Old PCsenvironmental hazard 3240

there were generally two different kinds of things referred to as IPL "warm start". one tried to scavanage old data laying around in memory at the time of the reboot and save it as part of restarting. the other was slightly analogous to fsck in unix ... although significantly faster and involving significantly less information.

when recoverable information needed by either process was too messed up, you fell back to a cold start.

search engine is your friend ... here is more detailed description of ipl, nip, and hasp with os-360 (predating hasp being renamed jes2 which managed the spool and the job queue; and os-360 being renamed mvs).

cold-warm was when you had gotten to the hasp initialization phase of system startup and had to reply warm-cold.

a little more overview:

various past postings mentioning hasp

it took quite awhile before os-360 got alternate console support. I remember having the whole system to my self on weekens and the system coming to a griding halt and ringing the bell. nothing would work. even rebooting-reipl just resulted in the bell ringing. i would eventually bang on the 1052-7 operator's console in frustration and the fan-fold paper would fall out the back of the 1052-7 ... and it was obvious the the system was waiting for new paper to be feed into the console.

the 1052-7 had a little finger sensor for when it ran out of paper ... and it would present "unit check", "intervention required" i-o error in response attempting to write to the console. the system then would ring the bell and wait until the operator and feed a new stack of paper into the operator's console.

it turns out that it was possible for the end of the paper feed to move past the finger sensor ... but it was sometimes positioned just so that the paper didn't actually finish falling out. from the front of the operator's console it still looked like it had good supply of paper. it wasn't until you banged in frustration on the keyboard that it jiggled the mechanism and the paper fell out (and then it was obvious what the problem was).

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