On Thursday, September 26, 2002, at 09:01 AM, Pierre Duhem wrote:
Bonjour Simon,
Le jeudi 26 septembre 2002, à 17:21, vous écriviez :
SB> Note thought that under HFS+ blocks size can be changed. Under HFS SB> it MUST be 512bytes.
I don't think this is true. My formatter computes the block size with a simple division: 1 + (nb_sectors / 0xFFFF). I think I found this formula on some Apple document (Inside Macintosh ?).
Um, not sure exactly what you're trying to do but this could be trouble. On HFS the allocation block size was, by default, the smallest multiple of 512 bytes that would make the total number of allocation blocks fit in 16 bits. On HFS+, however, the allocation block size must be a power of two multiple of 512, i.e. 512 bytes, 1K, 2K, 4K, 8K, etc. 3K, for instance, would NOT be a valid allocation block size!
See TN1150 (bottom of page 4).
SB> Changing it means its not a HFS disk anymore. SB> Perhaps HFS+ requires a partition table. Have a read of Technote SB> TN1150 for more information (regarding HFS+)
I read TN1150 several times along the years, from one of the first editions, in 1999. I didn't read anything about the need of a partition table. That is what one should conclude from reading IM and other documents, but it is never stated so clearly. On the other hand, I already saw many such media.
-- Best Regards Pierre Duhem Logiciels & Services Duhem, Paris (France) duhem@macdisk.com