A client-directed pre-stage operation of a cache memory used to access data blocks from a mass data storage device attached to a host computer through a channel control processor is provided by a method and apparatus comprising a channel control processor for retrieving data blocks from the mass storage device to be pre-staged within the cache memory, a channel interface coupled between the channel control processor and the host computer, a mass storage device interface coupled between the channel control processor and the mass storage device, and a cache memory coupled between the channel interface and the mass storage interface; the cache memory is further coupled to the cache control processor to provide the cache control processor access to data stored within the cache memory. The cache control processor receives a cache bitmap from the host computer to specify the data blocks from the mass storage device to be pre-staged into the cache memory. Each bit within the cache bitmap corresponds to a data block within the mass storage device which may be pre-staged into the cache memory.