From the dawn of time, human beings have always tried to find new ways to solve problems, be more productive, work with numbers faster, and have better ways of storing information. Possibly early humans used stones to count items, which lead to the abacus, then to the slide-rule, and then later calculators. These machines allowed human beings to do these things faster and better than they could do them in their minds.
Since the early ages of computer history there have been innovations that have led to the advancement of technology. The first computers were mechanical, and sometimes prone to errors. They were calculating machines. Blaise Pascal built a numerical wheel adding machine in 1642 in order to help out his father, who was a tax collector. It was a heavy burden to add numbers by hand, and Pascal had seen it as a chance to relieve that burden.
In 1673 Gothfried Willhelm von Leibniz, a German mathematician, built a calculator device that could add, subtract, multiply, and divide. It provided more functions than Pascal's machine and allowed users of it to solve more problems. Yet both Pascal's and Leibniz's machines were not totally dependable and suffered from flaws.
Joseph Jacquard, a French weaver, designed a punch card loom in 1805. A chain of punch cards in an certain order, provided instructions for the loom to control it. This allowed patterns in the weave as the machine weaved threads. The pattern could be changed by changing the cards used to different cards. This later lead to storing computer instructions on these cards.
Charles Xavier Thomas, another Frenchman, worked on a new mechanical computer. He called it the four-function machine and it was more reliable than Pascal's or Leibniz's machines. This was in 1820 as technology had progressed, and Thomas learned from Pascal's and Leibniz's works and flaws.
Charles Babbage and Ada Lovelace made contributions since 1842. The Difference Engine, the machine that became the template for the Analytic Engine, was an automatic logarithm tabulator and printer. It had a memory unit, automatic printout, sequential program control and punch-card input. The punch card idea was borrowed from Jacquard's loom.
Babbage had worked with computers for 20 years with the British government, and the government was threatening to withdraw funds because it had nothing to show for its investments. The project needed someone new to help out, and enter Ada Lovelace, daughter of Lord Byron and Lady Annabella Milbanke. Lovelace corrected some of Babbage's mistakes in the instructions and became the world's first debugger. It was a milestone for women in computer history. Lovelace suggested a binary system of numbers be used, which set the standard of future computers to use.
Sadly the Difference Engine did not function properly. The technology to create proper gears and shafts was not good enough to provide accuracy. Yet it helped pave the way for future computers. Later the IBM Corporation was able to build a working model of the Difference Engine using more modernized parts.
The first version of a programming language arose from work by Ada Lovelace, the benefactor and business partner of Charles Babbage. Unfortunately her work went mostly ignored since Babbage never built a completed Analytical Engine so there was no public deployment. She is remembered in the programming language still in use on military-grade projects, Ada.
Early work with analog and electromechanical computers did not involve programming languages the way we know them. Since early computers needed to be wired directly for each problem set, the process of setting plugs took the place of having a text-based distillation of an algorithm.
As electromechanical machinery gave way to mercury delay lines and drum memory, it became possible to write directly to addresses in memory and provide instructions without rewiring. This typically meant writing what we would call "machine code". This often gets called "hex" today, as modern 32-bit and 64-bit microprocessor systems read binary data in 8 or 16 hexadecimal chunks per clock cycle.
Writing code at the machine level is difficult: it requires that the programmer know the specific locations for registers in hardware and the instruction set for the processor. Reading machine code is often more difficult than writing it, thus tracking code changes is nearly impossible for a human.
The first upgrade to the machine code level of programming was assembly language. This provided a way to write machine code with string manipulators and names for instructions instead of the raw binary versions. It can still be difficult to read and still requires knowing which instructions and register locations exist, but it can be read on paper or screen and assembled into machine code cycle by cycle.
Assembly programming has not gone away. Most device drivers for computer peripherals are written in C code, but some real-time glitches are best resolved by hand optimizing the mid-step assembly output from the C compiler. This is becoming increasingly rare.
FORTRAN Stands for FORmula TRANslation. This language was invented at IBM in the mid-1950s for the IBM 704 series computer.
