I have a DOS-based application (QB4.5) which has been running for some years and I have now updated it to Visual Basic.
The application handles several async serial ports writingdata to random access file shared between all ports.
Due to the async nature of the program and the need to keepthe ports serviced, the DOS version used int 21H function68H (Commit File) every few seconds to flush the file buffersto disk. This avoids closing the files and any possibilityof serious data loss should there be power failure.
I can find no way of achieving the same thing in VB. Do youknow of any API function or DLL which gives access to therequired DOS interrupts,
Whenever you need to do a write, you open the file, append the data to it, and then close the file? This method is commonly used for writing messages to error logs. If you do not close the file, you cannot be guaranteed that the data is there. Also, if the program crashes, and you do not close the file you will lose your information also.