Reply to post: Re: Talking of 1-2-3

What’s the KEYBOARD SHORTCUT for Delete?! Look in a contextual menu, fool!

Peter Gathercole Silver badge

Re: Talking of 1-2-3

Chances are that the visible part of the sheet was sent as a 3270 form, and you would have been able to move between the cells/fields with tab and/or arrow keys, filling in multiple cells, and once all of the fields were how you wanted, you could hit enter and transmit all of the cells up at once, and have the sheet recalculate. This would have been quite familiar to a mainframe user, but completely foreign to anybody used to instant update.

I know that having grown up on full-duplex ASCII terminals on UNIX, DEC and other systems, moving into a 3270 world when I joined IBM frustrated the hell out of me until I worked out the best way to do it. But once the concepts were understood, it worked pretty well, only differently.

The reason for it working the way it did was because 3270 terminals had quite a lot of function built in, and would allow local editing of data on the screen without any involvement from the mainframe or terminal controller. This meant that you could attach a lot of terminals to a mainframe without it melting down, and that interacting with a remote terminal down low speed telecommunication lines was bearable, with only the download and upload screen refresh being slow.

For full-duplex ASCII terminals, the computer was involved in the most basic of functions, and ended up having to echo every key typed back to the terminal. Interrupt handling per keystroke sapped the life out of a lot of mini-computers unless they were good at it (like the PDP11 was).

PCs, where the computer had the keyboard and screen locally attached were a different proposition, and naturally lent themselves to update per keypress type applications.

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