Vax Unix tape problem

[Spencer W. Thomas]

In article <117 at gsg.UUCP> kathy at gsg.UUCP (Kathryn Smith) writes:
>	The first problem is that both the nightly and the level 0 dumps seem
>unable to cope with writing a full tape of information.  Dump aborts on a 
>tape write error consistently somewhere in the last 400 feet of a 2400 foot
>mag tape.  This is apparently a software error, since no hardware diagnostics
>are showing up on the console.  
>
>	I tried instumenting a copy of dump to find out what is going on, and
>found that the error is coming from the unix write primitive.  The error code
>returned is 'I/O error' (enlightening).  Right now we are functioning by 
>running dump with the size option specifying a tape size of 2000 feet, but 
>don't want to keep doing this for obvious reasons.

Ah yes... Good old dump and it's "tape estimating" feature.  Dump thinks
it knows how many blocks will fill a 2400 foot tape, but depending on
your tape drive, it can be pretty far off.  Looks like your drive writes
larger inter-record gaps than dump thinks it "should".  So, only "2000
feet" of data will fit on your tape.  The "I/O error" means that the
drive has seen the end-of-tape marker, and is not really an error at
all, except that dump can't handle it intelligently.

You will have to keep on using a "tape size" of 2000 feet, because
you're really using the whole tape.  Watch it sometime, and see.

-- 
=Spencer   ({ihnp4,decvax}!utah-cs!thomas, thomas at utah-cs.ARPA)
	"When wrath runs rampage in your heart you must hold still
	 that rambunctions tongue!" - Sappho