Recently I’ve been experimenting with freestanding C programs on Windows. Freestanding refers to programs that don’t link, either statically or dynamically, against a standard library (i.e. libc). This is typical for operating systems and similar, bare metal situations . Normally a C compiler can make assumptions…
QubesOS provides a desktop operating system made up of multiple virtual machines, running under Xen. To protect against buggy network drivers, the …
ramblings by Adam Perry
While there may be some situations in which DOS has a better command, Unix works better overall.
After failing to find good papers about distributed systems testing for many months, yesterday I asked a question in Twitter:
I’m hacking on an assembly project, and wanted to document some of the tricks I was using for figuring out what was going on. This post might seem a little basic for folks who spend all day heads down in gdb or who do this stuff professionally, but I just wanted to share a quick intro to some tools that others may…
Below is the first draft list of papers I plan to discuss in my distributed systems seminar in the Spring semester. If you have some suggest...
Suppose you have multiple processes appending output to the same file without explicit synchronization. These processes might be working in parallel on different parts of the same problem, or these might be threads blocked individually reading different external inputs. There are two concerns that come into play:
Wherein the author discusses the Plan 9 operating system. First of several.
Unikernel Profiling: Flame Graphs from dom0. This post investigates performance profiling of Unikernels, and with a proof of concept shows that with a little work a lot of observability is possible.
I was incredibly inspired by Tomasz Stachowiak’s hack of GCN . It made me wish I owned a GCN machine of my own to start trying insane things with. On the other hand, I dooo own an Intel Haswell GPU , and they dooo publish some really dense documentation that’s allegedly enough to write a complete driver with.
In an earlier post, I showed how to implement the “world’s simplest lock-free hash table” in C++. It was so simple that you couldn’t even delete entries or …
A whirlwind tour on acheiving agreement in a distributed system
$ curl ‐‐http2 https://daniel.haxx.se/ curl: (1) Unsupported protocol curl on mac curl has been shipped by default on Mac OS X since many years - I actually couldn't even manage to figure out exactly how many. It is built and bundled with the operating system by Apple itself and on Apple's own terms and even ……
Experienced professional software engineer based in York, UK
The current structure definition of the ion system heap involves a zero sized array:
Perf is probably the most widely used general purpose performance debugging tool on Linux. There are multiple contenders for the #2 spot, and, like perf, they're sampling profilers. Sampling profilers are great. They tend to be easy-to-use and low-overhead compared to most alternatives. However, there are large…
Dec 12, 2019 Update: This piece of software is no longer available as I have turned it off due to lack of interest. The article below used to contain a number of links which I have removed. The content below remains only for archival purposes.
Introduction Deflate compression has been around for over 20 years. It's the format used inside most ZIP files. It's used by HTTP to redu...
Do concurrency bugs matter? From the literature, we know that most reported bugs in distributed systems have really simple causes and can be caught by trivial tests, even when we only look at bugs that cause really bad failures, like loss of a cluster or data corruption. The filesystem literature echos this result …
Take a moment to go back in time with me, back to when life was simpler and the biggest threat to humanity was Y2k…
