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Cyhist Apr 11 1997 A
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Date: Fri, 11 Apr 1997 07:57:42 EDT
Reply-To: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> Sender: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> From: keith reid-green <kreid-green@ETS.ORG>
Subject: Re: 1401 trivia
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Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
Larry Press described the 1401 addressing scheme correctly. This naturally limited the 1401 to 16k of storage, although other machines used a paging method to jump from one block of storage to another. The 1410 and 7010 used a five-digit address.
Come to think of it, 16k is not quite right, is it? I mean, a "k" is 1,024 and the 1401 could only address 0 to 15,999.
Anyway, my only reason for responding to Larry's post is to point out that the middle character of the three-character address of the 1401 was used for indexing. The numeric portion was part of the address, but the A and B bits were for an index. A and B off, no index, so there were three possible indexes.
Keith Reid-Green
KReid-Green@ets.org
Princeton, NJ
______________________________________________________________________
Reply-To: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> Sender: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> From: keith reid-green <kreid-green@ETS.ORG>
Subject: Re: 1401 trivia
______________________________________________________________________
Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
Larry Press described the 1401 addressing scheme correctly. This naturally limited the 1401 to 16k of storage, although other machines used a paging method to jump from one block of storage to another. The 1410 and 7010 used a five-digit address.
Come to think of it, 16k is not quite right, is it? I mean, a "k" is 1,024 and the 1401 could only address 0 to 15,999.
Anyway, my only reason for responding to Larry's post is to point out that the middle character of the three-character address of the 1401 was used for indexing. The numeric portion was part of the address, but the A and B bits were for an index. A and B off, no index, so there were three possible indexes.
Keith Reid-Green
KReid-Green@ets.org
Princeton, NJ
______________________________________________________________________
