Data Block Addressing; Definition Of Data Space - Fujitsu MAX3073NC - SCSI,80, Dell DC961,Hard Drive Scsi Logical Interface Specifications

Command Processing
After this state occurs, the IDD reports the CHECK CONDITION status for all input/output operation
requests except the REQUEST SENSE command. The sense data reported at this time indicate
HARDWARE ERROR [=4] / Internal target failure [=44-nn]. If this state is reported continuously for
input/output operation requests, it is necessary for the INIT to generate a RESET condition or send a
TARGET RESET message and attempt to recover from the error state. For recommended procedures for
error recovery methods by the INIT, see the explanation in Section 5.2 "INIT's Error Recovery Methods
(Recommended)."
1.8

Data Block Addressing

1.8.1

Definition of data space

The IDD manages the data storage area on the disk drive in the following 2 types of data space.
•
User space: user data storage area
•
System space: IDD exclusive area
Within these 2 areas, the user can clearly access the user space. The data format and defect management
methods in this space are the same and it is possible to access this space by logical data block addressing
described in Section 1.8.2. System space is accessed by the IDD internally when the power is switched
on or during processing of specific commands, but it cannot be accessed directly by the user.
Figure 1.5 shows the data space configuration on the disk drive. The number of cylinders allocated to
user space can be referred by the user (MODE SENSE or MODE SENSE EXTENDED command).
A spare sector area (alternate area) for use as alternate sectors for defective sectors is allocated in the user
space. The IDD manages defects for each cell, which consists of several cylinders (see Figure 1.5). The
user can allocate the number of sectors in the last track of each cell as the alternate area (by the MODE
SELECT or MODE SELECT EXTENDED command). Alternate cylinders for the IDD cannot be altered
by the user.
Alternate data blocks are allocated in defect sector units for defective sectors on the disk media through
internal IDD defect management. Through this defect management, the INIT can access all the logical
data blocks in the user space as if they were error free.
For details concerning the data format on the disk media (cylinder configuration, track format and sector
format) and details concerning defect management techniques and alternate block allocation techniques,
Chapter 3 "Data Format" in the "Product Manual." For an outline of defect management techniques, see
"Disk Media Management" in Chapter 6 of this manual.
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