Destructive Imaging of DECTAPE II Media

Mark J. Blair nf6x at
Tue Jan 27 15:32:12 CST 2015

> On Jan 27, 2015, at 12:31 , Chris Elmquist <chrise at> wrote:
> I think we should take the tape out of the cartridges and build a thing
> that pulls it through a small pool of Magna-See (do they still make that
> stuff?  Is that what it was called?) and then image them with a camera and
> decode the data from the video.  Maybe even counting the bits by hand will
> be easier than trying to read those &(#$%*$ tapes in any sort of drive.

I think that reading them with magnetic heads will be much easier than trying to read them optically, but I wouldn't mind having some of that magnetic visualization fluid for experimental use anyway.

I've found the track dimensions of the DECTAPE II in a specification on Bitsavers, and I found dimensions of various tracks formats used on audio cassette tapes on another site. I'm about to compare them to see if there's any potential compatibility, since audio cassette tape heads generally have a built-in tape alignment guide that might make things easier mechanically vs. the TU58-XA head (assuming I didn't use a TU58-XA mechanism). I'll follow up with whatever I find. I did determine that both tapes are the same width: 0.15" or 3.81mm.

> In any case, I'm totally in support of any DC100 destructive methods.
> Using them instead of clay pigeons also comes to mind.  :-)

Once the data is recovered, of course. :)

Mark J. Blair, NF6X <nf6x at>

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