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Hard drive partition

( info from ntfs.com )

Logical Drives and Extended Partitions

When more than four logical disks are required on a single physical disk, the first partition should be a primary partition. The second partition can be created as an extended partition, which can contain all the remaining unpartitioned space on the disk.

Note

A primary partition is one that can be used as the system partition. If the disk does not contain a system partition, you can configure the entire disk as a single, extended partition.

Some computers create an EISA configuration partition as the first partition on the hard disk.

Windows NT detects an extended partition because the System ID byte in the Partition Table entry is set to 5. There can be only one extended partition on a hard disk.

Within the extended partition, you can create any number of logical drives. As a practical matter, the number of available drive letters is the limiting factor in the number of logical drives that you can define.

When you have an extended partition on the hard disk, the entry for that partition in the Partition Table (at the end of the Master Boot Record) points to the first disk sector in the extended partition. The first sector of each logical drive in an extended partition also has a Partition Table, which is the last 66 bytes of the sector. (The last two bytes of the sector are the end-of-sector marker.)

These are the entries in an extended Partition Table:

* The first entry is for the current logical drive.
* The second entry contains information about the next logical drive in the extended partition.
* Entries three and four are all zeroes.

This format repeats for every logical drive. The last logical drive has only its own partition entry listed. The entries for partitions 2-4 are all zeroes.

The Partition Table entry is the only information on the first side of the first cylinder of each logical drive in the extended partition. The entry for partition 1 in each Partition Table contains the starting address for data on the current logical drive. And the entry for partition 2 is the address of the sector that contains the Partition Table for the next logical drive.

The use of the Relative Sector and Total Sectors fields for logical drives in an extended partition is different than for primary partitions. For the partition 1 entry of each logical drive, the Relative Sectors field is the sector from the beginning of the logical drive that contains the Partition Boot Sector. The Total Sectors field is the number of sectors from the Partition Boot Sector to the end of the logical drive.

For the partition 2 entry, the Relative Sectors field is the offset from the beginning of the extended partition to the sector containing the Partition Table for the logical drive defined in the Partition 2 entry. The Total Sectors field is the total size of the logical drive defined in the Partition 2 entry.

Note

If a logical drive is part of a volume set, the Partition Boot Sector is at the beginning of the first member of the volume set. Other members of the volume set have data where the Partition Boot Sector would normally be located.

Hard drive trouble shooting

Information from Techadvice.com

1. There is some type of electrical connection problem

Make sure the cable connections are correct.

Check the 4-wire connector that carries power and make sure it is properly plugged in. This connector has a taper on one end and cannot be put on backwards.

When power is first applied to the computer, the hard drive light will momentarily come on which is a good indication that the drive is getting power. Also the vibration of the spinning platter and the slight hum will verify that the drive is plugged in.

Next check the data ribbon cable. This cable is a flat cable with a one edge colored red or blue to indicate the location of pin 1. Some of these cables are also keyed by having a small tab in the center of the connector's edge. On many hard drives pin 1 is the pin closest to the power supply connection, but not always, so check the hard drive documentation or look on this site in Hard Drives and locate your model.

You can find hard drive documentation on this site simply by using the index on top of each page to find the manufacturer and then on the manufacturers page will be a listing which would have links to each product and the technical support documents. Older drives are on different pages then newer drives. Once you find the page where the manufacturer's products are listed, look at the top of the page for a link that says "Older Models" and you will find them listed there.

If all the cables are connected properly, and power is applied, you should be able to hear and feel the drive spinning. If the drive is not spinning, turn off the power and try using a different power plug (maybe the one that the CD-ROM is connected). If the drive is not spinning then it is probably bad. *see step 3



2. The hard drive controller has failed

A controller failure is usually indicated by an error at boot up. There is not much that can be done except to replace the hard drive. See hard drive error codes

3. The hard drive has failed physically

There can be two indications for this condition.

1) The drive is not spinning. To troubleshoot this condition you need to physically access the drive while the computer is on. With the cover off, look at the drive and find the side which has NO components. With your hand touch that side and try to feel the spinning of the hard drive platter. A typical hard drive has a small amount of vibration and a slight whine.

2) The hard drive head has crashed onto the platter. This usually causes the drive to emit unusual sounds sometimes grinding and many times repeating on a regular basis. A normal hard drive has a smooth whine so its should be easy to identify the bad drive by just listening.

4. The hard drive has failed electronically

This will be indicated by an error message during the computer boot cycle. Not much can be done in this condition other then replace the drive.



5. There is a problem with the recording on the hard drive (read or write)

There are two conditions that can cause this problem.

1) The hard drive is unable to read a sector on the platter.

