[ozhero]

I started programming in 1978 (In Assembler) and wanted to know not only how the software worked but how the hardware worked.

Found a great kit using the Z80 and built it and spent many nights with a logic probe and oscilloscope learning digital eletronics. Also devoured the Z80 manual learning the instruction set.

I'm nearly 70 now but remember those days like they were yesterday.

Truly a magnificent CPU

[mrandish]

I started 3 years later than you on a 4K Radio Shack computer running a 6809 8-bit CPU. I can still remember quite a few opcodes and a few months ago helped some on retrocomputing.stackexchange.com find a rather tricky 6809 assembly language bug without looking anything up. It's weird how stuff sticks around in our heads, since I haven't written any 6809 code in more than 40 years.

Despite being entirely self-taught due to never having programming classes or books, I enjoyed a long, quite successful career as a serial startup entrepreneur. In 1981 the only info for 'toy micros' was small hobby zines, local user's groups and just learning by disassembling other people's code. I started with the ROMs in the computer and learned by looking up the opcodes on a Motorola quick reference card. I got it by cold calling Motorola trying to sound like an 'adult' and the salesperson took pity on me and mailed the card for free.

I still think there's something invaluable about learning computers from first principles down to the metal.

[djmips]

It feels a bit like a first language. That's the one that really sticks with you.

[ozhero]

Or a first love (of the human kind) :-)

[ozhero]

"I still think there's something invaluable about learning computers from first principles down to the metal"

Totally agree!

I never went to Uni either (at least not until I retired) yet have had a very succesful career in IT and still love tinkering like it sounds you do.

Those were heady days :-)

[KiwiJohnno]

May I suggest you check out the game "Turing Complete" https://turingcomplete.game/

It sounds like it may be right up your alley. Its a simplified digital logic simulator, you make basic circuits from NAND gates, and then build these into functional units in later levels, then further on you build an instruction decoder, and combine it with these functional units and before long you have a Turing complete architecture and you are writing your own assembly on it - Assembly language that you defined, from scratch. You'll find the need for new opcodes... so, you build them! Challenging game for sure, but very, very rewarding.

The game is still in early access, but very near a full release. They just put out a trailer: https://www.youtube.com/watch?v=goclUECM2ds

[mrandish]

This looks very cool. In a similar vein, there's https://www.nand2tetris.org/.

[ozhero]

Thanks for posting this.

[chasil]

Both the Z80 and the 6502 were products of corporate rejection.

I'd love to see another designer introduce a FORK86-64, but things are much more complex now.

[brucehoult]

We have RISC-V.

Software binary compatibility is less important now than it has been for 30 or 40 years of x86 dominance because now we are so over-served by hardware that most software runs just fine in emulation (especially transpiling/JIT).

Compatibility also wan't too important in the 70s and the 6502 wasn't compatible with anything else. Everyone expected to rewrite everything back then whether between manufacturers or just a new model from the same manufacturer.

[digitalsankhara]

Same! Also built external peripherals for my ZX81.