Tag Archives: test

iplayer: тест за обществена значимост на услугите на обществените медии

Post Syndicated from nellyo original https://nellyo.wordpress.com/2019/04/27/iplayer/

В Обединеното кралство всяка нова услуга преминава през тест за съответствие с обществената мисия от две части. През тест преминават и исканията за съществени промени.  Британският регулатор е поискал от обществената телевизия Би Би Си да проведе тест за обществена значимост (PIT), за да позволи публично разглеждане на промените в услугата  iPlayer на BBC.

Би Би Си отговаря, че планираните за 2018 и 2019 г. промени не са „съществени“ и следователно не изискват оценка. Регулаторът настоява, че оценка е необходима и иска Би Би Си да представи дългосрочна стратегия за трансформиране на услугата iPlayer, вкл. за  ефектите върху всички заинтересовани страни.  Обществената телевизия представя исканата стратегия.

Сега е ред на регулатора да прецени дали  цената на предложената промяна от гледна точка на значението на услугата – и в резултат регулаторът има три опции – положително решение (Би Би Си може да извърши промяната на iPlayer), отрицателно решение или положително решение с условия.

Регулаторът открива обществена консултация.

В методологическо отношение Би  Би Си използва количествен и качествен анализ за проучване както на нагласите на аудиторията, така и икономическите ефекти и влиянието върху конкуренцията.  Съпътстващи анализи, на които се основава стратегията:

В заключение:

Новите и съществено променяните услуги на обществените медии в ЕС трябва да отговарят на мисията на обществените медии и да се финансират – ако отговарят на мисията – адекватно, не повече и не по-малко.

iplayer  е такъв пример, тест се проведе например  и когато Би Би Си 3 премина от наземно към онлайн разпространение.

Сега да се върнем в родината.

Как точно се вземат решенията за нови услуги или съществени промени в съществуващите услуги? На базата на каква точно информация БНТ2  промени лицензията си – и СЕМ разреши промените –  просто защото това е един от последните примери, иначе може да се пита и за други програми и услуги.

Вярно, законът не изисква тест за обществена значимост на услугите. И все пак – изисква се обосновка, защото за тези услуги се разходва обществен ресурс – държавен бюджет.

Идват избори за генерални директори в двете обществени медии – може някой кандидат да запише в концепцията си, че ще работи за съответствие  мисия – бюджет и за модернизиране на правната рамка.


[$] A filesystem “change journal” and other topics

Post Syndicated from jake original https://lwn.net/Articles/755277/rss

At the 2017 Linux Storage, Filesystem, and Memory-Management Summit
(LSFMM), Amir Goldstein presented his work
on adding a superblock watch mechanism to provide a scalable way to notify
of changes in a filesystem. At the 2018 edition of LSFMM, he was back to
discuss adding NTFS-like change
to the kernel in support of backup solutions of various
sorts. As a second topic for the session, he also wanted to discuss doing
more performance-regression testing
for filesystems.

EC2 Instance Update – M5 Instances with Local NVMe Storage (M5d)

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/ec2-instance-update-m5-instances-with-local-nvme-storage-m5d/

Earlier this month we launched the C5 Instances with Local NVMe Storage and I told you that we would be doing the same for additional instance types in the near future!

Today we are introducing M5 instances equipped with local NVMe storage. Available for immediate use in 5 regions, these instances are a great fit for workloads that require a balance of compute and memory resources. Here are the specs:

Instance NamevCPUsRAMLocal StorageEBS-Optimized BandwidthNetwork Bandwidth
m5d.large28 GiB1 x 75 GB NVMe SSDUp to 2.120 GbpsUp to 10 Gbps
m5d.xlarge416 GiB1 x 150 GB NVMe SSDUp to 2.120 GbpsUp to 10 Gbps
m5d.2xlarge832 GiB1 x 300 GB NVMe SSDUp to 2.120 GbpsUp to 10 Gbps
m5d.4xlarge1664 GiB1 x 600 GB NVMe SSD2.210 GbpsUp to 10 Gbps
m5d.12xlarge48192 GiB2 x 900 GB NVMe SSD5.0 Gbps10 Gbps
m5d.24xlarge96384 GiB4 x 900 GB NVMe SSD10.0 Gbps25 Gbps

The M5d instances are powered by Custom Intel® Xeon® Platinum 8175M series processors running at 2.5 GHz, including support for AVX-512.

You can use any AMI that includes drivers for the Elastic Network Adapter (ENA) and NVMe; this includes the latest Amazon Linux, Microsoft Windows (Server 2008 R2, Server 2012, Server 2012 R2 and Server 2016), Ubuntu, RHEL, SUSE, and CentOS AMIs.

Here are a couple of things to keep in mind about the local NVMe storage on the M5d instances:

Naming – You don’t have to specify a block device mapping in your AMI or during the instance launch; the local storage will show up as one or more devices (/dev/nvme*1 on Linux) after the guest operating system has booted.

Encryption – Each local NVMe device is hardware encrypted using the XTS-AES-256 block cipher and a unique key. Each key is destroyed when the instance is stopped or terminated.

Lifetime – Local NVMe devices have the same lifetime as the instance they are attached to, and do not stick around after the instance has been stopped or terminated.

Available Now
M5d instances are available in On-Demand, Reserved Instance, and Spot form in the US East (N. Virginia), US West (Oregon), EU (Ireland), US East (Ohio), and Canada (Central) Regions. Prices vary by Region, and are just a bit higher than for the equivalent M5 instances.



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
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

Protecting coral reefs with Nemo-Pi, the underwater monitor

Post Syndicated from Janina Ander original https://www.raspberrypi.org/blog/coral-reefs-nemo-pi/

The German charity Save Nemo works to protect coral reefs, and they are developing Nemo-Pi, an underwater “weather station” that monitors ocean conditions. Right now, you can vote for Save Nemo in the Google.org Impact Challenge.

Nemo-Pi — Save Nemo

Save Nemo

The organisation says there are two major threats to coral reefs: divers, and climate change. To make diving saver for reefs, Save Nemo installs buoy anchor points where diving tour boats can anchor without damaging corals in the process.

reef damaged by anchor
boat anchored at buoy

In addition, they provide dos and don’ts for how to behave on a reef dive.

The Nemo-Pi

To monitor the effects of climate change, and to help divers decide whether conditions are right at a reef while they’re still on shore, Save Nemo is also in the process of perfecting Nemo-Pi.

Nemo-Pi schematic — Nemo-Pi — Save Nemo

This Raspberry Pi-powered device is made up of a buoy, a solar panel, a GPS device, a Pi, and an array of sensors. Nemo-Pi measures water conditions such as current, visibility, temperature, carbon dioxide and nitrogen oxide concentrations, and pH. It also uploads its readings live to a public webserver.

Inside the Nemo-Pi device — Save Nemo
Inside the Nemo-Pi device — Save Nemo
Inside the Nemo-Pi device — Save Nemo

The Save Nemo team is currently doing long-term tests of Nemo-Pi off the coast of Thailand and Indonesia. They are also working on improving the device’s power consumption and durability, and testing prototypes with the Raspberry Pi Zero W.

web dashboard — Nemo-Pi — Save Nemo

The web dashboard showing live Nemo-Pi data

Long-term goals

Save Nemo aims to install a network of Nemo-Pis at shallow reefs (up to 60 metres deep) in South East Asia. Then diving tour companies can check the live data online and decide day-to-day whether tours are feasible. This will lower the impact of humans on reefs and help the local flora and fauna survive.

Coral reefs with fishes

A healthy coral reef

Nemo-Pi data may also be useful for groups lobbying for reef conservation, and for scientists and activists who want to shine a spotlight on the awful effects of climate change on sea life, such as coral bleaching caused by rising water temperatures.

