Adaptec 1740 Controller Requires Double Buffering (84015)

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 6.0
    Microsoft Windows 3.0
    Microsoft Windows 3.0a
    Microsoft Windows 3.1
    Microsoft Windows for Workgroups 3.1
    Microsoft Windows for Workgroups 3.11

This article was previously published under Q84015


According to Adaptec documentation, using the Adaptec 1740 controller with Windows in enhanced mode or with the EMM386.SY/EMM386.EXE device driver requires a double buffering device driver.

However, if SMARTDrive (SMARTDRV.EXE) version 4.0 from Microsoft Windows version 3.1, is installed to perform double buffering, it may not detect that double buffering is required. If you are using SMARTDrive version 4.0, you can force SMARTDrive to perform double buffering by loading it with "/DOUBLE_BUFFER+". For example:
    device=c:\windows\smartdrv.exe /double_buffer+
If you are not using Windows 3.1, you can force SMARTDRV.SYS from MS-DOS 5.0 or Windows 3.0 to perform double buffering by loading it with "/b+". For example:
   device=c:\dos\smartdrv.sys /b+


When providing double buffering, SMARTDRV.SYS cannot be loaded into upper memory blocks (UMBs).

SMARTDRV.EXE (which is SMARTDrive version 4.0, included with Windows 3.1) separates the double buffering and disk caching functions. The double buffering portion is loaded in CONFIG.SYS and must be loaded in conventional memory. The disk cache portion of SMARTDrive is loaded from the AUTOEXEC.BAT file, and can be loaded into upper memory if an upper memory block (UMB) provider such as EMM386.EXE is loaded.

For more information on double buffering, query on:

double buffering definition

Modification Type: Major Last Reviewed: 11/26/2003
Keywords: KB84015