Maxtor 10K V manual Read Skip Mask Command E8h, 143READ Skip Mask Command-Data Format

5.25READ SKIP MASK Command (E8h)

The READ SKIP MASK command allows the initiator to condition the function of the READ commands to allow only selected data to be transferred over the SCSI interface. A READ SKIP MASK command precedes a READ (10) command; the READ (10) command must be linked to the READ SKIP MASK command or the skip mask is lost and a CHECK CONDITION status is returned.

Table 5-143READ SKIP MASK Command-Data Format

	Bit			7	6	5	4	3	2	1	0
	Byte
	0						Operation Code (E8h)
	1			(MSB)			Reserved				(LSB)
	2 - 5						Logical Block Address
	6						Skip Mask Length
	7 - 8			(MSB)			Transfer Length				(LSB)
	9			VU			Reserved			Flag	Link
		Table 5-144READ SKIP MASK Command-Field Description
Field							Description
Logical Block Ad-			This field specifies the first logical block of the corresponding READ (10) COMMAND. This al-
			lows a SEEK to begin immediately. The LBA of the following READ (10) command must be the
dress
			same as the LBA of the READ SKIP MASK command,
			This field indicated the length in bytes of the skip mask. The mask is up to 64 bytes, giving a data
			address capability of 256K. The mask consists of a sequence of bits where a "1" bit is for the blocks
Skip Mask Length			of data to be transferred and a "0" for the blocks of data that are to be skipped. The first "1" bit of
			the mask corresponds to the first LBA to be transferred. Any unused bits at the end of the last byte
			in the mask must be set to 0. The mask is transferred in the data-out buffer transfer of the skip mask
			command.
			This field must be equal to the transfer length in the linked READ (10) command. The transfer
Transfer Length			length field must be equal to the number "1" bits in the skip mask. If a READ (10) is used with 0
			as the transfer length, a transfer length of 256 data blocks is implied.

Maxtor Atlas 10K V 5-103