System Hangs with DCA E78 (IRMA) and EMM386.EXE (78412)

The information in this article applies to:
    Microsoft MS-DOS operating system 5.0
    Microsoft MS-DOS operating system 5.0a
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q78412


You are using Digital Communications Associates, Inc. (DCA) E78 terminal emulation software, and your IRMA Workstation for Windows software is unable to establish communications, causing the computer to stop responding (hang). You may also be unable to load EMM386.EXE.


DCA recommends that you use E78 versions 1.4.2 or later if you have EMM386.EXE installed on your machine.

If you are unable to access the mainframe through IRMA when EMM386.EXE tries to load or if EMM386.EXE refuses to install for reasons other than the inability to set a page frame, increase the DMA buffer size. The current buffer size may not be large enough to handle the amount of DMA transfers made by E78 versions earlier than 1.4.2. In the CONFIG.SYS file, the EMM386.EXE device line should include the d=nnn switch where nnn is the amount of memory in kilobytes to be reserved for buffered DMA:
   device=[drive]:\[dir]\emm386.exe d=48
where [drive] and [dir] are the location of the EMM386.EXE device driver.

The DMA buffer size should be increased to at least 48 (the default is 16). If the DMA switch does not solve the problem, you should upgrade E78.


DCA E78 is a 3270 terminal emulation that supports IRMA convertible communications adapters. IRMA links an IBM PC or compatible system to an IBM 3270 mainframe network without losing the independent processing functions of the PC or PC software.

For additional information, contact DCA.

The products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Modification Type: Major Last Reviewed: 5/12/2003
Keywords: KB78412