This problem can be identified by running a program that is capable in performing a hard drive surface test. In Windows 95 you can use the scandisk which is found in the Start/Programs/Accessories/System Tools folder. Another way is to use a utility program like Norton Utilities to perform the surface scan.

This problem can also be seen when you are formatting the hard drive and is indicated as "bad sectors" during the formatting. These bad sectors are normally recorded as such by the format program and the computer knows not to use them but more bad sectors can be created as the hard drive ages.

2) One or more files have been damaged by some process.

These type or problems are caused when the computer is unexpectedly rebooted after a lock-up or perhaps a power failure. They are easy to troubleshoot and repair. Simply run the scandisk program which is found in the Start/Programs/Accessories/System Tools folder and allow the computer to repair any errors found.

After such a repair it is very possible that one of more files were corrupted and are now unusable. It is impossible to tell which files will be affected in advance but if you write down the bad file names shown during the scan disk operation you can try to find the application which loaded them and re-install that application.



6. The CMOS settings are not correctly set

Check the CMOS settings. These settings must match the required settings of the manufacturer.

a) older computers

On these computers you have to go into the CMOS/BIOS during boot and change the setting by selecting a number from 1 to 48, by selecting a TYPE number of 1 or 2, or by selected the setting "User defined" and manually entering the hard drive parameters of "head", "cylinders", "spt", "WP", and "LZ". These settings can be found on your hard drive users manual, on the manufacturer's web site, or on this site by looking for the company, then the hard drive's model number.

After entering these parameters you will normally save them before exiting the BIOS program and then reboot the computer.

b) newer computers

On these computers you can almost always find a selection that allows the computer to "Automatically" find IDE style hard drives. There are two methods in use. First you can select "Auto" from the main BIOS screen for the drive C: D: E: or F:. After rebooting the drive will be automatically detected. Second, some Bios types have a selection called "Detect hard drive" which allows you to initiate a detection process which looks for a drive, presents you with the drive found and gives you the option of accepting or rejecting the detected drive. This process is repeated for each of the available drive assignments C D E and F.

Again you must save the BIOS changes and reboot the computer.

Very critical also is the LBA setting which can cause the drive to operate but not be able to see all the data. This comes into play with drives larger than 500 megabytes and is found by entering the computer BIOS at boot up and looking in the area where the hard drive is configured.

"Wrong LBA setting" Symptoms:

* Computer comes on, but you get many read errors
* Windows comes up sometimes other times it hangs
* you can save short files but larger ones don't seem to save
* Scandisk is not able to fix the problems it finds

Solution:

The LBA setting in the BIOS is not correct. Most likely on drives that are more than 528MB, the LBA setting is not enabled. Enter the BIOS and enable the LBA.

This can happen very easily when a drive is on a computer and works fine but then the motherboard is changed. The old BIOS had LBA enabled but the new one might not. After the drive is installed it seems to work but you get the symptoms described above.



7. There is a conflict with the IRQ settings

a) Normally the primary hard drive controller uses Interrupt Request Line (IRQ) number 14 which allows the hard drive C and D to operate correctly.. The secondary hard drive controller uses IRQ number 15 which allows the hard drives E and F to work properly.

What happens is some times a different device such as a sound card will use the IRQ 15 by default or because the settings was changed by a user. This causes the computer to not see the secondary hard drives immediately after the installation of this device using IRQ 15. The only way to fix this problem is to change this device so that it uses a different IRQ setting.

b) Another problem can be introduced in Windows 95 by CD-ROM device drivers which are loaded by the autoexec.bat and config.sys files at boot up. If windows 95 sees a conflict with these drivers it will switch itself into the DOS compatibility mode. This can be seen by going to Control Panel/System/Performance/File system.

A normal windows 95 installation uses 32 bit file access. When there is a conflict you will see that the system is switched to the DOS compatibility mode. Sometimes this can be fixed by using the procedure shown on this link.



8. There is a conflict with the jumper settings

All IDE hard drives must be properly setup using jumpers found on the hard drive. The users guide for each drive has instruction for these settings. Each drive can either be a Master or a Slave. Since there can be as many as two separate controllers on each computer the each controller can have a Master and a Slave.

A typical computer with 4 IDE hard drives would setup the primary channel as Drives C (master) and D (slave), and the secondary channel as Drive E (master) and Drive F (slave).

On 2 drive systems, the first drive should be setup as Master and the second as Slave and the secondary channel is ignored.

On many motherboards you must go into the BIOS and actually either enable or disable the secondary drive controller and save the changes. So if your computer came with 2 drives and you've added two more, before the new drives are detected you will need to go into the BIOS and enable the secondary IDE controller, save the changes and reboot.



