Apple IDE Cannot Access Beyond 137GB

An anonymous reader writes: "iMacLinux reported on a PenguinPPC story about Apple hardware being unable to address more than 137GB of space on IDE drives. The Apple computers only have ATA-66, which can only address 28 bits, while ATA-100/133 can address 48 bits. Solutions include using a PCI controller, FireWire or SCSI."

Comments

Re:Kings to Paupers

[Anonymous Coward]

The current ATA/66 IDE speed on the Mac is still faster than the fastest IDE drives made. None of todays fastest IDE drives go much over 40MB/sec. A 100MB interface will gain you nothing.

Even if Apple releases 800 Mbits/sec FireWire, the drives still won't go any faster. The ultimate bottleneck is the drives themselves. The fastest drives have a maximum sustained transfer rate of about 41MB/sec. That doesn't come close to the 50MB/sec theoretical rate of FireWire or the 66MB/sec theoretical rate of ATA/66.

Re:Kings to Paupers

[dtype]

You're somewhat right.

(1) The ATA/100 would still gain you the larger address space, allowing larger capacities. Since
160GB drives are here (and a scant us$250 to boot), this is quite important.

(2) I agree that the faster bus in theory won't get you more performance with a _single_ drive. But the fact is, that benchmarks say otherwise. For whatever reason, the faster burst speed of the bus has slightly improved the overall speed. I'm not a particularly good hardware engineer, but when I run `hdparm` on a couple of drives, I like the faster speed regardless of reason... (I still hate IDE and would much prefer SCSI, but I can't get a 160GB SCSI drive for $250.)

(3) ATA/100 controllers are dirt cheap. I can't believe that the extra few bucks wouldn't be worth it in marketing value alone.

Re:Waiting for SerialATA

[Daniel Wood]

While that thought did cross my mind, I doubt it. SerialATA has a long ways to go before it becomes standard. My guess is that for then next eight years(I don't expect to see SerialATA for at least another year) we'll have IDE and SerialATA on the same motherboard(How many years did it take to kill ISA?). My guess is that Apple will upgrade to ATA133 when they upgrade to DDR-SDRAM.

Re:Firewire?

[achbed]

Is there such a thing as a 'native firewire' drive?
Can having an ATA controller in a firewire case make it possible to get around the motherboard limitations?

1) Yes, it is possible to have a "native" firewire drive. However, since nobody but apple has an internal firewire port, no drive manufacturer is going to make one. They'll stick with bridge chipsets and cheap IDE disks.
2) Yes, a FireWire bridge is the second best method to get around chipset limitations. The best is to use a PCI expansion card, as the PCI bus is (currently) faster than FireWire in terms of transfer speeds.

A Note about Large disks vs. UDMA/100

[__david__]

By the way, I'm don't think it's necessarily correct to say the Apple hardware doesn't support ATA/100 and therefore doesn't support large disks. It seems the article and some of the posts here are confusing speed with large capacity capability. You can still do 48bit LBA in PIO mode if you want. Just this week I stuck a 160BG drive in an ancient Pentium 100 computer--and I used the whole disk (why you ask? It was for a backup server--large disk, extra cheap computer sitting around). There's no way the on-board IDE chip could have been ata/100 compliant. However, linux plus the ATA patch I installed supported the 48 Bit LBA commands from the ATA-6 spec, so I was able to use the whole disk. In PIO mode too. :-)

I mention this because it's quite possible that the solution to this problem is a little software update from Apple. You computer may not be obsolete yet. :)

Re:bits & bytes

[SJ]

Firewire over glass fibre tops out at 3.2Gbs

3200 / 8 equals roughly 400 MegaBytes per second.

Show me a drive that can saturate that!

Apple > ATA-66

[coolgeek]

New G4's have Ultra ATA-100, at least according to the guys at my local "Genius Bar". I know the specs on apple.com simply say "Ultra-ATA", that's why I asked. Planning on getting me one of those 933 pups here in a month or so... And for all the "Apple is slow" guys out here, my 667 TiBook running OS X totally runs circles around my old P-III/600 running either Linux or Win2K, and it's a lot easier to look at too.

Re:explain this:

[MarcQuadra]

Macs do things a bit differently than PCs. A PC hard drive will work fine in a mac (I have my G3 here running a new Maxtor D740X), but you have to 'prep' them first, because Macs put patches + low-level stuff on the drive itself. If you throw a PC orphaned drive into a mac, run Drive Setup on it and totally wipe it, or use 'dd bs=512 if=/dev/zero of=/dev/harddriveyouwantwiped' if you do Linux on your mac. Be careful with 'dd' it's far too powerful to toy with.