Have you ever downloaded some software only to find that it won't run on
your terminal, or that your terminal is not listed in the Instalation Program
that goes with it? It has sure happened to me with my Otrona Attache (say
what?). So I extracted the terminal display driver codes from James H.
Whorton's VINST11.COM, an installation program for his VDO25.COM, and
displayed them in the chart below. If the program you wish to adapt can be
installed for various terminals, and you have an installed version for one of
the terminals in the chart, you can do the following. Use a program like
PATCH to Search the program code for the strings of bytes that constitute the
display driver codes given in the chart for the installed terminal. If these
are found, replace them with the codes for your particular terminal.
For example, DAZLSTAR has the Osborne 1 on the list of terminals in its
Install Program. The addresses given in the documentation for the terminal
codes are not even right (for me at least). No problem; I just installed
DAZLSTAR for the Osborne, used PATCH to find the O1 terminal codes,
substituted the Otrona values for these; and it worked!
The terminal codes given in the chart are those used in VDO25. Many
programs don't use all of these; some use more. The same overall strategy
should work to find others as needed. To find codes used by the program you
could use COM-PARE or some such to locate the differences between
installations for two different terminals. The Labels for the various codes
at the top of the columns of the chart (sort of taken from WordStar) stand for
the following:
R Number of Rows (in HEX)
C Number of Columns (in HEX)
ERAEOL Erace to end of line
CLEAD1 Cursor Position Lead in
CLRSCN Clear Screen
LNINS Insert Line
LNDEL Delete Line
IVON Highlighting (Reverse Video) On
IVOFF Highlighting (Reverse Video) Off
In some programs a string-length byte (indicating the length in bytes of
the code that follows) is prefixed to some or all of these codes. For example
ERAEOL for the Zenith would be: 02 1B 4B, and CLEAD1 would be 03 01 1B 59. If
the program employes a string-length byte, it is already in the program. So
you don't need to insert it; you only need to change it if the string you are
patching in is of a different length than the original one.
Different types of Highlighting may be used (Reverse Video, Background
On, Boldface, Underline, etc.) depending on what your terminal is capable of.
For some terminals and some programs the values of IVON and IVOFF should be
switched to obtain the right affect.
The chart was sorted by the ERAEOL values so as to bring together the
terminals whose codes are most similar. Thus the ADM-20 is next to the Morrow
rather than next to the ADM-31.
In the chart I saved space by using some abbreviations which should not
pose a problem. "Hil" with the Kaypros is Highlighting. "L-Sieg" stands for
Lear-Siegler. "S120" is the Soroc 120. "WY-100/200/300" are Wyse terminals.
"TVid" stands for Televideo.
