• Please review our updated Terms and Rules here

Paper Tape ID's

Mike_Z

Mike_Z

Veteran Member
Joined
Dec 1, 2013
Messages
1,713
Location
Near Milwaukee Wisconsin
Winter is coming and some of my outside projects are coming to an end. I still have some suspenions work on my 1939 Chevy and some storm window painting to complete, but Soon I want to be spending more time in the basement with all my computer stuff. I'm still working on a raspberry PI code converter for my Flexowriter. I had it working and then decided to make a PCB board from the prototype breadboard, but there must be a mistake that I could not find prior to warm weather, because it doesn't work. One other project I want to take up is a way to ID paper tapes. I have made a bunch of MAINDEC paper tapes and have them in some small labeled boxes, but once they are out and about, I have to write on them what they are. I seem to remember, a long time ago, when I was using paper tapes for real, there was a program that could punch the filename, in English prior to the tape leader. I suppose I could write something, but there must be some code that I can either copy or alter and make work. Can anyone point to place to look? Thanks, Mike
 
Hello Dave. Hows things on the east side of the pond? I think what you have is just what the doctor ordered. Later in the week the temperature is to drop and we are to get some rain or some of the other stuff. This maybe the perfect time to fire up the PDP8E and see how this code works. Thanks, Mike
 
I know it seems like punching text into the tape is a good idea but it is quite a bit easier to read a sticky paper label like DEC used on the tapes originally. You can buy label stock and run it through your printer or just write on the label.

A "real" copy of a maindec would already include something like MAINDEC-08-D01A COPYRIGHT DIGITAL EQUIPMENT CORPORATION 1967 punched into the tape in what I think was a 4x6 font. Actually they changed fonts around 1969 or 1970 to a more friendly font.

There are several ways to look at paper tapes.
  1. If you want an exact copy of the original then you have to remove the sticky label and read the TEXT PUNCHES. This will get you the human readable stuff at the front of the tape. This tape is pretty worthless for anything except for reading with a paper tape reader because you skip past all that stuff and position the tape in the leader section when you load the tape. Simh does not have a way to do this so reading such a tape image on an emulator would result in frustration.
  2. You can strip off all that extra fun stuff at the front and have a standardized amount of leader. The Maindecs were supplied on fanfold and the leader was generally a couple of fanfolds in length. I am not sure how many leader characters PIP punches and it probably varied from release to release. These would work on a real paper tape reader and on an emulator.
  3. The last one would be a tape where the leader was reduced to a single frame and the same would be done to the trailer code at the end. Almost useless if you punch it and try to read on a physical tape reader it because it is difficult to position the single leader punch in the correct spot on the reader. This is the most efficient from a storage standpoint and having a single leader character makes comparing tape images easy.
We, me and Warren Stearns, discussed this at length and we captured a small portion of my paper tape collection. There are four files for each tape. One is the tape ID consisting of four lines with the text that was on the paper label. The second file is the contents of the tape with a standard number of leader and trailer punches. I think the number was the same as PIP would punch on the early version of OS/8 I had on my Straight 8. The third file is an octal dump of the tape with one octal number per line. The final file was all of the tape including the Human readable punches at the front. Not all of my captured tapes have this because the paper label covered some of the punches and for those I was hand adding what was covered up. My temptation today would be to take a photo of the paper label also.

One of the crazier ideas we had was to make a video of the tape being pulled past a lamp at a fixed speed. This of course would be useful to the AI overlords when they take over everything and want to see what a paper tape looked like.
 
Hello Dave, good to hear from you also. I do not have any DEC paper tape equipment. I have a REMEX reader and a Teletype ASR33. So originality is not necessary. What I'm looking for is convince of ID. I like the idea of sticking labels on the tape, much more information could be added. When I get time I want to experiment with punching the filename into the paper tape. Always thought that was neat, but will most likely also use the labels. Let you know how it works out, Thanks, Mike
 
Punching the front of the tape with human readable info is neat. But not all that useful in practice. With fanfold you get around 10 or so letters on each fold. And it is not easy to read unless you hold it up to the light. But it is still neat and was done by DEC.
 
Hi Mike.

Things are somewhat 'busy' on this side of the pond for me at work - so spare time is at a premium I am afraid.

Nice to see you back on the '8' now the winter is setting in. Keep warm...

Dave
 
You must log in or register to reply here.
Back
Top