Bleached coral

A bleached coral reef

Vote now for Save Nemo

If you want to help Save Nemo in their mission today, vote for them to win the Google.org Impact Challenge:

  1. Head to the voting web page
  2. Click “Abstimmen” in the footer of the page to vote
  3. Click “JA” in the footer to confirm

Voting is open until 6 June. You can also follow Save Nemo on Facebook or Twitter. We think this organisation is doing valuable work, and that their projects could be expanded to reefs across the globe. It’s fantastic to see the Raspberry Pi being used to help protect ocean life.

The post Protecting coral reefs with Nemo-Pi, the underwater monitor appeared first on Raspberry Pi.

Amazon SageMaker Updates – Tokyo Region, CloudFormation, Chainer, and GreenGrass ML

Post Syndicated from Randall Hunt original https://aws.amazon.com/blogs/aws/sagemaker-tokyo-summit-2018/

Today, at the AWS Summit in Tokyo we announced a number of updates and new features for Amazon SageMaker. Starting today, SageMaker is available in Asia Pacific (Tokyo)! SageMaker also now supports CloudFormation. A new machine learning framework, Chainer, is now available in the SageMaker Python SDK, in addition to MXNet and Tensorflow. Finally, support for running Chainer models on several devices was added to AWS Greengrass Machine Learning.

Amazon SageMaker Chainer Estimator

Chainer is a popular, flexible, and intuitive deep learning framework. Chainer networks work on a “Define-by-Run” scheme, where the network topology is defined dynamically via forward computation. This is in contrast to many other frameworks which work on a “Define-and-Run” scheme where the topology of the network is defined separately from the data. A lot of developers enjoy the Chainer scheme since it allows them to write their networks with native python constructs and tools.

Luckily, using Chainer with SageMaker is just as easy as using a TensorFlow or MXNet estimator. In fact, it might even be a bit easier since it’s likely you can take your existing scripts and use them to train on SageMaker with very few modifications. With TensorFlow or MXNet users have to implement a train function with a particular signature. With Chainer your scripts can be a little bit more portable as you can simply read from a few environment variables like SM_MODEL_DIR, SM_NUM_GPUS, and others. We can wrap our existing script in a if __name__ == '__main__': guard and invoke it locally or on sagemaker.

import argparse
import os

if __name__ =='__main__':

    parser = argparse.ArgumentParser()

    # hyperparameters sent by the client are passed as command-line arguments to the script.
    parser.add_argument('--epochs', type=int, default=10)
    parser.add_argument('--batch-size', type=int, default=64)
    parser.add_argument('--learning-rate', type=float, default=0.05)

    # Data, model, and output directories
    parser.add_argument('--output-data-dir', type=str, default=os.environ['SM_OUTPUT_DATA_DIR'])
    parser.add_argument('--model-dir', type=str, default=os.environ['SM_MODEL_DIR'])
    parser.add_argument('--train', type=str, default=os.environ['SM_CHANNEL_TRAIN'])
    parser.add_argument('--test', type=str, default=os.environ['SM_CHANNEL_TEST'])

    args, _ = parser.parse_known_args()

    # ... load from args.train and args.test, train a model, write model to args.model_dir.

Then, we can run that script locally or use the SageMaker Python SDK to launch it on some GPU instances in SageMaker. The hyperparameters will get passed in to the script as CLI commands and the environment variables above will be autopopulated. When we call fit the input channels we pass will be populated in the SM_CHANNEL_* environment variables.

from sagemaker.chainer.estimator import Chainer
# Create my estimator
chainer_estimator = Chainer(
    hyperparameters={'epochs': 10, 'batch-size': 64}
# Train my estimator
chainer_estimator.fit({'train': train_input, 'test': test_input})

# Deploy my estimator to a SageMaker Endpoint and get a Predictor
predictor = chainer_estimator.deploy(

Now, instead of bringing your own docker container for training and hosting with Chainer, you can just maintain your script. You can see the full sagemaker-chainer-containers on github. One of my favorite features of the new container is built-in chainermn for easy multi-node distribution of your chainer training jobs.

There’s a lot more documentation and information available in both the README and the example notebooks.

AWS GreenGrass ML with Chainer

AWS GreenGrass ML now includes a pre-built Chainer package for all devices powered by Intel Atom, NVIDIA Jetson, TX2, and Raspberry Pi. So, now GreenGrass ML provides pre-built packages for TensorFlow, Apache MXNet, and Chainer! You can train your models on SageMaker then easily deploy it to any GreenGrass-enabled device using GreenGrass ML.


I want to give a quick shout out to all of our wonderful and inspirational friends in the JAWS UG who attended the AWS Summit in Tokyo today. I’ve very much enjoyed seeing your pictures of the summit. Thanks for making Japan an amazing place for AWS developers! I can’t wait to visit again and meet with all of you.


MagPi 70: Home automation with Raspberry Pi

Post Syndicated from Rob Zwetsloot original https://www.raspberrypi.org/blog/magpi-70-home-automation/

Hey folks, Rob here! It’s the last Thursday of the month, and that means it’s time for a brand-new The MagPi. Issue 70 is all about home automation using your favourite microcomputer, the Raspberry Pi.

Cover of The MagPi 70 — Raspberry Pi home automation and tech upcycling

Home automation in this month’s The MagPi!

Raspberry Pi home automation

We think home automation is an excellent use of the Raspberry Pi, hiding it around your house and letting it power your lights and doorbells and…fish tanks? We show you how to do all of that, and give you some excellent tips on how to add even more automation to your home in our ten-page cover feature.

Upcycle your life

Our other big feature this issue covers upcycling, the hot trend of taking old electronics and making them better than new with some custom code and a tactically placed Raspberry Pi. For this feature, we had a chat with Martin Mander, upcycler extraordinaire, to find out his top tips for hacking your old hardware.

Article on upcycling in The MagPi 70 — Raspberry Pi home automation and tech upcycling

Upcycling is a lot of fun

But wait, there’s more!

If for some reason you want even more content, you’re in luck! We have some fun tutorials for you to try, like creating a theremin and turning a Babbage into an IoT nanny cam. We also continue our quest to make a video game in C++. Our project showcase is headlined by the Teslonda on page 28, a Honda/Tesla car hybrid that is just wonderful.

Diddyborg V2 review in The MagPi 70 — Raspberry Pi home automation and tech upcycling

We review PiBorg’s latest robot

All this comes with our definitive reviews and the community section where we celebrate you, our amazing community! You’re all good beans

Teslonda article in The MagPi 70 — Raspberry Pi home automation and tech upcycling

An amazing, and practical, Raspberry Pi project

Get The MagPi 70

Issue 70 is available today from WHSmith, Tesco, Sainsbury’s, and Asda. If you live in the US, head over to your local Barnes & Noble or Micro Center in the next few days for a print copy. You can also get the new issue online from our store, or digitally via our Android and iOS apps. And don’t forget, there’s always the free PDF as well.

New subscription offer!

Want to support the Raspberry Pi Foundation and the magazine? We’ve launched a new way to subscribe to the print version of The MagPi: you can now take out a monthly £4 subscription to the magazine, effectively creating a rolling pre-order system that saves you money on each issue.

The MagPi subscription offer — Raspberry Pi home automation and tech upcycling

You can also take out a twelve-month print subscription and get a Pi Zero W plus case and adapter cables absolutely free! This offer does not currently have an end date.

That’s it for today! See you next month.

Animated GIF: a door slides open and Captain Picard emerges hesitantly

The post MagPi 70: Home automation with Raspberry Pi appeared first on Raspberry Pi.

Getting Rid of Your Mac? Here’s How to Securely Erase a Hard Drive or SSD

Post Syndicated from Roderick Bauer original https://www.backblaze.com/blog/how-to-wipe-a-mac-hard-drive/

erasing a hard drive and a solid state drive

What do I do with a Mac that still has personal data on it? Do I take out the disk drive and smash it? Do I sweep it with a really strong magnet? Is there a difference in how I handle a hard drive (HDD) versus a solid-state drive (SSD)? Well, taking a sledgehammer or projectile weapon to your old machine is certainly one way to make the data irretrievable, and it can be enormously cathartic as long as you follow appropriate safety and disposal protocols. But there are far less destructive ways to make sure your data is gone for good. Let me introduce you to secure erasing.

