How the Windows Subsystem for Linux Redirects Syscalls (opens in new tab)

Side-by-side, comparing VMS to UNIX, and VMS's approach to a few key areas like I/O, ASTs and tiered interrupt levels are simply just more sophisticated. NT inherited all of that. It was fundamentally superior, as a kernel, to UNIX, from day 1.

I haven't met a single person that has understood NT and Linux/UNIX, and still thinks UNIX is superior as far as the kernels go. I have definitely alienated myself the more I've discovered that though, as it's such a wildly unpopular sentiment in open source land.

Cutler got a call from Gates in 89, and from 89-93, NT was built. He was 47 at the time, and was one of the lead developers of VMS, which was a rock-solid operating system.

In 93, Linus was 22, and starting "implementing enough syscalls until bash ran" as a fun project to work on.

Cutler despised the UNIX I/O model. "Getta byte getta byte getta byte byte byte." The I/O request packet approach to I/O (and tiered interrupts) is one of the key reasons behind NT's superiority. And once you've grok'd things like APCs and structured exception handling, signals just seem absolutely ghastly in comparison.

That does not follow from the example. All it shows is that Microsoft prefers to put a lot of functionality in one interface, while Linux probably prefers low-level functions to be as small as possible, and probably offers things like filtering on a higher level (in glibc, for example).

Neither explanation has anything to do with sophistication. I personally believe that small interfaces are a better design.

I'd also object NT kernel being more "powerful". Sure unixy kernels and NT has their differences but I don't think either one is superior.

Also, Windows development is infinitely more painful than Unix/Linux.

Are you implying that an increase in "power" can never be achieved through increasing simplicity?

Source?

It's not sophisticated enough or powerful enough to be the most used kernel on super computers (and in the world). Windows pretty much only dominates the desktop market. Servers, super computers, mainframes, etc, mostly use Linux.

A few years ago there was even a bug in Windows that caused degradation in network performance during multimedia playback that was directly connected with mechanisms employed by the Multimedia Class Scheduler Service (MMCSS), this is used on a lot of audio setups. If they can't even get audio setups right how can people consider anything Windows releases "sophisticated"?

It's made to do anything you throw at it I guess, it's definitely complicated, but powerful and sophisticated aren't words I would use to describe NT.

If I can't run the entire stack I use for dev under the subsystem then I will go the other route, which is to continue using VMs. I am excited about the initial release, and the prospect of being able to use Windows for all of the regular things I do, but it's clear that this isn't ready for primetime even as a dev tool.

https://msdn.microsoft.com/en-us/virtualization/hyperv_on_wi...

You can do it with NtCreateProcess: https://groups.google.com/d/msg/microsoft.public.win32.progr...

(The Win32 userland won't understand what you did, but you can still do it.)

The very precise mechanism, though, is extremely unstable. For example virtually every release of Windows (even sometimes SP) changes the syscall numbers. You have to go through the ntdll, which is kind of a more heavyweight version of the Linux VDSO. (The NTDLL approach was invented way before the VDSO, though)

Microsoft should take the Windows GUI and put it over Linux as a desktop manager. Microsoft could sell the Windows GUI for Linux users that want to run Windows apps.

Still considering the whole system, an instable user kernel interface has few advantages and tons of drawbacks. MS is extremely late to the chroot and then container party because of that (and let's remember that the core technology behind WSL emerged because they wanted to solve the chroot aside userspace system on their OS in the first place, NOT because they wanted to run Linux binaries) -- so yet another point why classic NT subsystems are useless.

Back to core kernel stuff, IRQL model is shit. Does not make any sense when you consider what really happens, and you can't really use arbitrary multiple levels. It seems cute and clean and all of that, but Linux approach of top and bottom halves and kernel and user threads might seem messy but is actually far more usable. Another point: now everybody uses multiprocessor computers, but back in the day the multiple HAL were also a false good idea. MS recognize it now and only want to handle ACPI computers, even on ARM. Other OSes do all kind of computers... Cutler pretended to not like the "everything is a file" approach, but NT does basically the same thing with "everything is a handle". And soon enough, you hit exactly the same conceptual limitations (except not in the same places) that not everything is actually the same, so that cute abstraction leaks soon enough (well, it does in any OS).

On a more result oriented approach, one of the things WSL makes clear is that file operations are very slow (just compare an exactly identical file heavy workload under WSL and then under a real Linux)

So of course there are (probably) some good parts, like in any mainstream kernel, but there are also some quite dark corners, and I am not an expert about all architectural design of NT but I'm not a fan of the parts I know, and I strongly prefer the Linux way to do equivalent things.

That's particular interesting now that SQL Server has been ported to Linux. Would be funny if they're going to use the Linux subsystem on Windows too.

Although I suspect SQL Server already talks to the kernel directly.

This is what I am looking forward to with WinRT, hence why Rust should make it as easy as C++/CX and C# to use those APIs. :)

An old HN commenter once wrote (mrb)

> There is not much discussion about Windows internals, not only because they are not shared, but also because quite frankly the Windows kernel evolves slower than the Linux kernel in terms of new algorithms implemented. For example it is almost certain that Microsoft never tested I/O schedulers, process schedulers, filesystem optimizations, TCP/IP stack tweaks for wireless networks, etc, as much as the Linux community did. One can tell just by seeing the sheer amount of intense competition and interest amongst Linux kernel developers to research all these areas.

>The net result of that is a generally acknowledged fact that Windows is slower than Linux when running complex workloads that push network/disk/cpu scheduling to its limit: https://news.ycombinator.com/item?id=3368771 A really concrete and technical example is the network throughput in Windows Vista which is degraded when playing audio! https://blogs.technet.microsoft.com/markrussinovich/2007/08/...

>Note: my post may sound I am freely bashing Windows, but I am not. This is the cold hard truth. Countless of multi-platform developers will attest to this, me included. I can't even remember the number of times I have written a multi-platform program in C or Java that always runs slower on Windows than on Linux, across dozens of different versions of Windows and Linux. The last time I troubleshooted a Windows performance issue, I found out it was the MFT of an NTFS filesystem was being fragmented; this to say I am generally regarded as the one guy in the company who can troubleshoot any issue, yet I acknowledge I can almost never get Windows to perform as good as, or better than Linux, when there is a performance discrepancy in the first place.

"Russia Factory for England" most likely exists inside of Russia and is for the English.

"John's mail for Sally [try: who is out of town]" even with the addition, I presume that John has authored mail for Sally and is not collecting the parcels to give to her.

Here's a trickier one:

"Sampsons' Dinner for Two". This could be the following:

1. A product named "Sampsons' Dinner for Two" bought from a retail store

2. An item "Dinner for Two" on a menu from a restaurant named "Sampsons"

3. A place named "Sampsons' Dinner for Two" with only two-person tables.

4. A product "Sampsons' Dinner" which comes in multiple sizes, one of them being designed for two people. (which is the ambiguous form - presuming there's also say Annie's Dinner for One/Two and Martha's Dinner for One/Two - each with a brand specific cuisine). Even here though, the ownership of which "Dinner for Two" product is still clear - it's the "Sampsons'" or "Martha's" brand.

Regardless of what kind of substitution, we go back to "Windows Subsystem for Linux" for the most part parsing as

"Windows [Subsystem for Linux]" like "Windows [Media Player]". I don't assume that it's "[Windows Media] Player" - as in some multi-platform software that is tasked with playing the proprietary windows media formats.

It seems weird, but I think it's unarguably the right choice.