Java Reference
In-Depth Information
A computer is an electronic device capable of performing commands. The basic com-
mands that a computer performs are input (get data), output (display results), storage, and
performance of arithmetic and logical operations. There are two main components of a
computer system—hardware and software. In the next few sections, we give a brief
overview of these components. Let's look at hardware first.
Hardware
Major hardware components include the central processing unit (CPU); main memory
(MM), also called random access memory (RAM); input/output devices; and secondary
storage. Some examples of input devices are the keyboard, mouse, and secondary storage.
Examples of output devices are the monitor, printer, and secondary storage.
CENTRAL PROCESSING UNIT AND MAIN MEMORY
The central processing unit (CPU) is the ''brain'' of the computer and the single most
expensive piece of hardware in a computer. The more powerful the CPU, the faster the
computer. Arithmetic and logical operations are carried out inside the CPU. Figure 1-1(a)
shows some hardware components.
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Input
Device
Central
Processing
Unit (CPU)
1000
54
A
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1001
Output
Device
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Main Memory
2000
2001
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Main Memory
Secondary Storage
(a)
(b)
FIGURE 1-1
Hardware components of a computer and main memory
Main memory, or random access memory (RAM), is connected directly to the CPU.
All programs must be loaded into main memory before they can be executed. Similarly,
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