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From: tk@rice-chex.ai.mit.edu (Tom Knight)
Newsgroups: comp.arch
Subject: Re: IBM 7094 II
Message-ID: <12073@life.ai.mit.edu>
Date: 28 Nov 90 04:13:12 GMT
References: <9011272349.AA25956@ucbvax.Berkeley.EDU>
Sender: news@ai.mit.edu
Organization: MIT Artificial Intelligence Laboratory
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This machine had approximately a 5 microsecond instruction time for
simple (clear accumulator) instructions.  For floating ops, I think
the time was more like 12-17 microseconds.  It used sign/magnitude
arithmetic and had a peculiar notion of a "logical" accumulator
(unsigned) and an "arithmetic" accumulator which included a sign bit.
These registers shared 35 of the 36 bits, only the MSB differed.  CLA
cleared the arithmetic accumulator, CAL cleared the logical
accumulator.  The machine had some very specialized instructions,
highly non-Risc like, such as TRQ (translate by replacement from MQ)
which could be used (it was said) to make COBOL more efficient.  It
was a predecessor of the 360 Edit and Translate instructions.

Almost all machines had a full address space consisting of 32K words.
The machines at MIT running CTSS had a second core bank of 32K words
which held the operating system and I/O buffers, but user programs
couldn't access it.

The major programming languages were MAD (Michigan Algorithmic
Decoder), Fortran II, and FAP (Fortran Assembly Program).

For all you FAP programmers out there: TSX $EXIT,4