Which Type of Drive Do You Have?

Before we start, you need to know whether you have a HDD or a SSD. To find out, or at least to make sure, you click on the Apple menu and select “About this Mac.” Once there, select the “Storage” tab to see which type of drive is in your system.

The first example, below, shows a SATA Disk (HDD) in the system.


In the next case, we see we have a Solid State SATA Drive (SSD), plus a Mac SuperDrive.

Mac storage dialog showing SSD

The third screen shot shows an SSD, as well. In this case it’s called “Flash Storage.”

Flash Storage

Make Sure You Have a Backup

Before you get started, you’ll want to make sure that any important data on your hard drive has moved somewhere else. OS X’s built-in Time Machine backup software is a good start, especially when paired with Backblaze. You can learn more about using Time Machine in our Mac Backup Guide.

With a local backup copy in hand and secure cloud storage, you know your data is always safe no matter what happens.

Once you’ve verified your data is backed up, roll up your sleeves and get to work. The key is OS X Recovery — a special part of the Mac operating system since OS X 10.7 “Lion.”

How to Wipe a Mac Hard Disk Drive (HDD)

NOTE: If you’re interested in wiping an SSD, see below.

    1. Make sure your Mac is turned off.
    2. Press the power button.
    3. Immediately hold down the command and R keys.
    4. Wait until the Apple logo appears.
    5. Select “Disk Utility” from the OS X Utilities list. Click Continue.
    6. Select the disk you’d like to erase by clicking on it in the sidebar.
    7. Click the Erase button.
    8. Click the Security Options button.
    9. The Security Options window includes a slider that enables you to determine how thoroughly you want to erase your hard drive.

There are four notches to that Security Options slider. “Fastest” is quick but insecure — data could potentially be rebuilt using a file recovery app. Moving that slider to the right introduces progressively more secure erasing. Disk Utility’s most secure level erases the information used to access the files on your disk, then writes zeroes across the disk surface seven times to help remove any trace of what was there. This setting conforms to the DoD 5220.22-M specification.

  1. Once you’ve selected the level of secure erasing you’re comfortable with, click the OK button.
  2. Click the Erase button to begin. Bear in mind that the more secure method you select, the longer it will take. The most secure methods can add hours to the process.

Once it’s done, the Mac’s hard drive will be clean as a whistle and ready for its next adventure: a fresh installation of OS X, being donated to a relative or a local charity, or just sent to an e-waste facility. Of course you can still drill a hole in your disk or smash it with a sledgehammer if it makes you happy, but now you know how to wipe the data from your old computer with much less ruckus.

The above instructions apply to older Macintoshes with HDDs. What do you do if you have an SSD?

Securely Erasing SSDs, and Why Not To

Most new Macs ship with solid state drives (SSDs). Only the iMac and Mac mini ship with regular hard drives anymore, and even those are available in pure SSD variants if you want.

If your Mac comes equipped with an SSD, Apple’s Disk Utility software won’t actually let you zero the hard drive.

Wait, what?

In a tech note posted to Apple’s own online knowledgebase, Apple explains that you don’t need to securely erase your Mac’s SSD:

With an SSD drive, Secure Erase and Erasing Free Space are not available in Disk Utility. These options are not needed for an SSD drive because a standard erase makes it difficult to recover data from an SSD.

In fact, some folks will tell you not to zero out the data on an SSD, since it can cause wear and tear on the memory cells that, over time, can affect its reliability. I don’t think that’s nearly as big an issue as it used to be — SSD reliability and longevity has improved.

If “Standard Erase” doesn’t quite make you feel comfortable that your data can’t be recovered, there are a couple of options.

FileVault Keeps Your Data Safe

One way to make sure that your SSD’s data remains secure is to use FileVault. FileVault is whole-disk encryption for the Mac. With FileVault engaged, you need a password to access the information on your hard drive. Without it, that data is encrypted.

There’s one potential downside of FileVault — if you lose your password or the encryption key, you’re screwed: You’re not getting your data back any time soon. Based on my experience working at a Mac repair shop, losing a FileVault key happens more frequently than it should.

When you first set up a new Mac, you’re given the option of turning FileVault on. If you don’t do it then, you can turn on FileVault at any time by clicking on your Mac’s System Preferences, clicking on Security & Privacy, and clicking on the FileVault tab. Be warned, however, that the initial encryption process can take hours, as will decryption if you ever need to turn FileVault off.

With FileVault turned on, you can restart your Mac into its Recovery System (by restarting the Mac while holding down the command and R keys) and erase the hard drive using Disk Utility, once you’ve unlocked it (by selecting the disk, clicking the File menu, and clicking Unlock). That deletes the FileVault key, which means any data on the drive is useless.

FileVault doesn’t impact the performance of most modern Macs, though I’d suggest only using it if your Mac has an SSD, not a conventional hard disk drive.

Securely Erasing Free Space on Your SSD

If you don’t want to take Apple’s word for it, if you’re not using FileVault, or if you just want to, there is a way to securely erase free space on your SSD. It’s a little more involved but it works.

Before we get into the nitty-gritty, let me state for the record that this really isn’t necessary to do, which is why Apple’s made it so hard to do. But if you’re set on it, you’ll need to use Apple’s Terminal app. Terminal provides you with command line interface access to the OS X operating system. Terminal lives in the Utilities folder, but you can access Terminal from the Mac’s Recovery System, as well. Once your Mac has booted into the Recovery partition, click the Utilities menu and select Terminal to launch it.

From a Terminal command line, type:

diskutil secureErase freespace VALUE /Volumes/DRIVE

That tells your Mac to securely erase the free space on your SSD. You’ll need to change VALUE to a number between 0 and 4. 0 is a single-pass run of zeroes; 1 is a single-pass run of random numbers; 2 is a 7-pass erase; 3 is a 35-pass erase; and 4 is a 3-pass erase. DRIVE should be changed to the name of your hard drive. To run a 7-pass erase of your SSD drive in “JohnB-Macbook”, you would enter the following:

diskutil secureErase freespace 2 /Volumes/JohnB-Macbook

And remember, if you used a space in the name of your Mac’s hard drive, you need to insert a leading backslash before the space. For example, to run a 35-pass erase on a hard drive called “Macintosh HD” you enter the following:

diskutil secureErase freespace 3 /Volumes/Macintosh\ HD

Something to remember is that the more extensive the erase procedure, the longer it will take.

When Erasing is Not Enough — How to Destroy a Drive

If you absolutely, positively need to be sure that all the data on a drive is irretrievable, see this Scientific American article (with contributions by Gleb Budman, Backblaze CEO), How to Destroy a Hard Drive — Permanently.

The post Getting Rid of Your Mac? Here’s How to Securely Erase a Hard Drive or SSD appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Measuring the throughput for Amazon MQ using the JMS Benchmark

Post Syndicated from Rachel Richardson original https://aws.amazon.com/blogs/compute/measuring-the-throughput-for-amazon-mq-using-the-jms-benchmark/

This post is courtesy of Alan Protasio, Software Development Engineer, Amazon Web Services

Just like compute and storage, messaging is a fundamental building block of enterprise applications. Message brokers (aka “message-oriented middleware”) enable different software systems, often written in different languages, on different platforms, running in different locations, to communicate and exchange information. Mission-critical applications, such as CRM and ERP, rely on message brokers to work.

A common performance consideration for customers deploying a message broker in a production environment is the throughput of the system, measured as messages per second. This is important to know so that application environments (hosts, threads, memory, etc.) can be configured correctly.

In this post, we demonstrate how to measure the throughput for Amazon MQ, a new managed message broker service for ActiveMQ, using JMS Benchmark. It should take between 15–20 minutes to set up the environment and an hour to run the benchmark. We also provide some tips on how to configure Amazon MQ for optimal throughput.

