[lug] ide drive questions

[Kevin Fenzi]

On Thu, 11 Jan 2007 14:45:28 -0800 (PST)
horlenkarl at yahoo.com (karl horlen) wrote:

> i have a system with 4 ide devices
> 
> 2 hard drives
> 1 cdrw 
> 1 dvd
> 
> file copies and moves between drives are slow.  i
> think it's because the hard drives share the same ide
> channel and the cdrw/dvd share the other.  my thought
> is that the file ops would be quicker if the drives
> were on separate channels.
> 
> is this true?

Yes, there are limitations with 2 drives on the same channel trying to
use the same ide bus. 

You could also have a ide controller that doesn't support DMA or
unmasked irq's or other things. If it's a pretty new ide controller
however, thats likely not the case. You can see by doing a
'hdparm /dev/hda' or the like. 
> 
> if so, is it possible to put each hard drive on a
> separate channel and then have the hd share that
> channel with a slower device (dvd / cdrw)?

Sure. Just move the drives/devices and then make sure you have their
jumpers configured for the appropriate master/slave setting. 

> i thought the slowest device on the channel is the
> determining factor for the channel speed.

I don't think thats the case... it's more of a matter of IDE channel
bandwidth. If one drive is sending a bunch of data over the channel, the
other drive has to try and fight with it to get data out. There is only
so much that will fit at once. 

kevin

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