What's the diff between "master" and "slave" drives?

[Bobby]

Can someone explain the difference between making a HD a master drive and
making it the slave drive?

I've laways presumed the master drive was bootable and the slave not. Is
that correct? If so, is that the only difference?

Cheers.

Bobby

 

[Alex Marshall]

It doesn't make any difference, both are still bootable. The system will
boot from the active partition, which could be on either drive.

 

[Bobby]

So what's the point is setting a device as master or slave?

 

[Alex Marshall]

Because you have two drives using the same cable, only one can be in use at
a time. So the system must have a way of differentiating between them. It's
similar to how you must assign SCSI devices their own unique number on the
chain. For IDE drives that is where the master and slave setting comes in.
The drive designated as Master has priority over the Slave drive. That is if
the slave drive is being accessed and a request is made to the master, the
slave must stop and wait for it to finish whatever it needs to do. This is
also why it's recommended to have both drives on separate channels if
possible; it improves performance because they can both be in use at the
same time. As before though this does not have anything to do with which
drive is capable of booting. Your hard drive will still boot even if it is
connected as a slave, though because the master has priority the system
drive is normally connected as master.

I hope that makes sense

 

[DaBa]

Sorry to hijack your thread Bobby/Alex

Alex, I guess from your description my configuration could
be 'souped up' a bit.

I have :-

PRI Master HDD (Boot Drive)
Slave HDD (Data Drive)
SEC Master CD-RW
Slave CD-ROM

Would you recommend a reconfigure to:-

PRI Master HDD (Boot Drive)
Slave CD-RW
SEC Master HDD (Data Drive)
Slave CD-ROM

or similar ?

My PC could certainly do with a performance boost !!

TIA

 

[Alex Marshall]

If it were me I'd probably leave it the way it is. You would definatly want
your hard drive and CD-RW on different channels since you're most likely
going to be using them both at once (when burning files from the hard disk
to a CD-R). So you've got that right on in my opinion. Another thing to
consider is that when you have two devices on the same cable, both will run
at the speed of the slowest device. So if you had an ATA-133 hard drive on
the same cable as an older ATA-33 hard drive or a CD-ROM, both would operate
at the slower transfer speed. I think the way you have it right now is
probably as good as you can get it, so I would not change anything.

 

[Bobby]

So if you had an ATA-133 hard drive on

the same cable as an older ATA-33 hard drive or a CD-ROM, both would operate
at the slower transfer speed.

That is a myth. The HD would only drop to the slower speed when both devices
are being accessed at the same time. Otherwise, the HD would operate at full
speed.

 

[Alex Marshall]

That is a myth. The HD would only drop to the slower speed when both devices
are being accessed at the same time. Otherwise, the HD would operate at full
speed.

I'm sorry but I think your are incorrect. Both drives would indeed run at
the transfer speed of the slower drive. Besides that, both devices cannot be
accessed at the same time if they are on the same cable.

 

[Jason Tsang]

Device transfer speeds on IDE channels are not dependent on the slowest
device on the channel (least not since ATA4 has been in place).

Prior to that, your statement is correct though.

 

[Kent W. England [MVP]]

You can have an active partition on each drive and the BIOS selects
whichever is the boot device.