[Info-vax] OT: IA-128 ???

Tue Oct 20 10:05:14 EDT 2009

Bob Koehler wrote:

> In article
> <d778eddd-e972-4279-84a8-e6f1b086ebb1 at d34g2000vbm.googlegroups.com>,
> "Bart.Zorn at gmail.com" <bart.zorn at gmail.com> writes:
>> 
>> A PDP 11/34, at least those without third-party add-ons, supported a
>> maximum of 256 KB memory. The 11/44 supported up to 4 MB.
>> 
>    I thought I recalle it as 256 KW.

No, 18 bit Unibus addressing means 128 KWords = 256 KBytes (more precisely
128-4, the I/O page overmaps memory).
Only machines with a Unibus map in addition to the MMU could address more,
up to 4MB-8KB: 11/23+,11/44,11/70,11/73,11/84.

--
Joseph Huber, http://www.huber-joseph.de