In <[EMAIL PROTECTED]>, on 10/17/2005
at 10:22 AM, Paul Gilmartin <[EMAIL PROTECTED]> said:
>But, what's a "data check"? A phrase search of the same publication
>reveals no definition, cross-reference, or glossary entry.
>Intuitively, I'd expect it to mean an inconsistency detected not by
>hardware, but by software, such as length read inconsistent with RDW,
>or not a multiple of LRECL; i.e. the block appears physically OK, but
>contains invalid data.
E: None of the above.
Each tape format includes some sort of error checking; the older
drives used simple parity (HRC and VRC), capable of detecting but not
correcting errors, while more modern drives used error correcting
codes capable of correcting bursts of errors. If the drive detects an
error in the redundancy check, or an uncorrectable error in the ECC,
then it generates a unit check with a data-check bit in the sense
data.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
ISO position; see <http://patriot.net/~shmuel/resume/brief.html>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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