Apparatus for recovering lost buffers in a data processing system.

摘要

The apparatus is used for recovering buffers in a data processing system comprising a memory divided into a plurality of buffers provided with buffer control blocks, by means of which source and destination users exchange information. A buffer management circuit (26) is responsive to requests from users for allocating buffers to source users in order said source users store the information to be sent to the destination users and building buffer queues and for dequeueing buffers from said queues to send the information contained therein to the destination users and releasing the buffers afterwards. A time register (TMR-40) is settable to n different values in a predetermined order. The value of said time register is changed at the expiration of a time period P. Each time a buffer is allocated to one user the current value of the time register is written into a time mark field of the buffer control block, and a state field is set to a first value (leased). When the buffer is released the state field is set to a second value (released). The contents of the buffer control blocks are read at regular times t distant from P, and the state field of every buffer control block is tested to determine whether it is set to the second value and if not the time mark field is compared with the value the time mark register had at the time t-xP, where x is a number such as 1<x<n and releasing the corresponding buffer in case of equality. <IMAGE>