I think I have bought the wrong hard drive...

E

Elliotjnewman

Registered
I have a G4 MDD 1.25, and after going onto the apple site and downloading the manuals I read that the hard drive is ATA/100, I have just bought an ATA/133 - will it be ok? or have I made a blunder?

Thanks, E.
 
No, there's not really a big difference, since the drive itself won't even take advantage of the bandwidth of ATA/100. The "100" in ATA/100 refers to the mb/sec that the interface is capable of handling... ATA/133 can handle 133mb ("mb" is not referring to "megabytes" in the traditional sense), but the drives themselves can't produce that kind of throughput -- they don't rotate fast enough, and the read/write heads don't move fast enough to produce that kind of throughput.

The G5s have a different interface for hard drives -- SATA (Serial ATA -- the drive you bought is PATA, or Parallel ATA). If you wanna give it a name, then it would be ATA/150, since SATA is capable of bandwidth in the neighborhood of 150mb/sec.
 
You can use two hard drives per ATA bus, so it depends on how many buses the MDD G4 has. I believe it has an ATA/33 for the optical drive(s), one ATA/66 and one ATA/100. That means, if you can find space, and if there aren't already 2 drives on those buses, you can configure 4 hard drives (5 if you wanna put one on the slow ATA/33 optical bus and have only one optical drive).

You'll notice that there are two hard drive connectors on the hard drive ribbon cable connected to the ATA bus connectors on the motherboard. The one at the very end is the "Master" and the one partway through the ribbon cable is the "Slave." With only one drive, you should use the "Master" connector. For your machine, you should set the jumpers on the drive for "Cable Select" or "CS" (read the drive manual to see how you change jumper settings on the drive).
 
It will work fine, but if you have bought an ATA drive bigger than 137GB, you will only see 137GB of it. This is because that is all ATA100 will handle. Among the theoretical faster speed of ATA133, it also allows for disks bigger than the 137GB limit of ATA 100.

If you bought one less than 137GB then you will be fine.
 
the difference between ATA 100 and ATA 133 is so small that western digital never even bothered making ATA 133 drives. their ATA 100 7200rpm drives with 8mb cache like mine beat even 10,000rpm SATA drives in a few benchmark tests.

Captain Code: western dig. makes 200+ GB ATA 100 drives. I thought ATA 66 solved the 137GB max?
 
It's not ATA/100 or ATA/133 that is relevent for "seeing" more than 137GB of the drive. It's whether or not the ATA controller uses 48-bit LBA (Large Block Addressing) mode. I've got a Sonnet Tempo ATA/100 drive that will "see" and be able to use all of 200+GB drives, simly because it supports 48-bit LBA mode.

As far as I know, the MDD G4s were the first to support this.

http://docs.info.apple.com/article.html?artnum=86178
 
I service a MDD G4 with 4 250GB drives, the MDD supports 48-LBA (meaning support for drives larger than 137 GB) regardless of the bus connection. It's all in the IDE controller. (I'm not certain about the ATA-33 controller that the optical drives use)
 
Well, I think that goes away from the standard then as ATA133 was the first to support drives larger than 137GB by using a wider bit address.
 
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