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Computer Hardware
What Is Hardware?
Hardware is any part of a computer you can touch. There are two categories of
hardware:
· internal-the components of the computer system contained inside the computer
case
· external or peripheral devices-those components that are attached to the
computer through cables or wireless technology
We will start by looking inside the computer.
[Figure 2.5 Inside a computer. Image has been omitted]
First of all, the computer needs a power supply. Electricity is brought into
the computer via a power cord. Once inside the computer, electricity travels
through metal tracks on the motherboard, which is the main circuit board of
the computer. All components inside the computer are attached to the
motherboard, as are external devices.
Electricity quickly makes its way to the CPU (central processing unit), which
is attached to the motherboard. Transistors then control the flow of
electricity. The CPU, also called the microprocessor, is the main computer
chip that manages information flow in the computer, as well as processing
instructions and data. There are some instructions and data that the CPU
needs to access frequently and quickly; these are often housed in a storage
area called a cache. The internal cache is the memory that is inside the CPU
and is the first place the CPU looks to find recently used data or
instructions. Because it is the first place that the CPU looks, the internal
cache is sometimes called L1 or level 1 cache.
The secondary cache is memory that used to be outside of the CPU but is now
right on the chip. The external cache is also used for high-speed storage of
recently used information. It is sometimes call the L2 or level 2 cache
because it is the second place the CPU looks to find recently used data or
instructions.
Expansion slots are sockets in the motherboard. Expansion cards can be added
to these slots for additional devices, such as a soundcard or a modem.
Beside the expansion slots, you will find the bus. It is a set of conductor
wires that transport data between the components of the computer through an
electronic path. Think of the bus as a highway for bits of information to
travel between components inside the computer case. The bus width is the
number of bits of information the bus can transport at one time. You can
think of the bus width as the width of a highway. If you have a wider highway
or one with more lanes, more traffic can pass without a jam and you get to
your destination faster. The same is true of a bus. The wider the bus or the
more bits the bus can carry, the faster information will travel from
component to component on the motherboard.
Drive bays are spaces in the computer case where disk drives are housed. A
computer can have several disk drives located here, including the hard drive,
as well as those for CDs (compact discs), DVDs (Digital Versatile/Video
Discs), and, increasingly less commonly, 3.5” floppy disks. USB (Universal
Serial Bus) flash drives, also known as memory sticks or memory keys, plug
into USB ports. The hard drive is the storage space of the computer, storing
both software and data files.
Memory chips are also attached to the motherboard. One type of memory is Rom
(read-only memory). It is also called the system BIOS, where information,
including instructions for start – up, is stored at the time of manufacture.
There will be one or more Rom Chips.
Ram (random access memory) is also called user memory. RAM is temporary
memory that stores information for the length of time a computer is left on
or a program is left running. The data you see on your monitor while using
your computer is stored in RAM.
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Once the computer is turned off or your program crashes, any information in
RAM is lost unless you saved it to another location (e.g., hard drive, USB
flash drive).