9. The drive is unable to boot

To troubleshoot this condition boot the computer with a bootable DOS disk. After the computer has booted with the disk try to access drive C: by issuing the standard directory command

DIR C: <enter>

If the C: drive is working and you can see the directory listing then you might be able to make the drive bootable again by issuing the system command which transfers the system files from the floppy drive to the hard drive as follows:

sys a: c: <enter>

The sys file has to be on the floppy disk. If it is not then find a disk that has the file or use another computer to copy the file to the floppy disk. You can also copy the command.com file from the floppy to the hard drive by typing...

copy a:\command.com c:\command.com <enter>

...the computer will ask you to verify the operation.

Note: A drive must also have the BOOT partition activated before it can boot properly. This is done using FDISK.exe ( of course you must take precautions doing this since fdisk can make your drive useless if mis-used).

To troubleshoot problems where the hard drive hangs at boot and the computer never responds, turn off the computer and disconnect the hard drive from the ribbon cable that connects it to the motherboard. When you turn the computer back on, you should at least get an error message about the drive being bad, and perhaps go into the BIOS. Once in BIOS you can change the hard drive type to AUTO and after shutting off the computer and reconnecting the hard drive, try again to see if it now works.

10. Fdisk reports wrong size when using drives larger then 64GB

According to Microsoft KB article Q263044, "When you use Fdisk.exe to partition a hard disk that is larger than 64 GB (64 gigabytes, or 68,719,476,736 bytes) in size, Fdisk does not report the correct size of the hard disk.

The size that Fdisk reports is the full size of the hard disk minus 64 GB. For example, if the physical drive is 70.3 GB (75,484,122,112 bytes) in size, Fdisk reports the drive as being 6.3 GB (6,764,579,840 bytes) in size."



Hard drive error codes

Typically a hard drive failure will be indicated by an error code while the computer is booting.

* 1701 - hard drive failure. ...BIOS Post Codes
This BIOS error code is displayed during the computer boot process when the hard drive has failed.

Also could be a cable connection problems as described above. IRQ conflicts and bad jumper settings could cause this problem as well.

One more possibility is that the CMOS battery has died. This can be verified by entering the BIOS during boot, then setting the hard drive settings and rebooting. If the hard drive error goes away then the battery is dead.

How to Format a Hard Drive

Information from techadvice.com

The Process

The formatting of a hard drive is a two step process.

Note : There are times when a drive needs to be "low level" formatting. This is not done normally, but if the needs arises go to the "Low Level Format" page for more information.

The first step is to use the Fdisk program and create partitions.

The second step is to use the "format" program to format the hard drive.

If the drive is drive C: (a bootable drive) you will need to use the /s parameter in order to transfer the boot files to the drive and make it bootable.



Preparing a hard drive

Note: You must never try to Low-Level Format an IDE hard drive. This is done at the factory and if you do perform a low-level format on your own you will not be able to access the hard drive.

Several operations need to be performed in order to make a hard drive useable.

If you are installing DOS such as version 6.x you can boot with disk 1 and allow the program to format the drive for you. There are plenty of instructions shown during the DOS installation for you to follow. The DOS install can also perform the Fdisk part of the drive. It is very simple using the installation disk, basically you insert disk 1 in the computer and turn the computer On.

If on the other hand you have either windows or DOS already installed and have or can create a boot disk you can follow the directions below to prepare a hard drive for use.

A hard drive needs to have partitions created, and then the drive has to be formatted.

Creating a partition

To create the partitions you need to use the program fdisk.exe which is found in the Dos disks, and also in the c:\windows\command folder. You would of course want to boot the computer with a boot disk, and the boot disk must have the fdisk program on it.



Please Note:

According to Microsoft KB article Q263044, "When you use Fdisk.exe to partition a hard disk that is larger than 64 GB (64 gigabytes, or 68,719,476,736 bytes) in size, Fdisk does not report the correct size of the hard disk.

The size that Fdisk reports is the full size of the hard disk minus 64 GB. For example, if the physical drive is 70.3 GB (75,484,122,112 bytes) in size, Fdisk reports the drive as being 6.3 GB (6,764,579,840 bytes) in size."





If you already have the partitions and just want to reformat the drive, go to the format the drive section of this page.

The following example takes an existing hard drive, which is already formatted, and after wiping the drive clean, reformats the drive.

1. Place a boot disk into the floppy drive and start the computer. This disk should have the file fdisk.exe on it.

The computer should boot and give you the A:> prompt.
2. At the prompt type on the keyboard

Fdisk <enter>

You will see the Fixed Disk Setup program with the following menu
1. Create DOS partition or Logical DOS drive
2. Set active partition
3. Delete partition or Logical DOS drive
4. Display partition information

enter choice: [1]

At this point if you already have an existing partition and want to delete it, continue with the instructions below.

