Destructive Imaging of DECTAPE II Media
mhs.stein at gmail.com
Tue Jan 27 22:48:52 CST 2015
----- 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:
>> 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.
> 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...
Can't tell from that pic - can't see internals.
Pics of the 9830 transport well down the page here:
Some tech details of use in the 9830:
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
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:
Start & stop: 10 ips
Continuous: 30 ips
Write speed: 10 ips
NRZ (2 tracks, clock & data)
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?
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