Benchmarking throughput for Amazon MQ

ActiveMQ can be used for a number of use cases. These use cases can range from simple fire and forget tasks (that is, asynchronous processing), low-latency request-reply patterns, to buffering requests before they are persisted to a database.

The throughput of Amazon MQ is largely dependent on the use case. For example, if you have non-critical workloads such as gathering click events for a non-business-critical portal, you can use ActiveMQ in a non-persistent mode and get extremely high throughput with Amazon MQ.

On the flip side, if you have a critical workload where durability is extremely important (meaning that you can’t lose a message), then you are bound by the I/O capacity of your underlying persistence store. We recommend using mq.m4.large for the best results. The mq.t2.micro instance type is intended for product evaluation. Performance is limited, due to the lower memory and burstable CPU performance.

Tip: To improve your throughput with Amazon MQ, make sure that you have consumers processing messaging as fast as (or faster than) your producers are pushing messages.

Because it’s impossible to talk about how the broker (ActiveMQ) behaves for each and every use case, we walk through how to set up your own benchmark for Amazon MQ using our favorite open-source benchmarking tool: JMS Benchmark. We are fans of the JMS Benchmark suite because it’s easy to set up and deploy, and comes with a built-in visualizer of the results.

Non-Persistent Scenarios – Queue latency as you scale producer throughput

JMS Benchmark nonpersistent scenarios

Getting started

At the time of publication, you can create an mq.m4.large single-instance broker for testing for $0.30 per hour (US pricing).

This walkthrough covers the following tasks:

  1.  Create and configure the broker.
  2. Create an EC2 instance to run your benchmark
  3. Configure the security groups
  4.  Run the benchmark.

Step 1 – Create and configure the broker
Create and configure the broker using Tutorial: Creating and Configuring an Amazon MQ Broker.

Step 2 – Create an EC2 instance to run your benchmark
Launch the EC2 instance using Step 1: Launch an Instance. We recommend choosing the m5.large instance type.

Step 3 – Configure the security groups
Make sure that all the security groups are correctly configured to let the traffic flow between the EC2 instance and your broker.

  1. Sign in to the Amazon MQ console.
  2. From the broker list, choose the name of your broker (for example, MyBroker)
  3. In the Details section, under Security and network, choose the name of your security group or choose the expand icon ( ).
  4. From the security group list, choose your security group.
  5. At the bottom of the page, choose Inbound, Edit.
  6. In the Edit inbound rules dialog box, add a role to allow traffic between your instance and the broker:
    • Choose Add Rule.
    • For Type, choose Custom TCP.
    • For Port Range, type the ActiveMQ SSL port (61617).
    • For Source, leave Custom selected and then type the security group of your EC2 instance.
    • Choose Save.

Your broker can now accept the connection from your EC2 instance.

Step 4 – Run the benchmark
Connect to your EC2 instance using SSH and run the following commands:

$ cd ~
$ curl -L https://github.com/alanprot/jms-benchmark/archive/master.zip -o master.zip
$ unzip master.zip
$ cd jms-benchmark-master
$ chmod a+x bin/*
$ env \
  SERVER_SETUP=false \
  SERVER_ADDRESS={activemq-endpoint} \
  ACTIVEMQ_USERNAME={activemq-user} \
  ACTIVEMQ_PASSWORD={activemq-password} \

After the benchmark finishes, you can find the results in the ~/reports directory. As you may notice, the performance of ActiveMQ varies based on the number of consumers, producers, destinations, and message size.

Amazon MQ architecture

The last bit that’s important to know so that you can better understand the results of the benchmark is how Amazon MQ is architected.

Amazon MQ is architected to be highly available (HA) and durable. For HA, we recommend using the multi-AZ option. After a message is sent to Amazon MQ in persistent mode, the message is written to the highly durable message store that replicates the data across multiple nodes in multiple Availability Zones. Because of this replication, for some use cases you may see a reduction in throughput as you migrate to Amazon MQ. Customers have told us they appreciate the benefits of message replication as it helps protect durability even in the face of the loss of an Availability Zone.


We hope this gives you an idea of how Amazon MQ performs. We encourage you to run tests to simulate your own use cases.

To learn more, see the Amazon MQ website. You can try Amazon MQ for free with the AWS Free Tier, which includes up to 750 hours of a single-instance mq.t2.micro broker and up to 1 GB of storage per month for one year.

Welcome Jack — Data Center Tech

Post Syndicated from Yev original https://www.backblaze.com/blog/welcome-jack-data-center-tech/

As we shoot way past 500 petabytes of data stored, we need a lot of helping hands in the data center to keep those hard drives spinning! We’ve been hiring quite a lot, and our latest addition is Jack. Lets learn a bit more about him, shall we?

What is your Backblaze Title?
Data Center Tech

Where are you originally from?
Walnut Creek, CA until 7th grade when the family moved to Durango, Colorado.

What attracted you to Backblaze?
I had heard about how cool the Backblaze community is and have always been fascinated by technology.

What do you expect to learn while being at Backblaze?
I expect to learn a lot about how our data centers run and all of the hardware behind it.

Where else have you worked?
Garrhs HVAC as an HVAC Installer and then Durango Electrical as a Low Volt Technician.

Where did you go to school?
Durango High School and then Montana State University.

What’s your dream job?
I would love to be a driver for the Audi Sport. Race cars are so much fun!

Favorite place you’ve traveled?
Iceland has definitely been my favorite so far.

Favorite hobby?
Video games.

Of what achievement are you most proud?
Getting my Eagle Scout badge was a tough, but rewarding experience that I will always cherish.

Star Trek or Star Wars?
Star Wars.

Coke or Pepsi?
Coke…I know, it’s bad.

Favorite food?
Thai food.

Why do you like certain things?
I tend to warm up to things the more time I spend around them, although I never really know until it happens.

Anything else you’d like to tell us?
I’m a friendly car guy who will always be in love with my European cars and I really enjoy the Backblaze community!

We’re happy you joined us Out West! Welcome aboard Jack!

The post Welcome Jack — Data Center Tech appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Protecting your API using Amazon API Gateway and AWS WAF — Part I

Post Syndicated from Chris Munns original https://aws.amazon.com/blogs/compute/protecting-your-api-using-amazon-api-gateway-and-aws-waf-part-i/

This post courtesy of Thiago Morais, AWS Solutions Architect

When you build web applications or expose any data externally, you probably look for a platform where you can build highly scalable, secure, and robust REST APIs. As APIs are publicly exposed, there are a number of best practices for providing a secure mechanism to consumers using your API.

Amazon API Gateway handles all the tasks involved in accepting and processing up to hundreds of thousands of concurrent API calls, including traffic management, authorization and access control, monitoring, and API version management.

In this post, I show you how to take advantage of the regional API endpoint feature in API Gateway, so that you can create your own Amazon CloudFront distribution and secure your API using AWS WAF.

AWS WAF is a web application firewall that helps protect your web applications from common web exploits that could affect application availability, compromise security, or consume excessive resources.

As you make your APIs publicly available, you are exposed to attackers trying to exploit your services in several ways. The AWS security team published a whitepaper solution using AWS WAF, How to Mitigate OWASP’s Top 10 Web Application Vulnerabilities.

Regional API endpoints

Edge-optimized APIs are endpoints that are accessed through a CloudFront distribution created and managed by API Gateway. Before the launch of regional API endpoints, this was the default option when creating APIs using API Gateway. It primarily helped to reduce latency for API consumers that were located in different geographical locations than your API.

When API requests predominantly originate from an Amazon EC2 instance or other services within the same AWS Region as the API is deployed, a regional API endpoint typically lowers the latency of connections. It is recommended for such scenarios.

For better control around caching strategies, customers can use their own CloudFront distribution for regional APIs. They also have the ability to use AWS WAF protection, as I describe in this post.

Edge-optimized API endpoint

The following diagram is an illustrated example of the edge-optimized API endpoint where your API clients access your API through a CloudFront distribution created and managed by API Gateway.

