Destructive Imaging of DECTAPE II Media

[Brent Hilpert]

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.
> 
> 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...

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.