28
votes
Accepted
How did the Altair 8800 front panel load the program counter?
Just about a week ago, I encountered the same question as I was thinking about the idea of building a front panel for my homebrew computer, but I didn't understand how could one "move" the CPU to ...
- 3,264
11
votes
Accepted
Identify this front panel
StarringTheComputer.com claims it is a GE 635. I could not find pictures of that particular system, but it is consistent with descriptions in the 635's System Manual and Programming Reference Manual.
...
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7
votes
Why did 1970s front panels prefer momentary toggle switches to push buttons?
There are usually multiple contacts made when a switch is operated (it's called
bounce). Debouncing a large number of (SPST) pushbutton switches is difficult (requires lots of
components, or even a ...
- 2,200
7
votes
What typeface was used on the DEC PDP-8/F faceplate?
Partial answer, mainly about the logo, but possibly this gives more hints for searches:
The history of the digital variant (which probably produced the SVG file you found) is described by Ned ...
- 30.5k
7
votes
How did the Altair 8800 front panel load the program counter?
How exactly does it load the program counter, given that there's no obvious way to tell the CPU to do this without excecuting instructions to do so?
Seams like you know it already :))
Does it ...
- 236k
6
votes
Identify this front panel
I came across this thread while doing the same type of image search (to ID the panel in Wrath of Khan). The Serenity panel is not the same one as the Wrath of Khan "deflector grid" panel the Star Trek ...
- 61
5
votes
Why did 1970s front panels prefer momentary toggle switches to push buttons?
On these front panels, as well as state set by ON-OFF switches, there's a need for momentary-contact switches [...]
Don't forget three way switches as well.
Was there any particular technical or ...
- 236k
4
votes
Accepted
Source code of front-panel entered Altair 8800 programs
A single example, but a neat one: Josh's 12-byte Microsoft 4K BASIC bootloader. Kind of needs a paper tape reader and 4K BASIC, but does save your fingers from those fiddly wee switches!
- 22k
3
votes
Could the 6502 have worked with an Altair-style front panel?
The Ohio Scientific 300 Trainer is one simple front-panel design for a 6502. It uses the RDY pin to hold the 6502 in a wait state while you're programming it. There are four 7417/7407 hex buffers, and ...
- 2,299
3
votes
Accepted
Could the 6502 have worked with an Altair-style front panel?
TLDR: From knowledge of their general principles of operation, it
appears that an Alatir-style front panel could be used with the 6502.
However, the devil is always in the details, so to be sure you'd ...
- 28k
3
votes
How did the Altair 8800 front panel load the program counter?
The IMSAI 8080 front panel seems to be nearly identical to the
Altair 8800 front panel.¹ I just stumbled across a 1999
document, IMSAI CPA Front Panel Control Board, that gives an
excellent ...
- 28k
2
votes
Could the 6502 have worked with an Altair-style front panel?
But in any case, doesn't the Altair front panel depend on the ability to do exactly what is described, tri-state the CPU in order to take over as a DMA device?
Would that be a significant obstacle to ...
- 236k
1
vote
Could the 6502 have worked with an Altair-style front panel?
Even without three-state drivers, one could have fairly easily built a computer with an Altair-style front panel by using three-position switches that included a contact for the middle position which ...
- 39.2k
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