Allocation Of File Space - IBM 5110 User Manual

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Allocation of File Space
Previously in this section, reallocating diskette file space using the
}FREE and )MARK commands was discussed (see Real/ocating
Diskette File Space). Using the )FREE and }MARK commands to
reallocate diskette file space can cause fragmented blocks of
unallocated file space on the diskette. For example, assume a diskette
has all the file space allocated, except the following 15K of file space
on a cylinder:
Diskette
Cylinder
D
12
~
10K of Unallocated
File Space
17
5K of Unallocated
File Space
Now, if you need that 15K of storage for a new file to be marked, the
storage is not available because it is not in 15K continuous bytes.
The fragmented blocks of unallocated file space can be made available
by the compress function (see the IBM 5110 Customer Support
Functions Reference Manual, SA21-9311). The compress function
closes the gaps caused by the unallocated file space and places all of
the unallocated file space in one continuous area.