Pedantry - it's an emulator, not a simulator. > Did the 1401 have a program timer?
No. It had no program-accessible "clock". It didn't know clock time at all, and dates were input via date cards that were application-specific. In most senses, there was no operating system and no supervisor. Any exceptional conditions were spotted simply: a) it stopped b) a peripheral had a light on, or some equally obvious state. There was, in the conventional sense and on the majority of systems, no console. There was a backlit panel, and next to it was a swing-out gate that let you do highly illegal things with the tape units. I can still close my eyes, reach for the little flap at the top of that gate, flip it upwards, reach in and squeeze the gate lock, and pull the gate forward and down. I must have done it thousands of times. In the early days of System/360, the great and infallible IBM shipped "Series 500" 2400' tapes from the plant with no tapemarks. I spent hour after happy hour mounting these tapes on 7330s attached to a 1401, dialing up each unit in turn, and flipping the "Write Tape Mark" switch. Whole shifts, sometimes. System reset, check reset, start. And what no one ever seems to mention - the 1401 had a _unique_ smell. And it was good for drying wet trainers. The 1406 Memory Extension Unit was just the ideal height for a standing four-handed card game. And even coffee-proof. You don't get that from an emulator. Back then, the operators used to reuse tape trimmings by taping them to the tops of all grey boxes so the fans made them stream upwards. If you saw one down, the fan had failed - call your friendly CE. We gave CEs free parking spots, free canteen meals, free coffee. Never had to look far for one. -- Phil Payne http://www.isham-research.co.uk +44 7833 654 800 ---------------------------------------------------------------------- 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
