The Essentials Of Computer Organization And Architecture 4th Edition by Linda Null,Julia Lobur

Exercise 68

A very small company has hired you to install a security system. The brand of system that you install is priced by the number of bits encoded on the proximity cards that allow access to certain locations in a facility. Of course, this small company wants to use the fewest bits possible (spending the least amount of money possible) yet have all of its security needs met. The first thing you need to do is to determine how many bits each card requires. Next, you have to program card readers in each secured location so that they respond appropriately to a scanned card.
This company has four types of employees and five areas that they wish to restrict to certain employees. The employees and their restrictions are as follows:
a) The Big Boss needs access to the executive lounge and the executive washroom.
b) The Big Boss's secretary needs access to the supply closet, employee lounge, and executive lounge.
c) Computer room employees need access to the server room and the employee lounge.
d) The janitor needs access to all areas in the workplace.
Determine how each class of employee will be encoded on the cards and construct logic diagrams for the card readers in each of the five restricted areas.