1/25-scale Cray C90 wristwatch

My Dad was at the forefront of the computer revolution. He talked about sharing time with Seymour Cray at his computer lab at the University of Minnesota. He said whenever Cray would show up on campus, it was like Mick Jagger or some other rock star type. People would flock to be around him and ask him questions.

He then worked alongside Cray and sold many of his computers when they were both at Control Data. He has a ton of stories of how he would go into huge companies like 3M and tell them everything they knew about data storage was about to change. He said their jaws would drop when he gave them numbers on how much they were going to save by using the new Cray computers.

Its very cool and nostalgic to hear people doing these projects and keeping the early days of the computer revolution alive.

This would be a great prop for time travel scifi movie.

Protagonist travels to 1991 and tries to convince scientist to help him. When asked for a proof, shows Gray C90 Wristwatch. "Our real computers are different, but I show you this because it does not pollute the timeline."

I love to imagine this kind of thing dug up by an alien civilization. That it displays the moons of Jupiter will be a fun puzzle and a source of wonder. “Obviously”, they will say, “these people must have worshipped Jupiter as a god and used the position of its moons to keep time.” But the pieces of the puzzle will never quite fit.

Who knows, maybe the Antikythera mechanism or the pyramids were a similarly ludicrous prank?

Will a future design include the external heat exchanger unit? Maybe belt attached? The SSD on the other wrist, perhaps? :)

I love to see these projects keeping the legacy of these old, great machines alive, if not running some fraction of unicos, at least aesthetically.

I am personally asking, because after decades of tech hobbies, I have a bit of a self awareness to 'fun':

I wonder what the fun part was, to them.

There is something rewarding about learning. There is something rewarding about completing things. There is something rewarding about showing other people.

I have the issue that everything I make should be practical. Either net me profit so I can make lots of money. Or useful to society so I can reduce the world's pain and increase pleasure, maybe this is a selfish way to fame.

I still get all 3 of those rewards I previously mentioned, but there is something different going on when I'm doing something for profit/others. Its a different feeling, not better/worse, just different. Better in some ways, worse in others.

I don't have anything to say, technical-wise, but this is absurd and I love it.

The round displays are so cool

Uses an FPGA lol damn that's hardcore

Best statement ever, "... using it should be as incomprehensible as my motivation for creating it in the first place!"

I thought this was funny until the last picture, then I thought it was great.

Thanks for the smile OP.

How soon until the 1/25-scale cray C90 gets as many MIPS as the original? Seems like the one he built is within shouting distance.

Love the project, writing style and what is was made of (fpga, round lcd, Jupiter moons sim... so cool). But now I'm frustrated I can't see the display animation.

Pointed a friend toward this. He thought it was cool, but said he’d never wear a Cray wristwatch because he heard they run fast.

The lead photo doesn't give you a good impression of the size of the thing, he saves that for the end.

His writing style cracks me up. What about battery life though?

” But how do you tell the time?

With great difficulty.”

No upholstery?!

So pointless it had to be done. Bravo!

That's so dang cool.

Absolutely amazing work!

I honesty dream of having a real old Cray 1 as a couch :-) - those designs were just something we don’t see today, huh!?

liquid cooled ?

Brilliant.

Does it run vim? :-)

Very ugly obviously

> The display shows a free-running simulation of Jupiter and 63 of its moons. For convenience, I just plot the X/Y coordinates of each moon in the ecliptic plane. The ephemerides come from the HORIZONS server that NASA operates, at a specified date and time. The J90 just dumps a new frame whenever the Teensy has pulled the previous one, so with a teensy (ha!) bit of calibration on the micro controller side, it would be pretty easy to have the frames dumped in ‘real time’, which, knowing the starting time and date, would allow you to not-at-all-easily infer the current time by looking at the positions of Jupiter’s moons.

Someone finally came up with a time system more difficult for people to use than Star Trek's stardates.

> [a picture of a cray c90 computer]

> A 25:1 Replica of my wristwatch

:)