IDE port sharing...

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lokem

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Hi all,

I was wondering if any knows how much performance degradation I'll get if I were to shared 2 devices (say a hard disk and a CDROM) on a single IDE port?

TIA.
 
Originally posted by lokem
Hi all,
I was wondering if any knows how much performance degradation I'll get if I were to shared 2 devices (say a hard disk and a CDROM) on a single IDE port?

Usually you can expect performance to drop one level... ie. ATA 100 -> ATA 66... That is if you're using both at the same time... When not, you shouldn't experience any performance degradation...

What this means in RL is hard to say, as it depends on the chip and drives used, but I wouldn't worry too much...

.02$
 
Thanks for the info. Dropping one notch is quite a bit IMO. Do you have any benchmarks for this?
 
I think that the ATA100 to ATA66 thing is purely speculation.

What is true, is that the controller on the master device drives both devices....

So you want to pick the device with the better controller as master...
 
What is true, is that the controller on the master device drives both devices....

So you want to pick the device with the better controller as master...

And how do you find out whether the controller on the IDE device is a good one or not?
 
Originally posted by Phantasm66
I think that the ATA100 to ATA66 thing is purely speculation.


Well, I read about it on Maxtor (or some other hdd manufacturer) researching likenesses 'tween RAID and SCSI....

Easiest way to find out is attaching two ATA 100 drives, and then running Sandra's hdd benchmark on them...
 
From Enhanced-IDE/Fast-ATA/ATA-2 FAQ:
4.4. Are old IDE drives compatible with EIDE and U-ATA interfaces?

This should work fine.

Older drives do not support the high-speed advanced transfer modes defined by ATA-2 and, later, Ultra-ATA. To retain compatibility with these drives, ATA-2 and Ultra-ATA interfaces have programmable timing. The driver or BIOS queries the drive regarding its maximum transfer rate and will configure the interface to match. A few interfaces are jumper configurable in which case the responsibility is yours.

If you intend to put an older drive on the same cable as an ATA-2 drive, you may want to verify that your interface is capable of using independent timing for master and slave device. Otherwise, your old drive might end up slowing down your newer one because the controller is forced to use the lowest common speed. Modern interfaces like the Intel PIIX3 (430HX and VX and 440FX chipset), PIIX4 (430TX chipset) and, to a lesser extent PIIX (430FX chipset) don't suffer from this problem.
 
Thanks for the info Mictlantecuhtli. Let's say I have 2 ATA100 hard disks in one IDE port/channel. How much slower does it get?
 
Don't you have anything to measure it? Copying from hdd to another slows down somewhat (varies) but moving files on one hdd doesn't.
I only provided that info to show that it's possible for drives to slow down (like ATA100 to ATA33), but it's quite rare nowadays.
 
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