[WBEL-users] That hard disk - again

[Pete Biggs]

On Mon, 2005-05-02 at 00:40 -0500, Edward Rudd wrote:
> On Sun, 2005-05-01 at 16:12, Francies Moore wrote:
> > Hi everyone,
> > 
> [snip]
> > 
> > The only different thing about this system is that the CD drive is the 
> > primary master (/dev/hda) - could this setup cause problems?  The failed 
> > disks were /dev/hdb and /dev/hdc.
> 
> I always have CDroms as slaves to harddrives. It's better to have the
> "faster" device the master.. and singles if possible.  

The critical thing is that the IDE bus will only go as fast as the
slowest device - so if you have an ATA-33 and an ATA-100 device on the
same IDE bus, ALL transfers will be at ATA-33 speed regardless of which
is master or slave.  CDROMs are invariably ATA-33, modern ATA hard disks
are usually ATA-100 or ATA-133, so mixing CDROM and hard disk on the
same bus will severely reduce the speed of the hard disk.

For single drives, have the hard disk on the first IDE bus and CDROM on
second. If you have two hard disks and simultaneous access to them at
full speed is not critical, then have them both on the first bus.  If
speed is critical than either ditch the CD drive or get more IDE buses.
If speed is really critical, then invest in SCSI!

P.

-- 
Pete Biggs :{)        pete @ physchem.ox.ac.uk   pete.biggs @ chem.ox.ac.uk
01865 275490 (Work)   pete1biggs @ gmail.com     pete @ biggs.org.uk