Fourth Generation of Computers

Microprocessors

1971- present

Altair 8800- first personal computer
for $439 as a kit price.

   The process of miniaturizing integrated circuits led to creating a microprocessor. The microprocessor is a single silicon chip composed of great number of integrated circuits. First microprocessors, called Very Large Scale Integrated circuits, contained 5000 transistors. First microprocessor, The Intel 4004 Chip, was developed by Intel in 1970 for Japanese company producing calculators.The central processing unit, memory,  and input/output controls were located on a single chip. As the distance influence the speed of electricity, very small size of microprocessors allowed computers to make more calculations in less time. Thus, even though first microprocessor was made for calculator, it eventually led to development of personal computers. Therefore, computers became faster but their size decreased. Finally, computers could be minimized from a wardrobe size to regular computer size like we see in our times. This revolutionary step in computer history finally allowed to start mass production of computers for regular households. One of the first personal computers was Altair 8800 computer kit produced in 1975. Altair used programming language made by Microsoft. Altair contained processor with a speed of 2 MHz and 256 bytes of RAM memory.

   During microprocessor era two main operating systems have dominated the computer market: MS-DOS created by Microsoft for IBM, and, UNIX. Main languages used for those systems were C and C++, DBASE. 

   As computers became smaller and more powerful, it allowed to connect them into networks. That was begging of the internet. Also, mouse became a popular device. 

Examples of the fourth generation computers:

-DEC 10

-STAR 1000

-PDP 11

-CRAY 1 "Super Computer"

-CRAY-X-MP "Super Computer"

IBM 5150 personal computer
-introduced: 1981
-CPU: Intel 8088, 4.77MHz
-RAM memory: 16kB
-Storage: 160KB 5.25-inch disk drives
-Price: US $1,565 ~ $3,000
-Operating System: PC-DOS 1.0 v.