1. Systems Comparing Devices

2. Decisions have to be made if you have to choose between two different devices. Each different device will have a number of different criteria to choose between. We shall look at how to compare different devices

3. Comparing Input Devices Mouse –Design –Cost Keyboard –Design –Cost Microphone –Design –Cost

4. Comparing Input Devices Scanner –Resolution (dpi) –Cost Digital Camera –Resolution (Megapixels) –Cost Webcam –Design –Cost

5. Comparing Output Devices Monitor –Screen size (diagonal) given in inches –Screen Type (TFT,LCD) –Cost Speakers –Size –Number of speakers –Cost

6. Comparing Output Devices Printers –Resolution: the higher the resolution the better the quality (measured in dots per inch dpi) –Speed: how fast they print (measured in pages per minute ppm) –Cost

7. All backing storage can be compared by the –Capacity (how much data it can hold) Megabytes, Terabytes or Gigabytes –Speed of data transfer (how fast the data can be read and written) Kilobits per second, Megabits per second –Cost Comparing Backing Storage

8. Comparing Computer Systems All computer systems can be compared by the –Speed of the processor (Gigahertz) –Backing Storage Capacity (Gigabytes) –Main Memory Capacity (Mega or Gigabytes) –Cost