Here are some images on an Elliott 803, an early British computer. This
is the console through which you could control the computer, load
programs or edit memory. One unique feature was a loudspeaker connected
to a bit in the currently executing instruction - thus every program
that was running had a characteristic 'tune' that accompanied it. This
allowed the experienced ear to tell when a program was about to fail,
and, of course, it allowed enterprising programmers to produce some of
the first computer generated music.
The console could be used to change locations in memory or to enter
simple programs. The Elliott 803 had a word length of 40 bits, one of
which was a parity bit leaving an odd number of bits for actual
instructions and data! Each word however could store two instructions (6
bit op-code, 13 bit address) and between them was the B-modifier bit
that allowed one instruction to modify how the other instruction
behaved.
You can see the Elliott 803 and many other early computers at the
National Computer Museum in England.
Software was loaded into the Elliott 803 using paper tapes. It had a
main memory of 4k or 8k words in one or two blocks of magnetic core
store. You could actually see where each bit was stored! Each bit had
its own ferrite bead with wires passing through it in both directions.
Amazingly you could turn the computer off and back on and wouldn't have
to reload your program into RAM. 30 years later we are finally getting
back to technology that can do that with modern SSD drives.
Paper tapes were prepared using a teleprinter. A single typing mistake
could mean you would have to copy the entire tape again up to the
mistake and then correct the mistake and then carry on copying it. Most
people wrote their programs on paper first and then transcribed them to
tape. To view the output from running your program you would take the
tape that was output by the Elliott 803 and then run it back through a
teleprinter. Some users learned how to read paper tapes without a
teleprinter and the more advanced user could edit paper tape without a
teleprinter using either a single-hole punch or a piece of tape and a
chad to fill in a hole. Of course this only worked for in-place, single
character edits. Later, teleprinters were connected directly to the
computer so it could output without the intermediary paper tape, and
thus the interactive session was born and thus interactive games became
possible. A Calcomp plotter also allowed the Elliott 803 to draw graphs,
and play more sophisticated games like Tank Battle and Lunar lander.
The computer itself was huge by modern standards. It required an entire
room to house the many cabinets.
The Elliott 803 was created long before integrated circuits existed but
they did contain a precursor to the modern IC in the form of Minilog
devices. You can see some of them on the board in this shot. Each was
a rectangular block with a hard white plastic outer. Inside was a small
circuit consisting of a couple of germanium transistors set in resin. A
single Minilog might implement a single flip-flop device whereas todays
integrated circuits contain billions of flip-flops in a much smaller
space.
Digital Twin are an online representation of a real world object, a copy of its properties in the digital world and a way to send updated and commands to it. In effect I've been making them for years but now they have a trendy name.
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Several years ago we did a major remodel. I did all of the finish electrical myself and supervised all of the rough-in electrical. I also put in all of the electrical system and water in our barn. I have opinions ...
