wescott@ncrcae.UUCP (Mike Wescott) (03/01/85)
System V mkfs does not properly handle the case of 1Kb filesystems built on disks with an odd number of 512-byte sectors per cylinder. The problem is that internal to mkfs the cyl size is truncated to the next lower even number. In the middle of the filesystem, the "logical cylinder" allocated by mkfs straddles physical cylinders; this causes excessive seeks as the free list is consumed. Fix by recoding mkfs, fsck, and dcopy to handle the odd sectors differently, for example put the 1K blocks that straddle cylinder boundaries at the end of the free list. Work around by using twice the track size instead of cylinder size as the last parameter to mkfs. This reduces the extra seeks but is not as good as the fix proposed above. Anybody got another idea? Mike Wescott NCR Corp. mcnc!ncsu!ncrcae!wescott usceast!ncrcae!wescott