From: J Ahlstrom Newsgroups: alt.folklore.computers,comp.arch Subject: IBM 1620 Date: Wed, 25 Apr 2001 10:44:12 -0700 Organization: Cisco Systems Inc. Message-ID: <3AE70CEB.5F8FCC91@cisco.com> X-Mailer: Mozilla 4.76 [en]C-CCK-MCD (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cache-Post-Path: sj-nntpcache-3!unknown@dhcp-171-68-135-147.cisco.com X-Cache: nntpcache 2.4.0b2 (see http://www.nntpcache.org/) X-Complaints-To: newsabuse@supernews.com Lines: 60 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.ifi.unizh.ch!news.imp.ch!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.stanford.edu!sn-xit-01!sn-post-01!supernews.com!corp.supernews.com!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:79299 Stan Mazor asked me to post this. I programmed the ibm 1620 for more than 3 years both in machine code, assembler, and Fortran in 1962-1964 and here is what I recall from my memory. the core memory had 12-bits per 'word' and held 2 decimal digits, but the memory had a decimal address for each digit. the digits bits were: 8 4 2 1 P F, (parity and flag). Fields were a minimum of 2 digits as addressed by the lower addressed location and terminating in the upper digit when the field marker was reached. hence the minimum data field was 2 digits: 00 to 99. Negative integer was representd by the flag over the least significant digit; therefore you couldn't have a single flagged digit, but you could have 2 digits in sequence with flags for field operations. instructions: add, subtract, compare and move field worked on these variable length data fields terminated when the field marker was encountered and worked from low digit to high digit propagating carry. records (move record) operated on multiple fields and were terminated by a field mark which was encoded using the 6-bits (don't recall the coding). Alphanumeric data was represented as 12-bits and represented as 2 digits, e.g. 'A' = 41. 2 instructions converted decimal digits to characters (transfer numeric field) or transferred characters to numeric data (transmit numeric strip). There may have been an instruction: move character that allowed the moving of a single decimal digit. Since I worked on both the IBM 1620 and Model 2 which had enhanced instrution set and indexing registers...I'm not sure about move character. thx. stan Stanley Mazor, Director Customer Services Numerical Technologies Inc. 70 West Plumeria Drive San Jose, Ca., USA, 95134-2134 408-273-4485 fax: 408-919-1920 email: smazor@numeritech.com Safe Harbor: this message is not -- The harder I work, the luckier I get. (various including Edison, Plato, Gary Player, Sam Goldwyn) ###### From: Howard S Shubs Newsgroups: alt.folklore.computers,comp.arch Subject: Re: IBM 1620 Date: Wed, 25 Apr 2001 23:10:19 -0400 Organization: ='SEQUENTIAL' Lines: 11 Message-ID: References: <3AE70CEB.5F8FCC91@cisco.com> NNTP-Posting-Host: p-520.newsdawg.com User-Agent: MT-NewsWatcher/3.1 (PPC) X-Face: "S"r{U%bs].&Ud}Pc~~~0a]M:t5l>>EN\1Faw10M9NK1Xq59wo7-"s0S+[{etQorO /Nf-Ci"i9v'MT!R8)J]N[4|2&x1r^Iq&{SB"6dknr0=+6UFb.>+{zMn_1=rw&/V+"d@* ZS5\LoW_ Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.ifi.unizh.ch!news.imp.ch!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.direct.ca!look.ca!pln-w!spln!dex!extra.newsguy.com!newsp.newsguy.com!hshubs Xref: chonsp.franklin.ch alt.folklore.computers:79368 In article <3AE70CEB.5F8FCC91@cisco.com>, J Ahlstrom wrote: > Since I worked on both the IBM 1620 and Model 2 > which had enhanced instrution set and indexing > registers...I'm not sure about move character. Are y'all involved with the restoration project? -- Howard S Shubs The Denim Adept ###### Newsgroups: alt.folklore.computers,comp.arch Subject: Re: IBM 1620 References: <3AE70CEB.5F8FCC91@cisco.com> X-Newsreader: NN version 6.5.6 (NOV) From: jot@visi.com (J. Otto Tennant) Lines: 34 Message-ID: <9c3G6.19460$9f2.1515513@ruti.visi.com> Date: Fri, 27 Apr 2001 00:38:29 GMT NNTP-Posting-Host: 209.98.98.8 X-Complaints-To: abuse@visi.com X-Trace: ruti.visi.com 988331909 209.98.98.8 (Thu, 26 Apr 2001 19:38:29 CDT) NNTP-Posting-Date: Thu, 26 Apr 2001 19:38:29 CDT Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.ifi.unizh.ch!news.imp.ch!