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IDE/ATAPI to SCSI Converters Reviewed
Anonymous Coward writes "Seems that someone has finally come out with IDE/ATAPI to SCSI converters to bridge the gap between the high-cost SCSI world and the low-cost IDE world. Addonics is the company and LinuxHardware.org has a full review of these two devices. The review does a good job of laying out installation and performance. These are just what I've been looking for and although a little pricey, they seem to do the job."
ACard have been making a really cool range of SCSI to IDE products for several years now called SCSIDE. They work very well too, especially the mirroring and interface bridge stuff I've had my hands on :)
:)
For more info take a look here
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For those not familiar, or trying to respond to others in this forum and don't know what to say: =)
IDE vs. SCSI article at PcMech.
SCSI & IDE Overview Good, informative, classroom materials for a university.
IDE to SCSI Adaptor Review of the ACard ARS-2000FW
ACARD Tech. - Makes SCSI to IDE converters.
These things have been around for years! I've had them for 2.5" SCSI notebooks in SparcBooks. There are pleny of SCSI-IDE bridges over at dirtcheap drives for like $50-$70 depending on whether you want wide or narrow scsi. $100 is too much.
And I've used these to hook up a bunch of 160GB IDE drives together to make a nice big huge raid array. They're great - only if you hook'em up to big drives where SCSI would be too expensive or to hook up DVD or CDRW's to Scsi only machines such as SUNs.
As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
No, that's not what they tested. They took a couple of IDE drives, and benchmarked them with and without the converter. These tests showed that the converter did not cause a performance hit; this is good to know, and cannot simply be assumed.
It's a nice idea, but the main reason that ISA-to-PCI is not a solution out there already is a simple one: physical contraints of the system. An ISA-to-PCI adapter would not fit in any standard chassis and still have enough room to mount the ISA card. The IDE-to-SCSI solution leverages the fact that there's room to move in a case; drives tend not to be tight fits, unlike cards.
That being said, if you find a good one someday, let me know! I have more ISA data acquisition cards in the lab than I can shake a stick at, and they're not cheap.
Usually, what I have done is too simply look for a newer used computer that still has 1 ISA slot left in it. Pentium chipsets still have these here and there up to the Pentium III, and AMD chipsets can be found that use today's Athlon XP 2200's. I myself have a Tbird 1000 running on a KT7A-RAID motherboard that has 1 ISA slot at home, though I don't use the slot. When I built computers for the lab, I used this mobo because of this reason.
Have you priced 120GB SCSI drives? $1000-ish. IDE would be about $120. Plus $100 for an adapter. $220 < $1000. Why do it? SCSI RAID controllers are still better in general and better supported in Linux is one case you might consider it. I dunno.
MTBFs are around 100,000hrs for scsi, around half that for IDE. IDE drives are designed to be fast to spin up, wioth low viscosity fluid bearings, good for worksstations/home use. SCSI drives have high viscosity fluid bearings which gives less wear, but the spin up time is greater [hence "spinning up drives" msgs on controllers]
;-)
also the scsi interface is technologically far superior, TCQ, 15 devices per channel, Connect/Disconnect etc
so the controller on the drive actually does a lot of work, in that it sorts out out of order execution ITSELF, CRC etc etc.
plus U320 is pretty neat
Err, the answer is painfully obvious.
Write down the cost of a 200GB IDE hard drive (the western digital ones are quite speedy and have 8MB cache). Then add the cost of IDE/SCSI converter.
Now, compare that figure with the cost of a 200GB SCSI drive- *IF* you can even find such a beast.
For bonus points, figure out how much an 8-drive IDE RAID enclosure that presents a SCSI interface to a host computer, or an 8-drive 3ware internal RAID controller will save you when populated with 200GB IDE drives over a pure SCSI solution.
Many usage patterns need high capacity, but not require the benefits that high end SCSI drives provide over IDE. Why pay 5X as much for them if you don't need to?
With a 5-fold savings, you can buy more drives and use a RAID, increasing both your reliability and your performance over a single scsi drive solution.
Excuse me, who CREATED the SCSI standard?