BASIC stands for Beginners All Purpose Symbolic Instruction Code
In computer programming, BASIC (an acronym for Beginner's All-purpose Symbolic Instruction Code[1]) refers to a family of high-level programming languages. It was originally designed in 1963, by John George Kemeny and Thomas Eugene Kurtz at Dartmouth College, to allow students not in science fields to use computers. At the time all computer use required writing custom software, which was something only scientists and mathematicians tended to do. It became widespread on home microcomputers in the 1980s, and remains popular to this day in a handful of heavily evolved dialects.
COBOL, an acronym that stands for COmmon Business Oriented Language, is a high-level programming language developed in the 1960s and still used in business applications. It is used extensively in the financial services industry for large scale mainframe based applications. It uses instructions resembling English statements and imposes an overall framework for a program. The design goal for COBOL was a language that self-documented so that it could be revised and maintained easily.
Programming Language 1 is a high-level programming language designed for scientific, engineering, and business applications. It is one of the most feature-rich programming languages and one of the very first in the highly-feature-rich category. It has been used by various academic, commercial and industrial users since it was introduced in the early 1960s, and is still actively used today. It supports recursion and structured programming. The language syntax is English-like and suited for describing complex data formats, with a wide set of functions available to verify and manipulate them.
When the PC was introduced, it needed an operating system. IBM approached a company named Digital Research, which was owned by Gary Kildall. IBM sought the use of Digital Research's CP/M, a popular operating system in earlier systems. (It was, in fact, the first operating system that wasn't hardware-specific.) IBM did not want to pay royalties, however, but sought a one time purchase, which included a rename. Digital Research refused, and IBM withdrew. They then approached Microsoft and Bill Gates, who purchased an existing operating system (Seattle Computer Company's 86-DOS) and renamed it MS-DOS. This name was later used on non-IBM models; Microsoft agreed to IBM's desire to use their own name, and the operating system was sold as PC-DOS on the PC.
86-DOS was modeled after CP/M, and Digital Research filed legal action for patent infringement. IBM settled by offering computer buyers a choice of either; however, CP/M-86 (as the PC version was named) cost almost $200 more than PC-DOS, and it did not sell well.
MS/PC-DOS quickly became the standard for the PC-compatible market. Digital Research would attempt to regain the market, eventually settling on an MS-DOS clone, DR-DOS. DR DOS was sold off the shelf (while MS/PC-DOS was only sold bundled with new computers), and would later gain a large market share with version 5, which had new memory management that broke down an early limitation of DOS, a maximum usable memory of 640 kB.
By this time, Microsoft was holding the market not only with MS-DOS, but Microsoft Windows, a graphical shell program for DOS. Windows was based on the Macintosh, and Apple filed suit. Complicating the matter was a suit against Apple by Xerox, claiming that Xerox was the rightful owner of the design. Eventually, it was ruled that the design factors in question could not be copyrighted, and Macintosh and Windows continued to coexist.
In 1995, Windows was re-worked to be a self contained operating system, Windows 95. By this time, DR-DOS had been sold twice, becoming Novell DOS 7, then Caldera DR-DOS 7. IBM had also split from Microsoft and was developing PC-DOS 6 separately. The new version of Windows that didn't coexist with DOS was ultimately the focus of an anti-trust lawsuit against Microsoft. Despite this, Microsoft was able to continue developing Windows.
Today, the market is dominated by the IBM PC-compatible computer, the majority of which run Microsoft Windows. Also present is an up-and-coming system, Linux, which is an open source system based on UNIX (an alternate PC-compatible system dating to the late 1970s; it was more complex and used for industrial, rather than home, use). On a separate platform, the Apple Macintosh also exists, running the newest Apple operating system, Mac OS X. Mac OS X is a combination of Mac OS 9 and the NextOS operating system that Steve Jobs second company Next Inc. created based on BSD Unix and the MACH kernel. Since it is based on Unix, Mac OS X is a much better operating system than previous Macintosh operating systems and helped save Apple from losing money as without it, it would not be able to compete against Linux, or modern Windows operating systems.
