[mjarski15]

I was wondering, because I know that a few people in this board have deleted classic, if anyone has OS X installed on top of the Unix file system instead of the HFS extended system. I beleive when you initialize the HD to do the install that you have the option to choose the standard Unix file system directory to install on top of, but you can't run OS 9 if you don't use HFS extended. My main question is that is OS X any faster, more stable, or any different performance wise if installed this way? just curious

[macmike42]

UFS (UNIX File System) is implemented only for compatibility reasons. It is slower, buggier, and supports fewer features than HFS+. The only reason to use it is if you *must* have a case-sensitivie filesystem (ie you cannot have makefile, Makefile, and MAKEFILE in the same directory with HFS+). Unless you are positive that you need case sensitivity for your filesystems, use HFS+ (Mac OS Extended).

[Fallout]

I believe UFS can't become fragmented, and is somewhat slower than HFS+.

[macmike42]

Originally posted by Fallout:
I believe UFS can't become fragmented...

This is an urban legend. Think about the repercusions if it were true. Say you had 1.1 GB of space left on your hard drive, and went to copy a 1 GB file to it. Now say that the largest free contiguous space was 200 MB. The filesystem would have to move all of the other 700 MB of data around before writing anything else to the disk, in order to avoid fragmentation. Furthermore, all subsequent write requests would simply have to block (since there is no way to guarantee enough RAM to store the information without hitting swap (hard drive) space). This would include any request for swapped-out memory or memory-mapped files (which *nix makes heavy use of for performance reasons). Such a filesystem would be practically unusable, and would actually forgoe almost all the benefits of preemptive multitasking.

Also, when a disk is formatted, all filesystems write the directory to the first available blocks. Imagine what would happen if the filesystem had to append something to the directory, fragmentation was not allowed, and the first block after the directory was occupied by a file 500 MB in size. In order to be able to find the directory, it has to exist (at least partially) at the beginning of a partition. In order to avoid fragmentation, the whole directory must be contiguous. Once again, in order to avoid fragmentation, the 500 MB file needs to be moved elsewhere (which may also result in other files being moved), simply so that you can append the name of a new folder to the directory.

Seriously, fragmentation is a *good* thing. Hard drives have ridiculously low seek times nowadays. If you are actually noticing a slowdown from a fragmented drive, you either have other (much more serious) hardware problems, or should consider leaving a little bit of free space on your hard drive.

As a general rule: Under normal use, as long as you always have enough free space to make two copies of the largest file on your hard drive, fragmentation should never get so bad as to be actually be detrimental to performance.

[Coxy]

HFS and HFS+ are very fragmentation-proof, if a file system can be said to have such an attribute.