On 4/7/2017 10:45 PM, Robert Riches wrote:
> On 2017-04-07, rickman  wrote:
>> On 4/7/2017 12:24 AM, Robert Riches wrote:
>>>
>>> In college, when I worked at the campus TV cable head end,
>>> professors would call in to schedule tapes (mostly U-matic 3/4"
>>> videocassettes) to be played on the cable for their classes, and
>>> students could call in to schedule individual showings.  The
>>> schedule was kept on a PDP-11, IIRC an 11/23.  When on the first
>>> morning shift, one of the duties was to boot up the PDP-11 using
>>> toggle switches to get the machine to read the cassette tape that
>>> held the program and data.
>>
>> Seems like an appointment book would have done the job pretty well
>> without needing an engineering degree.  lol
>
> The scheduling program had a few requirements that would have
> been difficult to meet with an appointment book made from dead
> trees:
>
>   1) The scheduling program was accessed by multiple (Hazeltine)
>      terminals in different rooms, often simultaneously.

I find the telephone is good for that.  It's often that people don't
mind waiting a minute to schedule something.


>   2) The schedule needed to be updated on the fly during a shift.

Yes, a pencil makes updates very easy.


>   3) The cable had nearly a dozen operating channels fed from
>      over a dozen VCRs and a few open-reel (1/2" and 1") video
>      tape machines.  The algorithm to determine where/when a
>      playback could be scheduled was too complex to be done by
>      gray matter without an unacceptably high error rate.

Really?  Sounds pretty simple to me.  Each device being scheduled has a
column vs. time on the vertical axis.  Machines can only be scheduled
while there are no more than the available number of channels in use.


> Now, if the Raspberry Pi had been available at that time
> (1979-1980), a whole lot more cool stuff could have been done.
> (Had to do something to keep the discussion on topic.  :-)

Sorry, still off topic.

--

Rick C

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