Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!lll-winken!ncis.tis.llnl.gov!helios.ee.lbl.gov!nosc!crash!simpact!jeh From: jeh@dcs.simpact.com Newsgroups: comp.dcom.modems Subject: Re: 134.5 baud == IBM 2741 Message-ID: <1325.2667b8d3@dcs.simpact.com> Date: 2 Jun 90 20:02:11 GMT References: <9686@discus.technion.ac.il> <1990May31.025608.18545@Neon.Stanford.EDU> <1990Jun2.020635.28825@Neon.Stanford.EDU> Organization: Simpact Associates, San Diego CA Lines: 73 X-Local-Date: 2 Jun 90 13:02:11 PDT In article <1990Jun2.020635.28825@Neon.Stanford.EDU>, kaufman@Neon.Stanford.EDU (Marc T. Kaufman) writes: > In article kindred@telesci.uucp writes: >> Along the lines of strange baud rates, I personally have run >>into the all time favorite baud rates of 134.5 and 1050. The 134.5 >>was used in a six bit commodities ticker,... > > 134.5 was also the baud rate used by the (half-duplex) IBM 2740 and 2741 > Selectric typewriters. This works out to 14.9+ characters per second, since > they used a 9-bit code (1 start, 1 stop, 7 data - sent HIGH BIT first). Eh, not quite. These beasts used 6 data bits, plus parity. In practice the stop bit from the host was stretched a bit yielding a quoted throughput of 14.7 characters/second. I suspect that the commodities ticker referred to ran at 134.5 simply because it was hooked to an IBM host that already had async ports for that speed. > 1050 was what.. anybody.. I seem to remember Kleinschmidt reperforators > (tape punches) running at that speed. > > Marc Kaufman (kaufman@Neon.stanford.edu) 1050 used to be widely used for "high speed" wire feeds to newspapers. And, yes, some of them used Kleinschmidt gear. The newspaper would receive the stuff on punched paper tape and then feed the tape directly to their typesetter. In later days, of course, the stuff fed directly into the computer for editing. Coincidentally, "1050" was also the series number for several pieces of IBM equipment that collectively behaved sort of like an ASR 2741. There was a separate printer, keyboard, paper tape punch, p.t. reader, and also a card reader. All running at 134.5 bits/sec. Switches on the front of the printer connected the various items to each other, in various combinations for example you could be copying one tape to another "off line" while carrying on a dialog with the host computer via the keyboard and printer. As Jerry mentioned in another posting, both the IBM 2741 and the 1050 were an m.e.'s dream. (As are many pieces of IBM gear. Compare a typical high- speed IBM punched card reader to a Soroban unit; you'll find enough moving parts in the IBM unit to make at least five Sorobans.) They were NOT, as is commonly believed, Selectric mechanisms in different cases; the printers were far more rugged than those in the office Selectric. Early DEC RSTS timesharing systems supported the 2741, probably for the same reason that TOPS-10 did: The 2741 was, for many years, the only way that most folks could get what we now call letter-quality output out of a computer. (The 2741 was around in the mid-60s and so predated daisy-wheel printers and terminals by at least 10 years.) The large amount of DEC documentation that used to be printed in typescript, with an IBM Courier typeface, should tell you something. I used one of these RSTS systems (with Ascii terminals) at Cal Poly Pomona in the late 70s. A favorite way for clowns to lock up a terminal port was to type "SET TERMINAL 2741" and walk away... there of course being NO way to type the command to set the port back to Ascii, or to log out for that matter, without hooking up a 2741 to the line... and of course there were no 2741's available anywhere. Eventually the systems people would notice the dead port and fix it. After several months of complaining about this, with no response, I got desperate enough to post the following message on the state-college-wide computer bulletin board: "Please do NOT type the command SET TERMINAL 2741 on any RSTS port. This will make the port unusable until corrected by the local system manager." Needless to say, this caused lots more people to try SET TERMINAL 2741, and the command was taken out of the command tables within a week. --- Jamie Hanrahan, Simpact Associates, San Diego CA Internet: jeh@dcs.simpact.com, or if that fails, jeh@crash.cts.com Uucp: ...{crash,scubed,decwrl}!simpact!jeh