LaCie Mobile Drive User’s Guide 04/17/2003 v.2
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5.3 Mac OS Standard vs. Mac OS Extended
There are basically two file systems for the Mac OS: Mac OS Standard (HFS) and
Mac OS Extended (HFS+).
Mac OS Standard
Mac OS Standard refers to the file system used by Mac OS 8.0 and earlier. This was
the original Hierarchical File System employed by Apple, and was used before
computers really began to see dramatic increases in hard disk drive sizes. In HFS, the
disk is divided into a maximum of 65,536 equal-sized blocks, with these blocks being
the destination point of data stored by the Mac.
Initially, these spaces were small, due to the lack of size in hard drives (i.e. hard
drives smaller than 1GB), but as hard drive space increased, the file system became
inefficient. With HFS, even the smallest file on any disk has to occupy at least one
block. For example, if you had a 4GB hard drive and divided it by 65,536, that
would equal roughly 64K, and that would be the smallest block size under HFS. So, if
you had a file that was only 4K, it would still have to occupy 64K.
Mac OS Extended
Mac OS Extended refers to the file system used by Mac OS 8.1 and later. HFS+
represents an optimization of the older HFS file system by using hard disk space more
efficiently. As hard disk capacity increased over the years, Apple realized that they
needed to improve the space-saving capabilities of their file system. Building off of
HFS, they increased the number of blocks from 65,536 to 4.29 billion. With HFS+,
you are no longer limited by block size. Now, for example, if you have a 4K file, it
will only take up 4K of space.
Guidelines for Choosing Mac OS Standard or Mac OS Extended
This is actually a fairly easy decision. You should only use Mac OS Standard if you
are creating a volume smaller than 32MB, you are using a Mac with a 680X0
processor or you are creating a file structure that will need to be used by Macs using
Mac OS 8.0 or earlier. Otherwise, you should select Mac OS Extended.