Regional API endpoint

For the regional API endpoint, your customers access your API from the same Region in which your REST API is deployed. This helps you to reduce request latency and particularly allows you to add your own content delivery network, as needed.


In this section, you implement the following steps:

  • Create a regional API using the PetStore sample API.
  • Create a CloudFront distribution for the API.
  • Test the CloudFront distribution.
  • Set up AWS WAF and create a web ACL.
  • Attach the web ACL to the CloudFront distribution.
  • Test AWS WAF protection.

Create the regional API

For this walkthrough, use an existing PetStore API. All new APIs launch by default as the regional endpoint type. To change the endpoint type for your existing API, choose the cog icon on the top right corner:

After you have created the PetStore API on your account, deploy a stage called “prod” for the PetStore API.

On the API Gateway console, select the PetStore API and choose Actions, Deploy API.

For Stage name, type prod and add a stage description.

Choose Deploy and the new API stage is created.

Use the following AWS CLI command to update your API from edge-optimized to regional:

aws apigateway update-rest-api \
--rest-api-id {rest-api-id} \
--patch-operations op=replace,path=/endpointConfiguration/types/EDGE,value=REGIONAL

A successful response looks like the following:

    "description": "Your first API with Amazon API Gateway. This is a sample API that integrates via HTTP with your demo Pet Store endpoints", 
    "createdDate": 1511525626, 
    "endpointConfiguration": {
        "types": [
    "id": "{api-id}", 
    "name": "PetStore"

After you change your API endpoint to regional, you can now assign your own CloudFront distribution to this API.

Create a CloudFront distribution

To make things easier, I have provided an AWS CloudFormation template to deploy a CloudFront distribution pointing to the API that you just created. Click the button to deploy the template in the us-east-1 Region.

For Stack name, enter RegionalAPI. For APIGWEndpoint, enter your API FQDN in the following format:


After you fill out the parameters, choose Next to continue the stack deployment. It takes a couple of minutes to finish the deployment. After it finishes, the Output tab lists the following items:

  • A CloudFront domain URL
  • An S3 bucket for CloudFront access logs
Output from CloudFormation

Output from CloudFormation

Test the CloudFront distribution

To see if the CloudFront distribution was configured correctly, use a web browser and enter the URL from your distribution, with the following parameters:


You should get the following output:

    "id": 1,
    "type": "dog",
    "price": 249.99
    "id": 2,
    "type": "cat",
    "price": 124.99
    "id": 3,
    "type": "fish",
    "price": 0.99

Set up AWS WAF and create a web ACL

With the new CloudFront distribution in place, you can now start setting up AWS WAF to protect your API.

For this demo, you deploy the AWS WAF Security Automations solution, which provides fine-grained control over the requests attempting to access your API.

For more information about deployment, see Automated Deployment. If you prefer, you can launch the solution directly into your account using the following button.

For CloudFront Access Log Bucket Name, add the name of the bucket created during the deployment of the CloudFormation stack for your CloudFront distribution.

The solution allows you to adjust thresholds and also choose which automations to enable to protect your API. After you finish configuring these settings, choose Next.

To start the deployment process in your account, follow the creation wizard and choose Create. It takes a few minutes do finish the deployment. You can follow the creation process through the CloudFormation console.

After the deployment finishes, you can see the new web ACL deployed on the AWS WAF console, AWSWAFSecurityAutomations.

Attach the AWS WAF web ACL to the CloudFront distribution

With the solution deployed, you can now attach the AWS WAF web ACL to the CloudFront distribution that you created earlier.

To assign the newly created AWS WAF web ACL, go back to your CloudFront distribution. After you open your distribution for editing, choose General, Edit.

Select the new AWS WAF web ACL that you created earlier, AWSWAFSecurityAutomations.

Save the changes to your CloudFront distribution and wait for the deployment to finish.

Test AWS WAF protection

To validate the AWS WAF Web ACL setup, use Artillery to load test your API and see AWS WAF in action.

To install Artillery on your machine, run the following command:

$ npm install -g artillery

After the installation completes, you can check if Artillery installed successfully by running the following command:

$ artillery -V
$ 1.6.0-12

As the time of publication, Artillery is on version 1.6.0-12.

One of the WAF web ACL rules that you have set up is a rate-based rule. By default, it is set up to block any requesters that exceed 2000 requests under 5 minutes. Try this out.

First, use cURL to query your distribution and see the API output:

$ curl -s https://{distribution-name}.cloudfront.net/prod/pets
    "id": 1,
    "type": "dog",
    "price": 249.99
    "id": 2,
    "type": "cat",
    "price": 124.99
    "id": 3,
    "type": "fish",
    "price": 0.99

Based on the test above, the result looks good. But what if you max out the 2000 requests in under 5 minutes?

Run the following Artillery command:

artillery quick -n 2000 – count 10  https://{distribution-name}.cloudfront.net/prod/pets

What you are doing is firing 2000 requests to your API from 10 concurrent users. For brevity, I am not posting the Artillery output here.

After Artillery finishes its execution, try to run the cURL request again and see what happens:


$ curl -s https://{distribution-name}.cloudfront.net/prod/pets

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML><HEAD><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<TITLE>ERROR: The request could not be satisfied</TITLE>
<H2>The request could not be satisfied.</H2>
<HR noshade size="1px">
Request blocked.
<BR clear="all">
<HR noshade size="1px">
Generated by cloudfront (CloudFront)
Request ID: [removed]

As you can see from the output above, the request was blocked by AWS WAF. Your IP address is removed from the blocked list after it falls below the request limit rate.


In this first part, you saw how to use the new API Gateway regional API endpoint together with Amazon CloudFront and AWS WAF to secure your API from a series of attacks.

In the second part, I will demonstrate some other techniques to protect your API using API keys and Amazon CloudFront custom headers.

Use Slack ChatOps to Deploy Your Code – How to Integrate Your Pipeline in AWS CodePipeline with Your Slack Channel

Post Syndicated from Rumi Olsen original https://aws.amazon.com/blogs/devops/use-slack-chatops-to-deploy-your-code-how-to-integrate-your-pipeline-in-aws-codepipeline-with-your-slack-channel/

Slack is widely used by DevOps and development teams to communicate status. Typically, when a build has been tested and is ready to be promoted to a staging environment, a QA engineer or DevOps engineer kicks off the deployment. Using Slack in a ChatOps collaboration model, the promotion can be done in a single click from a Slack channel. And because the promotion happens through a Slack channel, the whole development team knows what’s happening without checking email.

In this blog post, I will show you how to integrate AWS services with a Slack application. I use an interactive message button and incoming webhook to promote a stage with a single click.

To follow along with the steps in this post, you’ll need a pipeline in AWS CodePipeline. If you don’t have a pipeline, the fastest way to create one for this use case is to use AWS CodeStar. Go to the AWS CodeStar console and select the Static Website template (shown in the screenshot). AWS CodeStar will create a pipeline with an AWS CodeCommit repository and an AWS CodeDeploy deployment for you. After the pipeline is created, you will need to add a manual approval stage.

You’ll also need to build a Slack app with webhooks and interactive components, write two Lambda functions, and create an API Gateway API and a SNS topic.

As you’ll see in the following diagram, when I make a change and merge a new feature into the master branch in AWS CodeCommit, the check-in kicks off my CI/CD pipeline in AWS CodePipeline. When CodePipeline reaches the approval stage, it sends a notification to Amazon SNS, which triggers an AWS Lambda function (ApprovalRequester).

The Slack channel receives a prompt that looks like the following screenshot. When I click Yes to approve the build promotion, the approval result is sent to CodePipeline through API Gateway and Lambda (ApprovalHandler). The pipeline continues on to deploy the build to the next environment.

Create a Slack app

For App Name, type a name for your app. For Development Slack Workspace, choose the name of your workspace. You’ll see in the following screenshot that my workspace is AWS ChatOps.

