Difference between Primary and Secondary IDE Channels?

[Michael Reed]

Is there any difference between the primary and secondary IDE channels? I
have my harddrive on secondary and my DVD 16X burner on primary. I tried
this because when I put my DVD burner on secondary it would only get
Multi-Word DMA mode 2 while the HDD got UDMA mode 5 on the primary. This is
a new burner and capable of UDMA 4. After troubleshooting I switched
channels and got UDMA mode 4 on the DVD burner when on the primary as master
and still got UDMA mode 5 on the only HDD on the secondary as master. I
don't understand the difference and the computer works fine and it appears I
am getting the transfer modes I am supposed to.

 

[Anna]

Hi,

Usually you should connect the Hdd to Primary IDE channel as Master and
the
Optical drive to Secondary IDE channel as Master. Both drive jumpered as
master or cable select.

Always connect the fastest drive as master and the slower drive as slave
in
the same IDE channel.

For best performance, I would suggest you to use the 40 Pin 80 wires
shielded IDE cable for both drives; jumper both drives as cable select.

Peter

Michael:
With the modern IDE/ATAPI devices and motherboards we're working with today,
there is simply *no* difference in performance with these devices in terms
of their connections on IDE channels or their Master/Slave configurations.
Peter's recommendation to "Always connect the fastest drive as master and
the slower drive as slave in (sic) the same IDE channel" is incorrect. Each
device will perform at its rated transfer speed regardless of its
Master/Slave configuration on the IDE channel. There was a time when it
*did* matter, but that time is long gone.

Also, as a *practical* matter there is no performance issue between an
optical drive operating at either UDMA mode 2 or mode 4. Only the inherent
"speed" of the device will be a factor in its performance when operating at
one of those two modes.

So feel free to connect your devices in any configuration you determine is
practical given the physical placement of those devices in your computer
case. Using Cable Select, as Peter recommends, is fine as is jumpering the
devices as Master/Slave.

Having said all this...
There is one "but" we've run into (although it doesn't really apply in your
situation). We have come across motherboards that would not permit booting
from a HD unless it was connected as PM. A rare occurrence in my experience
but I have run into it. Of course, in virtually every case a user will
ordinarily connect his/her booting HD as PM so for most of us it's a
non-issue.
Anna