Advanced Micro Devices Corporation

Nicos S Syrimis

Vineet Dujari

Douglas G Gray

A buffer memory subsystem for a peripheral controller. A CPU is provided for initiating data transfer. A host adapter is also provided. A memory buffer is used to store data temporarily. The peripheral controller is adapted for operating in an environment having at least two data communications buses: a CPU data communications bus connected between the CPU and the peripheral controller, and a buffer data communications bus, isolated from the CPU data communications bus, and connected to the peripheral controller, to the memory buffer and to the host adapter. In this way, a mechanism is provided to allow the CPU to access the memory buffer by means of the peripheral controller.

Buffer memory subsystem for peripheral controllers

A novel technique for skipping defects on a magnetic or writable optical disk is described. The technique includes a sector format comprising a header (24) and data area (28), wherein the data area can include one or more 'bad areas' (108, 116) which will be skipped when data is being written to or read from the sector. The bad areas are variable in size and may be located anywhere in the data area, including in an EDAC. The header includes a defect descriptor (48) comprising a defect pointer (70, 72) for each of the bad areas supported. Each defect pointer contains a value (74, 78) indicating the number of bytes in the good data area (106, 114) preceding the bad area pointed to by the defect pointer, and a value (76, 80) indicating the number of bytes in the bad area. The value indicating the number of bytes in a good area is set to a value indicating a number of bytes at least as large as the sector size if there is no subsequent bad area in the data area.

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Santa Clara, CA, United States of America

Nicos S Syrimis