Disk image burning question - 02/15/11 10:20 AM
1. I burn a dmg to a dual-layer DVD using Disk Utility. (Edit: The source disc had already passed all my tests.)
2. I opt for "Verify," and it passes.
3. Disk Utility tells me that the disc was successfully burned (or some-such).
4. I run Disk Utility > Images > Checksum > CRC-32 image checksum, and the source and destination checksums match.
5. As a final test, I run "Duplicate" in Finder, and it spits out an I/O error (which I confirm with a second run, because I've gotten false negatives).
Are the results of step 4 inconsistent with those of steps 2 & 3, or am I misunderstanding what "Verify" and "Checksum" actually do?
Thanks.
2. I opt for "Verify," and it passes.
3. Disk Utility tells me that the disc was successfully burned (or some-such).
4. I run Disk Utility > Images > Checksum > CRC-32 image checksum, and the source and destination checksums match.
Quote:
Disk Utility > Help:
Verifying files are copied correctly from a disk image
After you use a disk image to restore a disk or burn a CD or DVD, you can use checksums to verify that the files were copied correctly. A checksum is a calculation of all the data on a disk or disk image that yields a specific number.
You can compare this number with the checksum of the source image. If the two numbers are the same, the files were copied exactly.
Verifying files are copied correctly from a disk image
After you use a disk image to restore a disk or burn a CD or DVD, you can use checksums to verify that the files were copied correctly. A checksum is a calculation of all the data on a disk or disk image that yields a specific number.
You can compare this number with the checksum of the source image. If the two numbers are the same, the files were copied exactly.
5. As a final test, I run "Duplicate" in Finder, and it spits out an I/O error (which I confirm with a second run, because I've gotten false negatives).
Are the results of step 4 inconsistent with those of steps 2 & 3, or am I misunderstanding what "Verify" and "Checksum" actually do?
Thanks.