| The four main components of a computer
are the Random Access Memory (RAM), the Central Processing Unit (CPU),
the Input/Output (I/O), and the hard disk or other mass storage
devices.
Random Access Memory (RAM)
Random Access Memory in the form of microchips is normally located on
the motherboard or the memory board of the computer. It is the main
computer memory, often referred to as primary memory or working
memory. Primary memory is that part of memory where the activity of
the running system takes place. When you hear, "My system has 64
MB (Megabytes) of memory," the speaker is talking about primary
memory or RAM.
Operating systems and software programs
usually reside on the hard disk. When the computer is started (booted),
an image or copy of the operating system is loaded into RAM.
Similarly, when a
program is activated, an image or copy of that program is loaded
into RAM. Images in RAM remain as long as they are needed. Once these
images are no longer required, they are overwritten by other images.
If power is lost or the system is rebooted, images in RAM disappear.
Central Processing Unit (CPU)
The Central Processing Unit is the computer's logic microprocessor chip
that executes instructions (processes) received from the primary
computer memory (RAM). These instructions are stored in binary
language.
Input/Output (I/O)
The Input/Output portion of the computer accepts or reads input from a
device (such as your keyboard) into memory, or it writes output from
memory to a device. For example, the keyboard and the mouse are the
primary user input devices; the monitor, printer, and tape drive are
the primary output devices. Disk drives are considered both input and
output since they can be both read from and written to.
Hard Disk (or Other Forms of Mass
Storage)
The hard disk is a magnetic storage device where information is
stored. All files, including the operating system and applications or
utilities, are stored on a hard disk. The contents of the hard disk
are managed by the File System, which will be covered later.
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