What's magtape good for anyway?

[Pete Turnbull]

On Apr 2, 22:15, Ed G. wrote:
> Subject: Re: What's magtape good for anyway?

> Was dectape an attempt to remedy some of these problems?  My
> hazy recollection was that you could treat dectape in some ways as if
> it were a disk.

Yes, in the sense that you could perform random-access operations on it.  I
used a PDP-8 that had twin DECtape instead of disks.  It supported 4(?)
teletypes in a multi-user environment.  But DECtape was not 1/2" tape, nor did
it use reels like the ones that later became standard.

> How much data can magtape hold?  If magtape was a portable media,
> does that mean that the manufacturers agreed on the width of
> the tape, the density of recording, the method of recording bits,
> etc.?

Yes to all of those, though there are three standard recording densities
(80bpi, 1600bpi, 6250bpi) and several recording methods (NRZ, NRZI, PE, etc).
 There are different standard lengths too:  600' 1200' 2400'.

> I have an old 9 track tape from a computer course I took in 1980.
> For sentimental reasons I'd love to get a copy of its contents.  Is
> this possible do you think?

Shouldn't be hard, unless it's suffered from print-through after 18 years.
 It's probably 800bpi (NRZI) or 1600bpi (PE).  Whether you can understand the
contents depends on the format of the data, of course.


-- 

Pete						Peter Turnbull
						Dept. of Computer Science
						University of York

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