Linux Now Supports Ultra ATA/100

salty dog writes: "Linux now supports Ultra ATA/100 HDDs, initially funded by SuSE Linux. Get the driver from: [www.linux-ide.org]." As you either know or have probably guessed, ATA/100 is the successor to the ATA/66 hard drive interface standard. And as the linux-ide.org site puts it, "Again Linux Beats MicroSoft to Future Technology Standard!" 'Nuff said.

Comments

A Traditional Holy War: ATA vs SCSI

[DragonHawk]

How does ATA/100 compare with SCSI in speed? Reliability? Price?

Reliability

These days, the HDA (Hard Disk Assembly) is usually the same for both SCSI and ATA (IDE) disk drives. They simply use a different PCB (Printed Circuit Board) for different bus interfaces. Thus, all other things being equal, reliability should be about the same.

Of course, all other things are not equal. Generally speaking, very-low-end systems will never see SCSI, and very-high-end systems will never touch ATA. Thus, some really cheap (i.e., unreliable) drives are only available in ATA versions, and some really expensive (i.e., more reliable) drives are only available in SCSI versions.

Price

Despite the fact that there is no practical difference in cost of materials, SCSI drives are almost always much more expensive then their ATA counter-parts. There are two reasons for this.

The first is volume. A lot more ATA drives get sold then SCSI. But the second reason is the more significant one: SCSI is still considered a "high end" technology. Such technologies command a premium price. Thus, manufactures charge more for SCSI drives, and people are willing to pay it.

Performance and Features

ATA does not support device disconnection. This means only one device at a time can be using the bus. Since your average hard drive is going to sustain maybe 15 MByte/sec throughput, if you're lucky, even ATA/33 is overkill. ATA/66 and ATA/100 are completely useless to everyone but marketing types.

SCSI is the clear winner here:

• 160 MByte/sec maximum transfer rate
• Up to 16 devices per bus
• External devices
• Cable lengths measured in feet, not inches
• More kinds of devices (scanners, etc.)
• Device disconnection
• Multiple buses per controller IRQ
• Multiple initiators (controllers) per bus
• Tagged command queueing

I've heard people claim that "most users don't need" the features and performance of SCSI. I disagree at two levels: One, I think they do. Even if it is just wondering why all their applications slow down when the CD-ROM drive is busy, regular users encounter the problems of ATA. And second, if regular users don't need that kind of performance, why are they bothering to upgrade ATA at all?

Speed is good, but is there demand?

[StudentAction.CA]

Right now, IBM has the (only?) ATA/100 drive on the market. Here's something I found at maximumpc.com

Similar to the adoption of ATA/66, ATA/100 support will first come to market with add-in PCI cards before being integrated into motherboard chipsets.

So the real issue isn't if Linux supports it, it's when/if the motherboard manufactures get on the ball and start making ATA/100 interfaces.
Now on another point, I found this while looking at the ATA/100 anounce at www.linux-ide.org:

Bridging the Gap to Serial ATA The Ultra ATA/100 interface provides a critical technology bridge between ATA/66 and the future availability of the Serial ATA interface, which is currently under development. Serial ATA has industry-wide support and is expected to be widely deployed in new computer systems by 2005. In the meantime, Ultra ATA/100 will provide mature technologies to meet the heightened throughput demands that large, complex files are placing on desktop systems. Once these higher performance systems and drives become available, the Ultra ATA/100 interface will require less time to boot a computer system and open applications.

My real question is "IS THERE A NEED FOR THIS?" I still have all standard ATA/33 drives, and none of my motherboards (all bought in the last year) have ATA/66 support. When serial ATA comes out, then I can see the need. I know the need is there is servers, but is there a real need on the desktop? Linux and windows run fast on my K6-III 400 with a 5400 RPM ATA/33.

Sure I'd like ATA/100, but the focus should be on getting wide acceptance for the current standard (ATA/66) before moving to the next one (ATA/100). If we just "keep moving forward" and always upgrading the interface, but then users are left in a constant upgrade cycle, with no clear standards. (The 3D card market, anyone?)

All in all, this is a great move for linux. Glad to see good 'ol Tux can beat M$ to the punch. I just don't want to see customers get screwed by constant upgrade cycles.