A)Hard Disk PartitionsHard disks are usually so large that they can contain more
than one type of operating system. For example, you can have DOS
3.3 manage one part of a disk and UNIX manage another. Each of
these sections is called a partition. You can have from one to
four partitions on a disk.
Partitions are used to make the hard disk, especially a very
large one, a more economical investment. They allow you to
effectively have up to four completely different computer systems
resident in one set of hardware. However, since they do not share
a common software environment, they cannot share data directly.
Two types of partitions can be set up for DOS: a primary DOS
partition and an extended DOS partition. The primary DOS
partition is the partition that contains DOS and is the first
partition on the disk. This is the only partition that must be on
the disk if your disk is no larger than 32 megabytes. The
extended DOS partition is a separate partition that cannot be
used for booting, but can be divided into separate logical
drives.
If you have more than 32 megabytes available on one hard
disk, you will need to create an extended DOS partition, which is
assigned the next logical drive letter. For example, if you had a
60-megabyte hard disk drive, and wanted access to all of it, you
would create a 32-megabyte primary partition and a 28-megabyte
extended partition. The primary partition could be accessed as
drive C, while the extended partition would be called drive D.
You could also subdivide the extended partition into more logical
drives (up to the letter Z).
You must create partitions before using a hard disk drive.
You will probably take the easiest route by simply making the
entire disk into one primary partition. The FDISK program
presented here, however, is necessary in several more advanced
situations. For example, you may plan on using multiple operating
systems from the same disk. FDISK will let you set up unique
partitions for each system. (Each of these would be a primary
partition, but only one could be designated the active partition,
the one that will gain control at boot up.) Then again, you may
be using one of the large hard disks (40 to 70 megabytes) that
are increasingly common. Since DOS can only access a logical
drive of 32 megabyte or less, you'll need to partition a larger
physical drive into multiple logical drives. Only in this way can
you store and retrieve information on the larger hard disk.
Note: If your disk is already being used and you wish to
make a new partition, you will have to first back up all of your
data and then run FDISK from a system diskette. Finally, you'll
need to reformat your disk before restoring your files to it.
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[For related topics, press R]
SEE ALSO
Configuration of DOS Partitions
Active Partitions, Changing of
Displaying of Partition Information
Deletion of DOS Disk Partitions
A)Configuration of DOS Partitions
In this section, you will see exactly how to use the FDISK
command. This procedure is very important, and it can have
serious consequences if done incorrectly. However, it can also
make your system more efficient, when done properly. FDISK is
only usable on hard disk systems.
Invoking the FDISK command is as simple as typing
FDISK
and pressing Return. emember to have your path set properly to
include the directory containing the FDISK command file.) After
this command creates the appropriate partition(s), you must then
logically format the disk.
Warning: All data on your disk will be destroyed when you
create partitions with FDISK.
When you first execute FDISK, the screen will clear and the
FDISK Options screen will appear. This contains the menu used to
get around in FDISK, as shown in the screen below.
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FDISK Options
Current Fixed Disk Drive: 1
Choose one of the following:
1. Create DOS partition
2. Change Active Partition
3. Delete DOS partition
4. Display Partition Information
Enter choice: [1]
Press ESC to return to DOS
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As you can see, there are four choices. If you have a system
with more than one hard disk drive, the number in the Current
Fixed Disk Drive: 1 line would be changed to the number of drives
in your system. Also, a fifth option, Select Next Fixed Disk
Drive, would be displayed on the screen. You can work on only one
hard disk drive at a time, but you can switch from the drive you
are working on to another drive. For now, let's assume you have
one hard disk drive and that the screen below is what you see.
Creating a Partition
The first option on the FDISK Options menu is to create a
DOS partition. Since you are using DOS, and not another operating
system such as UNIX, you can only create DOS partitions. Should
you wish to put another operating system onto the disk, that
system would have its own version of FDISK and could then create
its own partitions next to DOS'.
Tip: If you plan to use your hard disk to support another
operating system, do not partition the whole disk. Leave some
room so that another system can be loaded onto the disk.
Choosing the first option to create a DOS partition results
in the screen below.
