24 Jun
2025
24 Jun
'25
12:20 p.m.
On Tue, Jun 24, 2025 at 3:49 PM Mike Stein via cctalk
<cctalk(a)classiccmp.org> 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