Abstract: A modified driver program for an external hard disk drive for a personal computer which manages a cache in RAM on the motherboard to speed up disk access operations is disclosed. A block of 2000 bytes contiguous to the driver code is reserved at boot time. An "on/off" data byte flag is managed to indicate whether the data in the cache is valid. For read operations of a size less than the size of the cache, a number of sequential blocks of data from the disk are stored in the cache. Any write operation potentially invalidates the cache data so the flag is set "off". On subsequent read operations, if the cache flag is "on", the driver code compares the contents of the cache to the requested data to see if it is stored in the cache. If it is, the data is read from the cache as opposed to the disk thereby speeding up the access.