On: One Windows Kernel

[rayiner]

Solaris doesn't scale down to cell phones, and Darwin doesn't scale up to 896-core servers. Linux does scale like that, but Linux is pretty unusual in that regard too.

[detuur → rayiner]

That is actually a really good point. At the end of the day there are many, many kernels out there and only Linux, BSD, and NT scale from all the way at the bottom to all the way at the top. I actually even recall my scepticism when MS announced Windows for IoT platforms (not that this scepticism has abated, though).

[clhodapp → detuur]

Windows doesn't scale down quite as far and thus Microsoft's lastest answer for IoT is actually Linux: https://en.wikipedia.org/wiki/Azure_Sphere

[wvenable → clhodapp]

https://developer.microsoft.com/en-us/windows/iot

[icebraining → wvenable]

According to https://docs.microsoft.com/en-us/windows-hardware/design/min..., IoT Core needs 256MB of RAM. The Azure Sphere will run on 4. So that seems to validate that it can't actually scale down quite as far.

[pjmlp → clhodapp]

If you ever bothered to watch Sphere talks, the reason has nothing to do with scale, rather with OEMs, licensing and access to source code for customization.

[icebraining → pjmlp]

Or so they claim. Has anyone actually seen NT running on the MT3620 or equivalent? Can it run with 4 MB of RAM?

[pjmlp → icebraining]

Windows has an HAL, already targeted multiple architectures, and once upon a time 4 MB were good enough for NT.

Likewise making Linux fit into the same hardware I used for Slackware 2.0 is an exercise playing Tetris with source code.

[einr → pjmlp]

Windows NT 3.1, the first version, required 12 MB RAM.

[pjmlp → einr]

I wonder how it run on my humble P75 then.

[einr → pjmlp]

You must have had at least 12 MB of RAM ;)

The installer flat out refuses to continue if it detects less memory than that.

[pjmlp → einr]

I surely did not had more than 8 MB.

Got 32 MB with the P166 that I bought a couple of years later.

So even if I got it wrong on the 4MB recollection. That computer did not have those 12 MB.

[clhodapp → pjmlp]

Perhaps you had 16 megabytes of memory? It's a bit tough going but my research seems to show that in-period, people commonly ran Pentium 75 systems with anywhere between 8 and 32 megs of RAM.

[pjmlp → clhodapp]

I had 8 MB, got 32MB when I bought a P166 years later.

[jplayer01 → clhodapp]

What? There's been a Windows kernel for handheld devices since at least the late 90s/early 2000s.

[garaetjjte → jplayer01]

That was WinCE with its own kernel, not NT. (NT kernel on mobile devices is relatively recent, from Windows Phone 8)

[jplayer01 → garaetjjte]

Huh, you're right. I must've misremembered, since I was previously aware what a disaster the CE->NT move was on Windows Phone.

[Const-me → jplayer01]

I don't remember any issues. WP7 backward compatibility was very good on WP8, in WP7 they didn't supported any native code, it was all .NET so kernel change didn't matter.

[jplayer01 → Const-me]

One problem was all the phones that were sunsetted and never got the NT-based version, even though it was promised that many phones would get it.

Also, comments by the Windows head and others who say internally it was a nightmare.

[pjc50 → rayiner]

Solaris hasn't been scaled down to cellphones, but remember that today's cellphone is yesterday's high performance workstation. A Raspberry Pi outperforms a SPARCStation20: http://eschatologist.net/blog/?p=266

Windows also used to scale down quite well; I'd love to know how much really was common between NT and CE.

[icedchai → rayiner]

I'm skeptical. In the 90's, Solaris ran on boxes with 16 megs of ram, just like NextStep. It could easily scale to run on today's phones... if there was a reason.

[CyberDildonics → rayiner]

Are there servers with that many cores? I only know about Xeon Phis and 8 socket xeon servers that go up to around 160 cores / 360 threads/logical cores

[snazz → CyberDildonics]

Apparently it's a 32-socket system with Xeon Platinum 8180s in each socket. There's an article from Anandtech[0] in response to the blog post:

[0]: https://www.anandtech.com/show/13522/896-xeon-cores-in-one-p...

[rayiner → CyberDildonics]

Skylake-SP will do glueless UPI to 224 cores (8x28). HP SuperDome Flex scales up to 32 sockets (896 processors) using a custom interconnect based on SGI’s NUMAlink.

[snoman → CyberDildonics]

That's what the article is about. It has a screenshot of one with 1792 logical cores.