05987557 is referenced by 185 patents and cites 11 patents.

A low overhead, efficient, and simple protection check circuit is inserted into a data path between a master requester and a target resource such as a memory or input/output device. The master requester initiates a memory request, a pio access request, or a dma transaction directed to the target resource. For example, the master requester may be a processor accessing a memory, a processor performing programmed I/O (pio). Alternatively, the master requester may be a DMA device performing direct memory access of a memory. The protection check circuit is configured at initialization time by an operating system or a privileged software process, then passively monitors all transactions on the data paths, disallowing accesses that fail the protection check operation.

Title
Method and apparatus for implementing hardware protection domains in a system with no memory management unit (MMU)
Application Number
8/879124
Publication Number
5987557
Application Date
June 19, 1997
Publication Date
November 16, 1999
Inventor
Zahir Ebrahim
Mountain View
CA, US
Agent
Skjerven Morrill MacPherson Franklin & Friel
Agent
Ken J Koestner
Assignee
Sun Microsystems
CA, US
IPC
G06F 13/15
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