Overview History of personal computers

the history of personal computer mass-market consumer electronic devices began in 1977 introduction of microcomputers, although mainframe , minicomputers had been applied single-user systems earlier. personal computer 1 intended interactive individual use, opposed mainframe computer end user s requests filtered through operating staff, or time sharing system in 1 large processor shared many individuals. after development of microprocessor, individual personal computers low enough in cost became affordable consumer goods. personal computers – called microcomputers– sold in electronic kit form , in limited numbers, , of interest hobbyists , technicians.

mainframes, minicomputers, , microcomputers

computer terminals used time sharing access central computers. before introduction of microprocessor in 1970s, computers large, costly systems owned large corporations, universities, government agencies, , similar-sized institutions. end users did not directly interact machine, instead prepare tasks computer on off-line equipment, such card punches. number of assignments computer gathered , processed in batch mode. after job had completed, users collect results. in cases, take hours or days between submitting job computing center , receiving output.

a more interactive form of computer use developed commercially middle 1960s. in time-sharing system, multiple computer terminals let many people share use of 1 mainframe computer processor. common in business applications , in science , engineering.

a different model of computer use foreshadowed way in early, pre-commercial, experimental computers used, 1 user had exclusive use of processor. in places such carnegie mellon university , mit, students access of first computers experimented applications today typical of personal computer; example, computer aided drafting foreshadowed t-square, program written in 1961, , ancestor of today s computer games found in spacewar! in 1962. of first computers might called personal minicomputers such linc , pdp-8, , later on vax , larger minicomputers digital equipment corporation (dec), data general, prime computer, , others. today s standards, large (about size of refrigerator) , cost prohibitive (typically tens of thousands of dollars). however, smaller, less expensive, , simpler operate many of mainframe computers of time. therefore, accessible individual laboratories , research projects. minicomputers largely freed these organizations batch processing , bureaucracy of commercial or university computing center.

in addition, minicomputers relatively interactive , had own operating systems. minicomputer xerox alto (1973) landmark step in development of personal computers because of graphical user interface, bit-mapped high resolution screen, large internal , external memory storage, mouse, , special software.

in 1945, vannevar bush published essay called may think in outlined possible solution growing problem of information storage , retrieval. in 1968, sri researcher douglas engelbart gave later called mother of demos, in offered preview of things have become staples of daily working life in 21st century: e-mail, hypertext, word processing, video conferencing, , mouse. demo culmination of research in engelbart s augmentation research center laboratory, concentrated on applying computer technology facilitate creative human thought.

microprocessor , cost reduction

the minicomputer ancestors of modern personal computer used integrated circuit (microchip) technology, reduced size , cost, contained no microprocessor. meant still large , difficult manufacture mainframe predecessors. after computer-on-a-chip commercialized, cost manufacture computer system dropped dramatically. arithmetic, logic, , control functions occupied several costly circuit boards available in 1 integrated circuit, making possible produce them in high volume. concurrently, advances in development of solid state memory eliminated bulky, costly, , power-hungry magnetic core memory used in prior generations of computers.

a few researchers @ places such sri , xerox parc working on computers single person use , connected fast, versatile networks: not home computers, personal ones.

after 1972 introduction of intel 4004, microprocessor costs declined rapidly. in 1974 american electronics magazine radio-electronics described mark-8 computer kit, based on intel 8008 processor. in january of following year, popular electronics magazine published article describing kit based on intel 8080, more powerful , easier use processor. altair 8800 sold remarkably though initial memory size limited few hundred bytes , there no software available. however, altair kit less costly intel development system of time , purchased companies interested in developing microprocessor control own products. expansion memory boards , peripherals listed original manufacturer, , later plug compatible manufacturers. first microsoft product 4 kilobyte paper tape basic interpreter, allowed users develop programs in higher-level language. alternative hand-assemble machine code directly loaded microcomputer s memory using front panel of toggle switches, pushbuttons , led displays. while hardware front panel emulated used mainframe , minicomputers, after short time i/o through terminal preferred human/machine interface, , front panels became extinct.