DAVIET/ECE 1B/
DAVIET/ECE 1B/1408636
PRACTICAL NO. 1: FAMILIARIZATION WITH COMPUTER
SYSTEMINTRODUCTION TO COMPUTER Fig.1.1 Computer systemComputer is
an electronic device that is designed to work with Information. The
term computer is derived from the Latin term computare, this means
to calculate. Computer can not do anything without a Program. it
represents the decimal numbers through a string of binary digits.
The Word 'Computer usually refers to the Centre Processor Unit plus
Internal memory.Computer is an advanced electronic device that
takes raw data as input from the user and processes these data
under the control of set of instructions (called program) and gives
the result (output) and saves output for the future use. It can
process both numerical and non-numerical (arithmetic and logical)
calculations. The basic components of a modern digital computer
are: Input Device, Output Device, Central Processor. A Typical
modern computer uses LSI Chips.
Charles Babbage is called the "Grand Father" of the computer.
The First mechanical computer designed by Charles Babbage was
called Analytical Engine. It uses read-only memory in the form of
punch cards.
Fig.1.2 Block Diagram of ComputerCharacteristics of computer
Speed
Accuracy
Reliability
Storage
Retrieving data and programs
Automation
Versatility
Communication
DiligenceComponents A general purpose computer has four main
components: thearithmetic logic unit(ALU), thecontrol unit,
thememory, and the input and output devices (collectively termed
I/O). These parts are interconnected bybusses, often made of groups
ofwires.Inside each of these parts are thousands to trillions of
smallelectrical circuitswhich can be turned off or on by means of
anelectronic switch. Each circuit represents abit(binary digit) of
information so that when the circuit is on it represents a "1", and
when off it represents a "0" (in positive logic representation).
The circuits are arranged inlogic gatesso that one or more of the
circuits may control the state of one or more of the other
circuits.
The control unit, ALU, registers, and basic I/O (and often other
hardware closely linked with these) is collectively known as
acentral processing unit(CPU). Early CPUs were composed of many
separate components but since the mid-1970s CPUs have typically
been constructed on a singleintegrated circuitcalled
amicroprocessor.Arithmetic logic unit (ALU)The ALU is capable of
performing two classes of operations: arithmetic and logic.
The set of arithmetic operations that a particular ALU supports
may be limited to addition and subtraction, or might include
multiplication, division,trigonometryfunctions such as sine,
cosine, etc., andsquare roots. Some can only operate on whole
numbers (integers) whilst others usepoint to representreal numbers,
albeit with limited precision. However, any computer that is
capable of performing just the simplest operations can be
programmed to break down the more complex operations into simple
steps that it can perform. Therefore, any computer can be
programmed to perform any arithmetic operationalthough it will take
more time to do so if its ALU does not directly support the
operation. An ALU may also compare numbers and returnBoolean truth
values(true or false) depending on whether one is equal to, greater
than or less than the other ("is 64 greater than 65?"). The ALU can
perform basics operations like addition, subtraction,
multiplication, division, etc. and does logic operations like
>,";
cin>>n;
fact=rec(n);
cout