Page 29 - UNI 101 Computer Science Handout.

Faculty of Nursing
Adult care Nursing Department

At this point we have explored the various components that make up a computer system: one or more

CPUs, primary storage, I/O modules, various I/O devices, and the buses that connect everything

together. You have seen how the CPU processes instructions, and the kinds of instructions that are
executed. You have seen the different methods that are used to transfer data between an I/O device

and memory for use by the CPU. You’ve seen that the use of DMA and a completion interrupt is an

effective and efficient way to move large blocks of data quickly. You’ve also seen that programmed I/O
is more effective for small amounts of data, particularly when speeds are extremely slow. You’ve seen

how interrupts can be used together with programmed I/O to keep a pipeline of slow, character-based

I/O data moving, for example, from a program to a modem. In this section we are concerned about the

blocks and interconnections that make up the organization of a computer system. There are various

ways to interconnect the CPU, memory, and I/O peripherals, each with their own advantages and
disadvantages.

The blocks that make up the essential components of a personal computer or workstation are shown

as a simplified diagram in Figure below. The major components in this model are a CPU, memory, optical

disk drive, one or more hard disks, (or, perhaps, solid-state disks), the keyboard, and built-in video and
audio capability. The unit typically also provides USB, parallel, Ethernet, Wi-Fi, and modem interface

controllers and ports (perhaps Fire Wire, also, and maybe even Bluetooth).These ports can be used for

network connections, printers, modems, mice, and other devices. The package also includes plug-in
connectors for additional option boards that will interface to the master bus.

29 Academic Year 2025/2026