HP C737990900 Technical Reference Manual page 162

Buffer ID Specifies which buffer to read.
00h
01h
02h
13h
20h
21h
22h
23h
Where in the buffer the data should be written. This must be smaller than the size of the buffer and
Buffer Offset
must obey the specified offset boundary. When downloading new firmware, this field is ignored.
Parameter The amount of data. This must be smaller than the difference between the Buffer Offset field and
List Length the size of the buffer.
Main Buffer
Memory:
162 Commands
Main buffer (RAM) Offset Boundary: 1 byte
Processor addressable memory (RAM) Offset Boundary: 1 byte
SCSI burst buffer (RAM) Offset Boundary: 4 bytes
or FC burst buffer (RAM) Offset boundary: 512 bytes
PCA EEPROM Offset Boundary: 1 byte
Main buffer segment 0 (RAM) — see below for description)
Main buffer segment 1 (RAM) — see below for description)
Main buffer segment 2 (RAM) — see below for description)
Main buffer segment 3 (RAM) — see below for description)
Memory Sizes
The Main Buffer Memory is 64 MB
Two areas of the Main Buffer Memory (000000h–0FFFFFh and FC0000h–
FFFFFFh) are used by the firmware. These should not be written to and should
not be expected to retain values that are written to them.
Avoiding these areas, Write and Read Buffer tests can be performed to the
address range 100000h–FBFFFFh. These types of tests should be performed
while the drive is idle. If the drive is reading or writing, the data being written
or read can be corrupted.
Since the drive has more than 16 MB of Main Buffer Memory, additional
buffer IDs have been defined to allow the whole buffer to be accessed in 16
MB segments. These are defined as follows:
Buffer ID
20h 00000000h + Buffer Offset (same as Buffer ID 00h)
21h 01000000h + Buffer Offset (in other words, +16MB)
22h 02000000h + Buffer Offset (in other words, +32MB)
23h 03000000h + Buffer Offset (in other words, +48MB)
Address