What kind of data does the disk test read/write

The standard tests all create a 512MB file on disk. The file is extended to the full 512MB SetEndOfFile Windows API call, which leaves the files data in an ideterminate state.

• For the read test we read whatever happens to be in the file that was created.
• For the write test we create a data buffer the size of a single block and fill it with random data, we then overwrite the contents of the original file with this block repeatedly.
• For the Read/Write test, the write buffer is initially filled with random data, but then this buffer is overwritten with the data that is read. So in effect PerformanceTest writes back out the data it reads in (although to different locations)