The following message is a courtesy copy of an article that has been posted to bit.listserv.ibm-main as well.
[EMAIL PROTECTED] (Chris Mason) writes: > ... and thereby put the wait light out[1]. Having been brought up with > DOS (the original DOS), and, generally, S/360 Model 30s, I was used to > knowing how busy the machine was by observing the flickering of the > wait light. my first undergraduate programming job was to port MPIO from 1401 to 360/30. MPIO provided tape<->unitrecord/printer/punch front-end for university 709 running ibsys. it was possible to operate the 360/30 in 1401 emulation mode ... so i conjecture that the exercise was purely to get familiarity with new 360 ... which would eventually replace both the 709 and the front-end machine with 360/67. i got to design and implement my own monitor, device drivers, interrupt handlers, storage management, consol interface, etc ... and eventually had assembler program with approx. 2000 cards. running os/360 pcp (r6) ... the "stand-alone" version assembled in about 20-25 minutes elapsed time. I had conditional assembly that would also generate program that would run under PCP and used open/close and DCB macros. There were five DCB macros and you could tell from the wait light pattern when the assembler was processing a DCB macro ... and each one took 5-6 minutes elapsed time ... the os/360 conditional assembly version took an extra 30minutes (making the assembly nearly an hr total). ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
