Short Summary Version of the Question Why, when I try to copy an ISO CD image onto a USB flash device, do I get a lot of weird behaviours?
Original Version of the Question, with all the details — The following is asking for trouble: with a USB flash drive in /dev/disk1 and a CD-ROM in /dev/disk2 as follows (on Mac Os 10.4):
cas cas$ diskutil list # deleting irrelevant output /dev/disk1 #: type name size identifier 0: FDisk_partition_scheme *3.7 GB disk1 1: Apple_HFS usr-kodp 614.4 MB disk1s1 2: Apple_UFS glowline 1.8 GB disk1s2 3: DOS_FAT_32 VAR-KODP 1.2 GB disk1s3 /dev/disk2 #: type name size identifier 0: CD_partition_scheme *557.1 MB disk2 1: Apple_partition_scheme 485.1 MB disk2s1 2: Apple_partition_map 1024.0 B disk2s1s1 3: Apple_HFS KoDP 479.5 MB disk2s1s2
Try to clobber the flash drive's partition disk1s1 with the three partitions of the CDROM disk2s1:
cas cas$ dd if=/dev/disk2s1 of=/dev/disk1s1 bs=1024 count=496742
The resulting partition won't mount, and Disk Utility can't repair it:
Verify and Repair disk “disk1s1” Checking HFS volume. Invalid B-tree node size Volume check failed.
Now diskutil tells me:
/dev/disk1 #: type name size identifier 0: FDisk_partition_scheme *3.7 GB disk1 1: Apple_HFS usr-kodp 614.4 MB disk1s1 2: Apple_UFS glowline 1.8 GB disk1s2 3: DOS_FAT_32 VAR-KODP 1.2 GB disk1s3
What does it mean? It's almost certainly because my clobbering means that disk1's root partition map tells it that disk1s1 is still an Apple_HFS, even though its contents are a Apple_partition_scheme filesystem, but shouldn't Disk Utility be able to infer the type of disk1s1 if that's the problem? And why does diskutil tell me:
cas cas$ diskutil mount /dev/disk1s1 Volume /dev/disk1s1 mounted
...when in fact no filesystem gets mounted?