Abstract: A method and system for allocating memory in a RAID system. A RAID system requires the use of shared memory to store processed data related to operations of different mass storage devices. Certain RAID algorithms require different sizes of memory regions of the memory, and multiple requests to lock the required memory regions are therefore required. As multiple requests are made in parallel for different operations, the multiple requests for each operation are sorted in a predetermined order. This ensures that all memory regions for one operation can be locked. Requests for memory regions locked by a second operation are held in a pending state to wait for release of those memory regions by a first operation, at which point they are locked again by the second operation.