Un-necessary I/O devices that I would consider un-necessary would be a printer and a webcam. The reason that I say that a printer is un-necessary is because although it is an essential I/O device it is not something that you would need for an everyday use because of the fact that you would not need to print something every day. Due to this reason it is not considered necessary. Another un-necessary device would have to be a webcam. A web-cam is not considered necessary because it is not what is needed for an everyday use. For example would you need to see someone’s face every day? Why would you need to see someone’s face every day? For that reason it is considered un-necessary.
A modem is considered an I/O device because of the fact that it connects to a port on the computer. The modem after connection sends out information to the computer saying “hey I am a device” and then telling the computer that it is connected to internet. This being that it sends and collects data