dumping to 600' tape

[Joe Smith]

In article <8905121300.AA01476 at cobra.mitre.org> gfr at cobra.mitre.org (Glenn Roberts) writes:
>X-Sun-Spots-Digest: Volume 7, Issue 296, message 7 of 19
>X-Issue-Reference: v7n286
>
>> When I try to dump to a 600 feet, 1/4 inch tape I get an incorrect number
>> of tapes required if I use the following command:
>> 
>> 	dump 0ucsf 5175 /dev/rst0 /dev/sd0g
>> 
>> Basically, dump seems to under-estimate the number of tapes required
>> by a factor of 10.
>
>One way to avoid this problem is to avoid using the older quik-11 format
>/dev/rst0 - I always use /dev/rst8 (quik-24 format).  Things seem to work
>fine for me using the command exactly as described in the Sun manual:
>
>	dump 0ucfs /dev/nrst8 600 /dev/rsd0g
>
>the c option says this is a cartridge tape; the s option with parameter
>600 says the tape length is 600 ft (if you leave it out dump will assume a
>450 foot tape).

Glenn's advice works only for SunOS 4.0 and not 3.x, which the original
poster must be using.  The difference between rst8 and rst0 is not
relevant; they both hold 60 megabytes on a 600 foot cartridge.  (See page
83 of System & Network Administration, part #800-1733-10 9-May-88,
included in SunOS 4.0.)

The man pages for the version of dump that came with SunOS 3.5 says "to
estimate the size for a tape or cartridge of a nonstandard length, use the
formula: (length * tracks) * 0.95".  The size specified must include all 4
tracks on a 4-track cartridge (found only on Multibus Sun-2 systems) or
must include all 9 tracks on current 9-track cartridges.  That is, "s
3825" for 450 foot tapes and "s 5130" for 600 foot tapes.

The man pages for SunOS 4.0 says the default size for a 450 foot cartridge
is 425.  That is, dump no longer requires you to multiply the tape length
by the number of tracks.  Use "s 570" for a 600 foot tape.

Moral: RTFM.  And when you upgrade the OS, RTFM again.
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