[libre-riscv-dev] [Bug 154] Cell for Dependency Matrices is needed

[whygee at f-cpu.org]

On 2020-01-14 01:25, Luke Kenneth Casson Leighton wrote:
>> The CDC used DCTL (Direct Coupled Transistor Logic)

BTW it is detailed there :
https://hackaday.io/project/8449-hackaday-ttlers/log/148234-direct-coupled-transistor-logic

>> and asked Fairchild
>> to make a specific transistor, still sold today : the gold-doped 
>> 2N2369
> ooo so if we reeeally wanted to, we could actually reconstruct a 6600 
> from
> its original transistors.

which would be a desperate move since the Living Computer Museum @ 
Seattle
restores a couple of units (lower-performance but still Cray-zy 6400 and 
6500)
https://www.youtube.com/watch?v=4Zt03YsMyW4

I saw one video where the engineer explains his reverse-engineering of 
the boards
and how he made compatible assemblies with SMD transistors for easier 
access.
These SMT 2N2369 are identical silicon but much smaller :-)

Then he received a "special tool" from an ex-CDC tech ...

But I don't think you'll want to deal with the water chiller on the roof
and the 400Hz motor-generator.

As one ex-CDC guy said, "why would you want to make this run again ?"
We have FPGAs and incredibly fast computers today...

But it's true that the strong restrictions on what was possible back 
then
made these guys push in every direction and forced them to make the 
smartest design they could.
Mitch gave you a bit of insight and I'm not surprised that many people
reinvent the wheel (I did). Old designs are a well of inspiration and 
design lessons.

I have difficulty "getting" what you all write about in detail, so I 
hope
someday somebody will make sketches, diagrams, plans etc. to "show" what
you have in mind :-)

> thank you yg.
sorry for the distraction ;-)

> l.
yg