just keep accelerating freely.

    All of this is why I’m wary of using multipliers.

    Anyway, this leaves me with one last question about the effects of Doom’s friction: how long does it take to reach stable velocity? Barring precision errors, we’ll never truly reach stable velocity, but let’s say within 5%. First we need a closed formula for the velocity after some number of tics. This is a simple recurrence relation, and you can write a few terms out yourself if you want to be sure this is right.

    $$
    v(n) = v_0 \times friction^n + speed \times move factor \times \frac{friction^n – 1}{friction – 1}
    $$

    Our initial velocity is zero, so the first term disappears. Set this equal to the stable formula and solve for n:

    $$
    speed \times move factor \times \frac{friction^n – 1}{friction – 1} = (1 – 5\%) \times speed \times \frac{move factor}{1 – friction} \\
    friction^n – 1 = -(1 – 5\%) \\
    n = \frac{\ln 5\%}{\ln friction}
    $$

    Speed” and move factor disappear entirely, which makes sense, and this is purely a function of friction (and how close we want to get). For vanilla Doom, that comes out to 30.4, which is a little less than a second. For other values of friction:

    A graph of time to stability which leaps upwards dramatically towards the right

    As friction increases (which in Doom terms means the surface is more slippery), it takes longer and longer to reach stable speed, which is in turn greater and greater. For lesser friction (i.e. mud), stable speed is lower, but reached fairly quickly. (Of course, the extra “getting going” multiplier while in mud adds some extra time here, but including that in the graph is a bit more complicated.)

    I think this matches with my instincts above. How fascinating!

    What’s that? This is way too much math and you hate it? Then don’t use multipliers in game physics.

    Uh

    That was a hell of a diversion!

    I guess the goofiest stuff in basic game physics is really just about mapping player controls to in-game actions like jumping and deceleration; the rest consists of hacks to compensate for representing everything as a box.