Microsoft KB Archive/105070

= Microsoft Knowledge Base =

FastTips: MS-DOS 6.2 Backup Questions and Answers
Last reviewed: November 23, 1994

Article ID: Q105070

The information in this article applies to:


 * Microsoft MS-DOS operating system versions 6.2, 6.22

1. Q. My computer failed the Microsoft Backup compatibility test. What is causing this problem and how can I correct it?

A. One or more of the following conditions may cause your computer to fail the Microsoft Backup compatibility test:

- The floppy disk drive controller card does not support direct memory access (DMA).

- You are using an incompatible third-party virtual device driver (VxD) in Windows.

- A software or hardware compatibility problem exists (for       example, you are loading APPEND.EXE, POWER.EXE, or other        incompatible software).

When loaded in the [386Enh] section of the SYSTEM.INI file, the following software VxDs can cause the Microsoft Backup for Windows compatibility test to fail:

MYABU.386 FASTBACK.386 VFD.386 CPBVXD.386 VIRWT.386 CMSTAPE.386 CMSTAPED.386 CMSDTAPE.386 ABACKUP.386

For a complete list of possible failure causes and steps to     troubleshoot them, order FastTips Technical Library item Q97577, titled "Your Computer Fails the Microsoft Backup Compatibility     Test."

2. Q. When I try to use Microsoft Backup for MS-DOS, I receive the message "DMA Buffer Size Too Small." How can I correct this problem?

A. You can correct this problem by increasing the size of the direct memory access (DMA) buffer used by EMM386.EXE. To do     this, use the following steps:

1. Use an ASCII text editor, such as MS-DOS Editor, to open your CONFIG.SYS file.

2. Locate the EMM386.EXE command line.

3. At the end of the EMM386.EXE command line, add the parameter D=64.

4. Save the CONFIG.SYS file, then quit the text editor.

5. Restart your computer.

For more information about Microsoft Backup for MS-DOS, refer to     your MS-DOS 6.2 printed documentation.

3. Q. When I try to use Microsoft Backup for Windows, I receive the message: "DMA Buffer Size Too Small." How can I correct this problem?

A. You can correct this problem by increasing the size of the DMA buffer used by the extended memory manager and then modifying your system initialization file (SYSTEM.INI). To do this, use the following steps:

1. Use a text editor such as MS-DOS Editor to open your CONFIG.SYS file.

2. Locate the EMM386.EXE command line.

3. At the end of the EMM386.EXE command line, add the parameter D=64.

4. Save the CONFIG.SYS file, then quit the text editor.

5. Use an text editor to open your SYSTEM.INI file, which is        located in your Windows directory.

6. Locate the [386Enh] section and add "DMABuffersize=64" (without the quotation marks) after the section heading.

7. Save the changes to the SYSTEM.INI file, then quit the text editor.

8. Quit Windows if you haven't already done so, and restart your computer.