My Exabyte has a personality! It hates cp! HELP!!

[Jim Brennan]

In article <1991May2.044713.12583 at coplex.uucp> dean at coplex.uucp (Dean Brooks)
writes:
->
->      We just recently acquired an Exabyte 2.3 gig tape drive for our
->   Motorola SYS V.3.2 (V/88) 8864 system, and I have noticed something
->   unusual.
->
->      The two files will have different lengths, varying anywhere from
->   1,000 bytes difference to 38,400 bytes difference.  *However*, if I
->   use "cpio" to backup the file and then restore it, it works perfectly.
->
->   I have tried this test over and over with different files, and it *never*
->   works with the "cp" or "cat" command, but *always* works with cpio.
->
->   Is there a problem with "cat" or "cp" not doing an fflush or something
->   ignorant like that?  By the way, the /dev/exabyte file is a character
->   based device, not a block based device.
->
->   Any clues?

You must access character special tape devices on R32V2 in multiples
of the logical block size for the device.  Most tape devices have a
logical block size of 512 bytes (streaming tapes).  The exabyte uses a
logical block size of 1024 bytes (this is the most efficient record
size for the exabyte).  This is why cp and cat do not work.

You can use dd to do what you want, and specify a block size of 1024
bytes:

	dd if=/tmp/myfile of=/dev/exabyte bs=1024

Note: see the MVME328 manual page for more information.

->   --
->   dean at coplex.uucp (Dean Brooks)
->   Copper Electronics, Inc.
->   Louisville, Kentucky

--------
jbrennan at urbana.mcd.mot.com || uiucuxc!udc!jbrennan
Motorola Computer Group, Core Technologies
Urbana Design Center, Urbana, IL