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CTD - The final solution?


CTD -- The final solution?

by Stuart Baker
Stuart Baker Software
9370 Golondrina Drive
La Mesa, CA 91941-5654
(619) 466-8811

As many of you know, I am the author of the BIOC driver. By the way, before I get too far into this discussion I would like to set something straight. I spent a lot of time creating an expressive acronym. The meaning of BIOC is "Built In Operator Control" not "Bidirectional Input/Output Control." I am not sure who invented the latter acronym, but I still prefer the original meaning.

I started work on BIOC back on OS/32 revision R00 (boy does that date me). Over the years I added many features to the original driver. The flexibility incorporated into BIOC made it very popular with MTM users. I began giving out versions of BIOC to contacts on the west cost starting with OS/32 R02. It soon became the driver of choice for MTM users on the west cost. As memory serves me, I placed the BIOC driver into the Interchange library around 1979. As it grew in popularity, customers began requesting that it become a standard part of OS/32. In July of 1982, I turned all source files over to Perkin-Elmer for incorporation into the R06-01 version of OS/32. To my knowledge, this was the first user written driver to become a standard part of the OS/32 operating system.

Now that you know some background on BIOC, lets find out why there is a need to develop the CTD driver. First we have another acronym, CTD stands for Common Terminal Driver. I have this on good authority, and am sure I am not inventing a new meaning. The intent is to develop one driver that addresses the needs of RELIANCE and MTM users. Since BIOC's addition to OS/32, a rift developed between users of MTM and users of RELIANCE. MTM users got spoiled by the functionality of BIOC and were no longer satisfied using the ITAM driver. The drawback is that the BIOC driver does not work with RELIANCE. Concurrent's ECM program allows users to switch between MTM and RELIANCE, but it uses the ITAM driver with both environments. Users that prefer BIOC were not very happy with this situation. With this in mind, lets look at several solutions to this problem.

The first solution was SDECM, the San Diego Environment Control Manager. This program, developed by Jim Millard of Concurrent's San Diego office, is available through the Interchange library. The concept requires sysgening both a BIOC and an ITAM driver for each port on your system. You then inform SDECM of the names that make up each terminal pair. It automatically selects ITAM when going to RELIANCE and BIOC when going to MTM. This actually works well, in that it is transparent to the user. Since you must define two names for each port, sysgening becomes complex as well as increasing you system size. If your system has many ports, you may even have trouble exceeding the 64KB limit for servicing interrupts. SDECM offers several neat features above and beyond its handling of BIOC and ITAM. One big advantage of SDECM is that it supports MTM's foreground interface without interfering with the terminal exchange. SDECM also handles dial in lines correctly. The BYE command disconnects the current call. SDECM also allows you to use modems for inbound and outbound calls. This eliminates the need for dedicated outbound lines.

The second solution was TS, the Terminal Switch program. This program addresses the BIOC/ITAM problem in the same manner as SDECM. The TS program differs from ECM in that it presents an outer shell that you must sign on to. Additionally, you make selections from a menu instead of entering the name of the desired environment. TS also uses your userid and password to sign you on to MTM or RELIANCE. Even though the TS program is a new addition, it still dose not function with MTM's foreground interface. I do not understand why the specifications for new products do not automatically include support for all existing OS/32 interfaces. Also, the TS program does not support dial in or dial out lines, a rather large oversight in today's world of telecommunications.

The third solution came from MTM. Concurrent enhanced MTM's ADD command to allow specification of both the BIOC and ITAM device names. This approach did not remove the functionality of the foreground interface, in fact it really enhanced it. You can now go directly to RELIANCE from MTM, and still use the BIOC driver with MTM. MTM supports dial in lines, but there exists no mechanism to access unused lines for outbound calls.

All of these approaches have the same drawback. They all require sysgening both a BIOC and an ITAM driver for each port on your system. As I mentioned earlier, this makes sysgening complex and increases you system size. For the present, SDECM offers the most flexible solution to the problem.

The fourth solution is the development of CTD, the Common Terminal Driver. Having one driver that works with both environments simplifies sysgening and reduces operating system size. It also provides an auto baud feature that functions with both environments. This is one problem that none of the other approaches solved. The CTD driver supplies the functionality of BIOC for MTM users, as well as working with RELIANCE. I have read the preliminary documentation on CTD and am anxiously awaiting the opportunity to test it. CTD becomes a standard part of OS/32 R08-03. Beta test of this software is starting soon. You can look forward to a hands on report in the next Interchange news letter.

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Article Copyright 1989 Stuart J. Baker

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