Improve 16 bit DMA transfers by increasing DMA buffer size
1 January 2001 by Snakefoot | Comment » | Trackback OffWindows 9x is able to run 16 bit programs, and when they attempt to allocate DMA buffers to perform Direct Memory Access (DMA) transfers they are limited to the pre-allocated DMA buffer (with double buffering), unless they can provide a physically contiguous memory allocation themselves.
To configure the size of the pre-allocated DMA buffer, add this line in the file SYSTEM.INI in the section [386Enh]:
More Info MS KB Q82790
More Info MS KB Q124729
Note the above setting can also be configured by going to the "Control Panel" -> "System" -> "Device Manager", and expand the "System"-node, and select properties for "Direct Memory Access Controller", and select the tab "Settings" and set the "Reserve DMA buffer" to 64.
To configure the size of the pre-allocated DMA buffer, add this line in the file SYSTEM.INI in the section [386Enh]:
More Info MS KB Q82711[386Enh]
DMABufferSize=64 (Default - 16 Range 1-256)
More Info MS KB Q82790
More Info MS KB Q124729
Note the above setting can also be configured by going to the "Control Panel" -> "System" -> "Device Manager", and expand the "System"-node, and select properties for "Direct Memory Access Controller", and select the tab "Settings" and set the "Reserve DMA buffer" to 64.
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Updated: 2 July 2007