Old Computer technology forgotten

3 December 2016

Have we already forgotten how to use some of the computer technology from just a few years ago. Perhaps they need better (and older) tech consultants on programs. I was watching the latest episode of Timeless S01E08 Space Race. The plot takes us to the Apollo 11 moon landing and that a modern day virus is inserted into a 60’s era mainframe computer to disrupt the communications stranding Neil Armstrong and Buzz Aldrin on the moon.

A virus attacks flaws in the operating system or other privileged programs on a system. I suppose that we now have more knowledge of these problems, but how these would relate to operating systems of the 1960s is just not credible. So let us take the leap of faith and believe that a modern virus could affect computers of this era, and just look at the mistakes in dealing with this technology for a moment.

We enter into what looks like a IBM system/360 computer room. Firstly they insert a papertape program into the machine. This presumably is some form of bootstrap program, though that is not clear from the dialogue.

Loading the papertape machine

They have obviously just got a random bit of papertape and used that. In reality there would be a substantial leader of blank tape at the beginning. This would normally have either a typed label, or more likely, a handwritten description of the contents. The reader would normally have a sprocket wheel to thread the tape onto and a clip over tab to hold and guide the tape through.
I can remember it being cool to punch holes in the leader tape that made up dot-matrix like characters. This was a matter of setting up the bit image of the characters and adding this to the start of the punch sequence. That makes it sound much easer than it was.

example of fanfold papertape with printed label and punched characters

I mostly worked on Digital Equipment and Data General machines that used fanfold papertape, but there was also the teletype machines, that used loose tape. You would typically use a pair of plastic bins to hold the in and out portions of the tape. But this was quite untidy and the tape could easily be torn if it tangled up in the bins.

Next there is a sequence of loading a reel of ½” magnetic tape. In the background there are racks of tapes with the plastic surrounds (frequently called a “tape seal belt” because its purpose was to prevent humidity and dust on the media). There was a later innovation of these that usually matched with a automatic loading system. The tape, with the ring was loaded onto the drive, and the drive mechanism would open the seal, vacuum the tape through the machine onto the fixed takeup reel. The point is that you did not remove the seal belt before loading the tape. In the episode they remove the ring before taking the tape over to the machine. The tape drives do not appear to have the auto-loading mechanism, so they did this bit right.

Tape reels have an opaque side and a transparent side. The opaque side is the back of the reel and you would always load the tape with the transparent side outwards. As well there is a plastic ring that can be inserted into the back of the reel. This was a write protect ring. The drive would only be able to write to the tape if this ring was inserted. The ring was detected with a probe on the tape drive. so this ring must be on the back side of the reel when loaded into the drive. Also the tape on the reel was always loaded clockwise, inserting a reel back-to-front would not work at all.

Tape loaded back to front

With the write protect ring visable

They then press the top left button to supposedly load the tape. I suspect that this is the rewind button so it makes the drive spin as though it is doing something. I am surprised that they did not end up with lots of tape everywhere as the drive would try to unwind the rather than rewind. Perhaps they only had empty reels of tape, so they had to put them on backwards so you couldn’t see that there was no tape on them?

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