User Manual

SCSI Commands Reference Manual, Rev. J 479
www.seagate.com Parameters for direct access devices
ATOMIC ALIGNMENT field
The ATOMIC ALIGNMENT field indicates the required alignment of the starting LBA in an atomic write command. If the ATOMIC ALIGNMENT
field is set to 0000_0000h, then there is no alignment requirement for atomic write commands.
If the ATOMIC ALIGNMENT field is non-zero, then the starting LBA of an atomic write request shall meet the following:
atomic request starting LBA = n × atomic alignment
where:
n is zero or any positive integer value; and
atomic alignment is the value in the ATOMIC ALIGNMENT field,
ATOMIC TRANSFER LENGTH GRANULARITY field
The ATOMIC TRANSFER LENGTH GRANULARITY field indicates the minimum transfer length for a WRITE ATOMIC command. Atomic write oper-
ations are required to have a transfer length that is a multiple of the atomic transfer length granularity. An ATOMIC TRANSFER LENGTH GRANU-
LARITY field set to 0000_0000h indicates that there is no atomic transfer length granularity requirement.
ATOMIC BOUNDARY field
If the ATOMIC BOUNDARY field in the CDB (see 3.68 and 3.69) is set to a non-zero value, then a MAXIMUM ATOMIC TRANSFER LENGTH WITH
ATOMIC BOUNDARY field set to a non-zero value indicates the maximum transfer length in logical blocks that the device server supports for a
single atomic write command (see SBC-4). A MAXIMUM ATOMIC TRANSFER LENGTH WITH ATOMIC BOUNDARY field set to 0000_0000h indi
-
cates that the device server does not indicate a maximum atomic transfer length with atomic boundary. The maximum atomic transfer length
with atomic boundary indicated by the MAXIMUM ATOMIC TRANSFER LENGTH WITH ATOMIC BOUNDARY field shall be less than or equal to the
maximum transfer length indicated by the MAXIMUM TRANSFER LENGTH field. The maximum atomic transfer length with atomic boundary
indicated by the MAXIMUM ATOMIC TRANSFER LENGTH WITH BOUNDARY field shall be a multiple of the value in the ATOMIC TRANSFER
LENGTH GRANULARITY field. If the ATOMIC BOUNDARY field in the CDB is set to zero, then the MAXIMUM ATOMIC TRANSFER LENGTH WITH
ATOMIC BOUNDARY field is ignored.
MAXIMUM ATOMIC BOUNDARY SIZE field
A MAXIMUM ATOMIC BOUNDARY SIZE field set to a non-zero value indicates that the device server supports atomic write commands perform-
ing more than one atomic operation. The maximum atomic boundary size indicates the maximum number of logical blocks on which the
device server is able to perform atomic operations (see SBC-4). A MAXIMUM ATOMIC BOUNDARY SIZE field set to 0000h indicates that the
device server does not support atomic write commands performing more than one atomic operation. The MAXIMUM ATOMIC BOUNDARY SIZE
field shall be a multiple of the value in the ATOMIC TRANSFER LENGTH GRANULARITY field.