OS/2 was a joint project by IBM and Microsoft to create an Advanced DOS (ADOS was the code name, a replacement for MS-DOS that makes use of the 80286 and 80386 processors and breaks 8088/8086 limitations) OS/2 1.X was based on the MS-Windows GUI, but IBM and Microsoft broke off support of each other and IBM licensed the AmigaDOS/Workbench 1.3 code to create the Workplace GUI based on Workbench for OS/2 2.0 and stopped using the Windows 2.X shell and Commodore Amiga got the IBM REXX scripting language in exchange named AREXX (Amiga REXX) for AmigaDOS/Workbench 2.0 to have a scripting language. Microsoft took their OS/2 code and made Windows NT (codenamed MS-OS/2 3.0 but renamed Windows NT and NT stood for New technology) and Windows NT 3.1 Workstation and Server were invented by Microsoft. IBM improved OS/2 and named OS/2 3.0 as OS/2 Warp taking a Star Trek name and joked about "Arrive in Chicago earlier than expected" in that OS/2 Warp could do what Windows 95 code named Chicago could do but OS/2 Warp came out before Windows 95. Microsoft beat OS/2 Warp by using OEM agreements that each new PC would ship with Windows 95 and pay for a Windows 95 license even if the PC ran a different OS like OS/2 Warp, and shut IBM out of the PC market. IBM sold PS/2 and later VaulePoint and other systems like IBM Thinkpads with OS/2 Warp and then later OS/2 Merlin or OS/2 4.0. Eventually IBM gave up on OS/2 and migrated towards Linux, and licensed OS/2 to an OEM named Serenity Systems that made eComStation based on it, a more modern OS/2 based operating system. OS/2 was billed as "A better DOS than DOS, and a better Windows than Windows" because it ran MS-DOS programs in a Window, and used WIN-OS2 based on Windows 3.X to run 16 bit Windows programs. OS/2 also ran OS/2 command line and OS/2 GUI mode programs native as well. Some say OS/2's failure was that it ran DOS and Windows programs, so nobody wanted to make OS/2 native programs for it. Microsoft shut IBM out of the 32 bit Windows code and then OS/2 couldn't run Windows NT or Windows 95 software, until later when the ODIN project was based on the Linux WINE project to run some 32 bit Windows code. By that time it was too late and Microsoft Windows dominated OS/2.
The vacuum tube, also known as a valve because it controls electron flow the way a washer valve controls water direction, was originally developed to amplify radio signals. Its use as a logic gate, which practical, required massive power consumption and a steady supply of replacements.
Tubes were not meant to be turned on and off rapidly, thus they would burn out regularly on computers but can last decades on stereo and musical instrument amplifiers.
Vaccum tubes need a lot of electricity and also produce a lot of heat so they need plenty of ventilation or air conditioning.
Shockley, Bardeen and Brattain's invention of the junction transistor resolved the vacuum tube limitations and in the process started the shrinking of computers.
The transistor is a solid-state logic gate switch: it does not need to heat a filament nor make a change in physical contacts to cause a change in electron flow. Its centerpiece is a semiconductor, a solid material that can be a conductor or resistor depending on the adulteration of the substrate.
The original substrate for transistors was germanium. The move to silicon, one of the most readily available chemicals on Earth, made transistors cheap to manufacture and eventually made computers ubiquitous.
There are several types of transistors which combine to make full logic circuits.
Vaccum tubes were replaced by the transistors and a number of 1000 transistor were replaced by 1 microchip. Thus microchip were discovered.
The MITS Altair 8800 was designed around a new microprocessor, the Intel 8080, and debuted in 1975. Its announcement on the January 1975 issue of Popular Electronics magazine led the Albuquerque-based manufacturer to a four-month backlog attempting to fill orders.
The Altair is considered the first home computer. Its only input was a series of front-panel switches. However, it had a motherboard with a bus, which allowed other companies to provide keyboards, tape readers and other devices to access the registers.
A group of Harvard students wrote a BASIC interpreter for the MITS. These students -- Steve Ballmer, Paul Allen, and Bill Gates -- left school to focus on code development and not long afterward created MicroSoft.
