History of the Computer
The earliest mechanical calculating device was invented in 1642 known as the Pascaline.
In 1833, the Analytical Engine was design to follow a set of direction, process it and then
store the data. It was never made however its design served as a model for the modern
computer.
By the end of the 19th century, Hollerith invented a tabulating machine for the use of
counting number of the US Census.
In 1944 a team from International Business Machines (IBM) and Harvard University
completed the Mark 1.
The Mark 1 was not a computer but instead a highly sophisticated calculator.
The first electronic computer was built between 1939 and 1942. It was called the
Atanasoff-Berry Computer (ABC).
With the ABC, the binary number system was now being used.
In 1945 Neuman presented the idea of the store program concept. The stored program
computer would store computer instructions in a CPU.
Even at this point computer were large and expensive.
The invention of the transistor helped make computers smaller and less expensive.
In 1960s, IBM introduced the first medium size computer. Still expensive however
smaller.
With this second generation, computers also saw a change in the way data was stored.
Punch cards were replaced by magnetic tape and high-speed reel-to-reel tape machine.
A program is a list of instructions written in a special language that the computer
understands.
A computer is an electronic machine that accepts data, processes it according to
instructions, and provides the results as new data.
A computer can make simple decisions and comparisons.
In 1957, a team of researchers completed, Fortran, a programming language with
intuitive commands such as READ and WRITE.
COBOL is a high-level programming language that is most widely used.
In 1960s Basic was developed as another widely used programming language. Basic is
also known as Visual Basic, or VB.
The third generation computer had begun when the transistors were replaced with
integrated circuits (IC). ICs are also known as chips.
By 1964 computers became smaller in size and the price also dropped so now smaller
organization like colleges, could afford them.
A mainframe is a large computer system that is usually used for multi user applications.
The IBM System 360 was one of the first mainframes available.
Most people using mainframes communicate with the use of terminals. The mainframes
may be located on a different floor or even a different building.
In 1970 the microprocessor, an entire CPU on a single chip, was created.
The small microprocessor made it possible to build a computer called a microcomputer
that fits on a desktop. The first were built in 1975.
In 1976 the Apple computer was designed and built.
Microcomputers are often personal computers or PCs.
Input devices are devices from which the computer can accept data.
Keyboards, CD-Rom drive, disk drive, and a mouse are all examples of input devices.
Output devices are devices that display or store processed data.
Monitors, and printers are the most common visual output device.
The task of the CPU is to control the order in which tasks are completed. It is also
referred as the brain of the computer.
Software instructs the computer on what to do.
Operating system software is run automatically when the computer is turned on.
Computers have 2 type of memory, ROM and RAM.
ROM is a permanent part of the computer and cannot be changed.
RAM is temporary memory where data and instructions can be stored. This data can be
changed or released.
The binary number system uses 2 digits, 1 and 0.
Each 0 or 1 in the binary code is called a bit.
An 8-bit unit is called a byte.
Computer memory, file size, and storage device capacities are measured in bytes.
MB stands for megabytes. 1048576 bytes
GB stands for gigabytes. 1073741820 bytes
K stands for kilobytes. 1024 bytes
Two commonly used types of printers are laser and inkjet printers.
A laser printer uses a laser and tones to generate characters and graphic on paper.
An inkjet printer uses an ink cartridge to place very small dots of ink onto paper to create
character and graphics.
A network is a combination of software and hardware that works together to allow
computers to exchange data and to share software and devices.
The largest and most widely accessed network is the Internet, a worldwide network of
computers that is not controlled by any one organization.
The Internet is actually numerous networks all linked together thought routers.
Routers are devices that can connect different network technologies together.
Many organizations link their networks to the Internet. Individuals can get access to the
Internet thought telecommunications and an Internet service provider or an online
service. An ISP (Internet Service Provider) offers access to the Internet for a fee.
Cable Modem: Transmits data through a coaxial cable television network.
CD Disc made of Mylar with reflective coating that is sealed in clear, hard plastic.
Diskette: Sometimes called a floppy disk. Made of Mylar coated with a magnetic material
and then loosely encased in hard plastic.
DSL: (Digital Subscriber Line) Modem that uses an analog phone line called and ADSL
line to transmit data upstream at speeds up to 640 Kbps and receive data downstream at 8
Mbps.
Firewall: A network security system that prevents unauthorized access.
HTTP: (Hypertext Transfer Protocol) The protocol used by web sites to transfer data over
the Internet.
Internet service provider: (ISP) A company that offers access to the internet for free.
Local Area Network: (LAN) A network that connects computers within a small area.
Modem: Device that converts binary data into tones and tones back into binary data so
that computer data can be sent over telephone lines.
Netiquette: Network etiquette
Peer to Peer Network: A group of computers that share responsibilities and resources
equally without a server.
Server: A computer on the network of the Internet that provides information.
TCP/IP: Communication software used for computers connected to routers.
Telecommunication: transmitting and receiving computer data over telephone lines.
Wide Area Network (WAN): A network that connects computers over a long distance.
Zip drive: Drive used to read and write data to a Zip disk.
Zip disk: A disk, almost as small as a diskette that stores 250 MB of data.