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- This archive contains assembly listings and executable files to illustrate
- the technique explained in Clifford Vander Yacht's July 1989 Computer
- Language article, "Using Dummy Device Drivers to Load TSRs."
-
- The code presented here reduces the overhead associated with each TSR by a
- quarter megabyte or so...the only trick is, you have to give the TSR a .SYS
- extension and let CONFIG.SYS load it up.
-
- The files are:
-
- DDDPRE.ASM ; This is the 18-byte prefix. The double word at Header
- ; (FFFF) tells the device driver loader that this driver
- ; has only one device. The ASSUME statement tells the
- ; assembler to produce segment overrides where necessary.
- ; The resident part of the program follows this prefix.
- DDDMID.ASM ; This is the required installation heading for the
- ; resident portion of the device driver/TSR.
- DDDEND.ASM ; These are the termination instructions. The highest
- ; address plus one of the resident portion must be put
- ; into the second instruction.
- ;
- ; Assemble, link, and rename dummy device drivers made
- ; with this code with a .SYS extension. Or process with
- ; EXE2BIN into a binary file with a .SYS extension. Don't
- ; try to execute the .EXE file from the system prompt!
- ;
- DDDEXE.ASM ; This is an alternate termination sequence. Programs
- ; that use this code may be loaded as dummy device drivers
- ; or as conventional TSRs, assuming they are saved with
- ; the file extension .EXE.
- ;
- SCROLOCK.ASM ; Source code for a short dummy device driver that prevents
- ; the screen from scrolling away. Put DEVICE=SCROLOCK.SYS
- ; in your CONFIG.SYS file.
- SCROLOCK.EXE ; TSR version of SCROLOCK.
- TYPEAHED.ASM ; Source code for a keyboard-buffer enlargement program.
- TYPEAHED.EXE ; TSR version of TYPEAHED.
- TYPEAHED.SYS ; Dummy device driver version of TYPEAHED.