In any event, what exactly would be necessary to make use of this Time Machine function in my iMac? What frequency of backup might be warranted? And what might I use such backups for (since a crash of the iMac can't ostensibly be corrected by a backup, at least as far as I can comprehend the discussion in that thread).
Your under $100 limit for a Time Machine drive is unrealistic for the capacity your need with a drive/enclosure that is reasonably fast, reliable, and Mac friendly. Check
Other World Computing for external drives with just about any and all interfaces. Their drives are not fancy but they are fast, reliable, and 100% Mac compatible.
To make Time Machine function you need
- an external drive with 2 to 3 times the capacity of th drive you are backing up.
- The drive must be formatted Mac OS X Extended (journaled) with GUID partition table (easily done with Disk Utility)
- Spotlight turned ON
- Theoretically any interface will do, but as a practical matter the faster the better. USB 1 a.k.a. USB Full Speed is really too slow. USB 2 a.k.a. USB High Speed will work, Firewire 400 is better, Firewire 800 is great, Thunderbolt would be best if you could find one.
The Time Machine backup interval is every 60 minutes and those hourly backups consolidated into Weekly and monthly backups. Time Machine is efficient enough and smart enough that I have never found it necessary to modify the default backup frequency and I have on more than one occasion found the backup frequency
very helpful. Time Machine is a very different backup solution than most people are used to, but it offers just about the best possible security and flexibility. IMO tinkering with its timing interval only serves to make it less effective.
