31 Mar
2020
31 Mar
'20
11:16 p.m.
How did you format the tape?? A TU55 DECtape could be formatted, but I
thought that the cassette tapes had to be bought preformated.
On 3/31/20 5:14 PM, Clem Cole wrote:
exactly.? ?You could use some COTS tapes if you
carefully cut the case
with a box cutter to make the notch, which we as students got pretty
good at. IIRC Memorex worked best.? You could not use the really cheap
tape, but DEC used saturation recording.? ?The official DECcassettes
and compatible from the aftermarket sellers cost more than what you
got at the music store in Oakland.
On Tue, Mar 31, 2020 at 5:04 PM Dave McGuire <mcguire at neurotica.com
<mailto:mcguire at neurotica.com>> wrote:
? He's talking about DECcassette, not DECtape.? The DECcassette looks
like a standard Philips-style audio tape (of Walkman fame) but has a
notch in the top.
? ? ? ? ? ? -Dave
On 3/31/20 5:01 PM, Thomas DeBellis wrote:
Are you referring to DECtape II?? That was a
cassette.
I was referring to the (nearly indestructible) earlier format:
simply
called DECtape or DECtape I.? It's the same
media as LINCtape (a
small
reel), but with a very different controller.?
These could store
a little
over 70K (36 bit) words.
On 3/31/20 4:40 PM, Clem Cole wrote:
> Dave the TA11 (DEC proprietary Phillps Cassettes) were 150 ft
long.
> ?I just looked in my 1976 Peripherals
Handbook -- Tape capacity of
> 92,000 bytes (not kbytes mind you).? ?Two tapes?per TA11; one
for the
> OS and the other the user.? ?We had a couple
at CMU on 11/20's
running
> RT-11 in the EE Digital lab for the RT
system's course - in
fact, the
> famous "110v non-maskable
interrupt" occurred on one of those
machines
>
> On Tue, Mar 31, 2020 at 3:14 PM Dave McGuire
<mcguire at neurotica.com
<mailto:mcguire at neurotica.com>
> <mailto:mcguire at neurotica.com
<mailto:mcguire at neurotica.com>>>
wrote:
>
>? ? ?On 3/31/20 2:33 PM, Thomas DeBellis wrote:
>? ? ?> 32MB really was ginormous back in the day; our labs had RT on
>? ? ?RK05's,
>? ? ?> which held about 2.5MB.? Way more than a DECtape.
>
>? ? ?? When I started out, I had it on RL01s.? But I suspect you
have a
few
>? ? ?years on me. ;)? That was quite a bit of
space at the time.
>
>? ? ?? ? ? ? ? ? -Dave
>
>? ? ?--
>? ? ?Dave McGuire, AK4HZ
>? ? ?New Kensington, PA
>
--
Dave McGuire, AK4HZ
New Kensington, PA