From: "John W. Kennedy" <jwkenne@...>
Date: 2007-07-21T09:45:03+09:00
Subject: Re: Taking the bull by its horns [was background]

Morton Goldberg wrote:
> That's pretty complete. I've never read a history of IBM -- I was going 
> entirely from my memory of working with early IBM computers and the oral 
> tradition transmitted me by the many IBM employees I have known over the 
> years. BTW, you omitted the 1130, which I remember as small  
> scientific/engineering machine roughly contemporary with the 1620. But 
> we seem to have determined my memory isn't to be trusted. So where do 
> you place the 1130?

 From a marketing viewpoint, but not architecturally, it was the 
follow-on to the 1620, and the 1800, which had mostly the same 
instruction set as the 1130, was the follow-on to the 1710. (There was 
also a 1500, which was designed for CAI applications.) But the 1130 was 
post-360 -- IBM's first admission that the 360 couldn't handle every 
niche -- so I didn't include it.

The 1620 and 1130 were both noted for their omissions. The original 1620 
required an addition table and a multiplication table to be loaded by 
the operating system, or the arithmetic opcodes wouldn't work. This is 
why the 1620's code name, "Cadet", was elucidated by wags as "Can't Add, 
Doesn't Even Try". The later, advanced models didn't need the addition 
table, but still needed the other.

The 1130, on the other hand, was famous for its I/O facilities, which 
were comparable to systems of the early 1950s. For example, the console 
typewriter required the operating system to:
    read each stroke from the keyboard as a 12-bit code,
    translate the 12-bit code from a punched-card column to EBCDIC
      (the keyboard came straight off the 029 keypunch),
    translate the EBCDIC code to a code called Tilt-Rotate code, and
    send the Tilt-Rotate code to the "golf ball", to print the character.


-- 
John W. Kennedy
"Never try to take over the international economy based on a radical 
feminist agenda if you're not sure your leader isn't a transvestite."
   -- David Misch:  "She-Spies", "While You Were Out"