Download What is a Computer? - Erasmus DWSPIT Polkowice

University of Pitesti
Dolnośląska Wyższa Szkoła Przedsiębiorczości i Techniki
w Polkowicach
Information Technology
Simedre Mirel-Adrian
Dr inż. ZDZISŁAW PÓLKOWSKI
Polkowice, 2015
Definition of Information Technology
• Information technology is the technology that uses computing with
high speed communication links to spread information from one
place to another.
• Computer is a very important component of information technology
• The world has become “global village” due to advancement in IT.
• Information technology (IT) is the use of any computers, storage,
networking and other physical devices, infrastructure and processes
to create, process, store, secure and exchange all forms of
electronic data.
• Typically, IT is used in the context of enterprise operations as
opposed to personal or entertainment technologies. The commercial
use of IT encompasses both computer technology and telephony.
http://searchdatacenter.techtarget.com/definition/IT
What is a Computer?
• An electronic device that is programmed to accept data, process data
into useful information and store it for later use
• Computer consists of hardware and software
• Software is a set of instructions that tells a computer what to do
• Hardware is the physical part of a computer E.g. keyboard , mouse etc
• Relationship between hardware and software
• It is not only a machine which perform different functions on numeric
data but today more than 80% work perform by computer is non numeric
in nature.
http://www.webopedia.com/TERM/C/computer.html
Types of Computers
• Analog Computers
• Digital Computers
• Hybrid Computers
Analog computers are used to process analog data. Analog data is of
continuous nature and which is not discrete or separate. Such type of
data includes temperature, pressure, speed weight, voltage, depth etc.
These quantities are continuous and having an infinite variety of values.
A Digital Computer, as its name implies, works with digits to represent
numerals, letters or other special symbols. Digital Computers operate on
inputs which are ON-OFF type and its output is also in the form of ONOFF signal. Normally, an ON is represented by a 1 and an OFF is
represented by a 0. So we can say that digital computers process
information which is based on the presence or the absence of an
electrical charge or we prefer to say a binary 1 or 0.
http://www.byte-notes.com/analog-digital-hybrid-computers
History and Generations of computers
The computer as we see it today is a result of extensive
research and development through the decades. The reason of origin of
the computer and a brief history of its evolution are outlined below.
The six generations of computers are:
• Mechanical era(1623-1900)
• First generation electronic computers(1937-1953)
• Second generation (1954-1962)
• Third generation (1963-1972)
• Forth generation (1972-1984)
• Fifth generation (1984-1990)
• Sixth generation (1990 - present)
http://www.techiwarehouse.com/engine/51c38188/History,-Origins,-and-Generations-of-Computers
First generation Electronic computers
• First generation computers were used during 1942-1955 .
• They were based on Vacuum Tube which was a glass (tube) that
controlled and amplified the electronic signals
• Consume more power with limited performance
• High cost
• Uses assembly language – to prepare programs. These were
translated into machine level language for execution.
• Fixed point arithmetic was used
• 100 to 1000 fold increase in speed relative to the earlier mechanical
and relay based electromechanical technology
• Punched cards and paper tape were invented to feed programs and
data and to get results.
• Magnetic tape / magnetic drum were used as secondary memory
• Mainly used for scientific computations.
• Examples are: UNIVAC, Havard Mark 1, ENIAC
http://www.phy.ornl.gov/csep/ov/node10.html
Second Generation (1955-1964)
• Bell Lab invented the transistor – function like
vacuum tubes but smaller, lower power consumption, more reliable.
• Transistor is a small device that transfer electronic signals across a
resister
• Lower cost
• Magnetic core memories were used as main memory which is a
random-access nonvolatile memory
• Magnetic tapes and magnetic disks were used as secondary
memory
• Hardware for floating point arithmetic operations was developed.
http://www.phy.ornl.gov/csep/ov/node11.html
Third Generation (1963-1971)
• Jack Kilby developed Integrated Circuit (IC)
• An IC combined several electronic computers
on a small silicon chip
• IBM introduced
System/360 – a highly configurable,
highly backward compatible,
mainframe computer system.
• Small Scale Integration and Medium Scale Integration technology
were implemented in CPU, I/O processors etc.
• Smaller & better performance
• Comparatively lesser cost
• Faster processors
http://www.phy.ornl.gov/csep/ov/node11.html
Forth generation (1972-1984)
• Microprocessors were introduced as CPU– Complete processors
and large section of main memory could be implemented in a single
chip
• Tens of thousands of transistors can be placed in a single chip (VLSI
design implemented)
• CRT screen, laser & ink jet printers, scanners etc were developed.
• Semiconductor memory chips were used as the main memory.
• Secondary memory was composed of hard disks – Floppy disks &
magnetic tapes were used for backup memory
http://www.phy.ornl.gov/csep/ov/node11.html
Fifth Generation (1983-1990)
• Computers based on artificial intelligence are available
• Computers use extensive parallel processing, multiple pipelines,
multiple processors etc
• Massive parallel machines and extensively distributed system
connected by communication networks fall in this category.
• Introduced ULSI (Ultra Large Scale Integration) technology – Intel’s
Pentium 4 microprocessor contains 55 million transistors millions of
components on a single IC chip.
• Superscalar processors, Vector processors, SIMD processors, 32 bit
micro controllers and embedded processors, Digital Signal
Processors (DSP) etc have been developed.
• Memory chips up to 1 GB, hard disk drives up to 180 GB and optical
disks up to 27 GB are available (still the capacity is increasing)
• Object oriented language like JAVA suitable for internet
programming has been developed.
http://www.phy.ornl.gov/csep/ov/node14.html
Sixth Generation (1990 - )
• This generation is beginning with many gains in parallel computing,
both in the hardware area and in improved understanding of how to
develop algorithms to exploit diverse, massively parallel
architectures. Parallel systems now compete with vector processors
in terms of total computing power and most expect parallel systems
to dominate the future. One of the most dramatic changes in the
sixth generation will be the explosive growth of wide area
networking. Network bandwidth has expanded tremendously in the
last few years and will continue to improve for the next several
years.
http://www.phy.ornl.gov/csep/ov/node15.html
Computers Systems and its Components
• Input Devices
• Output devices
• System Unit
• Storage devices
• Communication devices
• Input Devices
An input device is any device that provides input to a computer. There
are many input devices, but the two most common ones are a keyboard
and mouse. Every key you press on the keyboard and every movement
or click you make with the mouse sends a specific input signal to the
computer.(Keyboard, Mouse, Trackball, Touchpad, Light Pen,
Magnetic ink character recognition, Optical mark recognition
(OMR), Bar code reader, Scanner)
http://oer.nios.ac.in/wiki/index.php/COMPUTER_AND_ITS_COMPONENTS
• Output Devices:
Output device receives information from the CPU and presents it to the
user in the desired from. The processed data, stored in the memory of
the computer is sent to the output unit, which then converts it into a
form that can be understood by the user. The output is usually
produced in one of the two ways – on the display device, or on paper
(hard copy).(Monitor, Printer, Plotter, Facsimile (FAX), Sound cards
and Speaker(s) )
http://studentcms.ise.canberra.edu.au/itw/kellkings/output-device/