Multiple Sclerosis: Causes, Symptoms and Treatments. Multiple sclerosis, also known as MS, is a chronic disease that attacks the central nervous system, i.e. the brain, spinal cord and optic nerves. In severe cases, the patient becomes paralyzed or blind while in milder cases there may be numbness in the limbs. Over 350,000 people have MS in the US.
Devices you think of as input-only, such as a keyboard, might also be an output device (keyboard status LEDs). Conversely, devices you think of as output-only might also serve as input devices (paper/toner/ink status messages back to the computer).
A special type of input device that stores pictures digitally and then transfers them to the computer's memory - This can also be output, since this device has a small monitor to show the image - Input and Output.