How to get past end of cpio archive on tape

[David Hoopes]

In article <1991Jan20.172639.364 at fishpond.uucp> fnf at fishpond.uucp (Fred Fish) writes:
>In article <1023 at mwtech.UUCP> martin at mwtech.UUCP (Martin Weitzel) writes:
>>I know this was allready mentioned earlier in this thread, but I think
>>I should repeat for all those who tuned in late:
>>
>>ALL THIS IS TECHNICALLY CORRECT BUT BOUND TO FAIL FOR TYPICAL CARTRIDGE
>>TAPE STREAMERS, SINCE THESE DEVICES PHYSICALLY ERASE ALL OF THE TAPE
>>WHEN WRITING THE FIRST TRACK!
>

True.  I have done this myself.  Once you start writing its gone.  Now
anytime I want to restore from a tape I turn the little write protect
notch to point at safe.  I reccomend this on any kind of a tape drive.
Chances are that by the time you go to restore something off a tape you
are worried about getting your data back.  This is the time that human
error is most likely to happen.  USE THE WRITE PROTECT!!!!

>Add to this that it is also bound to fail for any typical 1/4" cartridge
>which is written and later develops a "bad spot".  I know of no stock
>drives for which any portion of the tape after the bad spot will be
>readable.  Apparently the firmware refuses to have anything to do with
>any portion of the tape after the bad spot.
>

This is not true.  The hardware and firmware are capable of reading past
bad spots.  I also know that Tallgrass drivers will read past a bad spot. I
have tested this myself by creating bad spots both physically (punching a
hole in the tape) and with a magnet.  Of course the data at the bad spot
is lost but data past the bad spot can be recovered.  

Note that application software must have the ability to handle this.  Tar
and some versions of cpio do not.  The cpio that is created by PAX does and
our FileSecure IX software ( A Tallgrass Technologies product) does.


>>(IMHO the topic should go into the FAQ.)
>
>Amen.  This comes up at least once or twice a month.
>

I second the motion.

>-Fred
>-- 
># Fred Fish, 1835 E. Belmont Drive, Tempe, AZ 85284,  USA
># 1-602-491-0048               asuvax!mcdphx!fishpond!fnf


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David Hoopes                              Tallgras Technologies Inc. 
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