PDP 11/23 help needed

From: Philip.Belben_at_powertech.co.uk <(Philip.Belben_at_powertech.co.uk)>
Date: Wed Apr 22 11:08:55 1998

Seth and Pete were discussing the PDP11-23...

>> 2) Same as above, but for the M8044-DB boards. I could put one
>> of these in with the M8047's to get a full 64Kword of RAM, yes?
>> Does anyone know what the DIP-switch settings for these boards
>> are?
>
> Yes, but I'm not sure why you say "full" and 64Kword" together :-)
> 32KW (64KB) is the limit for 16-bit addressing, or 128KW (256KB) for 18-bit
> addressing. Ignoring the I/O page, that is.

Um... Am I way out here? Doesn't the 23 support 22 bit addressing? And
I never before heard of a 16 bit Qbus! ISTRT the F11 processor is
settable between 18 and 22 bit (128KW, 256KB and 2MW, 4MB respectively).
The 18 bit setting is used in the 23 on 18 bit Qbuses and in the 24 on
unibuses. The 22 bit setting is used on 22 bit Qbuses, but you need
extra hardware to use it in the 24 (i.e. on unibus).

Just my half groat's worth.

Philip.
Received on Wed Apr 22 1998 - 11:08:55 BST