Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.arch
Subject: Re: Multics paging, Address bits again, Article on new mainframe use
Date: Fri, 13 Sep 2024 02:55:59 -0000 (UTC)
Organization: A noiseless patient Spider
Lines: 19
Message-ID: <vc09ju$ljiq$3@dont-email.me>
References: <vb9r4g$2o1f$1@gal.iecc.com>
	<77d899f5feb9f06f611267885d157ad7@www.novabbs.org>
	<vbvm99$i56$1@gal.iecc.com> <vbvp59$esm6$5@dont-email.me>
	<vc07aa$2rd5$1@gal.iecc.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Injection-Date: Fri, 13 Sep 2024 04:55:59 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="fe8eaca0c36637cab02c0b5baab677cf";
	logging-data="708186"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1+fnAubaCHw1eEpf+zOzyGq"
User-Agent: Pan/0.160 (Toresk; )
Cancel-Lock: sha1:9i8BqKXBG0s6y2qzMRhdO/Y9uTo=
Bytes: 1752

On Fri, 13 Sep 2024 02:16:42 -0000 (UTC), John Levine wrote:

> According to Lawrence D'Oliveiro  <ldo@nz.invalid>:
>>
>>On Thu, 12 Sep 2024 21:26:01 -0000 (UTC), John Levine wrote:
>>
>>> The other choice would have been a page table per segment, like
>>> Multics did.
>>
>>Remember that Multics segments all existed within a common, directly
>>linearly-addressable address space.
> 
> Sigh.  Why guess wrong when it is so easy to look up the real answer?
> 
> https://bitsavers.org/pdf/ge/GE-645/LSB0468_GE-645_System_Manual_Jan1968.pdf

Nothing in there that contradicts what I’ve said.

Note that segment sizes are 18 bits, while memory addresses are 24 bits.