9 track tapes and block sizes
cclist at sydex.com
Sun Oct 4 22:47:25 CDT 2020
On 10/4/20 8:12 PM, jim stephens via cctalk wrote:
> On 10/4/2020 4:00 PM, Chuck Guzis via cctalk wrote:
>> On 10/4/20 1:50 PM, J. David Bryan via cctalk wrote:
>> I don't believe that you're missing anything. When I process these
>> files, I mask off the lower 24 bits as the block length. A 16MB tape
>> block is impossibly large in any case.
> Oil logging tapes write 9 tracks with no inter record gaps or file marks
> till EOT. I'm guessing you've not digitized any of those?
A couple of years ago, one of the NASA logging units turned up for not
much money. Big flight case. Basically consisted of a Kennedy
incremental drive (i.e. stepper) brought out to several BNC connectors.
My recollection is that the Kennedy 9000-series unit was NRZI and likely
800 bpi. Unlikely that you could get 16MB on a 10.5" reel with that.
Probably unreadable on standard tape drives with limited formatter
memory. I've also mentioned CDC 7-track "long tapes".
I've certainly seen the 9-track analog telemetry tapes also, but they're
a much different kettle of fish.
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