Disk imaging

DANNNG provides a list of factors to weigh in the decision between physical sector-by-sector ('raw') and logical copies: https://dannng.github.io/disk-imaging-decision-factors.html (the page uses 'disk imaging' to stand for physical disk images).

Harvard Library contracted a comparative study of disk image formats with respect to their adoption and sustainability. The report is available on the website of Harvard Library:

https://wiki.harvard.edu/confluence/display/digitalpreservation/Disk+Image+Formats

The report recommends the following disk image file formats for different types of carrier:

• Magnetic storage device - physical sector-by-sector copy or logical file system copy
  • uncompressed: RAW (IMG, DD), unless disk image exceeds size limit
  • compressed
    • RAW (IMG, DD) with TAR.GZ or ZIP compression applied
    • E01 using zlib compression option
• Optical storage device - physical sector-by-sector copy
  
  • uncompressed: BIN/CUE
• Optical storage device - logical file system copy
  
  • uncompressed: ISO