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Path: utzoo!watmath!clyde!burl!ulysses!harpo!seismo!mo
From: mo@seismo.UUCP (Mike O'Dell)
Newsgroups: net.unix-wizards
Subject: 1620 emulator
Message-ID: <1247@seismo.UUCP>
Date: Sat, 5-May-84 10:34:52 EDT
Article-I.D.: seismo.1247
Posted: Sat May  5 10:34:52 1984
Date-Received: Sat, 12-May-84 07:48:15 EDT
Distribution: net
Organization: Center for Seismic Studies, Arlington, VA
Lines: 23

While this discussion should probably be moved to net.arch, one passing
thought...

I too cut my first chops on a venerable 1620 and am quite fond of that
machine.  The software for it was pretty amazing, considering the
vintage and the table-driven hardware.  Anyway, I have on and off given
thought to building an emulator running on, say, a 68K system.  This isn't
very hard architecturally; 1620 I/O is synchronous (yes, that's right)
and a byte would store a digit just fine.  I suspect a 10-Meg 68K
could software-emulate a 1620 faster than the 1620 can.  Anyway,
there are some very strange things in the instruction set that I never
did master, even with the hardware manual, and would be worried about having
a precise enough description of the machine to work with.  

BTW - the machine I learned on was a Model 1 with Indirect Addressing,
hardware Floating Point, Transmit Numeric Strip and Fill, Record hardware,
40,000 digits of memory, a 1443 buffered printer, the usual card read/punch,
and 2, count 'em, 2 1311 disk drives!  That machine was a genuine Cadillac.
No machine I have used since has been as amply configured, based on what
was state-of-the-art in the machine's heyday and how richly the machine
could be configured.

	-Mike O'Dell