If the drive has NO partitions you can go to Create a Partition section below.

press the 3 key on the keyboard and press <enter>

the "delete DOS partition or Logical DOS drive" screen will be displayed with 4 options
1. Delete Primary DOS partition
2. Delete Extended DOS partition
3. Delete Logical DOS Drive(s) in the Extended DOS partition
4. Delete Non-DOS partition

select option 1 by pressing the 1 key on the keyboard and pressing the <enter> key

The screen will change and you will see...

-------------------------------------------------------------------------
Current fixed disk drive: 1

Partition... Status.. Type......... Volume Label Mbytes System.. Usage
C: 1 ............A.....PRI DOS............................540.......FAT16...100%

Total disk space is 540 Mbytes (1 Mbyte = 1048576 bytes )

Warning: Data in the deleted Primary DOS partition will be lost.
What primary partition do you want to delete...? [1]

Press Esc to return to FDISK Options
------------------------------------------------------------------------

The cursor will be flashing at the bottom right next to "....to delete..?[1]"

In this example the partition 1 will be deleted, so you press the number 1 on the keyboard and then press the <enter> key.

a new line will be displayed...

Enter Volume Label...........[ ________ ]

You need to type at the cursor the name of the existing volume which you can see on the top of the screen below the words "Volume Label". If the volume does not have a label you can leave it blank. Then you press the <enter> key.

A new line is displayed

Are you sure {Y/N)......? [N]

The default entry at the cursor is N. Since you are sure you want to delete the partition you press the Y key on the keyboard and press <enter>. (this operation can not be undone, so make sure you want to delete the partition).

You will next receive the message

Primary DOS Partition deleted

Press the <Esc> key to continue

3) Create a Partition

at the prompt 'Enter choice: [ 1 ]

press the 1 key on the keyboard and press <enter>

you will see a new screen

===========================================

Create DOS partition or Logical DOS drive

Current fixed disk drive: 1

Choose one of the following:

1. Create Primary DOS Partition
2. Create Extended DOS Partition
3. Create Logical DOS Drive(s) in the Extended DOS Partition

Enter Choice : [ 1 ]

==========================================

Select choice 1 by pressing the 1 key on the top of the keyboard and press <enter>

you will see....

=================================

Current fixed disk drive: 1

Do you wish to use the maximum available size for a Primary DOS Partition
and make the partition active (Y/N}..........? [ Y ]

=================================

Choose Yes by pressing the Y key on the keyboard and pressing enter

You will now see....

============================

System will now restart

Insert DOS system diskette in drive A:
Press any key when ready

============================

Note: You must also activate the DOS partition which you create. Use the "activate partition" option.



When you press any key the computer will reboot

4) Formatting the hard drive

Make sure you have a boot floppy disk in the computer. Allow the computer to reboot, or just shut off the computer and turn it back on with the disk inserted in the floppy drive. After the computer reboots, you should get the A:\> prompt.

If you need any files such as Fdisk for windows 95 go to the "Windows 95 files" page. There you will also find a link to a site that has a file you can download which will create a boot disk.

You should already have the format.com file on the disk. At the A:\> prompt, type on the keyboard

format c: /s <enter> ( for bootable drives like drive C

format d: <enter> ( for non-bootable drives like drive D

{ the word format is followed by a space then the forward slash the letter S and the enter key. }

you will receive the message...

==========================================
WARNING: ALL DATA ON NON-REMOVABLE DISK
DRIVE C: WILL BE LOST!
Proceed with Format (Y/N) ?
==========================================

select the Yes option by pressing the Y key on the keyboard and press <enter>

the message.....

=====================
Formatting xxxxM
.....xx percent completed.
=====================

...will be shown, and the formatting will take place. You should now see the 'percent complete' value increase as the drive is formatted.

when the format is finished, you will see the message...

==============
Formatting xxxM
Format complete.
System transferred

Volume label (11 characters, Enter for none )?
==============

The cursor will be flashing on the bottom of the screen, waiting for you to name the newly formatted drive. Type in a name (11 characters or less, don't use spaces) and press <enter>. You can use a simple name if you like such as "driveC" or "drive1", it really does not matter what its called.

After you press the <enter> key you will receive the final screen showing the drive statistics as shown below for an imaginary 100 megabyte hard drive.

==================================
106614784 bytes total disk space
.....186368 bytes used by system
106428416 bytes available on disk

....2048 bytes in each allocation unit.
..51967 allocation units available on disk.

Volume Serial Number is 1234-5C68
===================================

Finally you will see the A:\> prompt. At this point the drive is ready to be used as the primary boot drive. Remove the diskette from the floppy drive and reboot the computer by either pressing the reboot key or by turning the computer OFF and back On.



Finally you will need to install your programs using the provided floppy disks or CD-ROM disks