When you format a hard drive, be it an ADFS drive or a SCSI drive, you can choose between "Old map" and "New map" formats. To see which format your hard drive is in, type

*ADFS:Map :4

(or :5, 6 or 7)

If the output says "new map", you've got a new map format.

Some facts about the new map format:

• this format has the ability to store smallish files within the space taken on the disc by the directory. The maximum size of these files is the value given to the LARGE FILE ALLOCATION UNIT, or LFAU.
• the LFAU is specified when you format the hard drive. Apart from specifying the maximum size of a file which can be fitted within a directory space (NB *NOT* the maximum size of a file which can be stored on the disc), it is also related to the CAPACITY of the drive.

  Capacity               LFAU        "Size" of a directory (approx)
  ========               ====        ==============================
  Up to 124Mbytes        256         4K
  Up to 249Mbytes        512         8K
  Up to 499Mbytes        1024        16K
  Up to 999Mbytes        2048        32K

The "up to" values are inclusive. You can, of course, specify a large LFAU, but the side effect is that the larger the LFAU, the more disc space a directory takes, hence the "wasted disc space".

This arrangement, therefore, allows files up to the LFAU to be stored on the disc without taking up any more disc space, and without fragmenting the disc too much.

• when saving files to a new format disc, FileCore will automatically try and coalesce blocks to avoid fragmentation.
• to determine what value LFAU your drive has:

Some facts about the old map format:

• each directory always takes 4Kbytes
• the disc is not automatically compacted.