Shutter: The shutter opens and closes very rapidly to control the amount of light passing through the aperture. Some cameras allow this timing to be manually adjusted. Like shutters on your window, you can only see outside as long as the shutter is open.

Shutter Priority: Slow the shutter in dim lit or night settings to capture more natural light (8/1 = Shutter Open 8 Seconds, 4/1 = Shutter Open 4 Seconds) and the resulting image will appear brighter. Keeping the shutter open longer may cause movement to blur, so it is best to keep the camera on a stable tripod. An example of this blur is the long red glow of taillights on a freeway at night. Speed the shutter in bright settings to freeze the action of fast moving objects (1/1000 = Shutter Open 1/1000 of a Second). An example of fast shutter action is the ability to see individual spokes on a bicycle that was racing past. During Shutter Priority Mode on Toshiba Digital Cameras the Aperture is automatically set and the Flash is disabled to optimize performance. 

Software: Operating Instructions for specific task based applications. These instructions are carried out by the computers processors. These include all packaged for use like image editing, word processing, databases, CAD, CAM, games, and so on. Software has to be written for a specific Computer OS.