When a floppy disk is initialized, the system pre-allocates space for two data structures (the catalog and the extents tree); when the Finder sees the disk, it creates another data structure (the DeskTop file).
In order to speed up things, these three things allocate a lot of contiguous space, just to be sure that it will never be fragmented. In practice, however, that space is never fully used, hence even on a disk with "0 K free" there are still several kbytes free, which can't be used because they're reserved for those uses.
This little application, "1430K free", uses the standard way (documented in Inside Macintosh vol. IV page 240) to modify the sizes of the clump size (=> catalog size) and extent tree. It can't modify the size of the DeskTop file because before System 7 it was non-documented, and under System 7 it's created with a smaller size anyway.
It also allows you to logically format a floppy disk without physically formatting (i.e., performing the last step of disk initialization, "creating directory").
Using it under System 7 you may create disks which have slightly more than 1430 Kbytes free on a 1440 K disk, that's a percentually small improvement but sometimes it may be useful. Anyway, why should you leave those kbytes totally unused ? MS-DOS users get more than 1430 Kbytes free !
Guide to choosing the sizes
Entering "0" in one of the text boxes forces the System to use the standard value (12 on a 800K disk, 22 on a 1440 disk).
The extent tree size depends on the fragmentation of the disk: if you expect that a disk will never be fragmented (e.g. if you only store files and never delete/replace them) you may assign a very small size, e.g. 2 or 4, saving 20 sectors (10Kbytes).
The clump size (=> catalog size) should depend on the number of files you'll save on the disk: you may specify a very small size if you are going to save here only one huge file (e.g., it's a backup disk created with Redux or Compact Pro). A disk containing about 30 files may need a catalog of 10 to 15 sectors (the ratio is not fixed, it depends on the length of the file names).
Anyway, if you specify sizes which are too small the System will allocate more space when needed, the disk will be more fragmented and will be accessed more slowly but will be OK. Only specifying "1" you may cause troubles, it's really too little and you may get a disk error.
Notice
This program is public domain, and the source code is included. We are not willing to support it (we are too much occupied by another freeware program).
We've used it a few times, and since it uses standard methods and a well documented system call it should not create problems, but we are no responsible of any data loss which you could have on disks formatted with "1430K free".
