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Old 30th December 2008
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phoenix phoenix is offline
Risen from the ashes
Join Date: May 2008
Posts: 696

Nope, it won't (or, at least not by enough to make a difference):
[root@thehive /storage]# dd if=/dev/acd0 of=2k.iso bs=2K
230426+0 records in
230426+0 records out
471912448 bytes transferred in 208.567875 secs (2262632 bytes/sec)

[root@thehive /storage]# dd if=/dev/acd0 of=1m.iso bs=1M
450+1 records in
450+1 records out
471912448 bytes transferred in 208.797817 secs (2260141 bytes/sec)

[root@thehive /storage]# md5 /dev/acd0 2k.iso 1m.iso
MD5 (/dev/acd0) = d41d8cd98f00b204e9800998ecf8427e
MD5 (2k.iso) = 400fdb244d7540fd01b82d194d99c284
MD5 (1m.iso) = 400fdb244d7540fd01b82d194d99c284

[root@thehive /storage]# dd if=/dev/acd0 of=1m-2.iso bs=1M
162+1 records in
162+1 records out
170164224 bytes transferred in 88.262563 secs (1927932 bytes/sec)

[root@thehive /storage]# dd if=/dev/acd0 of=2k-2.iso bs=2K
83088+0 records in
83088+0 records out
170164224 bytes transferred in 88.409275 secs (1924733 bytes/sec)

[root@thehive /storage]# md5 /dev/acd0 2k-2.iso 1m-2.iso
MD5 (/dev/acd0) = d41d8cd98f00b204e9800998ecf8427e
MD5 (2k-2.iso) = 6830513ed854155bd0b0bba5ce0c3f92
MD5 (1m-2.iso) = 6830513ed854155bd0b0bba5ce0c3f92
But, it looks like the .iso files created are identical, so maybe it's only on the burning side that it makes a difference?

On a side note, anyone know how to create an md5 hash of a cdrom on FreeBSD? In Linux, one can just "md5sum /dev/cdrom" and get the same md5 hash as the .iso generated via dd, which doesn't seem to work on FreeBSD.

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