[G4] Newcomer to G4 - query on hard disks

[Philip J Robar]

On Dec 23, 2005, at 1:55 PM, John Baltutis wrote:

> On 12/23/05, Ian Piper <ianpiper at mac.com> wrote:
>
>> Is it possible to put an internal hard drive in the bay where the  
>> zip drive
>> would normally go (there is a second IDE bus with the DVD-ROM drive
>> on it and a spare IDE connector)?
>
> Yes, but that bus is much slower because it uses the ATAPI protocol  
> (intended
> for CD/DVD, tape, and ZIP drives) vice the ATA protocol (for HDs). See
> <http://www.ata-atapi.com/hist.htm#T4> and
> <http://www.stanford.edu/~csapuntz/ide.html> for details.

This is incorrect. The bus and controller on the motherboard or ATA  
add-in card do not determine the protocol, ATA or ATAPI, that will be  
used to talk to a device. This is specified by the device that is  
using the bus at the moment. However, the level of the protocol that  
is used is limited to the level that the controller implements. On  
most, if not all, G4 and lower Macs the second ATA controller is a  
less expensive, and therefore slower, controller.

Note that the difference in performance between an ATA 6/5/4 (ATA  
133/100/66 in marketing speak.) interface is very small. A modern  
hard drive will perform nearly identically on each. There isn't a  
noticeable drop in performance until you get to an ATA3 (ATA 33)  
interface.


Phil