旼컴컴컴컴컴컴컴쩡컴컴컴컴컴컴컴쩡컴컴컴컴컴컴컴쩡컴컴컴컴컴컴컴� 쿚ffset �# Bytes 쿏escription 쿝/W* � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �00h (00) �01h (01) 쿎ommand Code = 쿥 � � � �2 � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �01h (01) �01h (01) 쿞tatus 쿝 � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �02h (02) �01h (01) 쿓ost Adapter 쿥 � � � 쿙umber � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �03h (03) �01h (01) 쿞CSI Request 쿥 � � � 쿑lags � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �04h (04) �02h (02) 쿗ength of 쿥 � � � 쿞catter/Gather � � � � 쿗ist � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �06h (06) �02h (02) 쿝eserved for �- � � � 쿐xpansion = 0 � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �08h (08) �01h (01) 쿟arget ID 쿥 � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �09h (09) �01h (01) 쿗UN 쿥 � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �0Ah (10) �04h (04) 쿏ata Allocation쿥 � � � 쿗ength � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �0Eh (14) �01h (01) 쿞ense 쿥 � � � 쿌llocation � � � � 쿗ength (N) � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �0Fh (15) �04h (04) 쿏ata Buffer 쿥 � � � 쿛ointer � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �13h (19) �04h (04) 쿞RB Link 쿥 � � � 쿛ointer � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �17h (23) �01h (01) 쿞CSI CDB Length쿥 � � � �(M) � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �18h (24) �01h (01) 쿓ost Adapter 쿝 � � � 쿞tatus � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �19h (25) �01h (01) 쿟arget Status 쿝 � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �1Ah (26) �02h (02) 쿝eal Mode Post 쿥 � � � 쿝outine � � � � 쿚ffset** � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �1Ch (28) �02h (02) 쿝eal Mode Post 쿥 � � � 쿝outine CS** � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �1Eh (30) �02h (02) 쿝eal Mode Post 쿥 � � � 쿝outine DS** � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �20h (32) �02h (02) 쿛rotected Mode 쿥 � � � 쿛ost Routine � � � � 쿚ffset � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �22h (34) �02h (02) 쿛rotected Mode 쿥 � � � 쿛ost Routine CS� � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �24h (36) �02h (02) 쿛rotected Mode 쿥 � � � 쿛ost Routine DS� � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �26h (38) �04h (04) 쿛hysical 쿥 � � � 쿌ddress of SRB � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �2Ah (42) �16h (22) 쿝eserved for �- � � � 쿌SPI Workspace � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �40h (64) 쿘 쿞CSI Command 쿥 � � � 쿏escriptor � � � � 쿍lock (CDB) � � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴� �40h+M 쿙 쿞ense 쿝 � � � 쿌llocation Area� � 읕컴컴컴컴컴컴컴좔컴컴컴컴컴컴컴좔컴컴컴컴컴컴컴좔컴컴컴컴컴컴컴�
*The R/W column indicates whether the field is sent to ASPI (W), returned from ASPI (R), or reserved (-). **Used by OS/2 1.x only. Fields are not used under OS/2 2.x.
This command usually returns with zero status indicating that the request was queued successfully. Command completion can be determined by polling for non-zero status or through the use of the Post Routine Address field. If you are going to use polling, interrupts must be enabled. The SCSI Request Flags byte is defined as follows:
旼컴컴컴컴쩡컴컴컴컴쩡컴컴컴컴쩡컴컴컴컴쩡컴컴컴컴쩡컴컴컴컴쩡컴컴컴컴쩡컴컴컴컴� �7 �6 �5 �4 �3 �2 �1 �0 � 쳐컴컴컴컴탠컴컴컴컴탠컴컴컴컴탠컴컴컴컴탠컴컴컴컴탠컴컴컴컴탠컴컴컴컴탠컴컴컴컴� 쿝svd 쿝svd 쿞GE 쿏irection쿏irection쿝eserved 쿗ink 쿛ost � � � � 쿍its 쿍its � � � � 읕컴컴컴컴좔컴컴컴컴좔컴컴컴컴좔컴컴컴컴좔컴컴컴컴좔컴컴컴컴좔컴컴컴컴좔컴컴컴컴�
The Post bit specifies whether posting is enabled (bit 0 = 1) or disabled (bit 0 = 0). The Link bit specifies whether linking is enabled (bit 1 = 1) or disabled (bit 1 = 0). The Direction Bits specify the direction of the transfer:
00 - Direction determined by SCSI command. Length not checked.
01 - Transfer from SCSI target to host. Length checked.
10 - Transfer from host to SCSI target. Length checked.
11 - No data transfer.
The Scatter/Gather Enable (SGE) bit specifies whether scatter/gather is enabled (bit 5=1) or disabled (bit 5=0). The Target ID and LUN fields are used to specify the peripheral device involved in the I/O.
The Data Allocation Length field indicates the number of bytes to be transferred. If the SCSI command to be executed does not transfer data (such as Rewind, Start Unit, and so forth) the data allocation length must be set to zero.
The Length of Scatter/Gather List field is valid only when the scatter/gather enable bit in the flags is set. It contains the number of descriptors in the array pointed by the Data Buffer Pointer field.
The Sense Allocation Length field indicates the number of bytes allocated at the end of the SRB for sense data. A request sense is automatically generated if a check condition is presented at the end of a SCSI command.
The Data Buffer Pointer field is a pointer to the I/O data buffer. When scatter/gather is enabled, this field is a physical pointer to a scatter/gather list. A scatter/gather list is made up of one or more descriptors of the following format:
旼컴컴컴컴컴컴컴컴컴컴� 쿏WORD Buffer Pointer �
쳐컴컴컴컴컴컴컴컴컴컴�
� DWORD Buffer Size �
읕컴컴컴컴컴컴컴컴컴컴�
The SRB Link Pointer field is a pointer to the next SRB in a chain. See the SCSI Command Linking With ASPI for more information.
The SCSI CDB Length field establishes the length, in bytes, of the SCSI Command Descriptor Block (CDB).
The Host Adapter Status field reports the host adapter status, as follows:
00h - Host adapter did not detect any error
11h - Selection timeout
12h - Data overrun/underrun
13h - Unexpected bus free
14h - Target bus phase sequence failure
The Target Status field reports the target's SCSI status, including:
00h - No target status 02h - Check status (sense data
is in sense allocation area)
08h - Specified target/LUN is busy
18h - Reservation conflict
Note: The host adapter status and the target status are valid only when the status byte is either 2 or 4.
The Post Routine Address field, if specified, is called when the I/O is completed.
The SCSI Command Descriptor Block (CDB) field contains the CDB as defined by the target's SCSI command set. The length of the SCSI CDB is specified in the SCSI Command Length field.
The Sense Allocation Area is filled with sense data on a check condition. The maximum length of this field is specified in the Sense Allocation Length field. The target can return fewer than the number of sense bytes requested.