Burroughs used both type 1 and 2; the issue with the 'high speed' optical readers was not so much internal but external, when the tape would accidentally get tangled and torn. Mylar was just so much more forgiving, even after a hundred or more reads, by which time the normally fairly stiff mylar would have become as soft as a good quality toilet paper.
On Tue, Jun 24, 2025 at 3:20 PM Tony Duell <[email protected]> wrote: > On Tue, Jun 24, 2025 at 3:49 PM Mike Stein via cctalk > <[email protected]> wrote: > > > > Mylar tape was indeed used in hostile environments but also elsewhere > where > > it would be read many times, for loading programs, firmware or fixed > data; > > the much cheaper and more fragile paper tape would usually be used for > > transferring or archiving data which would either be stored and archived > or > > read once and discarded when an updated tape was made. > > It depends to some extent how 'kind' your reader is to the tape. > > There are basically 3 types of readers, least kind first : > > 1) Feed using the sprocket holes on a toothed sprocket, sense the data > holes with mechanical feelers (Creed call them 'Peckers' in their > service manuals). Often found as part of ASR teleprinters. > > 2) Feed using the sprocket holes on a toothed sprocket but use a > non-contact method to sense the data holes, Normally optical but there > was at least one capacitive reader. An example is the DEC PC04 or > PC05. There are many others. > > 3) Feed the tape between a smooth capstan and pinch roller. Sense the > sprocket and data holes using a non-contact method. HP2748, some > Elliot readers, the excellent Trend UDR700 or HSR500.etc. > > A paper tape may be damaged after a few passes through a mechanical > reader but will be good for hundreds of reads on one of type {3}. > > -tony >
