Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.xs4all.nl!newsfeed2.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.009 X-Spam-Evidence: '*H*': 0.98; '*S*': 0.00; '"> In-Reply-To: <52863B2A.5080309@chamonix.reportlab.co.uk> Date: Fri, 15 Nov 2013 10:32:54 -0500 References: <52863305.2060303@chamonix.reportlab.co.uk> <528637DB.6050504@chamonix.reportlab.co.uk> <52863B2A.5080309@chamonix.reportlab.co.uk> To: Robin Becker X-Mailer: Apple Mail (2.1283) Cc: "python-list@python.org" X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 107 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1384529579 news.xs4all.nl 15933 [2001:888:2000:d::a6]:50609 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:59538 --Apple-Mail=_1B9E2E7D-C6CB-4859-ABEF-CE99B5F56348 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii On Nov 15, 2013, at 10:18 AM, Robin Becker wrote: > The pdp 10/15 had 18 bit words and could be organized as 3*6 or 2*9 I don't know about the 15, but the 10 had 36 bit words (18-bit = halfwords). One common character packing was 5 7-bit characters per 36 = bit word (with the sign bit left over). Anybody remember RAD-50? It let you represent a 6-character filename = (plus a 3-character extension) in a 16 bit word. RT-11 used it, not = sure if it showed up anywhere else. --- Roy Smith roy@panix.com --Apple-Mail=_1B9E2E7D-C6CB-4859-ABEF-CE99B5F56348 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii
The pdp 10/15 = had 18 bit words and could be organized as 3*6 or = 2*9

I don't know about the 15, but the = 10 had 36 bit words (18-bit halfwords).  One common character = packing was 5 7-bit characters per 36 bit word (with the sign bit left = over).

Anybody remember RAD-50?  It let = you represent a 6-character filename (plus a 3-character extension) in a = 16 bit word.  RT-11 used it, not sure if it showed up anywhere = else.

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Roy Smith

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