The TRS-80 series computers were based on the Zilog Z80 processor and ran TRS-DOS on a monochrome monitor. It used floppy disks and then later hacks were made to use hard drives.
The TRS-COCO computer was developed as a home computer with color graphics and the TRS-80 series was marketed towards businesses. The COCO used a TV set as a monitor to save on costs and tried to compete against the Atari 400 and 800 and Commodore 64 series. The COCO used a 6809 Motorola processor and ran OS9 (no relation to Mac OS 9).
The Tandy 1000 series was based on the IBM PCJr graphics and sound chips, it used expansion slots but had the pins wired differently than PC and AT ISA expansion slots, and ran Deskmate as a GUI under Tandy DOS (Which was a modified MS-DOS that even reversed the DOS Interrupts to make sure it only ran on Tandy series computers.) Many MS-DOS video games were made with CGA, EGA, and Tandy graphics, and the Tandy version had advanced sound until the ISA sound cards like the AdLib and Sound Blaster got created. Eventually the IBM PS/2 series came out with VGA graphics and nobody wanted to buy the Tandy series PCs anymore. Once Windows 3.X became standard Radio Shack stopped selling the Tandy 1000 series, and then eventually dropped out of the PC business and sold PCs made by other companies like Dell or Compaq, and then eventually stopped selling computers.
The Apple II was produced by Apple Computer. It used a BASIC-type operating system and was marketed toward home use. The original Apple I computer was created by Steve Wozniak and Steve Jobs in a garage. Both were college drop-outs that wanted to make one of the first micro computers with a color screen for under $1000. Steve Wozniak carefully chose chips from a catalog to make sure he got the best price and quality and settled for a MOS 6502 processor, which was a Motorola 6500 clone with some of the pins changed to avoid copyright laws. The MOS 6502 processor was cheaper and helped make the Apple I and then later Apple II series cost effective. The original Apple I was $666, and sold enough units in custom wooden cases to not only pay back loans, but help fund the Apple II series. The Apple II series ran Apple DOS and then later Pro DOS and a version of BASIC. It had expansion slots for floppy drive controllers, modems, and other things like a Z80 CP/M card to run CPM-80 software. Steve Wozniak was in a plane crash and lost most of his memory and dropped out of Apple, and Apple tried to make an Apple III series but it was nothing like the Apple II and had series hardware issues like loose chips and Apple's fix was to drop it six feet from a chair to snap the chips back into place. After the Apple II, Apple II+, Apple IIe, the Apple IIc was developed to help Apple compete in the home market against the Commodore 64, Atari 800, and IBM PCjr. After the Macintosh and Amiga the Apple //GS was developed with a 65C816 16 bit CPU to run Apple II code and enhanced Apple IIGS code that was based on the Mac Finder GUI, and later the Macintosh II series replaced it and the Macintosh II NuBus slots had an Apple II emulator card to run Apple II software. Apple used to have the slogan "Apple II Forever" but eventually abandoned the Apple II series in favor of the Macintosh series.