After the Slack application has been created, you will see the Basic Information page, where you can create incoming webhooks and enable interactive components.

To add incoming webhooks:

  1. Under Add features and functionality, choose Incoming Webhooks. Turn the feature on by selecting Off, as shown in the following screenshot.
  2. Now that the feature is turned on, choose Add New Webhook to Workspace. In the process of creating the webhook, Slack lets you choose the channel where messages will be posted.
  3. After the webhook has been created, you’ll see its URL. You will use this URL when you create the Lambda function.

If you followed the steps in the post, the pipeline should look like the following.

Write the Lambda function for approval requests

This Lambda function is invoked by the SNS notification. It sends a request that consists of an interactive message button to the incoming webhook you created earlier.  The following sample code sends the request to the incoming webhook. WEBHOOK_URL and SLACK_CHANNEL are the environment variables that hold values of the webhook URL that you created and the Slack channel where you want the interactive message button to appear.

# This function is invoked via SNS when the CodePipeline manual approval action starts.
# It will take the details from this approval notification and sent an interactive message to Slack that allows users to approve or cancel the deployment.

import os
import json
import logging
import urllib.parse

from base64 import b64decode
from urllib.request import Request, urlopen
from urllib.error import URLError, HTTPError

# This is passed as a plain-text environment variable for ease of demonstration.
# Consider encrypting the value with KMS or use an encrypted parameter in Parameter Store for production deployments.

logger = logging.getLogger()

def lambda_handler(event, context):
    print("Received event: " + json.dumps(event, indent=2))
    message = event["Records"][0]["Sns"]["Message"]
    data = json.loads(message) 
    token = data["approval"]["token"]
    codepipeline_name = data["approval"]["pipelineName"]
    slack_message = {
        "channel": SLACK_CHANNEL,
        "text": "Would you like to promote the build to production?",
        "attachments": [
                "text": "Yes to deploy your build to production",
                "fallback": "You are unable to promote a build",
                "callback_id": "wopr_game",
                "color": "#3AA3E3",
                "attachment_type": "default",
                "actions": [
                        "name": "deployment",
                        "text": "Yes",
                        "style": "danger",
                        "type": "button",
                        "value": json.dumps({"approve": True, "codePipelineToken": token, "codePipelineName": codepipeline_name}),
                        "confirm": {
                            "title": "Are you sure?",
                            "text": "This will deploy the build to production",
                            "ok_text": "Yes",
                            "dismiss_text": "No"
                        "name": "deployment",
                        "text": "No",
                        "type": "button",
                        "value": json.dumps({"approve": False, "codePipelineToken": token, "codePipelineName": codepipeline_name})

    req = Request(SLACK_WEBHOOK_URL, json.dumps(slack_message).encode('utf-8'))

    response = urlopen(req)
    return None


Create a SNS topic

Create a topic and then create a subscription that invokes the ApprovalRequester Lambda function. You can configure the manual approval action in the pipeline to send a message to this SNS topic when an approval action is required. When the pipeline reaches the approval stage, it sends a notification to this SNS topic. SNS publishes a notification to all of the subscribed endpoints. In this case, the Lambda function is the endpoint. Therefore, it invokes and executes the Lambda function. For information about how to create a SNS topic, see Create a Topic in the Amazon SNS Developer Guide.

Write the Lambda function for handling the interactive message button

This Lambda function is invoked by API Gateway. It receives the result of the interactive message button whether or not the build promotion was approved. If approved, an API call is made to CodePipeline to promote the build to the next environment. If not approved, the pipeline stops and does not move to the next stage.

The Lambda function code might look like the following. SLACK_VERIFICATION_TOKEN is the environment variable that contains your Slack verification token. You can find your verification token under Basic Information on Slack manage app page. When you scroll down, you will see App Credential. Verification token is found under the section.

# This function is triggered via API Gateway when a user acts on the Slack interactive message sent by approval_requester.py.

from urllib.parse import parse_qs
import json
import os
import boto3


#Triggered by API Gateway
#It kicks off a particular CodePipeline project
def lambda_handler(event, context):
	#print("Received event: " + json.dumps(event, indent=2))
	body = parse_qs(event['body'])
	payload = json.loads(body['payload'][0])

	# Validate Slack token
	if SLACK_VERIFICATION_TOKEN == payload['token']:
		# This will replace the interactive message with a simple text response.
		# You can implement a more complex message update if you would like.
		return  {
			"isBase64Encoded": "false",
			"statusCode": 200,
			"body": "{\"text\": \"The approval has been processed\"}"
		return  {
			"isBase64Encoded": "false",
			"statusCode": 403,
			"body": "{\"error\": \"This request does not include a vailid verification token.\"}"

def send_slack_message(action_details):
	codepipeline_status = "Approved" if action_details["approve"] else "Rejected"
	codepipeline_name = action_details["codePipelineName"]
	token = action_details["codePipelineToken"] 

	client = boto3.client('codepipeline')
	response_approval = client.put_approval_result(


Create the API Gateway API

  1. In the Amazon API Gateway console, create a resource called InteractiveMessageHandler.
  2. Create a POST method.
    • For Integration type, choose Lambda Function.
    • Select Use Lambda Proxy integration.
    • From Lambda Region, choose a region.
    • In Lambda Function, type a name for your function.
  3.  Deploy to a stage.

For more information, see Getting Started with Amazon API Gateway in the Amazon API Developer Guide.

Now go back to your Slack application and enable interactive components.

To enable interactive components for the interactive message (Yes) button:

  1. Under Features, choose Interactive Components.
  2. Choose Enable Interactive Components.
  3. Type a request URL in the text box. Use the invoke URL in Amazon API Gateway that will be called when the approval button is clicked.

Now that all the pieces have been created, run the solution by checking in a code change to your CodeCommit repo. That will release the change through CodePipeline. When the CodePipeline comes to the approval stage, it will prompt to your Slack channel to see if you want to promote the build to your staging or production environment. Choose Yes and then see if your change was deployed to the environment.


That is it! You have now created a Slack ChatOps solution using AWS CodeCommit, AWS CodePipeline, AWS Lambda, Amazon API Gateway, and Amazon Simple Notification Service.

Now that you know how to do this Slack and CodePipeline integration, you can use the same method to interact with other AWS services using API Gateway and Lambda. You can also use Slack’s slash command to initiate an action from a Slack channel, rather than responding in the way demonstrated in this post.

HackSpace magazine 7: Internet of Everything

Post Syndicated from Andrew Gregory original https://www.raspberrypi.org/blog/hackspace-magazine-7-internet-of-everything/

We’re usually averse to buzzwords at HackSpace magazine, but not this month: in issue 7, we’re taking a deep dive into the Internet of Things.HackSpace magazine issue 7 cover

Internet of Things (IoT)

To many people, IoT is a shady term used by companies to sell you something you already own, but this time with WiFi; to us, it’s a way to make our builds smarter, more useful, and more connected. In HackSpace magazine #7, you can join us on a tour of the boards that power IoT projects, marvel at the ways in which other makers are using IoT, and get started with your first IoT project!

Awesome projects

DIY retro computing: this issue, we’re taking our collective hat off to Spencer Owen. He stuck his home-brew computer on Tindie thinking he might make a bit of beer money — now he’s paying the mortgage with his making skills and inviting others to build modules for his machine. And if that tickles your fancy, why not take a crack at our Z80 tutorial? Get out your breadboard, assemble your jumper wires, and prepare to build a real-life computer!

Inside HackSpace magazine issue 7

Shameless patriotism: combine Lego, Arduino, and the car of choice for 1960 gold bullion thieves, and you’ve got yourself a groovy weekend project. We proudly present to you one man’s epic quest to add LED lights (controllable via a smartphone!) to his daughter’s LEGO Mini Cooper.


Patriotism intensifies: for the last 200-odd years, the Black Country has been a hotbed of making. Urban Hax, based in Walsall, is the latest makerspace to show off its riches in the coveted Space of the Month pages. Every space has its own way of doing things, but not every space has a portrait of Rob Halford on the wall. All hail!

