Quantum FIREBALL PLUS AS 10.2 User Manual

ATA Bus Interface and ATA Commands
6-72 Quantum Fireball Plus AS 10.2/20.5/30.0/40.0/60.0 GB AT
6.7.27
6.7.276.7.27
6.7.27 Read Defect List
Read Defect ListRead Defect List
Read Defect List
The READ DEFECT LIST command enables the host to retrieve the drive’s defect
list. Prior to issuing the Read Defect List command the host should issue the Read
Defect List Length command. This command will not transfer any data. It instead,
stores the length in sectors of the defect list in the Sector Count register (1F2), and
the Sector Number register (1F3), with the Sector Count register containing the
LSB of the 2-byte value (see Table 6-26). The defect list length is a fixed value for
each Quantum product and can be calculated as follows:
length in sectors = (((maximum number of defects) * 8 + 4) + 511)/512
At the completion of the command, the task file registers 1F2 – 1F6 will contain
bytes necessary to execute the Read Defect List command, and the host will only
need to write the extended command code (F0h) to the Command register (1F7) to
proceed with the Read Defect List command execution.
Table 6-26
Table 6-26 Table 6-26
Table 6-26
READ DEFECT LIST LENGTH Command Bytes
Note:
Note:Note:
Note: Registers 1F2h through 1F5h must contain the exact values
shown. These values function as a key. The drive issues the
message ILLEGAL COMMAND if the bytes are not entered
correctly.
The AT Read Defect List command is an extended AT command that enables the
host to retrieve the drive’s defect list. The host begins by writing to address 1F6h to
select the drive. Then the host writes to addresses 1F2h – 1F5h using values
indicated in Table 6-27. When the host subsequently writes the extended command
code F0h to address 1F7h, the drive sets BSY, retrieves the defect list, sets DRQ,
and resets BSY. The host can now read the requested number of sectors (512 bytes)
of data. An INTRQ precedes each sector. Bytes 1F2h and 1F3h contain the 2-byte
number of sectors that the host expects to read, with address 1F2h containing the
LSB (see Table 6-27). The sector count (1F2h – 1F3h) may vary from product to
product and if the wrong value is supplied for a specific product, the drive will issue
the ILLEGAL COMMAND message. If the host does not know the appropriate
sector count for a specific product, it can issue the Read Defect List Length
command, described in the previous section to set up the task file for the Read
Defect List command.
ADDRESS
ADDRESSADDRESS
ADDRESS
VALUE
VALUEVALUE
VALUE
(Before)
(Before)(Before)
(Before)
DEFINITION
DEFINITIONDEFINITION
DEFINITION
VALUE
VALUEVALUE
VALUE
(After)
(After)(After)
(After)
1F2 0 Defect List Subcode Length in Sectors (LSB)
1F3 FFh Password Length in Sectors (MSB)
1F4 FFh Password FFh
1F5 3Fh Password 3Fh
1F6 AXh (Drive 0) Drive Select AXh = Drive 0
BXh (Drive 1) — BXh = Drive 1
1F7 F0h Extended Command Code Status Register

Quantum FIREBALL PLUS AS 10.2 Specifications

General

Brand	Quantum
Model	FIREBALL PLUS AS 10.2
Category	Storage
Language	English