|1024Byte||360K, 1.2M, 2.88M Floppies|
Two programs are widely available that analyze slack space:DISKSTAT (DISKST) and CHKDRV. Both programs contain minor errors in calculation involving files whose length is 0 or an even multiple of cluster size. Early Versions of CHKDRV have additional errors. It is also possible to determine lost space under DOS by comparing CHKDSK storage figures with Space Remaining reported by DIR.
Under Windows95 DIR /V /S will list the data needed to compute slack.
One formula for estimating slack is:
Slack = (Cluster_Size - Avg_File_Size) * Number_of_Files
It is claimed that slack in percentage is roughly equal to the cluster size divided by 1000. For example a disk with 16384K clusters would have about 16% slack.
Alternate file systems have far less slack. Compressed disks effectively have a 512 byte cluster size. FAT32 disks have smaller cluster sizes than FAT16.
|512Byte||up to 260mb|
|8192Byte||8Gb to 16Gb|
|16384Byte||16Gb to 32Gb|
|32768Byte||32Gb and larger|
Return To Index Copyright 1994-2008 by Donald Kenney.