Expanded Memory and 82592 On Board Ethernet Clash

See Also
IPB 1029 - IPB 1031 - IPB 1032 - IPB 1035 - IPB 1037
IPB 1042 - IPB 2060 - IPB 2084 - IPB 2086 - IPB 2118

There has traditionally been a problem supporting both Expanded Memory (EMS) with EMM386.EXE and a network connection via the Intel 82592 on board Ethernet (OBE) adapter, particularly on MCA systems. This combination results in a DMA clash which may drop the network connection at any time.

A modified version of EMM386.EXE is now available which will co-exist with the OBE. In order to achieve this, however, it was necessary to remove this driver's ability to support Upper Memory Blocks (UMBs). For this reason, the parameter RAM must NOT be used.

The following syntax is recommended at the beginning of CONFIG.SYS if UMB support is NOT required.

DEVICE=C:\DOS\HIMEM.SYS
DEVICE=C:\DOS\EMM386.EXE I=C000-EFFF M1 SIZE*
Where SIZE* is the amount of EMS required in KB.

If UMBs are required, i.e. if TSRs or device drivers are to be loaded into upper memory, this may be achieved by giving EMM386.EXE only sufficient memory to install an EMS page frame and then subsequently loading APRUMB.SYS to make use of the remaining upper memory.

The following syntax is recommended at the beginning of CONFIG.SYS if UMB support IS required:

DEVICE=C:\DOS\HIMEM.SYS
DEVICE=C:\DOS\EMM386.EXE X=C000-DFFF I=E000-EFFF M9 SIZE*
DEVICE=C:\DOS\APRUMB.SYS I=-C000-DFF X=E000-EFFF
Where SIZE* is the amount of EMS required in KB.

File Versions

EMM386.EXE must be 4.20.06X, which may be downloaded from area 42 of the Apricot Insight BBS (EMM386.ZIP). This is the only version of EMM386.EXE which will report its version when interrogated by WHAT.EXE, i.e. by typing WHAT EMM386.EXE at the DOS prompt. All other versions will not give any revision information, even though they may be the same length and have the same date stamp.

When APRUMB.SYS is used, as in the above example, if it is version 1.10 or later it is not necessary to include the I= and X= parameters after it. The latest version of APRUMB.SYS may also be downloaded from Area 42 of the Apricot Insight BBS (APRUMB.ZIP)

----------oOo----------