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Cyhist Apr 7 1997 B
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Date: Mon, 7 Apr 1997 12:22:44 -0500
Reply-To: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> Sender: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> From: Don Hyde <dhyde@BDCAST.COM>
Subject: Re: 1620 (Operating vintage computers as a hobby)
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Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
I haven't seen a 1620 in many years, but the mention of it brings back fond memories of that rather modest computer.
My encounter occurred when I was a freshman at Miami-Dade Junior College in about 1968 or '69. Its main attraction was that it was old and boring next to the spiffy new 360-20 on the other side of the glass partition, so they would let me actually TOUCH it. In fact I soon convinced the lab operators that I wasn't going to break it and spent many happy hours alone in the lab playing with it.
I don't remember the course I signed up for to get into the computer lab -- probably Fortran (which I had already learned using stolen computer time when I was in high school), but I spent most of my time messing around learning 1620 machine language -- you could punch it directly into a card and some sort of a boot load switch would read the card directly into memory and execute it. It was pretty funky because none of the arithmetic instructions would work until you loaded up the addition and multiplication tables.
I was fascinated with the possibility of loading the tables so that it would perform arithmetic in some other base than 10. Wouldn't it be a fabulous prank to leave it set up so that when the (mostly clueless) class came in, their Fortran programs would be doing arithmetic in base 13 or something? It seems like I got it to work in base 8, but that was boring, and there was some difficulty with getting it to do something really wierd like base 13.
Incidentally, the big selling feature of the 360-20 had been its ability to emulate the 1620 (and the 1401), which meant it could run all the old 1620 programs. I'm pretty sure the 1620 emulator was never actually used at MDJC, since all the software they ran on the 1620 was written in Fortran, and it was easier to recompile it.
The 360-20 emulated other machines easily because it was really an 8-bit computer that was designed to run emulators -- in fact its non-emulator mode was really just a 360 emulator. Emulation fans might find an old 360-20 interesting since that is what it was designed to do. I'll bet there were even some exotic emulators written for it back when. As I recall, Bell and Newell had an excellent description of this design, along with nice pictures of its Mylar printed-circuit ROM which was programmed with a hole puncher.
Speaking of Bell and Newell, does anybody know where I could get a decent clean copy? I sold mine years ago when I was a broke college student, and I miss it.
And now for a really obscure bit of trivia -- IBM offered the various 360 models in your choice of red, blue, or yellow. The pride-and-joy at Miami-Dade at the time was a 360-40 that was most jealously guarded by the administration's DP priests, and which I only once managed to barely glimpse through a door that was accidentally left open. It was bright yellow, and according to rumor was one of only two or three ever produced in that color.
Even though IBM is Big Blue, I think most 360's were ordered in red. I suspect it is like with sports cars -- everyone knows the red ones go faster...
Don Hyde
Broadcast Electronics, Inc.
Supplying specialized electronics and software to the radio broadcast industry.
dhyde@bdcast.com (217)224-9600 http://www.bdcast.com
______________________________________________________________________
Reply-To: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> Sender: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> From: Don Hyde <dhyde@BDCAST.COM>
Subject: Re: 1620 (Operating vintage computers as a hobby)
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
______________________________________________________________________
Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
I haven't seen a 1620 in many years, but the mention of it brings back fond memories of that rather modest computer.
My encounter occurred when I was a freshman at Miami-Dade Junior College in about 1968 or '69. Its main attraction was that it was old and boring next to the spiffy new 360-20 on the other side of the glass partition, so they would let me actually TOUCH it. In fact I soon convinced the lab operators that I wasn't going to break it and spent many happy hours alone in the lab playing with it.
I don't remember the course I signed up for to get into the computer lab -- probably Fortran (which I had already learned using stolen computer time when I was in high school), but I spent most of my time messing around learning 1620 machine language -- you could punch it directly into a card and some sort of a boot load switch would read the card directly into memory and execute it. It was pretty funky because none of the arithmetic instructions would work until you loaded up the addition and multiplication tables.
I was fascinated with the possibility of loading the tables so that it would perform arithmetic in some other base than 10. Wouldn't it be a fabulous prank to leave it set up so that when the (mostly clueless) class came in, their Fortran programs would be doing arithmetic in base 13 or something? It seems like I got it to work in base 8, but that was boring, and there was some difficulty with getting it to do something really wierd like base 13.
Incidentally, the big selling feature of the 360-20 had been its ability to emulate the 1620 (and the 1401), which meant it could run all the old 1620 programs. I'm pretty sure the 1620 emulator was never actually used at MDJC, since all the software they ran on the 1620 was written in Fortran, and it was easier to recompile it.
The 360-20 emulated other machines easily because it was really an 8-bit computer that was designed to run emulators -- in fact its non-emulator mode was really just a 360 emulator. Emulation fans might find an old 360-20 interesting since that is what it was designed to do. I'll bet there were even some exotic emulators written for it back when. As I recall, Bell and Newell had an excellent description of this design, along with nice pictures of its Mylar printed-circuit ROM which was programmed with a hole puncher.
Speaking of Bell and Newell, does anybody know where I could get a decent clean copy? I sold mine years ago when I was a broke college student, and I miss it.
And now for a really obscure bit of trivia -- IBM offered the various 360 models in your choice of red, blue, or yellow. The pride-and-joy at Miami-Dade at the time was a 360-40 that was most jealously guarded by the administration's DP priests, and which I only once managed to barely glimpse through a door that was accidentally left open. It was bright yellow, and according to rumor was one of only two or three ever produced in that color.
Even though IBM is Big Blue, I think most 360's were ordered in red. I suspect it is like with sports cars -- everyone knows the red ones go faster...
Don Hyde
Broadcast Electronics, Inc.
Supplying specialized electronics and software to the radio broadcast industry.
dhyde@bdcast.com (217)224-9600 http://www.bdcast.com
______________________________________________________________________