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!feed.nntp.primus.ca!feed.nntp.primus.ca!hermes2.visi.com!news-out.visi.com!ruti.visi.com!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:79463 Howard S Shubs writes: >In article <3AE70CEB.5F8FCC91@cisco.com>, > J Ahlstrom wrote: >> Since I worked on both the IBM 1620 and Model 2 >> which had enhanced instrution set and indexing >> registers...I'm not sure about move character. >Are y'all involved with the restoration project? "Restoration project?" I'd like to know more about it. Some years ago, I thought about writing a 1620 emulator, but I decided it was too tedious. And I'm not too sure about "restoration." I suspect that Rice University's home grown FLAG (Fortran Load And Go) compiler source has long since been eaten by mice or sent to a land-fill. It is odd what one remembers. When FLAG crashed, one would enter 4914584 (a branch to 14584) to restart it (the damage not being too severe.) Before I got bored and/or intimidated, I thought about using this exercise to learn X and produce a graphic representation of the 1620 main panel. >-- >Howard S Shubs The Denim Adept -- J.Otto Tennant jotto@pobox.com Forsan et haec olim meminisse juvabit. Charter Member of the Vast Right Wing Conspiracy ###### From: jfrancis@dungeon.engr.sgi.com (John Francis) Newsgroups: alt.folklore.computers,comp.arch Subject: Re: IBM 1620 Date: 27 Apr 2001 18:05:00 GMT Organization: Silicon Graphics, Inc., Mountain View, CA Lines: 19 Message-ID: <9ccccc$3ma15$1@fido.engr.sgi.com> References: <3AE70CEB.5F8FCC91@cisco.com> <9c3G6.19460$9f2.1515513@ruti.visi.com> NNTP-Posting-Host: dungeon.engr.sgi.com X-Trace: fido.engr.sgi.com 988394700 3876901 130.62.53.248 (27 Apr 2001 18:05:00 GMT) X-Complaints-To: news@fido.engr.sgi.com NNTP-Posting-Date: 27 Apr 2001 18:05:00 GMT Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.ifi.unizh.ch!news.imp.ch!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.direct.ca!look.ca!newshub2.rdc1.sfba.home.com!news.home.com!enews.sgi.com!fido.engr.sgi.com!dungeon.engr.sgi.com!jfrancis Xref: chonsp.franklin.ch alt.folklore.computers:79472 In article <9c3G6.19460$9f2.1515513@ruti.visi.com>, J. Otto Tennant wrote: >Howard S Shubs writes: > >>In article <3AE70CEB.5F8FCC91@cisco.com>, >> J Ahlstrom wrote: > >>> Since I worked on both the IBM 1620 and Model 2 >>> which had enhanced instrution set and indexing >>> registers...I'm not sure about move character. > >>Are y'all involved with the restoration project? > >"Restoration project?" I'd like to know more about >it. Some years ago, I thought about writing a >1620 emulator, but I decided it was too tedious. The Computer Museum History Center has a restored, working 1620 (mostly original components, with a few parts being emulated). ###### From: jsavard@ecn.ab.SBLOK.ca.nowhere (John Savard) Newsgroups: alt.folklore.computers,comp.arch Subject: Re: IBM 1620 Message-ID: <3aeccb27.1567735@news.powersurfr.com> References: <3AE70CEB.5F8FCC91@cisco.com> <9c3G6.19460$9f2.1515513@ruti.visi.com> X-Newsreader: Forte Free Agent 1.11/32.235 Lines: 14 Date: Mon, 30 Apr 2001 02:18:30 GMT NNTP-Posting-Host: 24.108.184.50 X-Complaints-To: abuse@powersurfr.com X-Trace: news-rep.ab.videon.ca 988596903 24.108.184.50 (Sun, 29 Apr 2001 20:15:03 MDT) NNTP-Posting-Date: Sun, 29 Apr 2001 20:15:03 MDT Organization: Videon CableSystems Alberta Inc. Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!codeine.org!news.stealth.net!nntp1.njy.teleglobe.net!teleglobe.net!cy2!newsfeed.shawcable.com!news-rep.ab.videon.ca!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:79572 On Fri, 27 Apr 2001 00:38:29 GMT, jot@visi.com (J. Otto Tennant) wrote, in part: >Before I got bored and/or intimidated, I thought >about using this exercise to learn X and produce >a graphic representation of the 1620 main panel. Which reminds me; in the movie "Colossus: The Forbin Project", although mostly Control Data equipment was used for the scenes in the movie, a couple of IBM 1620 front panels also appeared there. (They were the panels with the big round pointer knob on them.) John Savard http://home.ecn.ab.ca/~jsavard/crypto.htm