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Limited systems can be cheaper and better Writing a robust, general-purpose system is often quite expensive. For example, the memory allocator behind malloc() and new is the result of years of work and fine-tuning. It has to handle every weird allocation pattern, be completely thread-safe on 64-core processors, minimize memory fragmentation and overhead, etc. If the memory allocator is inadequate…
Some computer systems are obviously safety-critical. If you are working on flight-control software for Boeing or Airbus, everyone involved is aware that mistakes in this program could cause loss of life. So software like this is written very, very carefully - extremely detailed specifications, often proofs of correctness using a theorem prover, exhaustive testing, and so on. But there are also…
There’s a lot of discussion about Technical Debt in Software Engineering. I believe the term originated on the C2 wiki . It’s often used to explain to non-software-engineers why it’s important to invest in code quality. I’m far from the first person to think that the term Technical Debt is potentially misleading. Rob Jeffries has a discussion here . To oversimplify, debt…
Financial Perpetual Motion Every so often, someone claims to have created a perpetual motion machine , or a source of free energy - some kind of contraption which does work without any external power source. Anyone with a physics background knows that this is impossible due to the laws of thermodynamics, but these claims still find a small credulous audience. Normally the device is accompanied by…
Disclaimer: I’m not an expert on the crypto space, just a curious amateur. It’s quite possible I have misunderstood something important below. Do let me know of any corrections via the comment section! If you read the Ethereum website on DAO’s , you’ll see this: DAOs are an effective and safe way to work with like-minded folks around the globe. Think of them like an…
The official information on Cloud Shell’s file storage is here . It’s good stuff, and covers most things you might like to know, take a look! This blog contains a few more behind-the-scenes details for the curious. NB: We might change this in the future, this isn’t guaranteed. We can see from the docs that all your files are stored in an Azure File Share which belongs to you, and…
When you open Azure Cloud Shell and run Get-AzVM or az vm list for the first time, it works right away. But why? That may seem like an odd question. Of course it should work right away! But it doesn’t work quite the same way when you run PowerShell or Azure CLI locally - you need to run Connect-AzAccount or az login first. So what’s the difference? A surprising amount of things are…
Arc for Servers has an Azure CLI extension and PowerShell module. Because they are prerelease, they are not included (yet) in the main releases (ie, you don’t get this just by installing az cli or the Az module). However they are already functional and useful. Here’s how to do some simple operations with each of them. Install AZ CLI: 1 az extension add connectedmachine Azure…
Cloud Shell comes with a lot of tools, and we try to keep them up to date. But sometimes you need something a little bit more cutting edge or unusual. How do you install it? Using Cloud Shell is a little different from running your own Linux computer, but it’s a lot like using a multi-user Unix system. The main difference is you are not root and we won’t tell you the root password…
A few people have asked “Hey, uh, hypothetically, if I had typed a password or a secret at the Cloud Shell prompt, did you store it, and how would I delete it? Obviously I would never do this, asking for a friend.” Relax, we’ve all done it. And the answer is “Sort of”. In more detail, Cloud Shell does not store your history itself. But the shell you are running inside…
One issue which can trip you up when using command-line tools to configure Azure is a confusing lack of interaction between Azure CLI and Azure PowerShell. They both provide a “context” so you don’t have to keep specifying the subscription over and over. But Azure CLI (the az command) has a separate context from Azure PowerShell. You can see this by running 1 2 3 4 5 az account…