Inside HackSpace magazine issue 7

Diversity: advice on diversity often boils down to ‘Be nice to people’, which might feel more vague than actionable. This is where we come in to help: it is truly worth making the effort to give people of all backgrounds access to your makerspace, so we take a look at why it’s nice to be nice, and at the ways in which one makerspace has put niceness into practice — with great results.

And there’s more!

We also show you how to easily calculate the size and radius of laser-cut gears, use a bank of LEDs to etch PCBs in your own mini factory, and use chemistry to mess with your lunch menu.

Inside HackSpace magazine issue 7
Helen Steer inside HackSpace magazine issue 7
Inside HackSpace magazine issue 7

All this plus much, much more waits for you in HackSpace magazine issue 7!

Get your copy of HackSpace magazine

If you like the sound of that, you can find HackSpace magazine in WHSmith, Tesco, Sainsbury’s, and independent newsagents in the UK. If you live in the US, check out your local Barnes & Noble, Fry’s, or Micro Center next week. We’re also shipping to stores in Australia, Hong Kong, Canada, Singapore, Belgium, and Brazil, so be sure to ask your local newsagent whether they’ll be getting HackSpace magazine.

And if you can’t get to the shops, fear not: you can subscribe from £4 an issue from our online shop. And if you’d rather try before you buy, you can always download the free PDF. Happy reading, and happy making!

The post HackSpace magazine 7: Internet of Everything appeared first on Raspberry Pi.

C is to low level

Post Syndicated from Robert Graham original https://blog.erratasec.com/2018/05/c-is-too-low-level.html

I’m in danger of contradicting myself, after previously pointing out that x86 machine code is a high-level language, but this article claiming C is a not a low level language is bunk. C certainly has some problems, but it’s still the closest language to assembly. This is obvious by the fact it’s still the fastest compiled language. What we see is a typical academic out of touch with the real world.

The author makes the (wrong) observation that we’ve been stuck emulating the PDP-11 for the past 40 years. C was written for the PDP-11, and since then CPUs have been designed to make C run faster. The author imagines a different world, such as where CPU designers instead target something like LISP as their preferred language, or Erlang. This misunderstands the state of the market. CPUs do indeed supports lots of different abstractions, and C has evolved to accommodate this.

The author criticizes things like “out-of-order” execution which has lead to the Spectre sidechannel vulnerabilities. Out-of-order execution is necessary to make C run faster. The author claims instead that those resources should be spent on having more slower CPUs, with more threads. This sacrifices single-threaded performance in exchange for a lot more threads executing in parallel. The author cites Sparc Tx CPUs as his ideal processor.

But here’s the thing, the Sparc Tx was a failure. To be fair, it’s mostly a failure because most of the time, people wanted to run old C code instead of new Erlang code. But it was still a failure at running Erlang.

Time after time, engineers keep finding that “out-of-order”, single-threaded performance is still the winner. A good example is ARM processors for both mobile phones and servers. All the theory points to in-order CPUs as being better, but all the products are out-of-order, because this theory is wrong. The custom ARM cores from Apple and Qualcomm used in most high-end phones are so deeply out-of-order they give Intel CPUs competition. The same is true on the server front with the latest Qualcomm Centriq and Cavium ThunderX2 processors, deeply out of order supporting more than 100 instructions in flight.

The Cavium is especially telling. Its ThunderX CPU had 48 simple cores which was replaced with the ThunderX2 having 32 complex, deeply out-of-order cores. The performance increase was massive, even on multithread-friendly workloads. Every competitor to Intel’s dominance in the server space has learned the lesson from Sparc Tx: many wimpy cores is a failure, you need fewer beefy cores. Yes, they don’t need to be as beefy as Intel’s processors, but they need to be close.

Even Intel’s “Xeon Phi” custom chip learned this lesson. This is their GPU-like chip, running 60 cores with 512-bit wide “vector” (sic) instructions, designed for supercomputer applications. Its first version was purely in-order. Its current version is slightly out-of-order. It supports four threads and focuses on basic number crunching, so in-order cores seems to be the right approach, but Intel found in this case that out-of-order processing still provided a benefit. Practice is different than theory.

As an academic, the author of the above article focuses on abstractions. The criticism of C is that it has the wrong abstractions which are hard to optimize, and that if we instead expressed things in the right abstractions, it would be easier to optimize.

This is an intellectually compelling argument, but so far bunk.

The reason is that while the theoretical base language has issues, everyone programs using extensions to the language, like “intrinsics” (C ‘functions’ that map to assembly instructions). Programmers write libraries using these intrinsics, which then the rest of the normal programmers use. In other words, if your criticism is that C is not itself low level enough, it still provides the best access to low level capabilities.

Given that C can access new functionality in CPUs, CPU designers add new paradigms, from SIMD to transaction processing. In other words, while in the 1980s CPUs were designed to optimize C (stacks, scaled pointers), these days CPUs are designed to optimize tasks regardless of language.

The author of that article criticizes the memory/cache hierarchy, claiming it has problems. Yes, it has problems, but only compared to how well it normally works. The author praises the many simple cores/threads idea as hiding memory latency with little caching, but misses the point that caches also dramatically increase memory bandwidth. Intel processors are optimized to read a whopping 256 bits every clock cycle from L1 cache. Main memory bandwidth is orders of magnitude slower.

The author goes onto criticize cache coherency as a problem. C uses it, but other languages like Erlang don’t need it. But that’s largely due to the problems each languages solves. Erlang solves the problem where a large number of threads work on largely independent tasks, needing to send only small messages to each other across threads. The problems C solves is when you need many threads working on a huge, common set of data.

For example, consider the “intrusion prevention system”. Any thread can process any incoming packet that corresponds to any region of memory. There’s no practical way of solving this problem without a huge coherent cache. It doesn’t matter which language or abstractions you use, it’s the fundamental constraint of the problem being solved. RDMA is an important concept that’s moved from supercomputer applications to the data center, such as with memcached. Again, we have the problem of huge quantities (terabytes worth) shared among threads rather than small quantities (kilobytes).

The fundamental issue the author of the the paper is ignoring is decreasing marginal returns. Moore’s Law has gifted us more transistors than we can usefully use. We can’t apply those additional registers to just one thing, because the useful returns we get diminish.

For example, Intel CPUs have two hardware threads per core. That’s because there are good returns by adding a single additional thread. However, the usefulness of adding a third or fourth thread decreases. That’s why many CPUs have only two threads, or sometimes four threads, but no CPU has 16 threads per core.

You can apply the same discussion to any aspect of the CPU, from register count, to SIMD width, to cache size, to out-of-order depth, and so on. Rather than focusing on one of these things and increasing it to the extreme, CPU designers make each a bit larger every process tick that adds more transistors to the chip.

The same applies to cores. It’s why the “more simpler cores” strategy fails, because more cores have their own decreasing marginal returns. Instead of adding cores tied to limited memory bandwidth, it’s better to add more cache. Such cache already increases the size of the cores, so at some point it’s more effective to add a few out-of-order features to each core rather than more cores. And so on.

The question isn’t whether we can change this paradigm and radically redesign CPUs to match some academic’s view of the perfect abstraction. Instead, the goal is to find new uses for those additional transistors. For example, “message passing” is a useful abstraction in languages like Go and Erlang that’s often more useful than sharing memory. It’s implemented with shared memory and atomic instructions, but I can’t help but think it couldn’t better be done with direct hardware support.

Of course, as soon as they do that, it’ll become an intrinsic in C, then added to languages like Go and Erlang.


Academics live in an ideal world of abstractions, the rest of us live in practical reality. The reality is that vast majority of programmers work with the C family of languages (JavaScript, Go, etc.), whereas academics love the epiphanies they learned using other languages, especially function languages. CPUs are only superficially designed to run C and “PDP-11 compatibility”. Instead, they keep adding features to support other abstractions, abstractions available to C. They are driven by decreasing marginal returns — they would love to add new abstractions to the hardware because it’s a cheap way to make use of additional transitions. Academics are wrong believing that the entire system needs to be redesigned from scratch. Instead, they just need to come up with new abstractions CPU designers can add.

