| CHKDSK |
|
| Checks the status of a disk and displays a status report. Can also fix disk |
| errors. |
|
| The status report shows errors found in the MS-DOS filing system, which |
| consists of the file allocation table and directories. CHKDSK also displays |
| a summary of disk usage. (CHKDSK does not verify that the information in |
| your files can be accurately read.) If errors exist on the disk, CHKDSK |
| alerts you with a message. |
|
| Note: The ScanDisk program is the preferred method of fixing drive |
| problems, and should be used instead of the CHKDSK /F command. For |
| more information, see the SCANDISK command. |
|
| Syntax |
|
| CHKDSK [drive:][[path]filename] [/F] [/V] |
|
| To display the status of the disk in the current drive, use the following |
| syntax: |
|
| CHKDSK |
|
| Parameters |
|
| drive: |
| Specifies the drive that contains the disk that you want CHKDSK to |
| check. |
|
| [path]filename |
| Specifies the location and name of a file or set of files that you want |
| CHKDSK to check for fragmentation. You can use wildcards (* and ?) to |
| specify multiple files. |
|
| Switches |
|
| /F |
| Fixes errors on the disk. Do not use this option when running CHKDSK |
| from other programs; for more information, see "Using CHKDSK With Open |
| Files" in CHKDSK--Notes . In general, when fixing disk errors, use |
| ScanDisk instead of CHKDSK. |
|
| /V |
| Displays the name of each file in every directory as the disk is |
| checked. |
|
|
| CHKDSK--Notes |
|
| Format of status reports |
|
| MS-DOS displays CHKDSK status reports similar to the following example: |
|
| Volume Serial Number is B1AF-AFBF |
|
| 72,214,528 bytes total disk space |
| 73,728 bytes in 3 hidden files |
| 30,720 bytes in 12 directories |
| 11,493,376 bytes in 386 user files |
| 61,440 bytes in bad sectors |
| 6,055,264 bytes available on disk |
|
| 2,048 bytes in each allocation unit |
| 35,261 total allocation units on disk |
| 29,568 available allocation units on disk |
|
| 655,360 total bytes memory |
| 493,456 bytes free |
|
| Fixing disk errors |
|
| The ScanDisk program is the preferred method of fixing disk errors. For more |
| information, see the SCANDISK command. |
|
| If you want to use CHKDSK to fix disk errors, use the /F switch. (CHKDSK |
| corrects disk errors only if you specify the /F switch.) CHKDSK /F displays |
| a prompt similar to the following: |
|
| 10 lost allocation units found in 3 chains. |
| Convert lost chains to files? |
|
| If you press Y, MS-DOS saves each lost chain in the root directory as a file |
| with a name in the format FILEnnnn.CHK. When CHKDSK finishes, you can |
| examine these files to see if they contain any data you need. If you press |
| N, MS-DOS fixes the disk but does not save the contents of the lost |
| allocation units. |
|
| If you do not use the /F switch, CHKDSK alerts you with a message if a file |
| needs to be fixed but does not fix the error(s). |
|
| Using CHKDSK with open files |
|
| Never use CHKDSK when files are currently open. CHKDSK is designed for use |
| when the files on the disk are in an unchanging state -- that is, when they |
| are not open. When a file is open, it is probably changing, and MS-DOS will |
| update the file allocation table and the directory structure to reflect |
| changes. Such updates are not always made immediately, and updates to the |
| file allocation table and the directories occur at different times. If you |
| run CHKDSK when files are open on the disk, it interprets differences |
| between the directory structure and the file allocation tables as errors. |
| Running CHKDSK /F when files are open can result in corruption or loss of |
| data. Therefore, never run CHKDSK /F from another program, or when Microsoft |
| Windows or the MS-DOS Task Swapper is running. |
|
| Using CHKDSK with assigned drives and networks |
|
| The CHKDSK command does not work on drives formed by the SUBST command. You |
| cannot use CHKDSK to check a disk on a network drive. |
|
| Physical disk errors |
|
| The CHKDSK command finds only logical errors in the file system, not |
| physical disk errors. To identify and repair physical disk errors, use the |
| ScanDisk program. For more information, see the SCANDISK command. |
|
| Bad disk sectors |
|
| Bad sectors reported by CHKDSK were marked as "bad" when your disk was first |
| prepared for operation. ScanDisk and other physical disk-error correction |
| utilities can also mark sectors as "bad." Bad sectors pose no danger. |
|
| Cross-Linked Files |
|
| CHKDSK reports a cross-linked file if two files or directories are recorded |
| as using the same disk space. If CHKDSK finds a cross-linked file, it |
| displays a message similar to the following: |
|
| File is cross linked on allocation unit number |
|
| CHKDSK will not fix a cross-linked file, even if you specify the /F switch. |
| To correct a cross-linked file, run ScanDisk. Some of the information in |
| these files may be lost. |
|
| ERRORLEVEL parameters |
|
| If CHKDSK does not find any errors, it returns an ERRORLEVEL value of 0. If |
| CHKDSK found one or more errors, it returns an ERRORLEVEL value of 255. |
|
| Saving a CHKDSK status report to a file |
|
| You can save a CHKDSK status report by redirecting the output to a file. Do |
| not use the /F switch when you redirect CHKDSK output to a file. |
|
|
| CHKDSK--Examples |
|
| To find out how much data is stored on drive C and how much space is still |
| free, and to check the disk for errors, type the following command: |
|
| chkdsk c: |
|
| CHKDSK pauses and displays messages if it encounters errors. |
|
| To redirect the output of CHKDSK to a file named STATUS, type the following |
| command: |
|
| chkdsk a: status |
|
| Because the output is redirected, MS-DOS does not repair errors it |
| encounters during the check; but it records all the errors in a report file. |
| Afterward, you can use CHKDSK with the /F switch without redirection to |
| correct any errors noted in the status report. |
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|
