Chris Mathey wrote:
> Both disks are capable of UDMA mode 5, however /dev/hdc only lists up
> to udma2. Why do you think mode 5 is not listed? I haven't checked but
> It's possible a CD-ROM is slaved on the same channel. Could that be it?
Ooops. Missed that part of your email.
Yes. The bus is only as fast as the slowest component on it. If your
CD-ROM can only talk mode 2, that completely explains why the second
drive is so slow.
You would actually be better off putting _both_ of your IDE harddrives
on the _same_ bus, and the CD-ROM on the other.
While it may once have been true that putting a master/slave on the same
bus would slow it down, at UDMA mode 5+ rates, any slowdown is not
perceptible. You _might_ notice a 5-10% slowdown on that bus with
bonnie, at most, if at all.
Most delay today is not in the bus wiring, it is waiting for the drive
heads to seek on the platter and traffer data to the drive buffer. If
you can keep the buffers busy on the drives on a shared bus, there's
really no impact to having a master/slave setup anymore (falling back to
the highest mode that both drives can utilize the shared ATA bus).
- Ian C. Blenke <ian@blenke.com> http://ian.blenke.com/
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