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Cyhist Apr 7 1997 D
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Date: Mon, 7 Apr 1997 22:45:03 PDT
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: "Laurence I. Press" <lpress@ISI.EDU>
Subject: 1401 architecture
In-Reply-To: Your message of Tue, 8 Apr 1997 01:00:46 -0400
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Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
Keith wrote:
>The 1401 was a variable length instruction, 7-bit byte computer with word marks to delimit the length of an instruction or a data item like a number or
I believe it was 6 bits plus the "word mark." The word mark was a seventh bit used to delimit data fields and instructions. There were also instructions to set, clear, and test the bit mark, and memory- starved programmers could use them to pack in extra data as well.
They were not called "bytes," in those days, but "characters." (The character coding scheme was BCD -- binary-coded-decimal -- a 6-bit code with only upper case letters).
The term "byte" was used in the 360, and I believe it was coined by Bob Bemer (?).
>The 1620 was also a dead end computer. Neither the 1401 nor the 1620 contributed in a significant way to the development of the 360.
I'm not sure exactly what you mean by this, but the experience with the 1401 instruction set must have informed the 360 architects. Also the peripherals (like the 1403 line printer) were there. Everyone in IBM was familiar with the 1401 at the time.
Larry
______________________________________________________________________
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: "Laurence I. Press" <lpress@ISI.EDU>
Subject: 1401 architecture
In-Reply-To: Your message of Tue, 8 Apr 1997 01:00:46 -0400
______________________________________________________________________
Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
Keith wrote:
>The 1401 was a variable length instruction, 7-bit byte computer with word marks to delimit the length of an instruction or a data item like a number or
I believe it was 6 bits plus the "word mark." The word mark was a seventh bit used to delimit data fields and instructions. There were also instructions to set, clear, and test the bit mark, and memory- starved programmers could use them to pack in extra data as well.
They were not called "bytes," in those days, but "characters." (The character coding scheme was BCD -- binary-coded-decimal -- a 6-bit code with only upper case letters).
The term "byte" was used in the 360, and I believe it was coined by Bob Bemer (?).
>The 1620 was also a dead end computer. Neither the 1401 nor the 1620 contributed in a significant way to the development of the 360.
I'm not sure exactly what you mean by this, but the experience with the 1401 instruction set must have informed the 360 architects. Also the peripherals (like the 1403 line printer) were there. Everyone in IBM was familiar with the 1401 at the time.
Larry
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