Solve 4.5 when = 40. PROBLEM 4.5 A hand truck is used to move two kegs, each of mass 40 kg. Neglecting the mass of the hand truck, determine (a) the vertical force P that should be applied to the handle to maintain equilibrium when = 35, (b) the corresponding reaction at each of the two wheels.
5.0 : I/O MANAGEMENT One of the main functions of an operating system is to control all the computer’s I/O (Input/output) devices. It must issue commands to the devices, catch interrupts, and handle errors. It should also provide an interface between the devices and the rest of the system that is simple and easy to use. To the extent possible, the interface should be the same for all devices (device independence). The I/O code represents a significant fraction of the total operating system. I/O software can be structured in layers, with each layer having a well-defined task to perform. 5.1 PRINCIPLES OF I/O HARDWARE Different people look at I/O hardware in different ways. Electrical engineers look at it in terms of chips, wires, power supplies, motors, and all the other physical compone