History of personal computers

"[5] The history of the personal computer as mass-market consumer electronic devices effectively began in 1977 with the introduction of microcomputers, although some mainframe and minicomputers had been applied as single-user systems much earlier.

The minicomputer Xerox Alto (1973) was a landmark step in the development of personal computers because of its graphical user interface, bit-mapped high resolution screen, large internal and external memory storage, mouse, and special software.

In 1968, SRI researcher Douglas Engelbart gave what was later called "The Mother of All Demos", in which he offered a preview of things that have become the staples of daily working life in the 21st century: e-mail, hypertext, word processing, video conferencing, and the mouse.

But this is speculation and there is no sign of it so far.Simon was a small electro-mechanical computer project developed by Edmund Berkeley and presented in a thirteen articles series issued in Radio-Electronics magazine from October 1950.

The LINC consisted of a large unit that could fit on a desk with keyboard input and a monitor screen constructed from an oscilloscope, although it required a second chassis about the size of a wardrobe that contained the CPU and memory.

In 1967, Italian engineer Federico Faggin joined SGS-Fairchild of Italy where he worked on Metal Oxide Semiconductor (MOS) integrated circuits which had higher switching speeds and lower power consumption than alternatives.

There he developed self-aligned silicon gate technology (from an original idea by Bell labs) which improved the reliability of MOS transistors and assisted with the commercial viability of the process.

The designs were sometimes available assembled but were less commonly finished products and ranged from purely circuit diagrams supplied on paper, through to provision of a PCB with or without a selection of parts, to partially completed boards with some components soldered.

Through kits, personal computers were now in theory easily available to the general public but in practice some considerable expertise was required to construct and use these products, which restricted uptake to only the enthusiast market.

It was only a matter of time before one personal computer design was able to hit a sweet spot in terms of pricing and performance, and that machine is generally considered to be the Altair 8800, from MITS, a small company that produced electronics kits for hobbyists.

The Altair contained no operating system or other software in ROM, so starting it up required a machine language program to be entered by hand via front-panel switches, one location at a time.

Allen developed an Altair emulator for a minicomputer and with the assistance of friend Monte Davidoff they were able to write a BASIC interpreter on punched tape, which had 25 commands and fit in 4 KB of memory.

The 2006 Sony PlayStation 3 was originally specifically intended to have the option of being converted into a general purpose personal computer using the OtherOS feature, although the capability was controversially removed in later models.

[48] Hardware hackers have routinely prided themselves in demonstrating that dedicated game consoles can be persuaded to run personal computer operating systems such as Linux in combination with general purpose software despite not being intended to do so.

Even the first IBM PC model, aimed at the relatively well financed business market, originally included a cassette interface out of concern that purchasers might be dissuaded by the price of a disk drive.

Its other strong features were its full stroke QWERTY keyboard with numeric keypad (lacking in the very first units but upgradeable), small size, well written Microsoft floating-point BASIC and inclusion of a 64-column monitor and tape deck—all for approximately half the cost of the Apple II.

[57] The Model I also suffered from problems with its cabling between its CPU and Expansion Interface (spontaneous reboots) and keyboard bounce (keystrokes would randomly repeat), and the earliest versions of TRSDOS similarly had technical troubles.

A long-standing industry myth persists that IBM were unable to negotiate a non-disclosure agreement with Dorothy McEwen, Digital Research co-founder and Kildall's wife, who handled much of the business side of the company and departed.

Kildall ultimately believed he had reached a deal but IBM returned to negotiate with Gates who offered to provide 86-DOS (originally known as QDOS), an operating system similar to CP/M developed by Tim Paterson of Seattle Computer Products.

[86] When Digital Research became aware of the similarities between PC-DOS and CP/M they raised a dispute with IBM, who offered to resolve the matter by shipping the PC without bundling an operating system.

Although the PC and XT included a version of the BASIC language in read-only memory, most were purchased with disk drives and run with an operating system, the most popular of which was the Microsoft supplied PC-DOS.

Discovering how this worked was not difficult, a full copy of the BIOS source code with comments and annotations was helpfully printed in the IBM Technical Reference Manual for the 5150, the only problem for clone makers was that it was copyrighted.

Microsoft was however left in a strong commercial position, being a supplier to most of the clones and would begin offering OEM versions of MS-DOS aimed at small-scale system builders as opposed to larger companies in 1986.

In addition IBM launched the PS/2 range of computers in 1987 with the proprietary Micro Channel bus in an attempt to recapture control of the market through charging licenses for a key component, but this was not successful.

It received only tepid support from 3rd parties and PC cloners largely stuck with ISA until the short-lived VESA Local Bus and then Peripheral Component Interconnect (PCI) was released in 1992.

The Commodore Amiga 1000 was launched as a desktop personal computer in 1985 at an event featuring the artist Andy Warhol and the singer Debbie Harry (known professionally as Blondie).

The now ubiquitous WIMP (Windows, Icons, Menus and Pointers) graphical user interface style was developed from research ideas (pioneered by Douglas Englebart) into a fully functional product by Xerox PARC in the early 1970s.

Towards the end of the 1980s, IBM PC XT clones started to encroach on the home computer market segment, previously the preserve of low cost manufacturers such as Atari, Inc. and Commodore.

With less competition than ever before, Dell rose to high profits and success, introducing low cost systems targeted at consumers and business markets using a direct-sales model.

[104][105] The iMac was notable for its transparent bondi blue casing in an ergonomic shape, as well as its discarding of legacy devices such as a floppy drive and serial ports in favor of Ethernet and USB connectivity.