PDP-12 at the RICM
bqt at update.uu.se
Mon Jul 13 19:52:31 CDT 2015
On 2015-07-13 21:16, Rich Alderson wrote:
> From: Kip Koon
> Sent: Sunday, July 12, 2015 10:52 PM
>> I would be most interested in finding out more about this effort. Do you have
>> ongoing pictures documenting this effort? I'd love to have a PDP 8, 11, 12
>> someday, but I don't have the space for something like that much less the cost
>> involved so I'll have to be satisfied with emulators on my PC or eventually
>> building one or more of these systems with current technology like the SBC6120
>> if memory serves. Are there other possible alternatives? I used a PDP-8/E in
>> high school and college and have been quite interested in the high capability
>> PDPs like the PDP-11 Series for starters. I didn't know there were PDP 12
>> Series computers. Are there other PDP series computers as well?
> Don't confuse higher numbers with higher capabilities, or even as being related
> to each other. DEC created computers with 9 different architectures before the
> 32-bit VAX was even dreamed of.
> The list of Programmed Data Processors goes like this:
> PDP-1 18-bit word, 12-bit address
> PDP-2 24-bit word, paper design only
> PDP-3 36-bit word, paper design only
> PDP-4 18-bit word, 13-bit address
You could argue that the PDP-4 is the successor to the PDP-1. Unless I
remember wrong, it could run PDP-1 programs.
> PDP-5 12-bit word
> PDP-6 36-bit word, mainframe unrelated to PDP-3
> PDP-7 18-bit word, PDP-4 successor
> PDP-8 12-bit word, PDP-5 successor
12, 15 or 17 bit address. Depending on what hardware you have. Most
typical was/is 15-bit address space.
> PDP-9 18-bit word, PDP-7 successor
> PDP-10 36-bit word, PDP-6 successor mainframe
> PDP-11 16-bit word, 16-bit address
> PDP-12 12-bit word, PDP-8/i + LINC hybrid
> PDP-14 control processor for customer-built special purpose equipment
> PDP-15 18-bit word, PDP-9 successor
> PDP-16 Register-Transfer Module hard-wired processor, PDP-14 competitor
> There were later variants of some of these:
> PDP-8/s, PDP-8/i & /l, PDP-8/e & /f & /m, PDP-8/A
> After 1971, they stopped naming things "PDP-n", with the exception of models of
> the PDP-11 (which eventually consisted of more than 20 models designated
> PDP-11/nn), but even there the Pro-3x0 desktop systems were called something
> else. Later models were microprocessor-based.
> The later PDP-10 models were designated DECsystem-10 and DECSYSTEM-20.
> The later PDP-8 models were the DECmate, DECmate II, and DECmate III (word
> processing desktop systems) and the VT-78, all based on Intersil or Harris
> microprocessors which were roughly the PDP-8/e in silicon.
> "high capability PDPs" = PDP-10 & follow-ons. PDP-11? Pfeh.
As always, it depends on what people mean by "high capability". The
PDP-10 were undeniably physically larger, and had a much larger address
space. But they weren't exactly fast...
>  1 built by a customer, reputed to be an NSA front company.
You forgot the actual anchor in the text. This relates to the PDP-3.
>  With memory management, 18 or 22, in 16-bit segments. Late models could
> use separate instruction and data segments, for a total of 128KB in use at
> one time.
??? What segments??? The PDP-11 have a plain simple page table. No
segments anywhere in sight. And each page is 8K.
You obviously need more exposure to PDP-11s, Rich. ;-)
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
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