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Create DOS Partition
Current Fixed Disk Drive: 1
1. Create Primary DOS partition
2. Create Extended DOS partition
Enter Choice: [1]
Press ESC to return to FDISK Options
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If you select option 2 at this point, intending to create an
extended DOS partition before creating a primary partition, DOS
will display a message indicating that you cannot do so, and will
suggest that you press Esc to return to the main FDISK Options
menu. Assuming you are starting from scratch, you would select
choice 1 to create the primary DOS partition. You will then see
the screen shown below.
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Create Primary DOS Partition
Current Fixed Disk Drive: 1
Do you wish to use the maximum size
for a DOS partition and make the DOS
partition active (Y/N).........? [n]
Press ESC to return to FDISK Options
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If you want to use the whole disk for DOS, then you answer Y
on this screen. Doing so makes DOS use the whole disk. The
computer will allocate the entire disk, and then come back with
the message
System will now restart
Insert DOS diskette in drive A:
Press any key when ready . . .
Since you just created the partition, there is still nothing on
the hard disk. The system must be rebooted from the disk drive.
You can now format the entire hard disk just as you would a
floppy diskette.
If you answer N, you have the opportunity to create a
smaller partition, as shown in the screen below. As you can see,
there are 305 cylinders available on the total disk. A hard disk
consists of several platters, similar to a diskette; each platter
consists of a series of concentric tracks made up of sectors.
Each platter lies above another and is read by a different disk
head. Viewed vertically, a series of tracks (with the same track
number, but on different platters) located one above the other
constitute a cylinder. The brackets in the screen shown below
indicate the place where you may enter a number for cylinders
that is less than the default maximum (305 on this disk).
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Create Primary DOS Partition
Current Fixed Disk Drive: 1
Total disk space is 305 cylinders.
Maximum space available for partition
is 305 cylinders.
Enter partition size...........: [ 200]
No partitions defined
Press ESC to return to FDISK Options
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Notice that the second-to-last line on the screen tells you
that no partitions have been defined yet. If you are using your
disk for DOS alone, you should accept the default maximum
cylinder value. All disk space will then be available for DOS and
your DOS files. If you plan on splitting up your disk between DOS
and another operating system, however, you'll have to decide for
yourself what percentage of total disk space is needed for the
other operating system. In this example, you intend to create an
extended DOS partition, so 200 was entered for the number of
cylinders in the primary DOS partition.
Entering 200 results in the screen shown below. This screen
tells you that the first partition on drive C is a primary DOS
partition (PRI DOS) that starts at cylinder 0 and ends at
cylinder 199, constituting a total of 200 cylinders.
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Create Primary DOS Partition
Current Fixed Disk Drive: 1
Partition Status Type Start End Size
C: 1 PRI DOS 0 199 200
Primary DOS partition created
Press ESC to return to FDISK Options
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Pressing Esc at this point returns you to the FDISK Options
menu. If you again try to create a primary partition, DOS will
show the following message on your screen:
Primary DOS partition already exists.
Press ESC to return to FDISK Options
Note: There can only be one primary DOS partition. When DOS
boots up, the system files from this partition are loaded into
memory for your operations. In this example, you have only used
200 cylinders out of a possible 305, so you can make an extended
DOS partition. To do so, you select choice 1 (create a DOS
partition) on the FDISK Options menu and then select choice 2
(create Extended DOS partition) on the Create DOS Partition menu.
The resulting screen, shown below, allows you to create an
extended DOS partition. This screen tells you the current
partition information- -that is, that there are 305 total
cylinders available for use- -and also tells you that 105
cylinders remain unused. The 105 value is used as the default
entry at this stage. You only need to type in a number over the
105 to override the default. In the screen below, 55 was entered
for the desired extended DOS partition, leaving 50 cylinders
unused on the disk for another operating system.
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Create Extended DOS Partition
Current Fixed Disk Drive: 1
Partition Status Type Start End Size
C: 1 PRI DOS 0 199 200
Total disk space is 305 cylinders.
Maximum space available for partition
is 105 cylinders.
Enter partition size............: [ 55]
Press ESC to return to FDISK Options
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The screen will now clear, redisplay the partition
information (including that on the new extended DOS partition),
and print the message
Extended DOS Partition created
Press ESC to return to FDISK Options
near the bottom of the screen. Pressing Esc will result in the
next step of the process (see screen below).
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Create Logical DOS Drive(s)
No logical drives defined
Total partition sized is 55 cylinders.