Apple Computer followed the Apple II with the Apple Lisa, and after that, the Apple Macintosh. These computers were unique due to their graphical user interface (GUI), introducing the concept of icons, windows, pull down menus, and mice. (The GUI concept was actually taken from Xerox, via two of their computers, the Xerox Star and Xerox Alto). Apple was later sued by Xerox, but Xerox lost the lawsuit because the Macintosh GUI was different enough from the Xerox Star GUI to qualify as not the same GUI. The original Macintosh was $4000 and used the Motorola 68000 CPU and had 128K of RAM and a 400K 3.5" Floppy drive and a nine inch black and white monitor. It did not sell very well and Steve Jobs was fired from Apple and left and took key employees with him to found Next Inc. and base the Nextcube and NextOS on BSD Unix and the MACH kernel. Apple made the Macintosh II which had NuBus expansion slots and had color graphics like the Commodore Amiga and competed with the Commodore 2000 but had a 68020 32 bit CPU for faster speed. Eventually the Macintosh would be upgraded to the PowerPC processor via a joint effort by Apple, IBM, and Morotola to develop a processor to challenge the Intel 80386 and up processors. The new Macintosh series was called PowerMacs and continued on until Apple lost a lot of money due to Mac OS not being able to preemptive multi-task and have an error recovery system and ran sluggish. The PowerPC emulated the Motorola 68K series via software so the PowerMacs ran Classic Macintosh software. But Apple debated bringing Steve Jobs back to save the company, but also considered buying out Be Inc. the makers of BeOS and base future Macintosh systems on BeOS. Ultimately Apple decided to bring Steve Jobs back and buy out Next Inc. and merge Mac OS 9 and NextOS together to make Mac OSX. Steve Jobs got rid of nonprofitable products such as the Apple Newton and Apple printers and scanners and developed a new lower cost Mac named the iMac which was an all in one Macintosh inside a 15 inch monitor using translucent plastic colors and designs on the PowerPC G3 processor. Then Apple developed iTunes from Quicktime and developed the iPod to play music on it and later models played videos and movies. The iMac and the iPod were a success and Apple was able to turn itself around and start earning a profit again. The iMac series was updated to PowerPC G4 and G5 processors and became based on a LCD flat screen monitor and base. Mac OS X was finally finished and Apple made more profits from upgrades and ran Classic Mac software via the Carbon library and emulation. The the Mac Mini was made with a $599 price to migrate PC users to the Mac, and it didn't include a keyboard, mouse, or monitor, but could use PC ones. Eventually Apple moved to Intel processors as Motorola could not keep up with demand and made video game consoles have priority for PowerPC processors over Apple's Macintosh systems, and could not keep up with Intel's Ghz levels. The Intel Macs were made with Rosetta software to emulate PowerPC macs, and then later the Mac OSX binary format was invented that ran code on PowerPC or Intel Macs. The Apple made the iPhone based on the iPod to make a Touch Screen Cell Phone and then made the iPod Touch to have a Touch Screen like the iPhone but it can't make phone calls. Apple developed BootCamp to partition an Intel Mac hard drive to Boot and Install Microsoft Windows on it since Macs have Intel chips they are basically a PC Clone now. Thus Apple gave Mac users the option to boot Mac OSX or Windows.
The Commodore 64 was a revolution at the time it was released in 1981, expanding on the Vic 20's 8 colors to an amazing 16 colors and increasing the screen resolution to 40 columns and 25 lines. A 3 voice synthesizer topped off the features of this amazing computer.
In its time. the Commodore 64 was one of the most popular home computers in the market with thousands of games and business applications available. (I still have a copy of Microsoft Multiplan for the C64)
Its built-in BASIC and a plethora of magazines (ZZap64, Commodore, Compute's Gazette) with programs for readers to enter, enabled many people to learn BASIC and even Machine Code.
In 1986, the C64C was introduced, its changes (a lighter colored case and a different shape) were mainly cosmetic but still compatible with all previous add-ons and software.
Another version of the C64 was the SX-64. This was a "portable" version of the Commodore 64. I use the term portable very loosely, this thing was heavy. It contained a 5-inch color Cathode Ray Tube (CRT) monitor and a built-in disk drive. The keyboard doubled as the lid of the unit.
Commodore64 was a must for its time.
This computer offered:
The Amiga microcomputer, compared to other computers of its age, was much more advanced in the areas of graphical processing, display, and manipulation. The Amiga series used the 68000 series Motorola processor along with customized co-processors for audio, video, and I/O, and the series went as far as the 68040 processor before moving on to the IBM/Apple/Motorola PowerPC series for the Amiga One.
At the release of the original Amiga computer, the Amiga 1000, had the Amiga 1020 5.25" floppy drive that came with the PC-Transformer software that emulated an 8088 IBM Monochrome PC and ran MS-DOS at the speed of a 1.0 Mhz 8088, it was the only machine capable of displaying 12 bit color, using a format known as HAM-12, or Hold And Modify-12. This made it Amiga the only machine, for several years, to have as many as 4096 colors on screen at a time.
