and that the client and server computers may be somewhat differently configured with respect to the processing power of their respective processors and with respect to the amount of memory used computer system 201 includes a processing unit 203 and a system memory 205 a system bus 207 couples various system components including system memory 205 to processing unit 203 system bus 207 may be any of several types of bus structures including a memory bus or memory controller a peripheral bus and a local bus using any of a variety of bus architectures system memory 205 includes read only memory rom 252 and random access memory ram 254 a basic input output system bios 256 containing the basic routines that help to transfer information between elements within computer system 201 such as during start up is stored in rom 252 computer system 201 further includes various drives and associated computer readable media a hard disk drive 209 reads from and writes to a typically fixed magnetic hard disk 211 a magnetic disk drive 213 reads from and writes to a removable u201c floppy u201d or other magnetic disk 215 and an optical disk drive 217 reads from and in some configurations writes to a removable optical disk 219 such as a cd rom.