glen herrmannsfeldt <g...@ugcs.caltech.edu> writes: > Note, for example, the IBM 2741 does not use EBCDIC, but its > own code, with its own control characters.
but all the 2741 characters were defined in EBCDIC. when cp67 was installed at the univ in jan68 ... it had 2741 and 1052 terminal ... but the univ. had some number of tty/ascii terminals. I had to add tty/ascii support ... and there were some number of chars in tty that weren't ebcdic and vis-a-versa ... which resulted in translation issues. cp67 also had automatic termainl identification for 1052/2741 ... so i added tty support in a way to preserve automatic terminal identification for all three terminals types. I then wanted to have single dialup number with common "hung group" (pool) for all three terminal types. problem was that ibm terminal controller allowed for changing line-scanner for each port ... but hardwired line-speed. this somewhat motivated univ to start clone controller effort, reverse engineer channel interface and build controller interface card for interdata/3 (mini-computer) ... programmed to simulate mainframe terminal controller ... supporting both dynamic terminal type and dynamic line-speed. later four of us got written for (some part of) clone controller business (interdata picked up support and marketed it, continued after interdata was purchased by perkin-elmer). misc. past post mentioning clone controller business http://www.garlic.com/~lynn/subtopic.html#360pcm clone controller business was then major motivation for future system activity ... misc. past posts http://www.garlic.com/~lynn/submain.html#futuresys tale about 360 was originally going to be ascii ... but learson made one of the biggest mistakes of 360: http://www.bobbemer.com/P-BIT.HTM i had 2741 at home from mar70 until 1977 ... when it was replaced with 300baud cdi miniterm ... pictures of old 2741 apl typeball http://www.garlic.com/~lynn/aplball.jpg http://www.garlic.com/~lynn/aplball2.jpg 2741 wiki http://en.wikipedia.org/wiki/IBM_2741 from above ... 2741 code controlled tilt/rotate of the typeball (selecting the characters on surface of the typeball) so dynamic terminal type for 2741 ... differentiated 2741 from 1052 (and i added tty/ascii) ... selecting the corresponding controller line-scanner. then the software used default 2741 translate table on initial login ... and assuming first letter "l" ... however, if the first letter was "y" ... then reversed translated and retranslated with alternate translate table ... and again checked for "l" (actually checked for both uppercase and lowercase letters). -- virtualization experience starting Jan1968, online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
