EMM386 DMA Buffer and SCSI Devices

Last reviewed: November 23, 1994
Article ID: Q69086

The information in this article applies to:

Microsoft Windows operating system version 3.0, 3.0a

SYMPTOMS

If you are using EMM386.EXE in a system equipped with a SCSI host adapter, you may receive the error:

   EMM386:\377DMA buffer is too small. Add D=nn parameter and reboot.

CAUSE

Direct memory access (DMA) is used by SCSI host adapters for data transfer. EMM386 maintains a buffer for DMA data transfers. This error indicates that the DMA buffer maintained by EMM386.EXE is not large enough to handle the size of DMA transfers made by the SCSI device.

RESOLUTION

As the message states, the error can be eliminated by using EMM386 DMA buffer size parameter D= in the CONFIG.SYS file as follows:

   DEVICE=EMM386.EXE D=128

Start at a value of 32 and increase in increments of 16 until the error no longer appears. The default value is 16, the maximum value is 256.

KBCategory: kbother
KBSubcategory: win30
Additional reference words: 3.00 3.0 3.0a 3.00a win30 winmem

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Last reviewed: November 23, 1994
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