[Leaplist] CentOS question ....

[Fred Moore]

On Friday 19 January 2007 09:16, Steve Litt wrote:
> On Friday 19 January 2007 00:14, Damien McKenna wrote:
> > On Jan 19, 2007, at 12:14 AM, David Simmons wrote:
> > > It's weird that your optical drives doesn't show up in
> > > dmesg....maybe double
> > > check connections....replace IDE cables....re-quadruple check the
> > > jumpers
> >
> > Almost every time I've heard of a problem with a newly installed HD
> > or optical drive not working it has been because of the cable and/or
> > jumpers set incorrectly.  Remember, if you have to drives on a cable
> > the drive at the end of the cable should be jumperred for Master
> > while the one in the middle should be Slave (I don't do the cable-
> > select thing myself).  Also, it is best to do one drive per cable,
> > but still remember that it must be jumperred correctly or it probably
> > still won't work.
>
> I've never heard that. Is that for IDE drives? What would happen if the
> master were the middle and the slave were the end?

depends on the system.. sometimes its ok.. many times its not.. 
sometimes your bios saves you...  sometimes not..  more than likely not.. 

think 
controller (channel), next drive (slave), next drive (master)  no more cable 

then they by default get assigned during boot time.. (unless bios screws with 
you).. 

1st IDE controller  
	channel A, slave   (hda)   (first cable 1st drive)
		partition 1   (hda1)
		Partition 2   (hda2)
		....
	channel A,master (hdb)  (first cable 2nd drive)
		partition 1   (hdb1)
		Partition 2   (hdb2)
		....
	channel B, slave, (hdc)   (second cable 1st drive)
		partition 1   (hdc1)
		Partition 2   (hdc2)
		....
	channel B, master (hdd) (second cable 2nd drive)
		partition 1   (hdd1)
		Partition 2   (hdd2)
		....
2nd IDE controller
		....

if you use cable select (CS) on your drives this is the order they will be 
assigned..  But like others have said.. I always jumper my drives, don't 
really know why.. guess just an old habit.. getting too old to change.. 

and for performance you don't want slower things like cdroms on the same 
channel with your disk drives..   the channel always runs at the speed of the 
lowest device.. 

Steve I seem to remember we fixed one of your not booting mobo's by setting 
this correctly..  or perhaps I remember wrong.. . its been years.. many holes 
have developed in the gray matter.. Fred








>
> SteveT
>
>
> Steve Litt
> Author: Universal Troubleshooting Process books and courseware
> http://www.troubleshooters.com/
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-- 
Fred Moore
WD8KNI
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