| Electronics > Projects, Designs, and Technical Stuff |
| Experimenting with TTL Cpu, 74LS chips, old vs New? Retro style switches? |
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| jfiresto:
--- Quote from: rstofer on June 06, 2020, 07:03:42 pm ---... There's something comforting about knowing when your program runs off the rails by watching the lights.... --- End quote --- My LSI-11/xx machines had no blinking lights, so I did the next best thing and ran an analog CPU load meter off a spare serial line. DEC thoughtfully organized their serial interfaces in a way that reduced its device driver to an increment instruction added to the operating system idle loop. Good fun. |
| David Hess:
--- Quote from: rstofer on June 06, 2020, 06:35:25 pm --- --- Quote from: duak on June 06, 2020, 05:18:08 pm ---Regarding the IBM PC being the first computer without switches and lighs. The Apple II, Commodore PET and TRS-80 all preceeded the PC starting in 1977. --- End quote --- Obviously, you are correct. All of these were 'personal' computers as opposed to 'commercial' or 'hobby' computers. By 'commercial', I'm thinking about machines like the PDP-11, not Vaxen. My beginnings with the 'hobby' computer were with the Altair 8800. It certainly required a bit of toggling until EPROMs were used. Even then, we had to set the starting address to force the CPU to the beginning of the EPROM. Then we had sophistications like mapping and it became possible to just use the Reset switch and start from address 0000h Those were good days! A mere mortal could understand every aspect of the hardware and software. --- End quote --- Even before personal computers, there were S-100 based CP/M systems contemporary to the Altair, Imsai, and similar systems which only had power and reset buttons. They were more direct predecessors to the IBM-PC than personal computers like the Apple ][. |
| rstofer:
--- Quote from: David Hess on June 06, 2020, 08:06:27 pm ---Even before personal computers, there were S-100 based CP/M systems contemporary to the Altair, Imsai, and similar systems which only had power and reset buttons. They were more direct predecessors to the IBM-PC than personal computers like the Apple ][. --- End quote --- I have one of the CompuPro Z80 machines with a rack mount chassis. Plain black panel with a Reset and Power switch, nothing else. I think it was intended for industrial applications but I bought it for the blistering fast 6 MHz Z80. I also have dual 8" floppies in a rack mount chassis. It all worked, the last time I tried it, but it seemed strange for a system to not have switches and lights. I built up an FPGA Z80 system with a Compact Flash device for the disk drives. I used the CompuPro to send over everything I had on 8" floppies. It's been a while but I think the Z80 core was running at 50 MHz. I have forgotten how I ported Kermit to the new system. I also have a Zilog EZ80 board with a daughter card supporting a Compact Flash device and a pair of USB serial ports. It also runs at 50 MHz. CP/M is smokin' fast at 50 MHz. |
| CatalinaWOW:
--- Quote from: rstofer on June 06, 2020, 07:03:42 pm ---I miss the toggle switches and blinking lights. That's why I have a couple of the PiDP-11 computers running BSD2.11 and a bit of a web server. There's something comforting about knowing when your program runs off the rails by watching the lights. https://obsolescence.wixsite.com/obsolescence/pidp-11-overview The fun bit is using the original Unix tools with the original C compiler. OK, the editor is a PITA but if you don't know vi, you don't know much about computers. Emacs always seemed like too much effort... Real K&R C, not this modern rubbish! Note that BSD2.11 is very nearly identical to the more recent BSD4.3. This isn't some stripped down, obsolete, OS. I was never a PDP-11 user so I have a LOT to learn. --- End quote --- There are lots of tricks/hacks to know when the computer is running right. On the IBM 1620 you could tune an AM radio to the master clock and listen to the machine run. Some wrote code to make it play simple tunes, but you could tell when things were off on normal programs after a while listening. Other machines took the blinking lights thing to an extreme. An AstroData computer (sequencer? It was programmable) I encountered in one lab literally covered a wall. And had a plexiglass front through which you could watch a sea of blinking lights as it operated a rather trivial by today's standards test sequence. Based on the time frame these lights probably weren't LED's, and it is frightening to think of the maintenance on that many incandescent indicator bulbs. Not long after that machine was replaced with a Commodore PET. While I too sometimes wax nostalgic about those good old days, I am really, really glad we don't have to program a cold start loader and so on any more. Just as I am glad that punched cards and paper tape are in the rear view mirror. |
| tggzzz:
--- Quote from: CatalinaWOW on June 06, 2020, 11:36:18 pm --- --- Quote from: rstofer on June 06, 2020, 07:03:42 pm ---I miss the toggle switches and blinking lights. That's why I have a couple of the PiDP-11 computers running BSD2.11 and a bit of a web server. There's something comforting about knowing when your program runs off the rails by watching the lights. https://obsolescence.wixsite.com/obsolescence/pidp-11-overview The fun bit is using the original Unix tools with the original C compiler. OK, the editor is a PITA but if you don't know vi, you don't know much about computers. Emacs always seemed like too much effort... Real K&R C, not this modern rubbish! Note that BSD2.11 is very nearly identical to the more recent BSD4.3. This isn't some stripped down, obsolete, OS. I was never a PDP-11 user so I have a LOT to learn. --- End quote --- There are lots of tricks/hacks to know when the computer is running right. On the IBM 1620 you could tune an AM radio to the master clock and listen to the machine run. Some wrote code to make it play simple tunes, but you could tell when things were off on normal programs after a while listening. --- End quote --- Several machines had simple loudspeakers. The Elliott 803, a 576µs cycle time machine, has a loudpseaker connected to the top bit of the instruction register. Somewhere I have a tape of it playing various tunes, badly. |
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