Hi Neil, I'll try to reply to the questions you have asked me below.
On 13/12/2009, at 7:52 PM, Neil Houghton wrote: >> >> Hi Neil, >> >> This is purely my own thoughts & preferences, others might disagree ;-) >> I guess it's what suits your needs. >> >> I feel you will run into problems with the Leopard Clone being a Partition on >> the Snow Leopard iMac. > What kind of problems do you envisage? You should be ok, I tend to "err on the side of caution". ;-) You can read Snow Leopard partitions from Leopard. You cannot execute Snow Leopard applications from Leopard. Apple has applied compression to most of the system executable files in Snow Leopard. However they do not appear to apply it to data files for any applications, (but I could be wrong here). Apples documentation for ditto (go to terminal and type "man ditto" at the prompt, without the quotes) states: --hfsCompression When copying files or extracting content from an archive, if the destination is an HFS+ volume that supports compression, all the content will be compressed if appropriate. >This is only supported on Mac OS X 10.6 or later, and is only intended to be used in >installa-tion installation tion and backup scenarios that involve system files. Since files using HFS+ compression are not readable on versions of Mac OS X earlier than 10.6, this flag should not be >used when dealing with non-system files or other user-generated content. > >> I would prefer to have it on an External Firewire Drive, then you can boot >> Leopard from it. Sorry Neil, I did not read this part of your email thoroughly enough. You cannot boot Leopard on your new iMac. I explain "why" below. >> > Well, I actually have both since I have an external 1TB firewire drive which > is partitioned to match the internal drive and I clone each internal > partition to it's corresponding partition on the external drive. > > However, one of the problems with my original strategy is that the new i7 > iMac will not boot up into Leopard, only Snow Leopard :( > (I tried it from the Leopard partition on both the internal drive and the > External Drive - and I know the cloned system on the external drive is OK > because the old 24" iMac boots from it but the new i7 iMac doesn't). > > Interestingly, if I option start the i7 both the leopard and snow leopard > systems show up as selectable but, if I select a leopard system, then > start-up just hangs at the white screen with the Apple logo (but the moving > clock icon doesn't show). Also: > - running disc utility under SL and the Leopard partitions have the "verify > permissions" and "repair permissions" options greyed out. > - if I try to start the i7 using a Leopard installation DVD (to try a fresh > leopard install) it again refuses to boot from the Leopard installation DVD. > > I am assuming that the new processor/hardware has certain requirements that > are built-in to SL but not Leopard - since there were no i5 or i7 Macs > available when Leopard was the current OS. Yes, you cannot boot Leopard on the NEW iMac! Apple doesn't program any Macs not to allow an earlier version of the OS to be used. However, a Mac cannot successfully boot from an OS that does not include appropriate drivers for its hardware components, & more recent Macs have upgraded hardware that are not supported by the drivers shipped with older versions of the OS. For this reason, the OS installer package checks the hardware of the Mac targeted for the OS install & compares it to a list of what it can support. If the Mac isn't on that list, it will refuse to install the OS. For the same reason, if you bypass the installer, like by using a clone of the HD of a different Mac with an older OS version on it, it generally will not successfully boot a Mac with newer hardware. Note that the hardware differences can & usually do include things other than just the CPU or graphics processor. Check /System/Library/Extensions, which is the home of the drivers (as well as other extensions) & note that things like the System Management Controller (SMC) & various input/output (IO) devices each have drivers that correspond to subsystems typically implemented with different hardware on different Macs. > > >> Personally I don't partition my internal drive. I find Leopard & Snow Leopard >> run faster and cleaner on non-partitioned drives. >> I would partition an external drive into 2 partitions, and have 1 partition >> for your cloned Leopard, and the other for your EyeTV Recordings. > Yes, I hear what you are saying here - that's what I did with my 24" iMac > which has a 320GB HD - its just that (without the EyeTV recordings) I never > even came close to filling a quarter of the 320GB disc (around 74GB at last > look) and I already have four external 1TB drives (some partitioned) serving > as clones and TM drives for the various machines - so, given that the new > iMac has a 1TB drive, I wanted to go this route rather than buy more > external drives (given each then requires another back-up drive) - as I > didn't want to have large numbers of drives without much on each. Yes, I see what you mean. I have a 500GB HD and like to run my computers at only 50-75% full. My Drobo backup drives hold over 1TB of data, & have the capacity to hold around 4TB. If you let a disk get to less than 15% free space you run the risk of fragmentation that can make your Mac run more slowly, or worse you could lose data because your Mac has no space to save a file. Even more seriously, your Mac may hang, crash, or fail to startup if it runs out of physical RAM and runs out of disk space for virtual memory. But, I am over cautious with my Macs and I like them to run "lean & Clean" ;-) >> >> Another problem with partitioning is you'll never be satisfied with the >> sizes. >> After you make them you'll want more here and less there etc. > Yes, probably true - however: > - at present I have lots of spare space on each partition > - once I have fully migrated and rationalised my document filing the Leopard > partition will be erased and available for other uses > - disc utility will now allow resizing partitions on the fly (though I > wouldn't try it without at least 2 levels of back-up) > - given that I intend to have redundant back-ups, I guess I feel I can > always do a re-format and restore to a different partitions scheme (or even > a single partition scheme) in the future (probably at a system upgrade after > I have my new streamlined filing system) Again I understand your reasoning and can't see any real problems with your plan. > >> >> Cheers, >> Ronni > > Thanks again for the feedback Ronni - I have learnt so much about back-up > strategies from your previous posts - I'm just glad I got to implement some > improvements to my strategy before disaster struck! You're welcome Neil. I hope this clears things for you a little. Cheers, Ronni 17" MacBook Pro Intel Core 2 Duo 2.4 GHz / 4GB / 800MHz / 500GB OS X 10.6.2 Snow Leopard Windows 7 Ultimate (under sufferance) -- The WA Macintosh User Group Mailing List -- Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> Unsubscribe - <mailto:[email protected]>
