[SunRescue] any 3B2 users out there?

[Greg A. Woods]

[ On Wednesday, March 21, 2001 at 18:08:29 (EST), dave at cca.org wrote: ]
> Subject: Re: [SunRescue] any 3B2 users out there?
>
> A 3B2/300 (entry level) running SVR3.2 (circa mid-80s, if I'm not mistaken?)
> certainly didn't have that problem. I used to do 2Kx2K bitmap manipulations
> on mine, which had 2 meg of ram. It was *definately* swapping. :-)

It was probably still just paging, albiet heavily -- at least unless you
were also running a couple of instances of emacs and unpacking a small
newsfeed at the same time...  :-)

> That's an interesting question though - I don't know when AT&T caught up
> with BSD on the paging front.

AT&T beat the living daylights out of BSD on the demand-paging VM front
way back in the late 1980's, and of course BSD as released by CSRG never
really caught up again until 4.4BSD.  The biggest feature AT&T added was
this nifty feature called "copy-on-write".  BSD had vfork(), and indeed
vfork() can still save some time in some circumstances even with
copy-on-write, but still....

Eventually with 4.4BSD the CSRG folks picked up the Mach-2.x VM and
re-hacked its internal interfaces to their liking.  It's not a bad VM
system, and nicely portable, but not all that great for production
uses (it was never fully debugged and would never handle overload
gracefully).

Sun and AT&T went even further with the VM that's in SysVr4.2 and
Solaris -- in its later forms it's really quite a spectacular invention.

Of course the "free" *BSD folks had to start out with the Mach VM that
was in 4.4BSD.  Now the FreeBSD folk have their own new VM, and NetBSD
has its own new "uvm" (now with a unified buffer cache), and I'm not
sure what the OpenBSD guys are doing....

-- 
							Greg A. Woods

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