The present invention provides techniques, including a method and system, for transferring data between computer systems, for example, a mainframe and a Personal Computer (PC), having storage systems of different formats, efficiently. One embodiment provides a method for transferring data from a first system, having a first processor and a first memory, using a first format to a second system, having a second processor and a second memory, using a second format. The method includes a first system receiving data of a first format from a first disk unit; processing the data of the first format into transformed data, where the transformed data is the data transformed into the second format; storing the transformed data in the first memory; and sending the transformed data from the first memory to the second system responsive to a request from the second system.