how "reformat" DLT IV tape from 20/40 to 40/80?

[Palle Girgensohn]

--On tisdag, november 23, 2004 15.46.26 -0800 Josef Grosch 
<jgrosch at MooseRiver.com> wrote:

> On Tue, Nov 23, 2004 at 11:15:12PM +0100, Palle Girgensohn wrote:
>> Hi!
>>
>> I tried degaussing a tape, but the degaussed tape is not accepted by the
>> taper. The tape is ejected after about 30 s, the Media light flashes,
>> manual says:
>>
>>  An inappropriate tape has been
>>  loaded into the drive. The tape
>>  should automatically eject.
>>
>> Do I need to format the tape? I really doubt that, and how would I be
>> able  to do that anyway if the tape is not accepted by the taper? Was it
>> not  enough degaussed? Also seems odd, doesn't explain why the taper
>> ejects the  tape?
>>
>> Any ideas welcome!
>>
>> Regards,
>> Palle
>
> Most likely the tape is defective. These tape drives keep track of the
> number of defects it finds on a tape. If that number goes above a certain
> count, 20 I think, the tape is rejected. Also, the drives tries to read
> and/or write a header on the tape. If it can't the tape is rejected.
>
> Your best bet is to throw that tape away and get another. I used to have a
> box full of tapes that my 8mm drive rejected. I thought that I might be
> able to get them to work. Repeated degaussing never did the trick.

Maybe, but it was not defective before degaussing. According to specs, the 
DLT's need a pretty strong magnetic flux to be properly degaussed. My best 
guess is it was not enough degaussed. But perhaps it became defective by 
the degauss. It just seems so unlikely...

Thanks for the input!

/Palle