SCSI Description

￿￿￿#Many￿6TCPUHGTof the SCSI￿%QOOCPFcommands￿%QORQPGPVUcause data to be transferred between the initiator and the drive. The content and characteristics of this data are command-dependent. Table 5-8lists the information transmitted for all of the commands.

The “Length in CDB” column of Table 5-8identifies the Command Descriptor Block field used by the drive to determine how much command-related data are to be transferred. The units (bytes or logical blocks) for the different Length fields are implied by the Length Field Name as shown in Table 5-7:

 

 

 

Length Fields

 

 

 

 

 

 

 

 

 

 

 

%QOOCPFCHANGE

.GPIVJ0￿KP￿%&$Table&CVC5-7￿1WV￿￿--6Q￿&TKXG￿

&CVC￿+P￿￿6Q--￿+PKVKCVQT￿

 

Allocation Length

Bytes of data the drive is allowed to send to the initiator

 

Parameter List Length

Bytes of data the initiator has available for the drive

 

Transfer Length

Logical data sectors the initiator wants transferred or verified

 

Byte Transfer Length

Bytes of data the initiator wants transferred

The DATA OUT column in Table 5-8lists the information passed to the drive by the initiator as part of the command. The DATA IN column lists the information sent to the initiator by the drive.

Numbers in parentheses after an item indicate the item’s length in bytes. In some cases, additional length information is communicated during the DATA phase. For example, a FORMAT UNIT Defect List Header contains a Defect List Length field that contains the total length of the Defect Descriptors that follow the Defect List Header. Table 5-8does not include these cases.

 

(KGNF￿0COG

DATA-Phase Command7PKVUContents￿+ORNKGF

 

 

 

 

 

 

 

 

 

 

DEFINITION

 

 

 

 

 

 

 

 

 

 

 

 

Defect List Header

 

FORMAT UNIT

 

0

Initialization Pattern (6-8)

 

 

 

 

Defect Descriptors

 

 

 

 

 

 

INQUIRY

 

Allocation

---

Standard Inquiry or a Vital Prod-

 

uct Data page

 

 

 

 

 

 

 

 

 

LOG SELECT

 

Parameter List

--

--

 

(must be 0)

 

 

 

 

 

 

 

 

 

LOG SENSE

 

Allocation

---

Log Page

 

 

 

 

 

 

 

Parameter List

Mode Parameter Header

 

MODE SELECT

 

(4 Block Descriptor (8

--

 

 

 

 

 

Page(s))

 

 

 

 

 

 

MODE SENSE

 

Allocation

---

Block Descriptor (8)

 

 

 

 

 

 

 

PERSIST. RES. IN

 

 

 

 

 

 

 

 

PERSIST. RES.

 

Table5-8

 

 

OUT

 

 

 

 

 

 

 

READ (6) (10)

 

Transfer

---

Data

 

 

 

 

 

5-10 Maxtor Atlas 10K III

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Image 74
Maxtor 10K III manual Length Fields, Definition, Out