My project to build a relay computer

[IainMcPhee]

How many people can boast that they have designed a computer?
How many can boast that they have built one?

Although it is very basic, my computer can be considered to be a general-purpose machine.
STATS:

• Registers, 3 Internal, three external
  Memory, 63 Words @ 16 Bits
  Bus, 16 Bits
  ALU, 8-Bit Comparator and 8-Bit Parallel Adder/Subtracter, Zuse design
  Instructions, 1023, 10 bit instruction code, 6 bits for memory addressing

My only real problem right now is lack of relays.

Note: Attached is the only schematic I have thus far that makes any sense outside of its original context. The other schematics shall be posted eventually, after I edit them so that they will be understandable.

 

[flatulent]

This could be very expensive. The first computers were built with relays. This is the origin of the term "bug." A real bug happened to be sitting on a relay contact when it closed and mashed it and it stuck. This kept the contacts from having continuity.

 

[eltonjohn]

Oh .. When i was a kid 12, 13 years old i decided to build a primitive computer by using my own built relays (with nails and copper wire ) .So i started by making the box a huge wooden box . An there was no more money left for the rest copper wire and wire .This was in 1972.
Glorious days .The music was great and i was a little psycodellic.

 

[IainMcPhee]

Already have enough relays to build one part at a time and test my designs. For instance, the other day built the addition/subtraction part of the ALU. Got the adder done, it worked perfectly. Added the subtraction capability, it all went south. I have spent much time poking around with a multimeter since then. I think my B relays (the ones that handle inversion and half the XORs) have the subtraction inputs backwards, ie they dont invert half the time, and they latch the rest of the time...

 

[IainMcPhee]

Here are the pictures:

https://flickr.com/photos/relaycomputer/

Think that I have figured out the problem with the subtraction, just a matter of fixing (VERY tedious)

 

[IainMcPhee]

The Basic CPU Design

 

[IainMcPhee]

The major design work is now complete. I am working on aquiring relays, and am trying to find a cabinet of some sort to build it in. I am thinking of maybe a desk for the CPU, and other cabinets for periphrials. I will need to do one for memory, power supply, tape drive, etc.

 

[IainMcPhee]

I am still alive, just been doing some other work that needed doing.

I built another power supply, this one will be permanent in my adder/subtractor.