On May 18, 2010, at 5:32 AM, Nelsn Helm wrote: > I'm lost and trying to find my way.
We're all lost. Some of us are more so than others. > 1 -=-=-=-=-=-=- > > DiskUtilityDMI refers to GUID as "UNIX File System." You may have an Intel > Mac, but don't use MS-DOS File System. > > Intel starts up only from GUID, not Mac OS Extended. > PPC cannot see GUID; starts up only from Mac OS Extended. > > ( GUID only (either GUID or Extended)) > , ((either GUID or Extended) Extended only) > Intel boot neither boots from both PPC boot > Intel sees, PPC not Intel sees Intel > & PPC see. > > Can a single HD (physical disk) be formatted into a GUID volume and a Mac OS > extended volume? A hard drive may be divided into several partitions, each of which mounts as a volume on the desktop; they all look like separate drives, even though they're on one disk. The area of the disk that tells the operating system where each of the partitions is located on the disk is called the partition map. When you first set up a hard drive, Disk Utility gives you three choices for the partition map: GUID, APM and MS-DOS. MS-DOS is Microsoft's the older format for the partition map from way back in the early days. It can be read by nearly every type of computer, but only older Wintel computers can use it for a boot disk. There is hardly any reason ever to use it on a hard drive because it is really limited. APM is the older Apple partitioning scheme, and is the one you should use when you want to boot an older PowerPC-based Mac. GUID was introduced by Intel when they realized a more modern partitioning scheme was needed to go with the newer chipsets. When Apple switched to Intel machines, GUID became the standard for the newer Macs. Intel-based Macs will only boot off GUID disks and PowerPC-based Macs cannot boot off GUID disks. Any Mac can read all three partitioning schemes after it's up and running, so, if you don’t plan to boot off the disk, choosing APM or GUID is up to you. Any disk can be set up as any of the three schemes. You should choose APM or GUID, depending upon whether you want to use the disk for booting. > 2 -=-=-=-=-=-=- > > Hard to justify spending $75 on a 300gb HD to boot the Intel, which is > invisible to the PPC, > when I can buy 1tb (not Intel bootable) for $125. > > Why not make a non-bootable back-up of my start-up drive, > and should I need an external boot source, use the Mac OS DVD? Any disk you buy can be set up with Disk Utility to be bootable by one or the other type of machine. > 3 -=-=-=-=-=-=-=-= > > Some enclosures holding 2 HDs, e.g My Book Studio Edition II WDH2Q20000, can > be used as RAID, but seems to me tht both physical disks would be subject to > failure from the same cause, e.g. power surge, being dropped, tornado, so no > redundency within a single enclosure. All the RAID types, except RAID 0, provide redundancy across the disks to protect against failure. This is pretty good insurance against a bad block on one or the other of the drives, but nothing is better than a full backup in another location. > > 4 =-=-=-=-=-=-= > > Is Firewire on the way out? being replaced by eSATA? gigibit ethernet? Firewire is pretty much out for storage. It was pushed out of the way for cheap external storage by USB2 and is being replaced on the higher end by eSATA and iSCSI. > 5 -=-=-=-=-=-=- > > Hard to back-up external USB HDs to each other, bec they cannot connect thru > a hub, & Mac has limited jacks. I have several external USB2 drives connected through a hub right now. Either get a good externally-powered hub or, better yet, externally-powered hard drives. You probably can’t run several USB-powered hard drives off one bus-powered or low-powered hub.
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