Disk Type (format.dat) (System Administration Guide, Volume 1)

System Administration Guide, Volume 1

Disk Type (`format.dat`)

disk_type defines the controller and disk model. Each disk_type definition contains the physical geometry of the disk. The default data file contains definitions for the controllers and disks that the Solaris operating environment supports. You need to add a new disk_type only if you have an unsupported disk. You can add as many disk_type definitions to the data file as you want.

The keyword itself is assigned the name of the disk type. This name appears in the disk's label, and is used to identify the disk type whenever format is run. Enclose the name in double quotes to preserve any white space in the name. The table below describes the identifiers that must also be assigned values in all disk_type definitions.

Table 32-7 Required disk_type Identifiers


Identifier	Description
`ctlr`	Valid controller type for the disk type. Currently, the supported values for this assignment are SCSI and ISP-80 (IPI controller).
`ncyl`	The number of data cylinders in the disk type. This determines how many logical cylinders of the disk the system will be allowed to access.
`acyl`	The number of alternate cylinders in the disk type. These cylinders are used by `format` to store information such as the defect list for the drive. You should always leave at least two cylinders for alternates.
`pcyl`	The number of physical cylinders in the disk type. This number is used to calculate the boundaries of the disk media. This number is usually equal to `ncyl` plus `acyl`.
`nhead`	The number of heads in the disk type. This number is used to calculate the boundaries of the disk media.
`nsect`	The number of data sectors per track in the disk type. This number is used to calculate the boundaries of the disk media. Note that this is only the data sectors, any spares are not reflected in the assignment.
`rpm`	The rotations per minute of the disk type. This information is put in the label and later used by the file system to calculate the optimal placement of file data.

Other assignments might be necessary depending on the controller. The table below describes the assignments required for SCSI controllers.

Table 32-8 disk_type Identifiers for SCSI Controllers


Identifier	Description
`fmt_time`	A number indicating how long it takes to format a given drive. See the controller manual for more information.
`cache`	A number that controls the operation of the onboard cache while `format` is operating. See the controller manual for more information.
`trks_zone`	A number that specified how many tracks you have per defect zone, to be used in alternate sector mapping. See the controller manual for more information.
`asect`	The number assigned to this parameter specifies how many sectors are available for alternate mapping within a given defect zone. See the controller manual for more information.

Below are some examples of disk_type definitions:

disk_type = "SUN1.3G" \
        : ctlr = SCSI : fmt_time = 4 \
        : trks_zone = 17 : asect = 6 : atrks = 17 \
        : ncyl = 1965 : acyl = 2 : pcyl = 3500 : nhead = 17 : nsect = 80 \
        : rpm = 5400 : bpt = 44823

disk_type = "SUN2.1G" \
        : ctlr = SCSI : fmt_time = 4 \
        : ncyl = 2733 : acyl = 2 : pcyl = 3500 : nhead = 19 : nsect = 80 \
        : rpm = 5400 : bpt = 44823

disk_type = "SUN2.9G" \
        : ctlr = SCSI : fmt_time = 4 \
        : ncyl = 2734 : acyl = 2 : pcyl = 3500 : nhead = 21 : nsect = 99 \
        : rpm = 5400