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Summary

There are several differences between my simulator, real disks, and real disk defragmentation software.

1.
I assume that all tracks have the same number of sectors. This is not true of real disks.
2.
All tracks and sectors are treated identically. There is no differentiation between sectors holding boot data, directory entries, file system metadata, or data.
3.
Simulator allocates disk space assuming one cluster equals one sector. Multiple consecutive sectors would have to be specified in the input file in order to emulate clusters of more than one sector.

At present, there are two situations which can lead to a segmentation fault in the simulator.

1.
Simulator will crash with a segmentation fault if the number of sectors selected by the user is less than 3. This isn't really serious since there should not be any disks with so few sectors per track.
2.
Simulator will crash with a segmentation fault if the number of sectors required to hold all of the entries in the input file exceeds the number of sectors available (based on the number of tracks and sectors specified by user).

As shown by the simulator's help screen, these are the command line arguments that the simulator accepts:

--help                  this screen
--in <filename>         read from input file <filename>
--out <filename>        output to output file <filename>
--tracks <numtracks>    disk has <numtracks> tracks
--sectors <numsectors>  disk has <numsectors> sectors
--policy <type>         specify policy, where <type> is
                        1 for everything at beginning


next up previous contents
Next: Source Code Up: Disk Optimization Simulator Previous: Assumptions
Barnett Hsu
1998-10-31