jim@owlmnt.UUCP (11/19/87)
I have to develop a system that sets up a background TSR to receive and transmit files from an async port. I know how to do simple things with TSR's but I'm not sure about all the places where I might get burnt. More specifically, what, if anything, do I need to do to be able to safely open and close files from a TSR? Are the use of the DOS "Critical Region" flag and INT 28H enough? -- Jim McCool Owl Mountain Inc. Usenet: wright!owlmnt!jim
darrylo@hpsrlc.UUCP (11/20/87)
In comp.sys.ibm.pc, jim@owlmnt.UUCP (Nite Owl) writes: > I have to develop a system that sets up a background TSR to receive and transmit > files from an async port. I know how to do simple things with TSR's but I'm not > sure about all the places where I might get burnt. > > More specifically, what, if anything, do I need to do to be able to safely open > and close files from a TSR? Are the use of the DOS "Critical Region" flag and > INT 28H enough? > -- > > Jim McCool > Owl Mountain Inc. > Usenet: wright!owlmnt!jim > ---------- Writing a reliable TSR that does DOS calls, etc. is not much different than opening pandora's box. Not only should the "INDOS" flag be checked, but you have to make sure that a video or keyboard interrupt is not in progress (among many other things). If you or anyone is interested, I have some examples on how to write a TSR, some written in assembly (TSRDEMO.ASM, TSRDEMO2.ASM, & TSRSH.ASM) and one written in Turbo Pascal V3.0 (STAYRES 4.2). If you want a copy, send Email. -- Darryl Okahata {hplabs!hpccc!, hpfcla!} hpsrla!darrylo CompuServe: 75206,3074 Disclaimer: the above is the author's personal opinion and is not the opinion or policy of his employer or of the little green men that have been following him all day.