Maximum space available for logical
drive is 55 cylinders.
Enter logical drive size..........: [ 45]
Press ESC to return to FDISK Options
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Since you have just created an extended DOS partition, DOS
wants to know if you want to create logical drives within this
new partition. It tells you the total available cylinders in the
partition and asks you to enter a size for the logical drive. In
this example, you enter 45. The resulting screen will contain the
logical drive information (drive name, starting cylinder, ending
cylinder, and total cylinders used).
Suppose you wanted to create another logical drive, E, using
the remaining ten cylinders. You could again choose option 1 on
the FDISK Options menu. You would go again to the Create DOS
Partition menu, but there would be one new choice displayed:
3. Create logical DOS drive(s) in
the Extended DOS partition
This would bring you back to the screen for defining logical
drives, where you could then enter the information for drive E.
Going through this same sequence again in order to use the
remaining ten cylinders will result in the screen below. Notice
that the cylinder numbers are within the bounds of the extended
DOS partition. You are told that DOS created two logical drives,
D and E, with sizes of 45 and 10 cylinders. Furthermore, you're
reminded that no more available space remains for any other
logical drives. Press Esc, and you will once again be back at the
FDISK Options menu.
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Create Logical DOS Drive(s)
Drv Start End Size
D: 200 244 45
E: 245 254 10
All available space in the Extended DOS
partition is assigned to logical drives.
Logical DOS drive created, drive letters
changed or added
Press ESC to return to FDISK Options
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If you try to create another extended partition, you will
get a partition information screen and the message
Extended DOS partition already exists.
Press ESC to return to FDISK Options
------------------------------------------------------------------
[For related topics, press R]
SEE ALSO
Active Partitions, Changing of
Deletion of DOS Disk Partitions
Displaying of Partition Information
FDISK Command
Hard Disk Partitions
A)Active Partitions, Changing of
The active partition is the partition that is used to boot
the system. It is the default partition. Choosing option 2 on the
main FDISK Options menu leads you to a menu like that shown in
the screen below, in which the partition information is displayed
along with the total number of cylinders available on the disk.
FDISK now wants to know the number of the partition that you wish
to make active.
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Change Active Partition
Current Fixed Disk Drive: 1
Partition Status Type Start End Size
C: 1 PRI DOS 0 199 200
2 EXT DOS 200 254 55
Total disk space if 305 cylinders.
Enter the number of the partition you
want to make active.............: [2]
Partition selected (2) is not bootable,
active partition not changed.
Press ESC to return to FDISK Options
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If you enter the number 2, as shown in the figure, DOS will
inform you that only the primary DOS partition (1) may be made
active. Type the number 1 so that the primary DOS partition will
have control when the system comes up. Pressing Return will
result in the adjusted partition information display seen below.
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Change Active Partition
Current Fixed Disk Drive: 1
Partition Status Type Start End Size
C: 1 A PRI DOS 0 199 200
2 EXT DOS 200 254 55
Total disk space is 305 cylinders.
Partition 1 made active
Press ESC to return to FDISK Options
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Notice the letter A on the first line of this display. An A
under Status tells you that partition 1 is the active partition.
Pressing Esc takes you back to the FDISK Options menu.
------------------------------------------------------------------
[For related topics, press R]
SEE ALSO
Configuration of DOS Partitions
Deletion of DOS Disk Partitions
Displaying of Partition Information
FDISK Command
Hard Disk Partitions
A)Displaying of Partition Information
Option 4 on the FDISK Options menu is used to display
information about the partitions. This is useful because no extra
functions will be executed at the same time; you can simply look
at the information. Choosing option 4 yields the screen shown
below.
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Display Partition Information
Current Fixed Disk Drive: 1
Partition Status Type Start End Size
C: 1 A PRI DOS 0 199 200
2 EXT DOS 200 254 55
Total disk space is 305 cylinders.
The Extended DOS partition contains
logical DOS drives. Do you want to
display logical drive information? [Y]
Press ESC to return to FDISK Options
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The information at the top of the screen is familiar by now.
But what if you want to see information about the logical drives
that have been defined? Look at the bottom half of the screen,
where you are asked if you want to see this information. Replying
with Y results in a display of information about these logical
drives (see the screen below). Pressing Esc at this point will
return you to the FDISK Options menu.
