Abstract: A method and apparatus for defining a random miss list and producing a desired hit ratio in a benchmark test of computer disk storage are disclosed. The disk area to be tested is divided into N tracks. A random miss list of L tracks is defined as specified by the invention. The tracks in the miss list are subdivided into groups, with each group having G tracks. Each one of a plurality of concurrent processes is assigned a different group of G tracks from the miss list. A pointer for each process is initialized to point to the first track in the corresponding group of G tracks. A plurality of input/output (I/O) operations are performed for each process, with each I/O operation being performed on the track pointed to by the pointer for the corresponding process. For each process, prior to each I/O operation that is performed after the first I/O operation, a random decision is made whether or not to increment the pointer belonging to the process.