The machine was replaced by the Amiga 500, a slightly enhanced and stripped down version of the Amiga 1000, with some of the same capabilities, as well as some different expansion ports. After the Amiga 500, came the Amiga 2000, 3000, 600, 4000 and 1200 machines were released, each having minor enhancements over the previous. Currently, the Amiga corporation has handed off development of a new model, titled the Amiga One, to a separate company. This new machine would support speeds of up to 800 MHz, as opposed to the Amiga 4000, which had a top speed of 60 MHz, not counting the PPC enhancements which were released near the end of the Amiga 4000 life-cycle, which did not do well, due to lack of support from programming companies.
The Amiga 2000 and above supported PC BridgeCards, developed that contained most of a PC Clone with an 8088, 80286, 80386 processor on it to run MS-DOS and Windows 3.X. The Amiga could use the BridgeCard CPU as a co-processor when it didn't run MS-DOS. The AMax program emulated a Macintosh using a Macintosh Plus or under BIOS chip and used the Amiga resolution to get a better graphics mode than a Macintosh Plus. There also existed Commodore 64, Apple //, Atari 8 bit, and other emulators for the Amiga, and the Amiga was one of the first computers to offer emulators for almost any system. Now the Amiga Forever emulator runs Amiga software, and the open sourced UAE (Universal Amiga Emulator) and Fellows projects run Amiga software as well, with the difference that Amiga Forever comes with the Kickstart Disks and ROMs as well as Workbench boot disks as part of the license and the others require users to copy them from an Amiga or buy them from Amiga, Inc.
The Amiga series is still popular in parts of Europe and the old Motorola 68K series Amiga computers can have PowerPC upgrade boards to run the latest AmigaOS 4.0 and above operating systems. This is a link to the History of the Amiga via questions and answers in the early 1990's and the original Amiga patent in one PDF document at Scribd for those interested in history and patents.
Atari Inc. released it's first 8-bit computers, the 400 and 800 PCS's, in 1979. Jay Miner was integral in the development of the computer before leaving Atari to develop the 68000 based Lorianne under Amiga in the early 80's. Featuring custom graphics (CTIA/GTIA and Antic) and sound (POKEY) chips, and a custom expansion port (the SIO intelligent "plug and play" port), the systems are centered around the 6502 CPU. The 400 was intended to fill the low end gaming computer market and game with a membrane keyboard and 16K ram, while the 800 was intended to be the more serious computer with a full typewriter keyboard and 48k. In 1982 Atari released the 1200XL which changed the styling of the case, increased ram to 64k, and added function keys. Software compatibility issues caused it to only be on the market for a year before being replaced by the 600xl and 800xl computers. Similar in looks to the 1200XL, the 600XL (16K) and 800XL (64K), they included an expansion port in addition to the SIO standard, the Parallel Bus Interface (PBI).
In 1983-1984, Atari's video game section of it's Consumer Division suffered massive losses that effected the entire company and prompted Atari owner Warner Communications to try and sell the company. Jack Tramiel the founder of Commodore, left Commodore in early '84 and then went on to buy out Atari Consumer to form Atari Corporation in July of 1984. Jack released several 8-bit computers under Atari Corporation, upgrading the model line to the XE series in 1985. The 65XE (64K) and 130XE (128K) took on a new case style, and replaced the PBI with a semi-compatible bus called the Enhanced Cartridge Interface (ECI).
In 1987 Jack took the 65XE, restyled the case and moved to a detached keyboard, releasing it as the XE Game System (XEGS). When the keyboard was not plugged it, it functioned as a game console including Missile Command in it's ROM. When the keyboard was plugged in it functions as a full 65XE computer, with full peripheral support through it's included SIO ports.
