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homebuilt computer, and more

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awemawson:
I designed and made a 'bit slice' computer back in 1973/4 using the 74181 four bit logic slice family. All wired using very thin  'burn through' polyurethane insulated copper wire on epoxy copper prototype boards etched on the kitchen table  :ddb:

Took hours and hours - but it worked !  The main cpu bit slice performed simple boolean operations such as shift, add, or, nor etc and these were built up into more complex functions using microcode hard programmed with a diode matrix that could be called a rom I suppose.

S. Heslop:

--- Quote from: sparky961 on April 05, 2015, 10:10:55 PM ---Thanks for sharing this. I wish I had been born a few decades earlier when computers were this simple.

--- End quote ---

When I was a kid I got real excited about computers, this must've been around the start of the 2000s. I went to the library to get some books out on the topic but by that time all the books they had were of the 'windows 95 for dummies' variety. It was frustrating since I couldn't find any computer information worth a damn and kept reading that rubbish hoping to learn something. I think if I was born in the 70s I would've had a whale of a time with the computers that came out in the 80s.

Lew_Merrick_PE:
Ah, my first micro-computer was a 4-bit, discrete component, RTL processor running at a (then) screaming 16 kHz.  It had 256 BYTES of magnetic core memory and was programmed with bat switches with "output" on grain-o-wheat bulbs.  It ran it's first program in the spring of 1968.  I added a paper-tape reader to it in the winter of 1968.  [My brother's high school sweetheart was a member of the ARPA team at MIT and needed somebody who could "cut" PC boards and solder.]

Swarfing:
Just thought I would share some my history which started with my mother who worked at Plessey Semiconductor in my home town.

http://www.swindonweb.com/?m=8&s=116&ss=396&c=1327

Her claim to fame was working on the prototype silicon wafers for the first SIL's DILL's and quad flatpacks that put a start to some of the endeavours seen in this thread. My real start was a plain brown cardboard box with the contents of a beige Sinclair ZX80 that you had to put together yourself. I so longed for the day when i could afford a new fandangled mouse for my NEC 8086 4mhz proc and no maths co-processor. Thought i was the bees knees learning assembler and fortran as a kid. We all knew more than the teachers who tried to teach us computer programing as well.

Remember saving up for 128k or 256k DRAMS to populate your memory boards? Cutting holes in your 5 1/4 floppies to get more data on the other side? Real computing days.

vtsteam:
I'm sort of in between you and the earlier guys here, swarfing -- I do remember the ELF coming out in the pop electronics mag, but couldn't figure out what i was good for.  But a couple years later did know! And was saving up for 4116s to piggyback dead bug style on top of the 4K memories I had in a 6802 powered Color Computer. I think 16k was about $100 then.

I remember admiring the Sinclairs, actually, especially the price, but being on the wrong side of the Atlantic.

The LNW-80 had about 100 IC's to find (surplus mostly) and populate. And I don't know how many support components....hardest part to locate for me actually turned out to be the clock crystal!

I programmed the EPROMS myself, and overclocked the Z-80 to 5.33 mhz compared to the under 2 mhz of the TRS-80 model 1 which it was similar to. This was a "high resolution" color computer, too -- before the IBM PC came out, and higher resolution and faster even after it did. I did eventually get an original IBM PC (still have it) but it was a definite step back.

I programmed the LNW in FORTH, and wrote a wire frame graphics program to rotate and display boat lines in color and 3D from a table of offsets. At that time a terminal to do the same cost $20,000.

By 1991 it was outdated enough that I set it on top of the dustbin in front of my house, and hope somebody would take it before it was trashed.

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