Re: howto disable hardware compression on redhat linux

* Bruno Negrão <bnegrao-amanda AT engepel.com DOT br> [20030922 14:36]:
> Hi Martinez,
> 
> > The devices /dev/*st0
> >
> > Various letters in front of "st0" mean different things, like "no-rewind",
> "no-compress", etc.
> 
> I already knew that. But I´m asking for what is the exact letter for disabling
> hardware compression - if really there is one for red hat linux.
> If you know it, tell me.

That depends also on the hardware. At home I have an old 4mm dat
peregrine tape drive and to have no hardware compression all I have
to do is to specify it in /etc/stinit.def

manufacturer=ARCHIVE model = "Python 00095-001" {
scsi2logical=1 can-bsr can-partitions auto-lock
mode1 blocksize=0    compression=0 density=0x24
mode2 blocksize=1024 compression=0 density=0x24
mode3 blocksize=0    compression=1 density=0x24
mode4 blocksize=1024 compression=1 density=0x24}

Then you load the st module with /etc/modules.conf containing the
stanza:

post-install st /sbin/stinit

The just make the character (no-rewind and rewind) devives like:
~$ ls -l  /dev/nst0*
crw-rw----    1 root     disk       9, 128 Apr 11  2002 /dev/nst0
crw-rw----    1 root     disk       9, 224 Apr 11  2002 /dev/nst0a
crw-rw----    1 root     disk       9, 160 Apr 11  2002 /dev/nst0l
crw-rw----    1 root     disk       9, 192 Apr 11  2002 /dev/nst0m
~$ ls -l  /dev/st0*
crw-rw----    1 root     disk       9,   0 Apr 11  2002 /dev/st0
crw-rw----    1 root     disk       9,  96 Apr 11  2002 /dev/st0a
crw-rw----    1 root     disk       9,  32 Apr 11  2002 /dev/st0l
crw-rw----    1 root     disk       9,  64 Apr 11  2002 /dev/st0m

I left as an exercise to determine which device correspond to which
mode in stinit.def :)

bingo.
jf

> 
> Thank you,
> bruno.
> 
> >
> > Michael Martinez
> > Linux System Administrator
> > ISTM/CSREES
> > United States Department of Agriculture
> >
> > -----Original Message-----
> > From: Bruno Negrão [mailto:bnegrao-amanda AT engepel.com DOT br]
> > Sent: Monday, September 22, 2003 2:05 PM
> > To: amanda users
> > Subject: howto disable hardware compression on redhat linux
> >
> > Hi all,
> >
> > Howto disable hardware compression on redhat linux? In the "Unix & Backup
> > Recovery" book, the author says that this is done mostly by using a specific
> > device name. Which is this device for a redhat linux?
> >
> > Thank you,
> > Bruno Negrão
> >
> >
> >

-- 
fate amenable to change