Software by the yard

Here we have a few yards of software, neatly folded in a fanfold. This was the method of choice to distribute software for minicomputers in the 70’s.

DEC punched paper tape distribution

Below are some closeup views. The actual software code resided in the holes; each vertical line of 8 large holes represented one character (byte). The smaller holes fit a sprocket on the tape reader, which pulled the tape when it was being fed into the computer.

DEC punched paper tape distribution
Punched paper tape

The photo below shows the tricks you could play with these tapes – here we have a copyright notice punched in human-readable form.

Punched paper tape

As with any software, this medium could be, and was, copied. This was done with a Paper Tape Punch – a standard item in any computer lab (PDP computers were not something you had at home, remember). The copied tape would usually come out in a roll, not a neat fanfold like DEC’s; an example, from the lab I was a student in, is shown in the next photo. Copy protection had not been invented yet…

Punched paper tape

Exhibit provenance:
I bought this one on eBay, from a vendor specializing in DEC products. It came with a few pages of documentation, printed on paper. For a device supposed to make us paperless, the minicomputer certainly consumed a lot of trees!

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