Comment by ryan-c
10 years ago
In theory, you could make the disk performance even worse by alternating between the beginning and end of the disk, though you may need to do a little tweaking to ensure this doesn't inadvertently allow read-ahead to help.
That might not work given that the drive might have more than one platter. You'd probably want to know how many heads the drive has to determine how to stripe it in the most inconvenient way possible. I think going beginning to middle on a single platter and back for each file would be the best way to get the worst performance for each file. That'll make sure it has to seek for each subsequent block and it can't inadvertently get read-ahead since it has to back track all the time, and the separation should be far enough that it won't get it on the in order blocks either.
EDIT: Just realized that I don't think this can be done through normal means. I think it'd need a pathological FAT file system driver to do it, and you'd have to build the image ahead of time to do it.
I seem to recall that this was very bad juju for old HDDs, in that it would quickly wear out the mechanics of the RW arm.
There are stories of really old hard drives being made to move around a room with abusive disk access patterns.
http://www.catb.org/jargon/html/W/walking-drives.html
"Some bands of old-time hackers figured out how to induce disk-accessing patterns that would do this to particular drive models and held disk-drive races."
Now that i would loved to be witness to.