On Sep 3, 2008, at 2:38 PM, Peter wrote:
> >> You say it is not a hack, and you may well be right. It appears >> that >> it is only a property that is negotiated between the firmware and the >> drive. That is a guess on my part. How would you describe it? > > The large drive function is a protocol change which requires that the > command's data be supplied to the chip in two parts. > > Only one part is needed for drives which are smaller than 131,072 MB, > whereas two parts are required for larger drives. > > Enabling the LBA48 property enables the two-part protocol, whereas > disabling the LBA48 property returns to the one-part protocol. My understanding is this: 1) for small drives, one 24-bit CDB (command data buffer, a kind of parameter list which provides for feedback) is sufficient, whereas 2) for large drives, two 24-bit CDBs are required, thereby making up the required 48 bits. Apparently all the drives know about this, but not all host adapters do. More particularly, almost all PCI ATA cards do not know about this. That many of Apple's motherboards can be made to use the two CDB protocol, by enabling the ROM's LBA48 property, is a good thing, and is but one reason to use Apple's ATA channels exclusively. The property is there, and it can be easily enabled. I don't know which, if any, version(s) of Intech's "High Cap" kext actually works with Leo, but the version which I have certainly DOES NOT work with Leo, therefore, for the entire machine, which has FOUR bootable partitions, 10.3.9, 10.3.9 Server, 10.4.11 and 10.5.4, I enable the LBA48 property in the NVRAM, and leave it at that. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed Low End Mac's G3-5 List, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/g3-5-list?hl=en Low End Mac RSS feed at feed://lowendmac.com/feed.xml -~----------~----~----~----~------~----~------~--~---
