27 Jan
2015
27 Jan
'15
8:48 p.m.
----- Original Message -----
From: "Brent Hilpert" <hilpert at cs.ubc.ca>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Tuesday, January 27, 2015 10:04 PM
Subject: Re: Destructive Imaging of DECTAPE II Media
On 2015-Jan-27, at 6:51 PM, Mike Stein wrote:
----- Original Message ----- From: "Brent Hilpert" <hilpert at
cs.ubc.ca>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Tuesday, January 27, 2015 7:32 PM
Subject: Re: Destructive Imaging of DECTAPE II Media
On 2015-Jan-27, at 3:58 PM, Mike Stein wrote:
Can't tell from that pic - can't see internals.
Pics of the 9830 transport well down the page here:
http://www.cs.ubc.ca/~hilpert/e/HP9830/gallery/index.html
Some tech details of use in the 9830:
http://www.cs.ubc.ca/~hilpert/e/HP9830/hardware.html#tape
although I should correct my earlier statement: the HP uses 2 half-tracks
for 1 bits and 0 bits, not data and clock as you indicate for the Burroughs,
but they're still very similar, the diff would just be in the electronics.
----- Reply -----
No, completely different mechanically and electronically, and the analog and
most of the digital electronics are on a set of five cards at the back of
the unit.
But that doesn't mean they couldn't read each other's tapes with some effort
and a few jumper wires ;-)
Found the Tech manuals; FWIW:
Model: A9490
Read speed:
Start & stop: 10 ips
Continuous: 30 ips
Write speed: 10 ips
Mode:
NRZ (2 tracks, clock & data)
or (optional):
PE (Single track, can use both sides)
Rewind speed: 60 ips
Doesn't Al have one of these at the CHM on a B700 or something similar?
I can't find it at the moment but somewhere I
have a Burroughs digital
cassette drive, capstan-less and capable of high-speed bidirectional
seek. AFAIK it uses the standard half-track mono tape format, one track
for data and the other for the clock.
That description fits the tape system used in the HP9830. The tape
transport is actually a "DigiDeck" OEM'd by International Computer
Products, out of Dallas, Texas. The head is non-standard though, in that
it R/Ws both half-tracks simultaneously.
Don't know if it'd be useful and not sure
if I want to part with it
permanently, but keep it in mind if nothing else works out and you get
desperate ;-)
I don't think it would be of any benefit to the OP's interest over what he
already has to work with.=
----- Reply -----
Probably not, but I thought I'd mention it just in case; it doesn't use a
pinch roller though, and it is completely digital, FWIW.
I don't recall whether it was a DigiDeck, but ISTR that I compared the BBM
unit to another digital deck that was (relatively) popular way back when,
and I'm pretty sure that they were different.
http://www.picklesnet.com/burroughs/images/fullsize/burr0050.jpg
They were mostly used with Burroughs Series L machines, but I think some
of the small B series could also be equipped with them. I've still got a
few boxes of utility, game and program tapes for Burroughs L series
machine, but working L's are pretty thin on the ground so I sometimes toy
with building an emulator; that's why I still have the tapes and the
drives (although unfortunately I threw out a lot of paper tapes a long
time ago), but that project is pretty far down on the list... 