MXSUB.EXE - Microsoft Extensions Substitute (May 1990) By Digital Solutions Pty Ltd PO Box 178 Margate Qld 4019 AUSTRALIA Tel (Int.) 61-7-883-1851 The Problem..... While LANtastic supports CD-ROMs on work stations without Microsoft Extensions (MSCDEX.EXE) being loaded, some programs for accessing CD-ROMs make requests to MSCDEX for certain information. These programs would abort on work stations because MSCDEX was not present. The Solution..... We wrote MXSUB.EXE as a substitute for MSCDEX on work stations. As a general rule (though not necessarily the case) CD-ROM programs read the CD-ROM via normal DOS calls. However, several (World Book's Infofinder was one) ask MSCDEX for the number of CDs actually available (Sub-function 0h) and what the associated drive letters are for those CDs (sub-function 0Dh). MXSUB sets these values via parameters at load-time, and services these Int 2Fh function 15h calls according to these parameters. The Usage..... Let's say you have two CD-ROMs, set by Net Use commands as drives S: and W:. You would then load MXSUB like this... MXSUB S W ...MXSUB will then report back to you the fact that it installed successfully and the drive letters it will supply as available. Note that it does NOT actually service requests to these drives, merely reports their presence and number as previously described. MXSUB uses about 5K of RAM, and should be loaded before you run your CD software. Do NOT load MSCDEX or your CD Driver (.SYS file) on your work station, only on the server. MXSUB worked for Infofinder (World Book), Groliers Encyclopaedia and CDATA86 (Australian Census). If a program makes a call to a MSCDEX sub-function other than 0h or 0Dh, MXSUB will abort the program, showing the full register information, particularly the sub-function called, at the top of the screen. If this happens, PLEASE WRITE IT DOWN exactly as it appears, and write to us or phone, and tell us also what program you were running. We will endeavour to add this sub-function to the list supported by MXSUB. Kind Regards, Daniel Churchman National Sales Manager - LANtastic (AUSTRALIA) Jan '92 Edmund J. Sutcliffe Having done some phoning round Digital solutions have agreed that the source code be placed in the Public Domain under the GNU Public license agreement. I would like to be notified of any modifications so that people can be informed of there use etc.