MGMT 1040 Chapter Notes - Chapter 15: Input Device
8 May 2018
School
Department
Course
Professor
MGMT 1040 Chapter 15 Notes – Summary
Introduction
• There is iput that is epeted the appliatio progra i respose to a read
statement of some kind requesting input data for the program.
• Then there are other times when the user wishes to interrupt what the computer is
doing.
• On many computers, a character such as Control-C or Cotrol-D or Cotrol-Q a
be typed to stop the program that is running.
• Control-S is used o soe machines to stop the display from scrolling.
• Typing Control-Alt-Delete on a PC will stop normal processing and open an
administrative window that can be used to kill a program or shut down the computer.
• These are examples of unpredicted input.
• Since the executing program is not necessarily awaiting specific input at those times.
• Using the input method that we already described would not work.
• The unexpected input would not be noticed, possibly for a long time until the next input
instruction was executed for some later expected input.
• Finally, on a multiuser system, there may be many keyboards connected to a single
computer.
• The computer must be able to distinguish between them, must not lose input data even
if several keyboards send a character simultaneously.
• Must be able to respond quickly to each keyboard.
• The physical distances from the computer to these keyboards may be long.
• Another input device that will generate unexpected input is the mouse.
• When you move the mouse, you expect the cursor to move on the screen.
• Clicking on a mouse button may serve as expected input to a program.
• It may be unexpected and change the way in which the program is executing.
• In fact, unexpected input is fundamental to programs written in modern event-driven
languages such as Visual Basic and Java.
find more resources at oneclass.com
find more resources at oneclass.com
