Date: Mon, 26 Feb 2001 13:35:57 -0600
From: Don Holmgren
Subject: Re: 2.5-m Obs Log 20010223 (MJD 51964)
From the murmur log, I also think this was related to a tape with a bad
directory, and probably not a dirty head.
A "bad directory" occurs when a cartridge either has never been
initialized, or when the cartridge is loaded and in the middle of tape
when the tape drive is reset or power cycled.  The best thing to do is
to use a different cartridge if you notice this during pre-flight.
However, the DA will go ahead by default and use such a cartridge.
This is OK, as the tape drive will write a valid directory before the DA
starts writing.
Don Holmgren
On Sat, 24 Feb 2001, s. a. snedden wrote:
>                    APACHE POINT OBSERVATORY SDSS 2.5M
>
>                              OBSERVING LOG
>
>                         Friday, February 23, 2001
>
>                               (MJD 51964)
>
>
> During the pre-flight checkout, Dan got an error message saying "dirty
> head and/or bad tape" for id 3-1. This occurred while he was rewinding
> and mounting the tapes. The cleaning light, however, was not on and the
> tape archived a bias happily. The error messages I found were related to
> rewinding and mounting (bad tape directory):
>
> 	Feb 23 16:39:04 sdsshost   IDA 201265 TEXTONLY ...nding tape2s on id1
> id2 id3 id4 id5 id6
> 	Feb 23 16:39:04 sdssid3    dArchSrv   TEXTONLY archCmd: archRewind 1
> 	Feb 23 16:39:04 sdssid3    dRewind    dsc_E_archDirBad Bad tape
> directory drive ID 1
> 	Feb 23 16:39:04 sdssid3    dRewind    dsc_I_archTapeStat tapestat 1
> CX937R0298 (none) (none) 0 		34 0 0 0 0 0 0 267 35546 0 86 0
>
> 	Feb 23 16:39:58 sdssid3    dMount     dsc_E_archDirBad Bad tape
> directory drive ID 1
> 	Feb 23 16:39:59 sdssid3    dMount     dsc_I_tapeMounted Archiver
> mounted tape JL3678 drive 1
>
> Even though archiving appeared normal, we wonder if there might be
> trouble reading the tape later under these circumstances. A PR asking
> about this was filed.