HP C737990900 - Manual (Page 112)

112 Commands
Memory Sizes:
00011b The drive returns a 4-byte descriptor for the buffer identified by the Buffer ID field. Invalid
buffer IDs will return a buffer descriptor of all zeros.
The Buffer Offset field must be zero.
01010b The drive returns data from the Echo Buffer. The Buffer ID and Offset are ignored.
01011b The drive returns the Echo Buffer descriptor. The Buffer ID and Offset are ignored.
Buffer ID The Buffer ID indicates which buffer is to be read. The buffers are defined as follows:
Buffer ID Memory Area Category Offset Boundary
00h Main buffer memory RAM 1 byte
01h Processor addressable memory RAM 1 byte
02h SCSI burst buffer
or FC burst buffer
RAM
4 bytes
512 bytes
10h CM EEPROM EEPROM 1 byte
11h Mechanical EEPROM EEPROM 1 byte
12h Head assembly EEPROM EEPROM 1 byte
13h PCA EEPROM EEPROM 1 byte
20h Main buffer segment 0 RAM 1 byte see below for details
21h Main buffer segment 1 RAM 1 byte see below for details
22h Main buffer segment 2 RAM 1 byte see below for details
23h Main buffer segment 3 RAM 1 byte see below for details
Buffer Offset The Buffer Offset field may be set to any address in the buffer, but must obey the specified Offset
Boundary.
Allocation
Length
The amount of data to return. Allocation Length + Buffer Offset must be within the buffer size.
Main Buffer Memory Size: 64 MB, reported size FFFFFFh. Because the buffer is greater than 16 MB,
additional buffer IDs have been defined to allow the buffer to be accesssed in 16 MB
segments. these are as follows:
Buffer ID Address
20h 00000000h + Buffer Offset (same as Buffer ID 00h)
21h 01000000h + Buffer Offset (in other words, +16 MB)
22h 02000000h + Buffer Offset (in other words, +32 MB)