Emulex MD21/S2, Техническое руководство

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Disk Operations
Min bytes per In the Hard Sector mode this is the minimum
sector number of bytes between sector pulses that is
required by the controller. For a soft-sectored
drive, this is the sector length the controller
will use. This size includes all controller and
drive overhead, gaps, sync, and data fields.
Comments This column Mentions any non-standard ESDI
features supported by both the controller and
drive. Having this information may assist you in
setting option jumpers.
4.3 DISK OPERATIONS
The following subsections describe controller functions during
operations with the disk drive.
4.3.1 SECTOR AND TRACK FORMAT OPERATIONS
For hard-sectored disk drives, the controller formats each sector
as shown in Figure 4-1. For soft-sectored disk drives, the
controller formats each sector as shown in Figure 4-2. The Inter
Sector Gap (ISG) and PLO Sync fields vary between disks and their
sizes are returned by the disk drive over the disk interface (see
Figure 4-1 and 4-2). The controller formats each track with a
physical address in the header identification (ID) field of each
sector. The controller supports a 5-byte header as shown in Figure
4-1 and 4-2. The track address is defined as the cylinder and head
address of the specified track. Spare sectors may be allocated on
each track. The interleave factor may be specified during a format
operation (see the FORMAT UNIT command in the Emulex SCSI Disk
Controller Programming Reference Manual, manual number MD2352501).
When a data track develops multiple error conditions that cannot be
resolved by the use of spare sectors, the controller saves the data
from the track and reformats it as a flawed data track. The
defective data track is reformatted with the Defective Track bit
and the track address of the allocated alternate track in the
header of each sector. The data saved from the defective track is
written to the alternate track.
An alternate track is a track in the reserved-controller storage
area on the disk drive. When an alternate track is so allocated,
it is formatted with the sector address of the defective track.
The controller considers the interleave factor when it formats an
alternate track.
Drive Configuration Parameters 4-5