4 ms·

Great story. My somewhat similar one: In the early ‘50s my mother took the one and only computer class her university offered. At one point a guy from the loca

by jmull 7y ago

Great story. My somewhat similar one: In the early ‘50s my mother took the one and only computer class her university offered. At one point a guy from the local defense contractor comes in (!) and essentially offers everyone in the class with a half-decent grade a job at the end of the year. She took them up on it and that’s how she got into computers. She also claims she used to manually bootstrap a computer using toggle switches to initiate a loader and then feed it punch cards (when not in use, kept in a card-catalog cabinet like libraries used to have). I guess I shouldn’t doubt it too much. She did used to bring old (some used!) punch cards home from work for us kids to play with. I suppose they must have been clearing out obsolete equipment and systems.

madengr 7y ago
Why would you doubt her at all? Bootstrapping with toggle switches, such as in the PDP-11, was quite common. I have a Altair clone kit where it can be done.
tempguy9999 7y ago
> She also claims she used to manually bootstrap a computer using toggle switches to initiate a loader and then feed it punch cards Not implausible, check http://www.pdp-11.nl/peripherals/how-to-bootstrap.html http://www.pdp-11.nl/peripherals/how-to-bootstrap.html for booting a PDP11. I suspect it was before even this as I have never heard of a PDP11 with punched cards. Wasn't IBM the big punched card people? edit: @madengr 0 minutes ago: snap
earleybird 7y ago
I've manually loaded the boot-loader into a PDP-8 in about 1973. Since it had core memory, I'd typically load it as the last thing before leaving so that in the morning I could just load my paper tape and hit run. From a very fuzzy memory, it was about 30, 12bit words in length.
walshemj 7y ago
Very common on DEC PDP systems, more modern ones like the 11/40 and 11/03's I used had a separate sub system that did this for you. Sometimes these broke down and you could manually toggle the initial boot sequence in. Even more common in earlier systems I would imagine
Merrill 7y ago
The HP 2114 minicomputers had capacitive touch buttons that lit up like elevator call buttons. These were used for loading the boot loader, as well as for a variety of input/output functions. For example, you could insert a "halt" instruction with a code that would get displayed when execution reached that point in your program. You could then increment the program counter register and resume running.
jibal 7y ago
"I guess I shouldn’t doubt it too much." How ELSE would you do it, on a machine with no ROM? We always had to manually enter one instruction into memory to start up the card reader to read the bootstrap card. (This was long before the PDP-11's that others have mentioned.) "She did used to bring old (some used!) punch cards home from work for us kids to play with. I suppose they must have been clearing out obsolete equipment and systems." Old used punch cards were far more prevalent than new ones ... every time you type a line into your computer and then delete or correct it, that's equivalent to having an old punch card.
todd8 7y ago
I’ve had to do this, but it’s not as bad as it sounds. One just has to get the first card or two to load into some memory location. Usually this is filling a device register with an address and setting the PC to a location that has the ROM code to send a command to the card reader. After this the bootstrapping happens. The first card or two are machine instruction loaded by the ROM at a certain location that the ROM jumps to. These machine instruction read the next few cards into the addresses just after the current PC so they are executed next and these instructions read more cards. Eventually, the rest of the loop forming the real loader is read in. By writing the loader in machine language and putting it at the front of the program be loaded one minimizes the number of values that need to be manually inserted into memory with panel switches. Edit: In retrospect, I’m pretty sure the first system where I did this didn’t even have ROM support. It might have required actually keying in the values to a paper tape reader device control registers. (PDP-8 timeframe) However the idea was the same, a few values keyed into a memory location, set the PC, and then push run; the rest of the loader code was on the paper tape or punch cards ahead of the actual program. The system I’m thinking of was a kind of experimental system at MIT with odd peripherals. It had the first CRT I ever used. It had maybe 16 lines of perhaps 40 characters each. The phosphors used glowed orange and had a long persistence because of the low refresh rate. The room lights had to be very dim otherwise the characters would dim to invisibility. I used teletypes and other hard copy kinds of terminals and punch cards other than this weird homemade CRT system until I got to grad school in 1974.

by jmull 7y ago

madengr 7y ago

Why would you doubt her at all? Bootstrapping with toggle switches, such as in the PDP-11, was quite common. I have a Altair clone kit where it can be done.

tempguy9999 7y ago

> She also claims she used to manually bootstrap a computer using toggle switches to initiate a loader and then feed it punch cards Not implausible, check http://www.pdp-11.nl/peripherals/how-to-bootstrap.html http://www.pdp-11.nl/peripherals/how-to-bootstrap.html for booting a PDP11. I suspect it was before even this as I have never heard of a PDP11 with punched cards. Wasn't IBM the big punched card people? edit: @madengr 0 minutes ago: snap

earleybird 7y ago

I've manually loaded the boot-loader into a PDP-8 in about 1973. Since it had core memory, I'd typically load it as the last thing before leaving so that in the morning I could just load my paper tape and hit run. From a very fuzzy memory, it was about 30, 12bit words in length.

walshemj 7y ago

Very common on DEC PDP systems, more modern ones like the 11/40 and 11/03's I used had a separate sub system that did this for you. Sometimes these broke down and you could manually toggle the initial boot sequence in. Even more common in earlier systems I would imagine

Merrill 7y ago

The HP 2114 minicomputers had capacitive touch buttons that lit up like elevator call buttons. These were used for loading the boot loader, as well as for a variety of input/output functions. For example, you could insert a "halt" instruction with a code that would get displayed when execution reached that point in your program. You could then increment the program counter register and resume running.

jibal 7y ago

"I guess I shouldn’t doubt it too much." How ELSE would you do it, on a machine with no ROM? We always had to manually enter one instruction into memory to start up the card reader to read the bootstrap card. (This was long before the PDP-11's that others have mentioned.) "She did used to bring old (some used!) punch cards home from work for us kids to play with. I suppose they must have been clearing out obsolete equipment and systems." Old used punch cards were far more prevalent than new ones ... every time you type a line into your computer and then delete or correct it, that's equivalent to having an old punch card.

todd8 7y ago

I’ve had to do this, but it’s not as bad as it sounds. One just has to get the first card or two to load into some memory location. Usually this is filling a device register with an address and setting the PC to a location that has the ROM code to send a command to the card reader. After this the bootstrapping happens. The first card or two are machine instruction loaded by the ROM at a certain location that the ROM jumps to. These machine instruction read the next few cards into the addresses just after the current PC so they are executed next and these instructions read more cards. Eventually, the rest of the loop forming the real loader is read in. By writing the loader in machine language and putting it at the front of the program be loaded one minimizes the number of values that need to be manually inserted into memory with panel switches. Edit: In retrospect, I’m pretty sure the first system where I did this didn’t even have ROM support. It might have required actually keying in the values to a paper tape reader device control registers. (PDP-8 timeframe) However the idea was the same, a few values keyed into a memory location, set the PC, and then push run; the rest of the loader code was on the paper tape or punch cards ahead of the actual program. The system I’m thinking of was a kind of experimental system at MIT with odd peripherals. It had the first CRT I ever used. It had maybe 16 lines of perhaps 40 characters each. The phosphors used glowed orange and had a long persistence because of the low refresh rate. The room lights had to be very dim otherwise the characters would dim to invisibility. I used teletypes and other hard copy kinds of terminals and punch cards other than this weird homemade CRT system until I got to grad school in 1974.