On Fri, 13 Jan 2017 18:23:13 -0500, Randy Hudson wrote: >In article <[email protected]> Edward Finnell wrote: > >> I started at Southern Bell Co-op student in '66 on a 33ASR writing Basic >> Programs on I think it was a GE635 at one of the Banks in Atlanta. > >BASIC? I think Dartmouth BASIC was created around 1964, but I didn't >realize it was used in banking by 1966. > >> There were eight holes but the 4th from left was the sprocket feed. If >> you put the tape in upside down it would saw it in two. > >As I recall it, there were 8 possible holes punched, and a smaller >pinfeed/timing hole, on the ASR-33. In theory, the 8th data hole was to be >used for parity, though the ASR-33 punched 7-bit ASCII plus an always-on 8th >bit by default. > >> https://en.wikipedia.org/wiki/Teletype_Model_33 >> IIRC, and wikipedia seems to confirm, TTY-33 automatically generated even parity automatically. One could cause incorrect parity by pressing too many modifier keys (SHIFT, CTRL?) simultaneously. Some 8-bit UARTs used that 8th bit as a DATA READY flag, thus the "always-on" perception. It would have taken at least one more instruction to clear it.
For transmitting, the TTY-33 used wall electric power only to turn a motor; everything else was mechanical, or powered by the data lines. >> One of my early adventures was converting the Long lines accounting tapes >> to punch cards on an 029. It was like cloak and dagger as to what pins did >> what. We couldn't show the IBM guy our manual and he couldn't show us his. >> After a couple of attempts cooler heads prevailed and the IBM guy says I'm >> going for coffee and left his 029 manual open to the pin-out diagram. When >> he came back the 029 was punching cards. > Early 029 or late 026 era? -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
