PC Hardware in a Nutshell, 3rd Edition

Enabling bus mastering (DMA) support with Windows

All versions of Windows 98, 2000, and XP support DMA/UDMA modes. The exact steps required to enable DMA mode differ according to your chipset and the exact version of Windows you are using, as follows:

Windows 98/98 SE/Me

The original Windows 98 release and Windows 98 SE are both identified as 4.10.1998, and both are supplied with a native DMA driver, as is Windows Me. Use that driver rather than the driver supplied by Intel or another chipset manufacturer. The Microsoft drivers require DMA support in BIOS, so you may need to flash your system BIOS to the latest version before installing the driver. Before installing the Microsoft driver, remove the Intel BM-IDE driver (if present) by running the BM-IDE installation program and choosing deinstall. To install the Microsoft driver,

1. Right-click My Computer, choose Properties, and then click the Device Manager tab.

2. Locate the CD-ROM drive and double-click it to display the Properties sheet.

3. Click the Settings tab and mark the DMA checkbox in the Options section.

4. Close the dialog and reboot the system.

5. Redisplay the Properties sheet for the drive after rebooting to verify that the checkbox remains marked and that DMA is enabled.

   Note the following considerations for Windows 98/98 SE/Me and DMA:

   • On a clean install, we found that Windows 98/98 SE/Me automatically determines whether the chipset, drives, and BIOS support DMA. If so, DMA is automatically enabled by default.

   • On an upgrade install to ...