CFOG's PIP, February 1987, Volume 5 No. 4, Whole No. 52, page 9

Making MEX for Your Osborne

by Daryl Gelbach

[This is the second in a series of articles on MEX to be reprinted here. They originally appeared in Y.O.U.r Newsletter, the newsletter of the Yankee Osborne Users Group. -- bhc]

Modem Executive (MEX) is a very powerful program. It has the potential for becoming a truly universal modem program. The secret is that MEX proper is distributed without I/O drivers. It will run but is unable to address the modem or machine ports. This feature allows MEX to be adapted to a variety of systems. This is done by installing within MEX a series of overlays. These allow MEX to use the full capabilities of the system. This article will present the steps to create a fully installed MEX for the Osborne I and Exec.

The first step in constructing MEX for your system is to find the appropriate overlays. It is possible to use MDM7 or other overlays, but to take advantage of all MEX features it is better to use custom-made overlays. These may be found on Yankee One in the MEX-OVL library.

MXO-OC11.AQM	-->	Osborne I with Comm-Pac
MXO-OS22.AQM	-->	Osborne I
MXO-OSEX.AQM	-->	Osborne Executive
MXO-OX15.AQM	-->	Osborne Executive

[There are lots of other overlays in the MEX-ovl.lbr series. --bhc] You will also need from the board MEX114.com and Mload23.com. MLOAD is a nice program that combines the parts of the program without the use of DDT.

For Comm-Pac Modem users the construction of MEX is quite simple. First unsqueeze the source code for the overlay. Then:

ASM MXO-OC11.BBZ
MLOAD MEX.com=MEX114.com, MXO-OC11

That's it. You now have a working copy of MEX that uses the Comm-Pac modem.

For the Osborne I and Executive the procedure is a bit more difficult. After you unsqueeze the source code, it may be necessary to modify some of the equates in the program. Once that is finished proceed as above. (For Executive owners substitute your chosen overlay for MXO-OS22.)

ASM MXO-OS22.BBZ
MLOAD MEX.com=MEX114.com, MXO-OS22

This MEX program will work, but will not be able to use the special features (if any) of your modem unit. You will need to add the correct overlay for your modem. At this time Yankee One contains:

MXO-SM14.AQM	-->	Smartmodem Overlay
MXO-PR10.AQM	-->	Penril Overlay

To configure MEX to your modem follow these steps. (Remember to substitute your overlays for the ones shown here.) The file order given for MLOAD is important. Please make sure to overlay the computer hex file before the modem hex file.

ASM MXO-OS22.BBZ
ASM MXO-SM14.BBZ
MLOAD MEX.com=MEX114.com,MXO-OS22,MXO-SM14

Now your MEX is fully installed to use all of the features of both your Osborne and your modem.

Finally, for the truly ambitious programmer MEX is distributed with a Mexpat11.asm overlay. This allows the user to customize operating parameters, some not available through STAT variables. Alter the values in this file then:

ASM MEXPAT11.BBZ
MLOAD MEX.com=MEX114.com, MEXPAT11

The patch may be loaded along with other overlays but should be in the first position for proper installation.

MEX has great potential. The obvious advantage to this overlay process is seen if you work with more than one computer. MEX helps you avoid the problem of having to learn a different set of commands for each system. Other advantages will be explored in future articles.

[CFOG members may find it advantageous to get one of the already configured versions of MEX in the CFOG library and avoid the necessity of assembling and loading it. MEX has a big advantage in that you can change most of its features and then use the CLONE command to make a new copy with those changed features. MEX also comes in a commercial version, MEX Plus, $49.95 through the Lillipute Z-Node (649-1730). A version for MS-DOS is also available ($99.95) so that CP/M users who deviate to that system can take MEX with them. -- bhc]