scm, scs --
Storage Device Interface (SDI) command structures
The scm and scs structures
are used by target drivers
to send a command to a SDI device.
The scs structure
defines the layout for a group 6 (six-byte
command length) command descriptor block (CDB);
scm is a group 10 (ten-byte command length) CDB.
Refer to the ANSI manual referenced in
``SCSI interface'' in HDK Technical Reference
for more information about individual structure members.
sm_pad0 member ensures that the
sm_addr member does not cross a 32-bit word boundary.
The members of the scm structure are:
int sm_pad0 : 16; /* 16-bit pad */
int sm_op : 8; /* Opcode */
int sm_lun : 3; /* Logical unit number */
int sm_res1 : 5; /* reserved field */
unsigned sm_addr; /* Block address */
int sm_res2 : 8; /* reserved field */
int sm_len : 16; /* Transfer length */
int sm_cont : 8; /* Control byte */
The members of the scs structure are:
int ss_op : 8; /* Opcode */
int ss_lun : 3; /* Logical unit number */
int ss_addr : 21; /* Block address */
int ss_len : 8; /* Transfer length */
int ss_cont : 8; /* Control byte */
Because of the
sm_pad0 member, you must
add 2 to the address of the scm structure
when specifying it in the scb structure.
sdi: 2, 3, 4
``SDI pass-through interface'' in HDK Technical Reference
19 June 2005
© 2005 The SCO Group, Inc. All rights reserved.
OpenServer 6 and UnixWare (SVR5) HDK - June 2005