The Benefits of Side Projects

Post Syndicated from Bozho original https://techblog.bozho.net/the-benefits-of-side-projects/

Side projects are the things you do at home, after work, for your own “entertainment”, or to satisfy your desire to learn new stuff, in case your workplace doesn’t give you that opportunity (or at least not enough of it). Side projects are also a way to build stuff that you think is valuable but not necessarily “commercialisable”. Many side projects are open-sourced sooner or later and some of them contribute to the pool of tools at other people’s disposal.

I’ve outlined one recommendation about side projects before – do them with technologies that are new to you, so that you learn important things that will keep you better positioned in the software world.

But there are more benefits than that – serendipitous benefits, for example. And I’d like to tell some personal stories about that. I’ll focus on a few examples from my list of side projects to show how, through a sort-of butterfly effect, they helped shape my career.

The computoser project, no matter how cool algorithmic music composition, didn’t manage to have much of a long term impact. But it did teach me something apart from niche musical theory – how to read a bulk of scientific papers (mostly computer science) and understand them without being formally trained in the particular field. We’ll see how that was useful later.

Then there was the “State alerts” project – a website that scraped content from public institutions in my country (legislation, legislation proposals, decisions by regulators, new tenders, etc.), made them searchable, and “subscribable” – so that you get notified when a keyword of interest is mentioned in newly proposed legislation, for example. (I obviously subscribed for “information technologies” and “electronic”).

And that project turned out to have a significant impact on the following years. First, I chose a new technology to write it with – Scala. Which turned out to be of great use when I started working at TomTom, and on the 3rd day I was transferred to a Scala project, which was way cooler and much more complex than the original one I was hired for. It was a bit ironic, as my colleagues had just read that “I don’t like Scala” a few weeks earlier, but nevertheless, that was one of the most interesting projects I’ve worked on, and it went on for two years. Had I not known Scala, I’d probably be gone from TomTom much earlier (as the other project was restructured a few times), and I would not have learned many of the scalability, architecture and AWS lessons that I did learn there.

But the very same project had an even more important follow-up. Because if its “civic hacking” flavour, I was invited to join an informal group of developers (later officiated as an NGO) who create tools that are useful for society (something like MySociety.org). That group gathered regularly, discussed both tools and policies, and at some point we put up a list of policy priorities that we wanted to lobby policy makers. One of them was open source for the government, the other one was open data. As a result of our interaction with an interim government, we donated the official open data portal of my country, functioning to this day.

As a result of that, a few months later we got a proposal from the deputy prime minister’s office to “elect” one of the group for an advisor to the cabinet. And we decided that could be me. So I went for it and became advisor to the deputy prime minister. The job has nothing to do with anything one could imagine, and it was challenging and fascinating. We managed to pass legislation, including one that requires open source for custom projects, eID and open data. And all of that would not have been possible without my little side project.

As for my latest side project, LogSentinel – it became my current startup company. And not without help from the previous two mentioned above – the computer science paper reading was of great use when I was navigating the crypto papers landscape, and from the government job I not only gained invaluable legal knowledge, but I also “got” a co-founder.

Some other side projects died without much fanfare, and that’s fine. But the ones above shaped my “story” in a way that would not have been possible otherwise.

And I agree that such serendipitous chain of events could have happened without side projects – I could’ve gotten these opportunities by meeting someone at a bar (unlikely, but who knows). But we, as software engineers, are capable of tilting chance towards us by utilizing our skills. Side projects are our “extracurricular activities”, and they often lead to unpredictable, but rather positive chains of events. They would rarely be the only factor, but they are certainly great at unlocking potential.

The post The Benefits of Side Projects appeared first on Bozho's tech blog.

Working with the Scout Association on digital skills for life

Post Syndicated from Philip Colligan original https://www.raspberrypi.org/blog/working-with-scout-association-digital-skills-for-life/

Today we’re launching a new partnership between the Scouts and the Raspberry Pi Foundation that will help tens of thousands of young people learn crucial digital skills for life. In this blog post, I want to explain what we’ve got planned, why it matters, and how you can get involved.

This is personal

First, let me tell you why this partnership matters to me. As a child growing up in North Wales in the 1980s, Scouting changed my life. My time with 2nd Rhyl provided me with countless opportunities to grow and develop new skills. It taught me about teamwork and community in ways that continue to shape my decisions today.

As my own kids (now seven and ten) have joined Scouting, I’ve seen the same opportunities opening up for them, and like so many parents, I’ve come back to the movement as a volunteer to support their local section. So this is deeply personal for me, and the same is true for many of my colleagues at the Raspberry Pi Foundation who in different ways have been part of the Scouting movement.

That shouldn’t come as a surprise. Scouting and Raspberry Pi share many of the same values. We are both community-led movements that aim to help young people develop the skills they need for life. We are both powered by an amazing army of volunteers who give their time to support that mission. We both care about inclusiveness, and pride ourselves on combining fun with learning by doing.

Raspberry Pi

Raspberry Pi started life in 2008 as a response to the problem that too many young people were growing up without the skills to create with technology. Our goal is that everyone should be able to harness the power of computing and digital technologies, for work, to solve problems that matter to them, and to express themselves creatively.

In 2012 we launched our first product, the world’s first $35 computer. Just six years on, we have sold over 20 million Raspberry Pi computers and helped kickstart a global movement for digital skills.

The Raspberry Pi Foundation now runs the world’s largest network of volunteer-led computing clubs (Code Clubs and CoderDojos), and creates free educational resources that are used by millions of young people all over the world to learn how to create with digital technologies. And lots of what we are able to achieve is because of partnerships with fantastic organisations that share our goals. For example, through our partnership with the European Space Agency, thousands of young people have written code that has run on two Raspberry Pi computers that Tim Peake took to the International Space Station as part of his Mission Principia.

Digital makers

Today we’re launching the new Digital Maker Staged Activity Badge to help tens of thousands of young people learn how to create with technology through Scouting. Over the past few months, we’ve been working with the Scouts all over the UK to develop and test the new badge requirements, along with guidance, project ideas, and resources that really make them work for Scouting. We know that we need to get two things right: relevance and accessibility.

Relevance is all about making sure that the activities and resources we provide are a really good fit for Scouting and Scouting’s mission to equip young people with skills for life. From the digital compass to nature cameras and the reinvented wide game, we’ve had a lot of fun thinking about ways we can bring to life the crucial role that digital technologies can play in the outdoors and adventure.

Compass Coding with Raspberry Pi

We are beyond excited to be launching a new partnership with the Raspberry Pi Foundation, which will help tens of thousands of young people learn digital skills for life.

We also know that there are great opportunities for Scouts to use digital technologies to solve social problems in their communities, reflecting the movement’s commitment to social action. Today we’re launching the first set of project ideas and resources, with many more to follow over the coming weeks and months.

Accessibility is about providing every Scout leader with the confidence, support, and kit to enable them to offer the Digital Maker Staged Activity Badge to their young people. A lot of work and care has gone into designing activities that require very little equipment: for example, activities at Stages 1 and 2 can be completed with a laptop without access to the internet. For the activities that do require kit, we will be working with Scout Stores and districts to make low-cost kit available to buy or loan.

We’re producing accessible instructions, worksheets, and videos to help leaders run sessions with confidence, and we’ll also be planning training for leaders. We will work with our network of Code Clubs and CoderDojos to connect them with local sections to organise joint activities, bringing both kit and expertise along with them.

Get involved

Today’s launch is just the start. We’ll be developing our partnership over the next few years, and we can’t wait for you to join us in getting more young people making things with technology.

Take a look at the brand-new Raspberry Pi resources designed especially for Scouts, to get young people making and creating right away.

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