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Display Logical DOS Drive Information
Drv Start End Size
D: 200 244 45
E: 245 254 10
Press ESC to return to FDISK Options
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------------------------------------------------------------------
[For related topics, press R]
SEE ALSO
Active Partitions, Changing of
Configuration of DOS Partitions
Deletion of DOS Disk Partitions
FDISK Command
Hard Disk Partitions
A)Deletion of DOS Disk Partitions
As with most things, what DOS giveth, DOS can taketh away- -
with a little prodding from you. Selecting choice 3 on the FDISK
Options menu produces the Delete DOS Partition menu, shown below.
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Delete DOS Partition
Current Fixed Disk Drive: 1
Choose one of the following:
1. Delete Primary DOS partitions
2. Delete Extended DOS partition
3. Delete logical DOS drive(s) in
the Extended DOS Partition
Enter choice: [ ]
Press ESC to return to FDISK Options
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Using this menu, you can delete any of the information
you've already set up. You may want to expand or contract other
partitions, or you may no longer want to use a partition in the
manner you originally designed. In any case, you can only make
changes in a certain order. You cannot delete the primary DOS
partition without first deleting the extended DOS partition. If
you try, DOS will give you this message:
Cannot delete Primary DOS partition on
drive 1 when Extended partition exists
Press ESC to return to FDISK Options
In addition, you cannot delete an extended DOS partition
without first ``undefining'' (deleting) the logical drives in
that partition. Trying to delete the extended DOS partition
before deleting the drives in it will simply display the current
partition information with the patient message
Cannot delete Extended DOS partition
while logical drives exist.
Press ESC to return to FDISK options
Choice 3 in the Delete DOS Partition menu is probably the
first selection you will need to make; you work your way
backwards through the order in which you created things.
ctually, you will find that this is a fairly natural process.)
Selecting choice 3 produces the screen shown below, which
contains the logical drive information and the size of the
extended DOS partition the drives are in. You are also warned
that any data contained in the logical disk drive to be deleted
will also be deleted. If you still want to delete the drive,
simply enter the drive identifier. You will then be asked to
confirm this step. In the screen below, you have selected drive E
to delete first, and confirmed the choice by typing Y. If you had
entered N, you would have been returned to the FDISK Options
menu.
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Delete Logical DOS Drive
Drv Start End Size
D: 200 244 45
E: 245 254 10
Total partition size is 55 cylinders.
Warning! Data in the logical DOS drive
will be lost. What drive do you wish
to delete.........................? [e]
Are you sure......................? [y]
Press ESC to return to FDISK Options
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Once FDISK deletes the logical drive, it updates the display
at the top of the screen and asks for another drive to delete. If
you wanted to regain all the space used by this partition, you
would then enter drive D, confirm your entry, and end up with the
screen shown below. Pressing Esc twice at this point would
bring you back up through the menu screens to the main FDISK
Options menu.
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Delete Logical DOS Drive
Drv Start End Size
D: drive deleted
E: drive deleted
Total partition size is 55 cylinders.
All logical drives deleted in the
Extended DOS partition
Press ESC to return to FDISK Options
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Now that the logical drives are gone, you can delete the
extended DOS partition itself if you choose to do so. Choosing
option 2 on the Delete DOS Partition menu results in the familiar
form of an FDISK screen (see below). Again, you are shown the
partition information display, warned that data will be lost, and
asked if you really want to delete the extended DOS partition.
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Delete Extended DOS Partition
Current Fixed Disk Drive: 1
Partition Status Type Start End Size
C: 1 A PRI DOS 0 199 200
2 EXT DOS 200 254 55
Warning! Data in the Extended DOS
partition will be lost. Do you wish
to continue.......................? [y]
Press ESC to return to FDISK Options
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If you reply Y, the screen will be updated to show only the
primary DOS partition and the message
Extended DOS partition deleted
Press ESC to return to FDISK Options
Press Esc to return once again to the FDISK Options menu.
------------------------------------------------------------------
[For related topics, press R]
SEE ALSO
Active Partitions, Changing of
Configuration of DOS Partitions
Displaying of Partition Information
FDISK Command
Hard Disk Partitions
A)active partition
The section of a hard disk containing the operating system to be
used when the hardware powers up.
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[For related topics, press R]
SEE ALSO
hard disk
hardware