On Tue, 24 May 2016, Jon Elson wrote: > The PDP-5 I did a fair bit of work on needed a bootstrap program loaded > in from switches, it had no internal ROM for that.
How long did it usually take to do it? > And, whenever a program crashed, it generally wiped the entire contents > of memory, so the boot had to be reloaded by hand. Uhh, ouch! That'll learn ya! You'd better be a careful coder, then I guess. Sheesh. > So, that was a big advance, a one-button boot. Man, it seems so elementary now. Everything had to be invented sometime, I suppose. > You could use the switches to patch a program you were debugging, look > at memory locations to examine temporary data values, etc. It seems like that'd make working with computers a lot more "intentional" if you know what I mean. > A few machines had lighted switches. These would generally be white > buttons with lamps behind them. Hmm, so not as cool as 60's and 70's TV and movies seemed to suggest. Still at least it did happen. :-) > The only one I know of that changed color was the power button ("key" in > IBM-speak) on IBM 360's. Heh, my grandmother was a Cobol programmer on IBM 360s for Western National Gas (now Diamond Shamrock). She had mixed feelings about them, but she said they had a decent development environment vis-a-vis some of the competition at the time. > IBM tape drives and disk drives had lighted buttons to show status, > different color buttons and indicators gave them different colors, but > they were generally just lit and unlit, but not multi-color. Hmm, yeah, I seem to remember some similar style lights on old TEAC reel-to-reel audio gear from that era, too. > DEC PDP machines generally had a few switches that were multi-position, > Such as stop/single-step and load address/examine, otherwise they were > all on-off. Those multi-position switches are really cool. They remind me more of avionics style controls (which always seem to be the nicest physical gear in terms of build quality). -Swift