Q67586: Action Taken on Abort, Retry, Ignore, Fail
Article: Q67586
Product(s): Microsoft Disk Operating System
Version(s): MS-DOS:3.x,4.x,5.x,6.0,6.2,6.21,6.22
Operating System(s):
Keyword(s):
Last Modified: 17-DEC-2000
-------------------------------------------------------------------------------
The information in this article applies to:
- Microsoft MS-DOS operating system versions 3.1, 3.2, 3.21, 3.3, 3.3a, 4.0, 4.01, 5.0, 5.0a, 6.0, 6.2, 6.21, 6.22
-------------------------------------------------------------------------------
SUMMARY
=======
This article explains the actions that MS-DOS takes when a critical error
happens during a disk access. MS-DOS takes specific actions for each of the four
possible Critical Error (Interrupt 24h) responses: Ignore, Abort, Retry, or
Fail.
MORE INFORMATION
================
According to the "MS-DOS Encyclopedia," MS-DOS takes the following actions for
each possible critical error response.
Error Action
----------------
Ignore The MS-DOS function call returns to the application
program as if the function had completed successfully.
For example, if the program is trying to read from the
disk, MS-DOS tells the program that all is well. This
can result in corrupted data in your disk file or
in data returned to your application.
Retry The critical error handler signals MS-DOS to reissue the
last function call made to the device that caused the
critical error.
Abort The current application is terminated immediately.
Unwritten disk buffers are NOT written to disk, the
directory information is not updated, and modified
interrupt vectors are not reset. Choosing this option can
leave the system in a very unstable state.
Fail This causes MS-DOS to return to the application software>
with an error condition. In programming terms, the carry
flag is set upon exit from the INT 21h DOS function call.
This allows the application program to handle the error
itself and take appropriate action, rather than letting
MS-DOS do it.
The MS-DOS kernel and device drivers do not mark a FAT entry as being bad when a
critical error occurs, or at any other time. This task must be done by a
separate utility. The RECOVER utility provided with MS-DOS can do this, but only
if the bad sector exists within a file's allocated clusters -- free bad clusters
are not checked by RECOVER. The FORMAT utility is typically the best solution,
since it scans all areas of the disk for bad sectors. The disadvantage is that
FORMAT also destroys any data on the drive.
Some third-party disk utilities provide disk-scanning features that examine the
entire disk data area for bad sectors, and then mark them as bad in the FAT
(without disturbing other data on the disk).
Additional query words: 6.22 3.20 3.21 3.30 3.30a 4.00 4.01 5.00 5.00a 6.00 6.20
======================================================================
Keywords :
Technology : kbMSDOSSearch kbMSDOS321 kbMSDOS400 kbMSDOS320 kbMSDOS330a kbMSDOS621 kbMSDOS622 kbMSDOS620 kbMSDOS600 kbMSDOS310 kbMSDOS500 kbMSDOS330 kbMSDOS401 kbMSDOS500a
Version : MS-DOS:3.x,4.x,5.x,6.0,6.2,6.21,6.22
=============================================================================
THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.
Copyright Microsoft Corporation 1986-2002.