Path: news.eternal-september.org!eternal-september.org!feeder3.eternal-september.org!2.eu.feeder.erje.net!3.eu.feeder.erje.net!feeder.erje.net!weretis.net!feeder8.news.weretis.net!reader5.news.weretis.net!news.solani.org!.POSTED!not-for-mail
From: Richmond <dnomhcir@gmx.com>
Newsgroups: comp.misc
Subject: Re: On Binary Digits
Date: Mon, 12 May 2025 19:56:06 +0100
Organization: Frantic
Message-ID: <86o6vx8xq1.fsf@example.com>
References: <vsh2fn$3fpam$1@dont-email.me> <86v7rnj0vn.fsf@example.com>
	<vsjp4s$29slh$1@dont-email.me>
	<67ed69b2$0$707$14726298@news.sunsite.dk>
	<vspaeo$75m8$2@dont-email.me>
	<slrn101udtl.198p.anthk@openbsd.home.localhost>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Injection-Info: solani.org;
	logging-data="624696"; mail-complaints-to="abuse@news.solani.org"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux)
Cancel-Lock: sha1:LzHieGTRG9CmOHHmupcuVFoXp3Y= sha1:6Hmwb0Wg24RwapSdU0YIEI3l3sg=
X-User-ID: eJwFwQEBACAIA7BK6OFQR5H3j+AW4GKnM+ihUD363gmPl9C6aYQNrFu08UbPnWKp/cQ5+gwiEVw=

anthk <anthk@openbsd.home> writes:

> On 2025-04-04, Lawrence D'Oliveiro <ldo@nz.invalid> wrote:
>> On 02 Apr 2025 16:45:38 GMT, Aharon Robbins wrote:
>>
>>> Octal was used heavily on the PDP-11, if you used the assembler.
>>
>> All DEC’s systems used octal heavily, prior to the VAX. That’s when they 
>> started using hex.
>>
>> All the DEC machines prior to the PDP-11 had word lengths that were 
>> multiples of 3 (12, 18, 36), so octal worked nicely. Even though the 
>> PDP-11 was a 16-bit machine, fields in its instruction format were still 
>> designed to line up with octal digits.
>
> Why? "octal" means base eight ( as 'ocho' in Spanish, same Latin root).
>
> forth>3 8 lcm .
>
> 24
>
> Not very fitting for a 36 bit machine except for opcodes.

Octal numbers are 3 bits per digit, and 36 divides by 3.