FYI: "FSF work on a GNU OS" posted to comp.arch

Curtis Yarvin cgy at cs.brown.edu
Sat May 11 03:00:36 AEST 1991


In article <110 at fbits.ttank.com> Mariusz at fbits.ttank.com (Mariusz Stanczak) writes:
>In article <1991May8.035642.28195 at cs.yale.edu>, yarvin-norman at cs.yale.edu (Norman Yarvin) writes:
>> The problem with this that the Mach 'microkernel' is about as big as the
>> entire 3b1 OS, and then some monster compatible with 4.4BSD is to run as a
>> process on _top_ of that.  There is no way it will fit in a 3b1.
>
>Well Norman, you must be more in the known, and I have not seen the code,
>but all that I have read about the effort (Mach microkernel, not GNU kernel),
>its design goals, and the intent/idea behind it (on a theoretical level)
>left me with a completely different picture.  One of the pieces I read (about
>the differences between Mach kernel, and the future microkernel [I think in
>CTR]) mentioned a 1000 line C code for the whole thing.

Your decimals need some work.

We have Mach 3.0 code here.  Note that this is NOT the version with BSD
wedged into the kernel.

Kernel source alone is about 100,000 lines of code.  This does not include
any of the machine-specific sections, which can be quite large; for example,
the i386 machine-specific code is 40,000 lines.

>True, the microkernel needs many layers glued onto it (the BSD "look&feel"
>in this case) to become an OS, but it, in itself, should be a few K's big
>for all I understand.  What do you know that leads you to believe in what
>you stated above?  It's quite a revolation(sp) to me.

I can't quote a source on this, but I believe I remember a discussion -
maybe in comp.arch - initiated by a shocked reader who booted Mach on his
386 and found it was 300k.

>> The other factor to note is that this is _very_ heavy vaporware.  Even the
>> details of 4.4BSD are not yet out, mostly because it is still in the process
>> of being written.
>
>Very true, but then isn't anything that's just being started "vaporware"?
>The microkernel idea is just few years old(new), 

The idea is about ten years old.

>and OSF's implementation (with all its resources, and commitment) is a
>couple years away.

A prerelease version of OSF/1 is running quite stably on a Decstation 3100
here at Brown.  Note that OSF/1 is BSD wedged into the microkernel, not
built around it.

>I'd begg to differ... vaporware are things that are announced with a
>particular date (and usually shady intent), and then not delivered.

Vaporware is any software or hardware which has been announced but not yet
completed.

Curtis



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