Characteristics of Computers
The characteristics of computers that have made them so powerful and universally useful are speed, accuracy, diligence, versatility and storage capacity
1. Speed:
Computers work at an incredible speed. A powerful computer is capable of performing about 3-4 million simple instructions per second
2. Accuracy
In addition to being fast, computers are also accurate. Errors that may occur can almost always be attributed to human error (inaccurate data, poorly designed system or faulty instructions/programs written by the programmer) rather than technological weaknesses
A special term GIGO (Garbage In Garbage Out) has been coined to represent a scenario where faulty results are got due to inaccurate instructions or faulty data
3. Diligence
Unlike human beings,
computers are highly consistent. They do not suffer from human
traits of boredom and tiredness resulting in lack of concentration. Computers,
therefore, score high over human beings in performing voluminous and
repetitive jobs.
4. Versatility
Computers are versatile machines and are capable of performing any task as long as it can be broken down into a series of logical steps. This means that their capability is, once again, limited only by human intelligence.
5.Storage Capacity
Today’s computers can store volumes of data. Unlike human memory where unimportant information is relegated to the back of the mind and forgotten as time progresses, a piece of information once recorded (or stored) in the computer, can never be forgotten and can be retrieved almost instantaneously!
HARDWARE
The term hardware refers to the tangible parts of a computer system, that is, the physical equipment of the computer. It includes all the electrical, electronic, mechanical and magnetic components that make up the computer system. The CPU, disk drives, internal chips and wiring, modem, peripheral devices like the monitor, keyboard, mouse, printer, speakers etc. are together termed as computer hardware
Hardware: Motherboard and CPU
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1. Access time: This
is the time required to locate and retrieve stored data from the storage unit
in response to program instructions.
2. Storage capacity: It
is the amount of data that can be stored in the storage unit.
3. Cost per bit of storage.
Units of memory
The computer stores a
character in the storage cells with binary (0,1) mechanism.
Thus
the basic unit of memory is a bit (binary digit 0,1).
To store a character, a
computer requires 8 bits or 1 byte. This is called the ― word
length‖ of the storage unit.
Hence the storage capacity
of the computer is measured in the number of words it can store
and is expressed in terms of bytes.
Units of memory
The different units of measurement are:
8 Bits = 1 Byte 210(or)
1024 Bytes = 1 Kilo Byte (KB) 210
1024 KB = 1 Mega Byte (MB)
1024 MB = 1 Giga Byte (GB)
Hardware: Memory (Storage)
A computer memory is of two
types
1. Primary Memory ( Internal storage)
2. Secondary Memory ( External storage)
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Hardware:
Primary Memory
It is the main memory of
the computer and it can be quickly and directly accessed by the CPU for reading
or storing data. It consists of RAM, cache memory and ROM
Random access memory (RAM) is the computer’s primary working memory, in which program instructions and data are stored so that they can be accessed directly by the CPU. RAM is volatile, it can not retain data once power is switched off
Cache memory is a small unit of ultra-fast memory that is used to store recently accessed or frequently accessed data so that the CPU does not have to retrieve this data from slower memory circuits such as RAM.
Read-only memory (ROM) is the portion of a computer’s primary storage that does not lose its contents when one switches off the power. ROM contains essential system programs that neither the user nor the computer can erase
Hardware: Secondary memory
It is used to store large
volume of data on a permanent basis which can be transferred to
the primary memory whenever required for processing. It consists of equipment
designed to store large volumes of data for long-term storage.
Secondary storage devices
are nonvolatile and do not lose their contents when the computer is
turned off
Some of the devices of secondary storage are Hard Disk, CD-ROM, DVD and Flash drive.
Hardware:
Secondary memory
The hard disk is made up of
a collection of discs known as platters which are coated with magnetic
sensitive material on which the data is recorded.
Compact disk-read-only
memory (CD-ROM) drive—an optical drive designed to read the
data encoded on CD-ROMs and to transfer this data to a computer.
Compact disk-read-write
(CD-RW) drive—an optical drive that enables users to erase existing data
and to write new data repeatedly to a CD-RW.
Digital video disk (DVD)—a
CD-ROM format capable of storing up to a maximum of 17 GB of data; enough for a
full-length feature movie.
DVD-ROM drive is a read-only drive designed
to read the data encoded on a DVD and transfer the data to a computer.
Digital video disk-read/write (DVD-RW)—a standard for DVD discs and player/ recorder mechanisms that enables users to record in the DVD
SOFTWARE
Software of a
computer cannot be seen. It is a set of instructions given to the computer to
carry out a function is called a program. A group of programs is called
Software. Software makes the hardware of computer to work. Without software
computer is a dead pile of lead. The basic difference between the Hardware and
Software is just the same as that exists between TV and TV studio. Without TV
studio (software) from where the programs are telecast, the TV (Hardware) is a
dead machine
Types
of Computer Software
The
two main types of software are
a)
system software and
b)
application software.
SYSTEM SOFTWARE
System software controls how the various technology tools work together along
with the application software.
System Software is usually supplied by the manufacturer of a given computer
component. When one buys a printer it comes with CD software that enables it to
work with other system components of a computer.
System software is the ‘background’ software that helps the computer to
manage its internal resources.
The system software performs important tasks
such as running the program, storing data, processing data etc
System software includes both
a)
operating system software and
b)
utility software
Operating System Software
Operating system software
controls the application software and manages how the hardware devices work
together.The operating system acts as interface between the hardware and
user programs and facilitates the execution of programs.
Examples of Operating
Systems are Windows XP, Vista, 7 and 8, also Unix, Linux and Mac OS
Functions of Operating system
a)
An operating system controls the loading and running of
programs
b)
controls the use of peripherals such as
disc drives and printers
c)
organizes the use of the computer’s
memory.
d)
handles interrupts (signals from
devices)
e)
maintains security (passwords etc)
Utility Software
Utility software provides additional functionality to the operating system. Utility software includes antivirus software, screen savers, and antispam software.They are pre-written programs supplied by the manufacturer for maintaining day to day activities of computer system
APPLICATION SOFTWARE
Application software is used for specific information processing needs, including payroll, customer relationship management, project management, training, etc.
Application software is used to solve specific problems or perform specific tasks
Examples of Application Software
Word-processing packages that are responsible for creating, editing and printing of documents.
Spreadsheet packages which are specifically for analysis, planning and modeling. They are designed for working with numbers in terms of arithmetic (addition, multiplication, subtraction, division)
Database
Management Packages (e.g. Microsoft Access) are designed for handling and
manipulation of large volumes of data.
Some other examples are
accounting packages (for ledgers, trail balances), marketing packages (for
sales analysis), operations management (for inventory control), and a whole
host of mathematical, statistical and engineering packages. One such example
is E views used by economists in regression
.
Types of Application Software
Musa Kazimoto
IT
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