Quicksilver big drive mystery solved
A tip of the hat to the Mac OS 9 Lives website for getting to the bottom of a mystery. The original Quicksilver Power Mac G4 from 2001 is not listed by Apple as a model that supports big hard drives (over 128 GB), yet many readers have reported that it works. They've discovered that it's a matter of which logic board is installed - 820-1276-A does not support large drives, but 820-1342-B does. We're in the process of updating our 2001 Quicksilver profile to include this helpful tidbit. Lots more at http://macos9lives.com/mac%20os%209%20lives_003.htm -- You received this message because you are a member of G-Group, 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 g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: Quicksilver big drive mystery solved
A tip of the hat to the Mac OS 9 Lives website for getting to the bottom of a mystery. A number of G4 motherboards, other than those mentioned, are internally capable of LBA48 operation, and persistently, too. The LBA48 Property (which see, just Google it) may be persistently added just about every QS 2001 and earlier G4 which I have personally had experience with. Whenever it (the drive's capability for 120 MB drives, which limit is actually more like 131,072 MB, that is) has been detected it is necessary to ship TWO packets of information to the drive to access the area greater than can be defined by one packet. The lower 128 MB is specified in the first packet; the remainder is specified in the second packet. The large drives are expecting TWO packets, but their firmware is designed with a legacy mode which will only require ONE packet, hence why these large and very large drives (up to 750 GB) work well as virtual 128 GB drives. Now, there are THREE versions of the LBA48 Property, depending upon whether the the ATA bus controller is ATA-6, ATA-5 or ATA-4. On most Macs, the hard drive bus is the faster of the two. So, for a QS 2001 without the special motherboard revision, you would apply the ATA-6 patch AND the ATA-5 patch, and that would give you full large drive support on both buses. At least until the PRAM has been reset, in which instance you must go back and add the LBA48 Property again. But, the two buses (or only one, if you so desire) are indeed persistent as the properties have actually been added to the PRAM of the motherboard. For best compatibility, in case the LBA48 Property has been lost, it is best to size your primary boot partition as 131,072 MB, or less. This makes the boot partition accessible with a single packet, as described above, and everything thereafter becomes accessible using dual packets, so you can still recover from an inadvertent Cmd-Opt-P-R. I have run some of my QS 2001 machines for years using this technique, or Intech's large drive support extension. The sheer beauty of the LBA48 property is it is already in the ROM, so you may indeed boot from a very large partition. With Intech's Hi-Cap extension, the capability of accessing very large partitions is available only after OS X has been successfully booted, therefor it is not usable for the boot partition itself. -- You received this message because you are a member of G-Group, 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 g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: Quicksilver big drive mystery solved
-- Original message -- Subject: Re: Quicksilver big drive mystery solved Date:Thursday, 08. November 2012 From:peterh...@cruzio.com To: g3-5-list@googlegroups.com The LBA48 Property This Open Firmware NVRAM property does not work with Mac OS 9. Although large drives (i.e. LBA48) is supported only in Mac OS 9 respectively Mac OS X 10.2 onward, this property does only effect Mac OS X, specifically the KeyLargoATA.kext, which communicates directly with the KeyLargo ATA chip. This chip, wich is used in all Appler Power Mac G4 desktops with AGP does support LBA48 regardless of the Open Firmware property, but the Open Firmware needs to be LBA48-aware in order to boot from partitions (volumes) exceeding the first 137 GB. Result: on Macs with the KeyLargo ATA chips (every Power Mac G4 with AGP) LBA48 is always possible AFTER Mac OS X has started (10.2 and newer). On Power Macs newer and including the Quicksilver 2002 (Rev. B mainboard) the Open Firmware is also aware of the LBA48 capability and enables booting from a larger than/exceeding 137 GB first volume. http://support.apple.com/kb/HT2544 http://www.sonnettech.com/support/techtips/temporaid133.html Note: Mac OS 9 supports only partition sizes up to 200 GB (Apple) or 190 GB (Sonnet). (Which one is right?) Cheers, Andreas aka Mac User #330250 -- You received this message because you are a member of G-Group, 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 g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
