HP Q153090901 Technical Reference Manual page 185

Memory sizes
Main buffer memory:
The Main Buffer memory is 128 MB.
Areas of the Main Buffer memory are used by the firmware. These should not be written to and
should not be expected to retain values that are written to them. Any Write and Read Buffer tests
can 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 Address
20h 00000000h + Buffer Offset (same as Buffer ID 00h)
01000000h + Buffer Offset (that is, +16 MB)
21h
22h 02000000h + Buffer Offset (that is, +32 MB)
23h 03000000h + Buffer Offset (that is, +48 MB)
24h 04000000h + Buffer Offset (that is, +64 MB)
25h 05000000h + Buffer Offset (that is, +80 MB)
26h 06000000h + Buffer Offset (that is, +96 MB)
27h 07000000h + Buffer Offset (that is, +112 MB)
Main processor memory:
Not all the Processor memory space is accessible. Take care when writing to any addresses within
this buffer.
SCSI burst buffer:
Addressable range from 00000h through 3F8000h.
PCA EEPROM:
The write range is limited to 500h bytes, starting at 100h (TapeTools area).
WRITE BUFFER 3Bh 185