After leaving Commodore in January of 1984, by the Spring of 1984 Jack had decided to return to the computer business and formed Tramel Technology Ltd. (TTL). Key engineering and management began to leave Commodore to join Jack, and in early May of 1984 former Commodore 64 engineer Shiraz Shivji lead a team to build Jack's next generation computer - code named Rock Bottom Price (RBP). Initially based around the National Semiconductor NS32032, the design soon moved to a 68000 based system. A wire wrap of RBP was completed by late August and in September began working with Digital Research Incorporated (DRI) on porting it's GEM GUI and newly developed GEMDOS to run as part of the TOS (The Operating System). ST also stood for SixTeen because the 68000 that powered it had a 16 bit I/O bus. The first ST series model, the 520ST, was released in 1985, to be followed by the 1040ST the following year. Later the Atari TT used the 68020 and 68030 processors that were Thirty Two bits. The Atari Falcon was developed and released in 1992 to provide a 32 bit multimedia system and included a DSP audio chip, enhanced graphics modes, and a multi-tasking operating system. Like the Amiga, the Atari ST and above suffered lack of third party software support and lack of proper marketing. When the IBM PC Clones used 80386 processors and above and ran Microsoft Windows 3.X and used VGA or SVGA and the Sound Blaster or similar sound card, they were cheaper than the Amiga or Atari series computers and drove both companies into almost bankruptcy. Atari was resold many times, and now is a Video Game company for modern game consoles and Windows and Macintosh computers. A version of the Atari ST software is available via the MiNT project for the Atari St series hardware, an Ubuntu port of MiNT is being done to run Atari ST software under Ubuntu. When Windows 95 and above became standard many Atari ST users migrated to PC Clones and Windows, while others went to the Macintosh. The Atari ST had a Macintosh emulator called Magic Sack that used an old Macintosh Plus and under BIOS chip to emulate a Macintosh Plus or under system.
The IBM PC was a personal computer built around the Intel 8088 microprocessor (which was modeled after the Intel 8086). It became standardized, and today, the majority of personal computers are IBM compatible. IBM started out with the IBM DisplayWrite word processor, and then later made the IBM 5150 aka IBM PC based on the Intel 8088 processor. IBM had Microsoft write IBM Personal Computer DOS 1.0, and reserved DRI's CP/M-86 and Microsoft Xenix as standby operating systems. But DOS was the more popular operating system. IBM made the IBM PC/XT which was like the IBM PC but had more expansion slots, and then the IBM PC/AT based on the Intel 80286 16 bit processor (Skipping the Intel 80186) and 16 Bit ISA bus. Originally IBM had two displays MGA (Monochrome) 80X25 text graphics, and CGA (Color Graphic Adapter) with 80X25 text mode and 16 colors, 320x200 in 4 out of 16 colors and 640x200 in 2 colors. To compete with Atari and Commodore IBM made the IBM PCJr for home use, but it flopped despite having a wireless infrared keyboard and cartridge slot to make loading software easier. Each expansion took place on a sidebus and the more sidebus adapters added to it the larger it got. The PCJr had better graphics and a sound chip and the original PC series only had a PC speaker with limited sounds, so PCJr video games were better, but IBM sold the PCJr graphics and sound to Tandy for their Tandy 1000 series. IBM invented EGA graphics which used 16 colors in 320x200 mode and 4 colors in 640x200 mode. Eventually IBM moved on to the PS/2 series and OS/2, Personal Series 2 computers (A PS/1 was made with IBM PC specs but a better graphics card aka VGA) and PS/2 series had VGA graphics 256 colors out of 16 million and up to 640x480 graphics. Most of the PS/2 series had MCA slots or Microchannel slots that were not ISA compatible like the original IBM PC (and PS/1) and IBM considered it their "Clone Killer" while PC Clone makers tried to push EISA also a 32 bit expansion bus but backward compatible with 16 bit ISA. Ultimately either one caught on and Intel's PCI bus replaced ISA and Intel's VESA Local Bus briefly caught on that extended ISA with another slot in front of it for 32 bits, but ultimately PCI and later PCI Express beat all. Briefly video cards had an AGP video standard, but PCI Express beat it later on. IBM made the ValuePoint series using ISA slots, and the Thinkpad as a laptop, but eventually offshored work to Lenovo for making their PC systems to save on costs.
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