History of Computer

History of Computer:

-important people

Allen, Paul G. - Co-founder of Microsoft Corp. Allen left the company in 1985 but remained on the board of directors and as founded or financially supported several innovative computer ventures, including Asymetrix and Starware Corp. He is involved with a variety of other projects, including a Jimi Hendrix Museum in Seattle.

Amdahl, Gene M - South Dakota native who helped design the IBM 704, the S/360 series. He was the founder of the Amdahl Corp.

Andreessen, Marc - Co-founder (at the age of 22) of Netscape Communications, along with Silicon Graphics founder James H. Clark. Before Andreessen graduated from the University of Illinois in Champaign, he had created the NCSA Mosaic prototype with a team of students and staff at the university's National Center for Supercomputing Applications.

Babbage, Charles (1791-1871) - Eccentric, English mathematician who is considered to have conceptualized the modern computer a century before technology let it be built. He conceptualized the Difference Engine, a machine that would have computed lengthy scientific tables, but money, labor, and health problems prevented its completion. The Analytical Engine, a more ambitious plan, would have done a wide range of calculating tasks. With it, Babbage recognized the need for an input device, memory, a central processing unit, and an output device, and for this he is known as the Father of Computing.

Backus, John W. - Mathematician from Philadelphia who headed the research team at IBM that created FORTRAN, the first machine independent programming language.

-important devices/developments

Floppy Drive - The floppy drive is always called "Drive A:". A floppy disk can hold 1.5 megabytes of data. That's about 1,500,000 characters or letters (or about 300,000 words). That's more than enough space for the text of a large book. Pictures, however, take up a great deal of room. You could only fit a small number of good-quality pictures (or graphics) on a floppy disk.

Hard drive - This drive uses disks that are made of aluminium or glass (and therefore 'hard'). Each disk can store much more information than either a floppy or CD-ROM. Sometimes, there may be several disks in a hard drive. However, the disks in a normal hard drive can not be removed or replaced. Today, hard drives are measured in gigabytes. That's one thousand million bytes. 1 gigabyte is about 11/3 CD-ROM disks.

Motherboard - Everything inside the computer is connected to a circuit board called the 'motherboard'. The motherboard has sockets for the computer's brain, called a CPU; the computer's memory (RAM, ROM and CMOS); and for add-on cards to control the video (picture), audio (sound), printer and anything else that might be connected to the computer. You may also find a modem inside on an add-on card.

RAM - This stands for 'Random Access Memory'. Everything you do with the computer is stored in RAM until you save your work to a disk. If the computer should lose power, everything in RAM is wiped out. You would have to start all over again (unless you saved it)! Today computers have 16 megabytes of RAM or more. (Some older computers may have less.)

CPU - This stands for 'Central Processing Unit' and is the 'brain' of the computer. Most CPU's today are made by Intel and bear such names as 'Pentium', 'Pentium Pro' and 'Pentium II'. Older Intel CPU's include the 80486 and 80386 families. Other manufacrurers also make CPU's: Motorolla for the Macintosh, AMD and Cirrus for PC's and others.

-generations

General Features of First Generation Computers

1. The First Generation was from 1946 to 1956

„X Computers in this generation did from 2,000 to 16,000 additions per second

„X Had main memory from 100 bytes to 2 kilobytes (2,000 bytes)

2. All computers of this generation used vacuum tubes to perform calculations

„X Vacuum tubes are expensive because of the amount of materials and skill needed to make them.

„X Vacuum tubes get hot and burn out light an incandescent light bulb.

3. All computers in this generation where very large machines

„X Needed special rooms to house them with air conditioning because of the heat generated by the vacuum tubes

„X All required specially trained technicians to run and maintain them

General Features of the Second Generation

1. From 1959 to around 1965

2. Smaller, faster, and more reliable than the First Generation of computers

o Used transistors instead of vacuum tubes for performing calculations

o 6,000 to 3,000,000 operations per second

o 6 kilobytes to 1.3 megabytes of main memory

o Contained in four cabinets about 6 feet high by 4 feet wide, each weighing 250 pounds

3. Cost about one-tenth the price of a First Generation computer

4. Computers become common in larger businesses and universities

Third Generation - Integrated Circuits

General Features of the Third Generation

1. Form 1965 to around 1972

2. Used integrated circuits - many transistors on one piece of silicon

3. Computers become smaller, faster, more reliable, and lower in price

„X Size of a stove or refrigerator, some can fit on desktops

„X Can do 100,000 to 400,000,000 operations per second

„X Cost about one-tenth the amount of second generation computers

4. Computers become very common in medium to large businesses

General Features of Fourth Generation Computers

1. Form 1972 until