VAX9000 unearthed
Bill Gunshannon
bill.gunshannon at hotmail.com
Sun Feb 20 15:20:40 CST 2022
On 2/20/22 15:31, Chuck Guzis via cctalk wrote:
> On 2/20/22 10:10, Mark Kahrs via cctalk wrote:
>> I heard Butler Lampson once exclaim that ECL design was in some ways easier
>> than TTL. If you terminated every line, you get controlled impedances with
>> controlled edges. This was the design philosophy for the Dorado.
>
> Indeed--ECL WW prototype boards usually had a 3rd row for SIP
> termination resistors alongside the DIP sockets. One nice thing about
> ECL is that there are many fewer problems with power rail spikes. On
> the other hand, the constant power consumption needs beefier power supplies.
>
> I recall that Honeywell redid one of their mainframe designs in ECL,
> with somewhat disappointing performance results. I don't recall the
> details offhand.
It's long enough ago that my mind is fuzzy, but I think Primes were
ECL.
bill
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