fdisk(1M) INTERACTIVE UNIX System fdisk(1M)
NAME
fdisk - create or modify fixed disk partition table
SYNOPSIS
fdisk [ argument ]
DESCRIPTION
This command is used to create and modify the partition
table that is put in the first sector of the fixed disk.
This table is used by MS-DOS (DOS) and by the first-stage
bootstrap to identify parts of the disk reserved for dif-
ferent operating systems, and to identify the partition con-
taining the second-stage bootstrap (the active partition).
The optional argument can be used to specify the raw device
associated with the fixed disk; the default value is
/dev/rdsk/0s0.
The program displays the partition table as it exists on the
disk, and then presents a menu allowing the user to modify
the table. The menu, questions, warnings, and error mes-
sages are intended to be self-explanatory.
If there is no partition table on the disk, the user is
given the option of creating a default partitioning or
specifying the initial table values. The default partition-
ing allocates 10 percent of the disk for DOS and 90 percent
for the UNIX System, and makes the UNIX System partition
active. In either case, when the initial table is created,
fdisk also writes out the first-stage bootstrap code (see
disk(7)) along with the partition table. After the initial
table is created, only the table is changed; the bootstrap
is not modified.
Upon start-up, the fdisk command will check any extended DOS
partition entries, and if they need correcting before they
can be used by the UNIX System, you will be prompted:
Do you want to fix the Extended DOS Partitions for UNIX access?
Please type "y" or "n":
Type y to correct the information for the extended DOS par-
titions. Type n if you do not want to correct the informa-
tion.
WARNING: If you do not correct the information but you
still try to mount an extended DOS partition, the system
will mount the primary DOS partition as the extended DOS
partition, thereby causing great damage to your system. To
make this change take effect, you must reboot the system.
The DOS partition types are currently listed as DOS12 and
DOS16 for the type of file allocation table (FAT) used on
each DOS partition.
Rev. Page 1
fdisk(1M) INTERACTIVE UNIX System fdisk(1M)
Menu Options
The menu options given by the fdisk program are:
Create a partition
This option allows the user to create a new partition.
The maximum number of partitions is 4. The program
will ask for the type of the partition (MS-DOS, UNIX
System, or other). It will then ask for the size of
the partition as a percentage of the disk. The user
may also enter the letter c at this point, in which
case the program will ask for the starting cylinder
number and size of the partition in cylinders. If a c
is not entered, the program will determine the starting
cylinder number where the partition will fit. In
either case, if the partition would overlap an existing
partition or will not fit, a message is displayed and
the program returns to the original menu.
Change Active (Boot from) partition
This option allows the user to specify the partition
where the first-stage bootstrap will look for the
second-stage bootstrap, otherwise known as the active
partition.
Delete a partition
This option allows the user to delete a previously
created partition. Note that this will destroy all
data in that partition.
Display partition table
This option allows the user to display the primary par-
tition list. If there are any extended logical DOS
partitions, the system will prompt:
Do you want to display the Extended DOS Partitions?
Please type "y" or "n":
Type y to display the extended DOS partition. Type n to
return to the main menu. If you type y, the system will
then prompt:
Hit return to continue
The system will display a partition number. This partition
number is the name that the DOS partition must be mounted
with, i.e., /dev/dsk/0p5 to mount the first extended DOS
partition. Use the following options to include your modif-
ications to the partition table at this time or to cancel
the session without modifying the table:
Exit This option writes the new version of the table
created during this session with fdisk out to the
fixed disk, and exits the program.
Rev. Page 2
fdisk(1M) INTERACTIVE UNIX System fdisk(1M)
Cancel This option exits without modifying the partition
table.
DIAGNOSTICS
Most messages will be self-explanatory. The following may
appear immediately after starting the program:
Fdisk: cannot open <device>
This indicates that the device name argument is not
valid.
Fdisk: unable to get device parameters for device <device>
This indicates a problem with the configuration of the
fixed disk, or an error in the fixed disk driver.
Fdisk: error reading partition table
This indicates that some error occurred when trying
initially to read the fixed disk. This could be a
problem with the fixed disk controller or driver, or
with the configuration of the fixed disk.
Fdisk: error fixing disk
This indicates that an error occurred when trying to
correct the extended DOS partition information.
Fdisk: error reading extended DOS partition table
This indicates that some error occurred when trying
initially to read the fixed disk. This could be a
problem with the fixed disk controller or driver, or
with the configuration of the fixed disk.
These messages may appear after selecting the Exit option
from the menu:
Fdisk: error writing boot record
This indicates that some error occurred when trying to
write the new partition table out to the fixed disk.
This could be a problem with the fixed disk controller,
the disk itself, the driver, or the configuration of
the fixed disk.
Fdisk: error writing extended DOS partition table
This indicates that some error occurred when trying
initially to write to the fixed disk. This could be a
problem with the fixed disk controller or driver, or
with the configuration of the fixed disk.
FILES
/dev/rdsk/0s0
SEE ALSO
mkpart(1M), disk(7).
Rev. Page 3
fdisk(1M) INTERACTIVE UNIX System fdisk(1M)
WARNING
Compatible with MS-DOS Versions 3.3 or earlier.
ADDED VALUE
This entry, supplied by INTERACTIVE Systems Corporation,
contains enhancements to UNIX System V.
Rev. Page 4