[TUHS] History of top

Clem Cole clemc at ccc.com
Wed May 30 00:18:57 AEST 2018

On Tue, May 29, 2018 at 2:53 AM, Lars Brinkhoff <lars at nocrew.org> wrote:
> The copyright notice goes back to 1976, which is about then TOPS-20 was
> first released, right?
​Tops-20 or TENEX (aka Twin-Ex).   Tenex was earlier, and came in house to
DEC and was renamed Tops-20 when DEC released the DEC System20 series
(20/40 and 20/60 originally).​

> Is this a TOPS-10 version of SYSDPY?  It was copyrighted in 1970.
> http://pdp-10.trailing-edge.com/bb-jr93e-bb/14/7,6/ap014/sysdpy.x14.html

​Could be -- looks about right,  I do not have a running 10 in simh to
check it these days.  But that looks reasonable,​

> I didn't mean to start a mine-is-older-than-yours

​Sorry, did not mean to start that.  I just wanted to make sure people knew
that Top was not really a Unix-ism or anything new with VMS, or the PDP-10s
for that matter and clarify the origin.  The idea of displaying status was
pretty important in those days for the system as a whole.
As Lyndon pointed out, being able to monitor the batch systems was another
use of this type of display; but that was slightly different than dpy, peek
and the like.
​  This was really to tell the user, when the system would get to your
work.   BTW, ^T was cool on Tenex, because being interactive, it was just
your process and helped you know how where ​your 'active' process stood
relative to the other things the system was doing (i.e. was it running or
waiting and how busy was the system as a whole).

As terminals (paper and glass) became more the norm (*i.e.* interactive /
time sharing system​
s), both the operators of the system as well as the users wanted to keep
track of what was going on to the system -- i.e. processes that were in the
run queue.   In those days, most systems were in a 'computer room' and the
human operator could do much to keep the system running, from mounting mag
tapes to changing system priorities, assigning resources as needed.
Remember in late 1960s dollars, a 4Mbyte 360/67 like what CMU had at the
time, was valued in the $5M range, a PDP-10 was likely to be about $1.5M.
 So the cost of a human operator was valuable, you really wanted to get
100% out of that system - and the people who actually paid for computing
(like the business office or some research project) needed to get
priority.   A tool like this was needed for the operators to know what was
going on and adjust.

The CDC systems had a glass display as the console, that ran the tool
mentioned before.   The Univac, DEC and IBM systems tended to use paper
based consoles for commands and operator status, but often had some sort of
glass display near the console that the operators monitored (I have picture
of me in the CMU computer room from those days and the displays are on my
left).  I don't know how the the GE/Honeywell system were equipted for a
console, as while I was user of same early in my career, I was never an
operator/system admin - i.e. never behind the glass door with them.

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