Microsoft KB Archive/79308

= Microsoft Knowledge Base =

FastTips: MS-DOS 5.0 Configuration Sequence Q&A
Last reviewed: April 9, 1996

Article ID: Q79308

The information in this article applies to:


 * Microsoft MS-DOS operating system version 5.0

SUMMARY
This article contains the complete text of the &quot;MS-DOS 5.0 Configuration Sequence&quot; fax script.

This fax script is available to customers who call the Microsoft FastTips Service for Operating Systems at (800) 936-4200.

MS-DOS 5 Configuration Sequence
1.Q. I can't load DOS high. What can I do?

A. To load DOS into the High Memory Area, which is the first 64K area of extended memory, you must have an 80286 processor or    higher, 64K of extended memory, and you must include the following statements in your CONFIG.SYS file:

device=himem.sys dos=high

The DOS=HIGH statement can be included in any area of the CONFIG.SYS file. If your system meets these conditions and you can't load DOS high, your system might have a device driver, application program, or hardware device that is controlling the high memory area. Please disable the device driver or program that is controlling the high memory area by referring to the appropriate hardware or software documentation and following the instructions given. 2.Q. I am having problems loading programs and device drivers into

upper memory. What can I do?

A. To use the MS-DOS commands that can load programs and device drivers into upper memory, you must have an 80386 or 80486 microprocessor. In addition, please verify that in your CONFIG.SYS file you are loading the device driver HIMEM.SYS followed by EMM386.EXE, using either the RAM or NOEMS switch. Also include the DOS=UMB command in your CONFIG.SYS file. If you are loading device drivers into high memory, make sure that you have DEVICEHIGH in the CONFIG.SYS file. If you are loading programs high, verify that LOADHIGH is being used in the AUTOEXEC.BAT file. If you are using an 80286 or lower microprocessor, please contact your local retail outlet for information about third-party upper-memory-management software. For more information, please refer to pages 313 to 330 in the Microsoft MS-DOS &quot;User's Guide and Reference&quot; for version 5.0. 3.Q. What is the difference between extended memory and expanded

memory?

A. Extended memory is available on 80286 and higher microprocessors and begins at the 1 megabyte (MB) or 1024K address line. This memory can be used only by applications and devices that are written specifically to take advantage of it.

Expanded or EMS memory is memory that is either located on an    expanded memory card or simulated using extended memory. Usually, it is managed by an expanded memory manager such as EMM386.EXE or a    memory manager that is packaged with the expanded memory card.

Expanded memory is divided into 16K segments called pages. The expanded memory manager copies pages to a 64K contiguous region area in the upper memory area (UMA) called a page frame.

For more information on extended and expanded memory, refer to    pages 275 through 276 in the Microsoft MS-DOS &quot;User's Guide and Reference&quot; for version 5.0. 4.Q. What does the phrase &quot;clean boot&quot; or &quot;minimal configuration&quot; mean

in reference to booting up my computer system, and when would I    need to do this?

A. &quot;Clean boot&quot; and &quot;minimal configuration&quot; refer to the minimum requirements necessary to boot MS-DOS on a computer system. A clean boot minimizes the number of statements in the CONFIG.SYS and AUTOEXEC.BAT files.

Clean booting is useful when you are troubleshooting a software or    hardware problem. By doing so, you can reduce the number of factors or    variables that may be causing the problem. Another reason to clean boot is to free up as much conventional memory as possible for a    software application that cannot run due to insufficient memory. Although CONFIG.SYS and AUTOEXEC.BAT files are not required when booting, some systems require device drivers or other statements in    these files to operate correctly. 5.Q. When I boot up my computer, I get the message &quot;ERROR: Unable to

control A20 line.&quot; What should I do?

A. The A20 line is the start of the first 64K of extended memory, known as the high memory area. The HIMEM.SYS device driver must control the A20 line to provide management of extended memory. The error message will be reported by HIMEM.SYS if it incorrectly identifies the extended memory handling mechanism of the computer, or if the handling method of the machine's BIOS is    unknown. To correct the error, or if you have problems using MS-DOS in the high memory area, you may have to use the HIMEM.SYS /machine switch to specify an A20 handler or upgrade your machine's BIOS. For more information concerning HIMEM.SYS, please refer to pages 610 to 613 of the &quot;Microsoft MS-DOS User's Guide and Reference&quot; version 5.0 manual, and to Section 2.15 of the README.TXT. 6.Q. When I boot my system I receive the message &quot;Unable to create

page frame.&quot; What should I do?

A. EMM386.EXE cannot find the 64K contiguous space in the upper memory area (UMA) that is required to create a page frame. If you receive this message and are using applications that require expanded memory, you may need to change the upper memory addresses that the hardware adapters use in order to provide a 64K contiguous space for expanded memory. You can use a memory-browsing application to determine which areas are available. In some cases, EMM386.EXE may not detect all the available upper memory space. If this is the case, use the /I switch to force EMM386.EXE to use free and available upper memory space for a    page frame.

If you do not have applications that use expanded memory, you can use the NOEMS option on the EMM386.EXE line in the CONFIG.SYS file to    disable expanded memory emulation.

For more information regarding EMM386.EXE, please refer to pages 605 through 609 in the Microsoft MS-DOS &quot;User's Guide and Reference&quot; for version 5.0. 7.Q. After installing the MS-DOS Upgrade there is a file named

WINA20.386 in the root directory. What is this file for?

A. When installing on systems capable of running Windows 3.0 in    enhanced mode, the MS-DOS 5.0 Upgrade will place a read-only file named WINA20.386 in the root directory. This file provides support for Windows 3.0 when it is running in enhanced mode. For more information and instructions on how to relocate this file into a subdirectory, please refer to Section 4.3 of the README.TXT file.