Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!wuarchive!mit-eddie!bbn.com!fwebb
From: fwebb@bbn.com (Fred Webb)
Newsgroups: comp.arch
Subject: Re: Looking for a really odd computer
Message-ID: <59911@bbn.BBN.COM>
Date: 9 Oct 90 20:55:23 GMT
References: <1990Oct3.234941.16768@nsc.nsc.com> <14900017@hpdmd48.boi.hp.com> <4155@bingvaxu.cc.binghamton.edu>
Sender: news@bbn.com
Reply-To: fwebb@BBN.COM (Fred Webb)
Organization: Bolt Beranek and Newman Inc., Cambridge MA
Lines: 26

In article <14900017@hpdmd48.boi.hp.com> sritacco@hpdmd48.boi.hp.com
 (Steve Ritacco) writes:
>It is my understanding that DEC actually made a few 18 bit word machines.
>It was the PDP-? (I can't remember)!

The following DEC machines were 18 bits:

    PDP-1
    PDP-4
    PDP-7
    PDP-9
    PDP-15

The following were all 12 bits:

    PDP-5
    PDP-8
    PDP-12

Note that these numbers are both divisors of 36 bits, which was the "standard"
IBM word size of the time (701/704/709/7090/7094).

Until the PDP-8, essentially all of DEC's machines were 18 bits (the PDP-5
wasn't a very large seller).

					-- Fred