DOS‐tips Available to Purchase

Perhaps you've had the experience of starting up a program, such as a compiler or file conversion program, then realizing that you forgot to make some vital changes to your file. So you hit 〈CTRL〉〈BREAK〉, your all‐purpose “panic button,” and—nothing happens!? Finally, several seconds (or minutes) later, a ˆ C shows up on the screen and the program finally terminates. What gives? As it turns out, DOS only checks to see whether 〈CTRL〉〈BREAK〉 has been pressed when it reads the keyboard for input or sends a character to the screen. Some programs (like compilers) run for a long time without ever reading the keyboard or writing to the screen. Result—your 〈CTRL〉〈BREAK〉 is not acted on immediately.