How to use your large/cheap ATA drives with your SCSI controller.

[Zepper]

Tom's Hardware just posted a review of a device that allows you to do just that: ATA -> SCSI . Seems very neat. Check it out.
..bh.


Please bump - Thanks!

Edit: This new one is for LVD SCSI host adapters. The same company, www.acard.com.tw, had made another adapter earlier for SE boards.bh.

 

[Workin']

I've been using that exact device for probably more than a year now. I have an IDE Yamaha CDRW drive in an external case with the Acard IDE-SCSI converter and it works perfectly. The price of the external enclosure, IDE drive, and the converter was $80 less at the time than the exact same Yamaha drive packaged as an external drive from Yamaha. The Yamaha external drive was $295 and the one I made myself from the IDE drive was $215. The drive itself is identical - Yamaha's external SCSI drives are IDE drives with a IDE-SCSI converter.

 

[Peter]

With CD devices, these are OK.

Using IDE HDDs on SCSI however completely defeats the purpose of SCSI. 'Cause the IDE drive still is an IDE drive - can't take multiple requests at once, doesn't release the bus while busy. These are the exact two points why SCSI is so massively faster in multitasking environments - much higher single drive performance aside.

 

[Zepper]

This new one allows hooking to an LVD channel. The older ones were SE.
.bh.

 

[Peter]

So? By using a SCSI adapter, IDE drives still don't magically learn how to do disconnect/reselect and tagged command queuing. THIS is where SCSI's excellent performance comes from, not just the drive being faster mechanically.

 

[Zepper]

Peter,
. That's irrelevant. If you NEED all the neat stuff that SCSI does, of course you'll get SCSI. Cost be damned.. However, if all you need is massive, cheap storage...
.bh.

 

[Peter]

... what'd you do with a SCSI controller then?

 

[Zepper]

Apparently Peter just can't seem to get it. Perhaps some extra red meat in his diet might help, along with extra vitamins E and C and Ginkgo.
.bh.

 

[Haden]

I don't really get this too.
You can connect lots of IDE drives which will cost +70$ each, but
performance won't be any better so why not just buy several cheap ide cards instead of SCSI controller?

Also if it doesn't release bus while working wouldn't performance die with 15 drives on controller?

 

[LED]

Seems like 1 expensive marketing ploy/toy to me...this and the ATA Serial IDE adapters...for the costand no performance increase I'd rather buy another SCSI HD and/or use the large Capacity IDE HD to back the data up

 

[Zepper]

I really think that they mainly did it so folks can put an IDE CD-RW on their SCSI systems. CD-RW makers pretty much stopped making SCSI burners so that's the only way to get newer tech on there. It looks like Plextor finally came out with 40x SCSI. Does anyone know if that is true SCSI or adapted like Yamaha and this. IAC, the Plextor probably costs more than a really good IDE plus one of these adapters.
.bh.

 

[LED]

Originally posted by: Zepper
Apparently Peter just can't seem to get it. Perhaps some extra red meat in his diet might help, along with extra vitamins E and C and Ginkgo.
.bh.

He who dares not offend cannot be honest. -- Thomas Paine.

 

[Zepper]

Yup, just looked on PW. Plextor 40x SCSI burner is ~$200.!!! Must be trueSCSI.
aaaaarGH.
.bh.

 

[Peter]

Originally posted by: Haden
I don't really get this too.
You can connect lots of IDE drives which will cost +70$ each, but
performance won't be any better so why not just buy several cheap ide cards instead of SCSI controller?

Also if it doesn't release bus while working wouldn't performance die with 15 drives on controller?

Exactly that's the point. One converted IDE drive on a SCSI channel will eat the entire bandwidth when loaded, just like master and slave block each other out on a real IDE channel. With multiple converted IDE drives on SCSI, performance will suck beyond recognition.

If you however want to put a CDROM on a second SCSI channel that is detached from the performance critical drives, then go ahead - most "real" SCSI CDRWs don't do disconnect-reselect anyway.
But you might just as well connect these drives onto the mainboard's IDE channels that have become vacant because your HDD(s) are on SCSI ...

The only occasion where it makes sense to use those adapters is with off-mainstream systems that don't have anything but SCSI. There's manier musical equipment that wants SCSI drives, high end laser printers, older Apple systems, that kind of stuff.

 

[Zepper]

Hey Peter, you really can't see the big picture can you? What if I disabled my on-board IDE channels (yes, both of them) to free up IRQ's 14 and 15 for other devices including a SCSI host adapter or two? There are a lot of scenarios where this could make sense. Just because you can't see them...
.bh.

 

[Peter]

How on earth does it make sense to put a performance brake onto a fast storage channel? Particularly if you do have the native connection for the thing available? Just to save money? Why'd you buy SCSI then? And don't even start me on the shared-IRQ tales.

What Tom's article blatantly misses to examine, and what you fail to understand so far, is that with a typical SCSI setup (multiple drives on one channel), IDE drive(s) (or SCSI drives that don't do disconnect/reselect and tagged queuing) will screw up performance royally. Sure, one IDE drive alone on a SCSI channel is about as fast as if you'd put the same drive onto an IDE channel, but what gives?

 

[chizow]

Originally posted by: LED
Seems like 1 expensive marketing ploy/toy to me...this and the ATA Serial IDE adapters...for the costand no performance increase I'd rather buy another SCSI HD and/or use the large Capacity IDE HD to back the data up

Exactly. What's teh point of buying this card again? No perf. gains and expensive adapters...

Chiz