Help reading a 9 track tape

[Paul Koning]

> On Aug 6, 2021, at 1:21 PM, John Foust via cctalk <cctalk at classiccmp.org> wrote:
> 
> At 11:45 AM 8/6/2021, Jay Jaeger via cctalk wrote:
>> On 8/5/2021 2:57 PM, Len Shustek via cctalk wrote:
>>>> On Aug 5, 2021, at 8:39 AM, Jay Jaeger via cctech <cctech at classiccmp.org> wrote:
>>>> I know Paul well (we were contemporaries at U. WI).
> 
> Where did Paul work at UW-Madison?  I don't recall him.  I was on campus
> from 1981 to 1985.
> 
>> There is also this one for 9 track drives:
>> https://github.com/jakubfi/ninetracklab
> 
> Has anyone ever developed a method of reading a magnetic tape
> with some sort of array of new sensors capable of the pre-1908s
> densities and tracks?  A fine array of Hall effect sensors?
> At 6250 BPI the bits are pretty tiny, aren't they?

That was done by a number of people using MR (magneto-resistive) heads.  John Bordynuik was one of them, years ago; some others have done likewise.  Those heads were built by IBM for high density tape cartridges; 6250 is low density for them.  They have some nice properties, from what I understand, one of them is that the output signal levels don't depend on the tape speed as regular inductive heads do.  So for old tape recovery you can readily run at very low speeds if needed to protect fragile media.

	paul