CHKDSK Does Not Subtract EBDA Memory (69582)



The information in this article applies to:
    Microsoft MS-DOS operating system 4.0
    Microsoft MS-DOS operating system 4.01
    Microsoft MS-DOS operating system 5.0
    Microsoft MS-DOS operating system 5.0a
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q69582

SUMMARY

The total memory that the CHKDSK utility in MS-DOS versions 4.x and later reports does not reflect the missing memory caused by the extended BIOS data area (EBDA). Running CHKDSK from MS-DOS version 3.3 shows that 1K is missing on some PS/2-compatible machines with an extended BIOS; running CHKDSK in MS-DOS version 4.x or later reports that memory as part of the total memory.

MORE INFORMATION

After CHKDSK obtains the total amount of memory through Int 12h, it determines the amount of memory used by the EBDA and adds that memory to the total previously obtained. Thus, the reduction of total memory due to the EBDA is nullified by CHKDSK.

Because the CHKDSK report shows the total memory and not available memory, it is correct that EBDA size be included in the total. To see a report of available memory, use the MEM command.

Modification Type: Major Last Reviewed: 5/12/2003
Keywords: KB69582