In looking into my Altair 8800 front panel design, I checked out a lot of old computers around that time. In my opinion, the big breakthrough in making computers really useful came with Apple. The big difference was that instead of using a separate terminal with a serial interface, the keyboard and monitor were built-in as part of the computer. The keyboard was fairly simple - you pushed a key and it put an 8-bit value on the bus. Really it was just an off-the-shelf 6502 CPU that lots of other computers were using, but the video circuit was where the genius engineering was. That's what made the difference between useful and not-so-useful. And it had a built-in bootloader, so turn it on and start programming.

I'd compare a lot of the CPU projects on here to the Altair 8800 - a solid CPU design, but their peripheral interfaces need to be expanded. Loading a program with DIP switches, or pulling off an EEPROM to program separately is kind of a pain. And looking at an output on LEDs or a 2x16 LCD dot-matrix is neat, but makes it really tough to develop on the computer itself. Sure a video interface is tough to do with TTL chips, but if it was easy it wouldn't be fun.

I'd like my computer to be at least as useful as the original Apple computer. But I'd prefer not to do an obsolete video interface like composite or even VGA. If possible I may take a stab at DVI or HDMI. That's pretty advanced for a TTL type computer, but there may be ways to simplify. HDMI has three serial data channels (one for each color) plus a clock channel. And they run FAST. However, I think it's outside the scope of this project. It could easily be the follow-on project to this one - an HDMI interface for simple TTL computers.