On Tue, 9 Oct 2001 at 9:08am, Jeremy Wadsack wrote
> Joshua Baker-LePain ([EMAIL PROTECTED]):
>
> > On Mon, 8 Oct 2001 at 5:36pm, Jeremy Wadsack wrote
>
> >> >> define tapetype EXB-8505XL {
> >> >> comment "Exabyte 8505XL tapes (works with Exabyte 10h changer)"
> >> >> length 9584 mbytes
> >> >> filemark 917280 kbytes
> >> >> speed 667 kps
> > define tapetype Eliant-820 {
> > comment "just produced by tapetype program"
> > length 6680 mbytes
> > filemark 0 kbytes
> > speed 949 kps
> > }
> So do you have any idea how tapetype wrote 9.5GB to a 7GB tape?? If
> hardware compression would have made it less, then do you think that
> there was some kind of tape error?
No, I have no idea. But if you can figure it out, patent it quick! ;)
Actually, the fact that your filemarks are nearly 900MB big would seem to
indicate that there *is* some sort of a hardware/software/firmware/driver
issue. What OS are you running? Is there some sort of a st.conf file
that needs updating?
> > Do you mean that in a single night's run, using multiple tapes,
> > you're only getting 2GB per tape?
>
> I'm only using one tape per run. But it's only putting 2GB (1GB last
> night) on the tapes that had 5GB last week. The change that resulted
> in this was the change of tapetype.
That may very well have to do with the filemark value, again.
> Does anyone know how to turn off hardware compression on an Exabyte
> 8505 drive? I can't find any reference to it in the manuals...
With this drive (on Linux, at least), compression is controlled by setting
the density via mt. 'mt densities' shows the following relevant entries:
[jlb@chaos jlb]$ mt densities
Some SCSI tape density codes:
code explanation code explanation
*snip*
0x14 EXB-8200 (RLL 43245 bpi) 0x80 DLT 15GB uncompressed
0x15 EXB-8500 or QIC-1000 0x81 DLT 15GB compressed
*snip
0x1c QIC-385M 0x8c EXB-8505 compressed
0x1d QIC-410M 0x90 EXB-8205 compressed
So to write in uncompressed mode, you do
'mt -f /dev/nst0 setdensity 0x15',
and to write in compressed mode you do 'mt -f /dev/nst0 setdensity 0x8c'.
--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University
