Abstract: This invention relates to a device and a method of representing a transfer of data between a main memory and a storage device in a storage system. The invention uses scatter gather lists to describe the data area of both the main memory and of the storage device that are relevant for the data transfer. Further is a direction indicator used to specify whether the disk location is source and the part of the main memory is destination or the other way around. Preferably a surplus previously un-used bit is used as the direction indicator. In this way, an efficient way of handling read, write and/or modify processes is enabled. Further, no actual data is moved during CPU processing, since only references to the data, i.e. tuples, are copied between SGLs which greatly reduces storage and bandwidth requirements.

Abstract: This invention relates to a first method of referencing a first number for data (29) to be stored and a second method of referencing a first address for data to be retrieved. Said data is shared among a producer and a consumer. Said first method comprising the steps of computing said first number (24, offset) equalling p (25) minus Vaprod (26), wherein p is in the virtual address space of the producer, and Vaprod is in the virtual address space of the producer (20); and storing said first number as the address for said data in a scatter gather list. Optionally said first method comprises the step of storing (300) data at location p.