Contiguous disk space allocation method

In contiguous disk space allocation method, files are assigned to contiguous areas of secondary storage. A user specifies in advance the size of the area needed to hold a file to be created. If the desired amount of contiguous space is not available, the file cannot be created.

Two most common strategies are

  1. First fit
  2. Best fit.

1. First fit

In this case as soon as the first hole (that is big enough) is encountered, searching is stopped and memory is allocated for creating a file.
Searching can start either at the beginning of the set of holes or where the previous first-fit search ended.

2. Best fit

In this case the entire list is searched for and the smallest hole, that is big enough, is allocated for creating a file.