That would be NCR - the specific division was spun off as Symbios for a few years which was then purchased by LSI Logic. So, if you were thinking, maybe, uhm, perhaps, Adaptec, then you would be wrong.
http://www.datoptic.com/fwu2-ide.html
- 20 0.htm
d uc ts.htm
http://www.usbgear.com/usa/item_420.html
http://www.veriplus.com/pages/media-storage/UDA
http://www.deltrontech.com/USB/USBIDE/U-IDE.htm
http://www.indigita.com/products/prod_bridgepro
Ever since 40MB/sec SCSI came out...there really is no need for anything faster in a workstation...until hard drives become dramatically faster. Most workstations have no more than two hard drives (get it? 2 X 20MB/sec = 40MB/sec).
This is quite bogus. A single drive can easily exceed 40MB/s sequential transfer and your hard drive is the slowest storage device on most pcs.
I still don't see 10,000 or 15,000RPM IDE drives, do you?
It is quite a bit more difficult to build a 10k or 15k drive than it is to build a 7.2k rpm drive. You don't see 10 or 15k ide drives only because of cost. Probably in the next year or so you'll see the first 10k ide drive. 10k is almost a necessity with todays computers as 7200 has such a high average access time.
Chris
These products are NOT new others have been making them for years.w .html or this onew .html this one looks alot like the one addonics is selling doesn't it?
Here is one that mounts UNDER a low profile (aren't most of them like this?) ide
drive making it about the same height as an atapi cdrom drive.
http://www.acard.com/eng/product/scside/ars-2000f
http://www.acard.com/eng/product/scside/aec-7720u
Just because some company gets a write up on something at linuxhardware.org
does not make it new or news.
sparkeyjames
If sense were common everyone would have it!
You really should read the documentation before sounding like an @$$:
IDE Converter:
"The converter also supports SCSI performance up to Ultra LVD160 SCSI standard, ensuring maximum performance of the fastest ATA133 hard drive."
ATAPI Converter:
Although the web page states that the converter only supports 80MB/sec, the documentation that comes with the drive states that it does tell the SCSI bus that it's a U160 device. This may not have been on the Addonics website but there was no reason to question the reviewer if you weren;t sure.
Go to the TPC website and take a look at score reports for the TPC-C benchmark, which is an online transaction processing (OLTP) benchmark going back 10 years or so.
Score reports for most mid-end IA-32 quad-processor servers reveal that they are using several four-channel Ultra-160 SCSI RAID controllers, and fifteen hard drives per channel. My professional experience with TPC-C shows that the hard drives' throughput get maxed out way before the SCSI channel bandwidth does, and we're talking 15 drives per SCSI channel. That's why these benchmark results are still obtained with Ultra-160 controllers and drives instead of Ultra-320. The extra bus bandwidth of Ultra-320 SCSI doesn't buy you much because the fastest disks out there cannot churn out data fast enough to max out a Ultra-160 interface.
I was recently looking at both IDE and SCSI drive specs on manufacturers' websites. I saw Ultra-160 and Ultra-320 SCSI devices with seek times of 3.5 ms and rotational speeds of 15,000 RPM. But most IDE drive families are still at 7,200 RPM max and have seek times of 8.5 ms or more. The better seek times and rotational speeds are the main reason I would upgrade my storage to SCSI (if the costs were not so high, that is :-). The product reviewed here provides exactly the reverse of the functionality I want. As such, I think it's useful only for specialized applications like putting an IDE CD-RW in a SCSI-only workstation or server.
SCSI is a parallel interface standard used by Apple Macintosh computers, PCs, and many UNIX systems for attaching peripheral devices to computers. Nearly all Apple Macintosh computers, excluding only the earliest Macs and the recent iMac, come with a SCSI port for attaching devices such as disk drives and printers.
This info is a bit outdated. Every Mac since 1999 comes with on board IDE instead of SCSI. The consumer Macs even had IDE back in 1996 (when I got a Performa 6300). Apple switched from SCSI to IDE in the pro-line when they released the B&W G3s. Today PCI SCSI cards are a BTO option in PowerMacs.
SCSI was also used by graphics pros to hook scanners up to. Printers were more often on the printer port (a serial Mac port) or on a network connection.
The problem with all of these IDE vs. SCSI performance discussions is that "performance" is a context-sensitive term.
Today's IDE drives can probably push more streamed data per unit time through an interface, however, if you can't afford intermittent burps in sustained throughput, SCSI still outperforms, and once you load a bus with multiple drives and try to use them simultaneously, IDE really begins to falter because the IDE specification is not terribly friendly to bus sharing.
And of course in database-type environments with many, many seek and small read and write operations going on, IDE drives completely suck in comparison to the much smaller average access and command queueing of SCSI.
So it depends on what "performance" means to you...
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