27 Jan
2017
27 Jan
'17
4:22 p.m.
On 01/27/2017 03:41 PM, Stan Sieler wrote:
My recollection is that DDS-1 (and perhaps -2?) had
'set marks' that
few people knew about, and even fewer ever used. The explanation I
recall is that the drive could do a "forward to next setmark" *much*
faster than "forward to next EOF". (BTW, when reading, a setmark was
reported like an EOF (although if you requested extra status you
could tell them apart).)
I believe that ANSI refers to them as "partitions", IIRC, defined by a
special page in the MODE_SELECT command. Each partition has its own EOD.
Using the MODE_SENSE code page 11h will turn up information as to a tape
bing multi-partitioned.
Few people made use of the partitioning feature, as far as I know.
All of this is doubtless covered by one or several ANSI X3B5 pubs.
--Chuck