: :On Sat, Jul 06, 2002 at 04:42:22PM -0700, Matthew Dillon wrote: :> Negative block numbers are used by UFS to represent the indirect blocks :> associated with a file, while positive block numbers represent the :> contents of the file. : :I never saw any negative block numbers in on-disc structures. :Now I wonder if it was just hidden behind macros. :What is the reason to handle it that way? :Do you have some code reference for homework?
LOGICAL block numbers, not physical block numbers. :> These are logical block numbers, which are fragment-sized (1K typically). :> So, 2^31 x 1K = 2TB. :> :> Physical block numbers are 512-byte sized, with a range of 2^32 :> in -stable. This also winds up being 2TB. So increasing the fragment :> size does not help in -stable. : :It's a proven fact that there is a 1T limit somewhere which was :explained with physical block numbers beeing signed. : :-- :B.Walter COSMO-Project http://www.cosmo-project.de test1# vnconfig -e -s labels -r reserve -S 2t vn0 test1# disklabel -r -w vn0 auto test1# disklabel vn0 ... bytes/sector: 4096 ... 8 partitions: # size offset fstype [fsize bsize bps/cpg] c: 536870912 0 unused 0 0 # (Cyl. 0 - 2097151) Theoretically VN can create up to an 8TB virtual disk because the sector size for a swap-backed VN device is 4K, but I'm not sure I would want to test the theory. With a regular file: test1# vnconfig -e -s labels -T -S 2047g vn0 test.dat test1# disklabel -r -w vn0 auto test1# disklabel vn0 ... bytes/sector: 512 ... c: 4292870144 0 unused 0 0 # (Cyl. 0 - 2 test1# ls -la test.dat -rw---xr-- 1 root wheel 2199023255552 Jul 7 00:31 test.dat test1# (of course, god help you if you tried to 'newfs' the above!) -Matt Matthew Dillon <[EMAIL PROTECTED]> To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message