Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!think!paperboy!curley!meissner
From: meissner@curley.osf.org (Michael Meissner)
Newsgroups: alt.folklore.computers
Subject: Re: Y VAX? [was : TECO on a DEC-System 10]
Message-ID: <2839@paperboy.OSF.ORG>
Date: 18 Jan 90 22:22:56 GMT
References: <153.UUL1.3#5131@mvac23.UUCP> <457@ns-mx.uiowa.edu> <1990Jan18.193530.22427@utzoo.uucp>
Sender: news@OSF.ORG
Reply-To: meissner@curley.osf.org (Michael Meissner)
Organization: Open Software Foundation
Lines: 28

In article <1990Jan18.193530.22427@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>In article <457@ns-mx.uiowa.edu> jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H MLH,3193350740,3193382879) writes:
>>                         (the 11/15 was the OEM version of the 11/20?)
>
>Correct.
>
>>                         (the 11/40 was the OEM version of the 11/45?)
>
>Nope, quite unrelated.  (The 45's number has always been a bit of a
>mystery.)  The 40 was a cheaper, slower, cut-down 45 -- the new "mid-range"
>model to replace the 20 -- and originated the brain-dead low-end version
>of the MMU.

The '40 also had a completely different floating point unit.  I
remember well watching a V6 PDP-11/40 emulate the PDP-11/45 floating
point via SIGFPU (you could watch the console lights to tell when a
stat program was running).

I remember one summer writing standalone code that needed to run on an
LSI11-03, PDP-11/40, and a simulated PDP-11/70 running on a K?-10, and
the only way I could mask out interrupts between each of the different
PDP's was to push an address to jump to and the new interrupt mask on
the stack and do a return from interrupt instruction (yech!).

Michael Meissner	email: meissner@osf.org		phone: 617-621-8861
Open Software Foundation, 11 Cambridge Center, Cambridge, MA

Catproof is an oxymoron, Childproof is nearly so