Time Machine back-ups bit per bit?

Discussion in 'macOS' started by HiFiGuy528, Feb 11, 2009.

  1. HiFiGuy528 macrumors 68000

    Jul 24, 2008
    In the audio world, bit per bit is important. When TM makes back-ups, are they bit per bit of the original?
  2. PrinceOfEgypt macrumors member

    Jul 2, 2008
    i might be missing something, but how else could it be? the files are copied to the backup drive.. bit per bit is the only way i know of to make a copy of a file..
  3. Amdahl macrumors 65816

    Jul 28, 2004
    I don't know what the opposite of bit-per-bit is, but I can tell you that Time Machine does not do incremental back per file. If you have one gigantic file, and a single bit changes in that file, Time Machine recopies the whole file. This is why Virtual Machines are often automatically excluded from Time Machine and must be backed up separately.
  4. brand macrumors 601


    Oct 3, 2006
    Actually Time Machine does perform incremental backups on a per file basis.
  5. Amdahl macrumors 65816

    Jul 28, 2004
    Perhaps I have the wrong words, but what I thought I wrote is what I was thinking, and is correct. ;)

    Using the definitions available at your link, I should have said 'doesn't do block-level incremental backups'.
  6. mlts22 macrumors 6502a

    Oct 28, 2008
    If you have a huge file like a VMWare virtual machine image, what helps is to put it in a sparsebundle disk image. Then when Time Machine goes to back things up, it will just need to back up the 8 MB bands that were changed rather than the complete file.
  7. Amdahl macrumors 65816

    Jul 28, 2004
    Serious? That would be great. Is there a downside? How many 8MB bands would there likely be after a boot/shutdown of a VM?

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