How do I enable tape drive's hardware compression? - BSD

This is a discussion on How do I enable tape drive's hardware compression? - BSD ; On my Compaq internal AIT-2 tape drive running OpenBSD 3.4: # mt -f /dev/rst0 status says density is 49 (0x31) which corresponds to AIT-2. That's correct. That's just an indication of its native (uncompressed) capacity. Linux's mt(8) has a 'compression' ...

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Thread: How do I enable tape drive's hardware compression?

  1. How do I enable tape drive's hardware compression?

    On my Compaq internal AIT-2 tape drive running OpenBSD 3.4:

    # mt -f /dev/rst0 status

    says density is 49 (0x31) which corresponds to AIT-2. That's correct.

    That's just an indication of its native (uncompressed) capacity.

    Linux's mt(8) has a 'compression' argument to enable or disable drive's
    hardware compression.

    I don't see a similar option or equivalent for OpenBSD's mt(8).

    How does one enable drive hardware compression when writing to tape
    under OpenBSD 3.4?

    (I'm using dump -0au -f ...)

    This is a decent tape drive (and OS), so I'm hoping to make the most of
    both if possible.

    Any ideas or comments would be most welcome.

    Thanks!!

    -Dan

  2. Re: How do I enable tape drive's hardware compression?

    In article ,
    Dan Foster wrote:

    > On my Compaq internal AIT-2 tape drive running OpenBSD 3.4:
    >
    > # mt -f /dev/rst0 status
    >
    > says density is 49 (0x31) which corresponds to AIT-2. That's correct.
    >
    > That's just an indication of its native (uncompressed) capacity.
    >
    > Linux's mt(8) has a 'compression' argument to enable or disable drive's
    > hardware compression.
    >
    > I don't see a similar option or equivalent for OpenBSD's mt(8).


    man mtio:
    When the device last number is between 0-7 the device will operate
    at 800
    BPI (or its lowest density), between 8-15 it will operate at 1600
    BPI (or
    its second density), and between 16-23 it will operate at 6250 BPI.


    so in /dev you should have /dev/st0 /dev/st8 ...

    so try mt -f /dev/rst8 status
    (you might have to use MAKEDEV to create st8 ...)

    Havn't got a tape drive to test this theory - but worth a try

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