Reasoning behind strange PCB artwork on Cray board

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Hi guys,

I've been looking over pictures of old boards and noticed something strange on one old Cray 1 board (see attatchment origBoard ).

First:
Is the artwork in delayLines.jpg delay lines? Or something like delay matching for high frequency signals? Impedance matching?

Second:
Is there a reason for the Mystery patern? The bars? I can't really think of any good reason for them.

Thanks,

David

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There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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I remember reading about Seymore Cray drawing each board on a yellow pad. The line lenths are all equal for equal propagation delay, so those must be where he hanked up the slack. The bottom of the cabinets had the extra cables. The Cray 1 had a bunch of cabinets arranged in a circle like stonehenge, presumably due to cable length.

Imagecraft compiler user

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Yes, I've also read how matching and adjusting (for correct slew) delays was critical to get those supercomputers running properly.

Don't know what the vertical bars accomplish.

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That's really cool.

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I've seen a Cray X-MP in the Musee des Arts at Metiers in Paris. It's very impressive. The power supplies were built into the padded seating around the base.

Leon Heller G1HSM

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Quote:
The power supplies were built into the padded seating around the base.

And if they had only patented that idea, car manufacturers today would still be paying royalties on it :lol:

Wiki Cray-1 is interesting reading, and has some nice photos.

JC

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I wondered where you got that pic, so I googled it and found this interesting place:
http://www.cpushack.com/category/museum-news/

/Jesper
http://www.yampp.com
The quick black AVR jumped over the lazy PIC.
What boots up, must come down.

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I've seen one of those for myself while in London (science museum). VERY impressive toy. But the cabling... see photo at http://lh5.ggpht.com/_zVRpARSKEV...

So in effect it's just a delay line for the purpose of having the exactly the same delay as on it's sister signals?

As for the bars... I was wondering if it's not some kind of technological thingie while making the PCB. If it was some kind of analog GHz thingie I would be wondering about some kind of antenna (looks like some bizzare Yaggi antenna), but I don't think that's the case.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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The vertical bars are likely just copper levelling due to the sparse nature of the board. As the board would have been taped out by hand, bars would have been easier than the grids that we typically use these days.

[edit]fixed some typo's

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

Last Edited: Thu. Dec 16, 2010 - 01:54 AM
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jesper: Yup. By what keywords did you find it?

But anyway, there's no shortage of Cray pictures. What I miss are the schematics! And how the hell did they do something as amazing as that so long ago with only the tools of the day. Stuff like this makes me feel ashamed of myself whenever I complain on the tools at hand.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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dagg: it was the host of the cray PCB picture when I googled for "cray pcb".

Here's a funny Seymour Cray story:
When asked what kind of CAD tools he used for the Cray-1, Cray said that he liked #3 pencils with quad paper pads.

And another funny one:

When he was told that Apple Computer had just bought a Cray to help design the next Apple Macintosh, Cray commented that he had just bought a Macintosh to design the next Cray.

The cabling is insane.

And it got worse.


It should have a label: "CPU(s) inside". :D :shock:

/Jesper
http://www.yampp.com
The quick black AVR jumped over the lazy PIC.
What boots up, must come down.

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I stumbled across this Cray-on-an-FPGA recently:

http://chrisfenton.com/homebrew-...