11 Mar
2005
11 Mar
'05
10:48 a.m.
On Thu, 10 Mar 2005, Loboyko Steve wrote:
Actually, it's possible to build a reader fairly
easily. [...]
[...]
The real problem in a paper tape "ecosystem"
is in the
punches, "handling equipment" and the tape itself; I
got lucky and got a lot of Mylar cheap some time ago,
as well as some real DEC fanfold and reel tape. Mylar
tape is now fabulously expensive at retail.
I concur with all you wrote. There are a lot of 1970's era tape
reader mechanisms around, and they're really easy to interface to.
I made one from a Plessey read head (they're common) and a PIC,
basically it steps until it sees the sprocket hole, then outputs
the byte. (Sprocket hole is smaller, therefore you get good
overlap).
Punches are indeed the harder part. I've got a DSI in decent
shape, nice serial interface for general use, but punch mechanisms
are harder to find, esp. ones easily interfaced. THere seems to be
10 times the number of readers as punches (makes perfect sense in
context of what paper tape was must used fo rin the computer
world).
Paper tape is a PITA and fun at the same time. I like
to point out to friends that the data on the
metallized Mylar tape will be readable (even
visually!) and usable long, long after their hard
disks are very deep down in landfills!
Yup! Even the non-oiled paper will last 500 years if it's kept
dry. It indeed suffers in the data-density department but it's fun
to work with on a non-production basis!