Page 32 - UNI 101 Computer Science Handout.

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Figure 5 Major PC System Components

A clock controls the operation of the CPU. Interrupt and direct memory access (DMA) capabilities are
provided to enable rapid and efficient I/O processing. L1 and L2 cache memory for each CPU is included

within the same integrated circuit as the CPU for most modern processors. The wiring for the primary

buses that interconnect the CPU and its peripheral components is printed on the motherboard.

Connectors on the motherboard combine with the frame of the case to hold the motherboard and plug-

in peripheral cards in place, and, of course, the connectors on the motherboard provide the electrical
connections between the peripherals and the buses. The main frame computer is packaged differently,

since the mainframe computer is much larger physically, as well as operation ally. Still, the essential

components and operations are similar to those of the personal computer.

Figure 6 The Components in a Typical Desktop PC

Figure below illustrates the basic pathways required in a CPU-memory-I/O system. There are five basic
components involved in the interfaces between the CPU, memory, and the I/O peripherals: 1. The CPU

or CPUs. 2. The I/O peripheral devices. 3. Memory. Except for single pieces of input or output that can

be transferred directly from a register, data from input or intended for output is normally stored at least

temporarily in memory, where it can be accessed by the appropriate program, even for situations
preferring programmed I/O. 4. I/O modules. The I/O modules act as interfaces between the CPU and

32 Academic Year 2025/2026