[its-hackers] 1967 ITS mentioned

Jack Haverty jack at 3kitty.org
Wed Aug 18 20:41:00 CEST 2021


> It is a tribute to the modesty and especially to the irreverence of
>    the early hackers that when they created the world's first timesharing
>    system at MIT, they provided it with a name that was completely
>    opposite from what it really was: the Incompatible Timesharing System.

Just to set the record straight for historians...

Actually, I think this book is incorrect about the "first timesharing 
system".   From personal experience -- I was a freshman at MIT in fall 
1966, and took a beginning programming course (6.47), in which we used 
Fortran and punch cards to use the MIT 7094.   So the commentary about 
punch cards and printouts is what I experienced in 1966, and was the 
norm at the time for using computers.   You punched your card deck, put 
in the hopper at the Computer Center, at some point an operator took it 
away, and you came back later to get your printout.

Somewhat later, probably fall 1968, I had a student job with the 
Metallurgy Department, programming in APL (if you think TECO macros are 
convoluted programming, look at APL!).   APL ran on a timesharing system 
hosted at IBM in New York, accessed by a weird interconnection of 
machines and phone lines, and involving running running one operating 
system in a virtual machine on another O/S, communicating with yet a 3rd 
mainframe by dialup.    The APL environment, and the OS it ran on (IBM's 
TSS IIRC?) had been around for at least a few years before 1968.

  I also had a job using CTSS (MIT's Compatible TimeSharing System) on a 
7094 run by the Computer Center as a computing utility for the campus.   
That was a "production" environment, so no hacking of the OS was 
allowed.   At about the same time, Multics was in development as the 
next generation timesharing technology, and I did a project there to 
build a compiler in 1969.    CTSS had been around since 1963 as a 
campus-wide computing service.   Multics was going to replace it.

There were other timesharing systems developed outside MIT.  E.g., BBN 
developed such an OS for the PDP-1 which was running around 1962 or so.

So there was lots of activity in the 60s to build timesharing systems.  
CTSS was operational before I arrived, and had been running for a few 
years before 1966.  Multics was targeted as the successor timesharing 
utility.  But neither CTSS nor Multics were easily "hackable", largely 
because the hardware required was so expensive.   When cheaper hardware 
became available, that spawned ITS - the name an irreverent play on 
words contrasting it as a feisty competitor to CTSS.   A PDP-6 was much 
cheaper than an IBM mainframe.  A similar thing happened with Unix at 
Bell Labs in reaction to the expensive and therefore unavailable 
timesharing of Multics.   A PDP-9 running Unix was much cheaper than a 
GE/Honeywell 645 running Multics.

So I don't think it's not accurate to say that ITS was "the world's 
first timesharing system".  It wasn't even the first timesharing system 
at MIT.

/Jack Haverty
(MIT 1966-1977)





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