Abstract: Apparatus is disclosed for transferring data between multiple peripheral processors (PPs) which are operating under control of a host processor in a multi-processor computer system. In a high data rate application a number of dedicated special purpose PPs are arranged in fixed sequence to provide individual data processing steps. A data path is provided between each PP data memory and the next. A PP transfer unit associated with each PP data memory controls data transfer simultaneously between all PPs. Separate read/write address mapping is provided for each PP data memory. Control information may be associated with each mapped PP data memory location to provide logic functions and data rearrangements during the transfer process. Data from several PPs may be interleaved or may be logically or arithmetically combined with other PP data or constant information.

Abstract: An improved arrangement for controlling access to data files by computer users. Access permission bits are used in the prior art to separately indicate permissions for the file owner and nonowners to read, write and execute the file contents. An additional access control bit is added to each executable file. When this bit is set to one, the identification of the current user is changed to that of the owner of the executable file. The program in the executable file then has access to all data files owned by the same owner. This change is temporary, the proper identification being restored when the program is terminated.