18 Nov
2011
18 Nov
'11
2:25 p.m.
From: Phil Budne
Sent: Thursday, November 17, 2011 9:45 AM
Al Kossow wrote:
> On 11/16/11 9:43 PM, Chuck Guzis wrote:
>> I also recall that the Philco System 2000 was
one of the few
>> commercial versions utilizing that idea. "Asynchronous" was part of
>> their advertising campaign--and, for a very short time, they had one
>> of the fastest transistorized machines.
> I have been told that the 2000 was also unreliable
because of this.
The DEC PDP-6 and the KA10 (the original PDP-10 CPU)
were async;
> From: "Carl R. Friend" <carl.friend
at stoneweb.com>
> ....
> The PDP-6 (the -10's progenitor) and the KA-10 were asynchronous
> machines, the KI-10 was a synchronous time-state machine, and the KL-
> and KS-10 were microcode implementations (pretty much by definition
> synchronous).
The PDP-6 was a cranky beast, with large boards that
were prone to
failure.
Hey, Phil! Long time.
I don't think the crankiness in the PDP-6 was due to the async nature of
the machine, but rather to the decision to go from the single connector
on DEC's System Modules(TM) to connectors on two opposite edges of cards
that were twice as large as System Modules.[1] Any component level failure
required unsoldering the card from both sides of its placement in the
machine, along with unsoldering one side of every board to which it was
connected.
Scanned schematics of the PDP-6 are at
http://web.archive.org/web/20041209120010/http://www.ai.mit.edu/people/tk/p…
Thanks for that pointer. I didn't know that was around. It certainly
doesn't surprise me that Knight would have (had) it, though.
[1] System Modules were DEC's first product, for those who don't know. Far
larger than FlipChip(TM) cards, which were introduced with the PDP-7.
Rich Alderson
Vintage Computing Sr. Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104
mailto:RichA at vulcan.com
mailto:RichA at LivingComputerMuseum.org
http://www.LivingComputerMuseum.org/