Configuring AutoCAD 386 or AutoCAD Release 11 with MS-DOS (73580)

The information in this article applies to:
    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 Q73580


Autodesk's AutoCAD 386 running under MS-DOS version 5.0 or later may appear to either run very slowly or to hang the machine. AutoCAD 386 is a VCPI (virtual control program interface) program; it will access and use all of the extended memory on a system without the need for HIMEM.SYS.

AutoCAD 386 is the same product as AutoCAD release 11.


There are four ways to get AutoCAD 386 to run under MS-DOS 5.0 or later:
    If you are using release 11(c2), run the program NEWDX.EXE found on the AutoCAD disk "Dxfix / Newdx / B1_step". This program updates the Phar Lap 386/DOS-Extender. The new updated DOS-Extender allows AutoCAD 386 to use the XMS memory that HIMEM.SYS provides.

    NOTE: If you are also using EMM386.EXE, AutoCAD reverts to the VCPI (as opposed to XMS) specifications for memory allocation. You must use at least a 16K page (LIM 4.0) if you use EMM386.EXE. -or-

    On the HIMEM.SYS line in the CONFIG.SYS file, specify /INT15=xxxx, where xxxx equals the amount of memory you want to allocate to AutoCAD 386. This parameter allows other memory schemes other than the XMS to co-exist. For example:
          device=c:\dos\himem.sys /int15=2048

    Specify EMM386 to use expanded memory, which AutoCAD 386 can use as well. Make sure HIMEM.SYS is loaded first. An example of choosing expanded memory is
          device=c:\dos\emm386.exe xxxx ram
    where xxxx is equal to the amount of expanded memory you want. -or-

    Remove HIMEM.SYS from the CONFIG.SYS file altogether; however, there are disadvantages to doing this. You will lose the capability of loading MS-DOS high; also, you will not be able to load TSRs and other programs in the UMA (upper memory area).
For more information on AutoCAD 386 (Release 11), refer to the "AutoCad 386 Installation and Performance Guide" or contact Autodesk.

The products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Modification Type: Major Last Reviewed: 5/12/2003
Keywords: KB73580