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124-466: Apple II ("apple two ") is a series of microcomputers manufactured by Apple Computer, Inc. from 1977 to 1993. The first Apple II model , that gave the series its name, was designed by Steve Wozniak , and was first sold on June 10, 1977. Its success led to it being followed by the Apple II Plus , Apple IIe , Apple IIc , and Apple IIc Plus , with the 1983 IIe being the most popular. The name

248-428: A system call to perform a block I/O write operation, then the system call might execute the following instructions: While the writing takes place, the operating system will context switch to other processes as normal. When the device finishes writing, the device will interrupt the currently running process by asserting an interrupt request . The device will also place an integer onto the data bus. Upon accepting

372-756: A 16-bit processor, the Apple II GS , was added in 1986. It remained compatible with earlier Apple II models, but the II GS has more in common with mid-1980s systems like the Atari ST , Amiga , and Acorn Archimedes . Despite the introduction of the Motorola 68000 -based Macintosh in 1984, the Apple II series still reportedly accounted for 85% of the company's hardware sales in the first quarter of fiscal 1985. Apple continued to sell Apple II systems alongside

496-554: A DOS, and with Wozniak inexperienced in operating system design, Jobs approached Shepardson Microsystems with the project. On April 10, 1978, Apple signed a contract for $ 13,000 with Shepardson to develop the DOS. Even after disk drives made the cassette tape interfaces obsolete they were still used by enthusiasts as simple one-bit audio input-output ports. Ham radio operators used the cassette input to receive slow scan TV (single frame images). A commercial speech recognition Blackjack program

620-574: A breakout cable which connected to the back of the card, the user could attach up to two UniDisk or Apple 5.25 Drives , up to one UniDisk 3.5 drive , and a DE-9 Apple II joystick. Many of the LC's built-in Macintosh peripherals could also be "borrowed" by the card when in Apple II mode, including extra RAM, the Mac's internal 3.5-inch floppy drives, AppleTalk networking, any ProDOS-formatted hard disk partitions,

744-501: A built-in BASIC programming language. The motherboard holds eight expansion slots and an array of random access memory (RAM) sockets that can hold up to 48  kilobytes . Over the course of the Apple II series' life, an enormous amount of first- and third-party hardware was made available to extend the capabilities of the machine. The IIc was designed as a compact, portable unit, not intended to be disassembled, and cannot use most of

868-563: A built-in disk controller that could control external drives, composite video (NTSC or PAL), serial interfaces for modem and printer, and a port usable by either a joystick or mouse. Unlike previous Apple II models, the IIc had no internal expansion slots at all. Two different monochrome LC displays were sold for use with the IIc's video expansion port, although both were short-lived due to high cost and poor legibility. The IIc had an external power supply that converted AC power to 15 V DC, though

992-446: A built-in music synthesizer that far exceeded any other home computer. The Apple II GS evolved the platform while still maintaining near-complete backward compatibility. Its Mega II chip contains the functional equivalent of an entire Apple IIe computer (sans processor). This, combined with the 65816's ability to execute 65C02 code directly, provides full support for legacy software, while also supporting 16-bit software running under

1116-595: A computer based on a microprocessor – the Intel 8008 8-bit microprocessor. This Micral-N was marketed in early 1973 as a "Micro-ordinateur" or microcomputer , mainly for scientific and process-control applications. About a hundred Micral-N were installed in the next two years, followed by a new version based on the Intel 8080. Meanwhile, another French team developed the Alvan, a small computer for office automation which found clients in banks and other sectors. The first version

1240-645: A computer even if they are not compatible with the base operating system. A library operating system (libOS) is one in which the services that a typical operating system provides, such as networking, are provided in the form of libraries and composed with a single application and configuration code to construct a unikernel : a specialized (only the absolute necessary pieces of code are extracted from libraries and bound together ), single address space , machine image that can be deployed to cloud or embedded environments. The operating system code and application code are not executed in separated protection domains (there

1364-463: A computer had to be big in size to be powerful, and thus decided to market them as calculators. Additionally, at that time, people were more likely to buy calculators than computers, and, purchasing agents also preferred the term "calculator" because purchasing a "computer" required additional layers of purchasing authority approvals. The Datapoint 2200 , made by CTC in 1970, was also comparable to microcomputers. While it contains no microprocessor,

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1488-585: A development of MULTICS for a single user. Because UNIX's source code was available, it became the basis of other, incompatible operating systems, of which the most successful were AT&T 's System V and the University of California 's Berkeley Software Distribution (BSD). To increase compatibility, the IEEE released the POSIX standard for operating system application programming interfaces (APIs), which

1612-422: A disk operating system included in a series of programmable read-only memory chips (PROMs); 8 Kilobytes of RAM; IBM's Basic Assembly Language (BAL); a hard drive; a color display; a printer output; a 150 bit/s serial interface for connecting to a mainframe; and even the world's first microcomputer front panel. In early 1973, Sord Computer Corporation (now Toshiba Personal Computer System Corporation ) completed

1736-484: A large legal settlement was paid. In the twenty-first century, Windows continues to be popular on personal computers but has less market share of servers. UNIX operating systems, especially Linux, are the most popular on enterprise systems and servers but are also used on mobile devices and many other computer systems. On mobile devices, Symbian OS was dominant at first, being usurped by BlackBerry OS (introduced 2002) and iOS for iPhones (from 2007). Later on,

1860-442: A library with no protection between applications, such as eCos . A hypervisor is an operating system that runs a virtual machine . The virtual machine is unaware that it is an application and operates as if it had its own hardware. Virtual machines can be paused, saved, and resumed, making them useful for operating systems research, development, and debugging. They also enhance portability by enabling applications to be run on

1984-447: A malformed machine instruction . However, the most common error conditions are division by zero and accessing an invalid memory address . Users can send messages to the kernel to modify the behavior of a currently running process. For example, in the command-line environment , pressing the interrupt character (usually Control-C ) might terminate the currently running process. To generate software interrupts for x86 CPUs,

2108-419: A minicomputer or time-sharing service the opportunity to automate business functions, without (usually) hiring a full-time staff to operate the computers. A representative system of this era would have used an S100 bus , an 8-bit processor such as an Intel 8080 or Zilog Z80 , and either CP/M or MP/M operating system. The increasing availability and power of desktop computers for personal use attracted

2232-530: A multitude of programs developed under the CP/M operating system, including the dBase II database and the WordStar word processor. There was also a third-party 6809 card that would allow OS-9 Level One to be run. Third-party sound cards greatly improved audio capabilities, allowing simple music synthesis and text-to-speech functions. Eventually, Apple II accelerator cards were created to double or quadruple

2356-790: A new OS. The OS eventually included a Macintosh-like graphical Finder for managing disks and files and opening documents and applications, along with desk accessories . Later, the II GS gained the ability to read and write Macintosh disks and, through third-party software, a multitasking Unix-like shell and TrueType font support. The GS includes a 32-voice Ensoniq 5503 DOC sample-based sound synthesizer chip with 64 KB dedicated RAM, 256 KB (or later 1.125 MB) of standard RAM, built-in peripheral ports (switchable between IIe-style card slots and IIc-style onboard controllers for disk drives, mouse, RGB video, and serial devices) and, built-in AppleTalk networking. The final Apple II model

2480-455: A particular application's memory is stored, or even whether or not it has been allocated yet. In modern operating systems, memory which is accessed less frequently can be temporarily stored on a disk or other media to make that space available for use by other programs. This is called swapping , as an area of memory can be used by multiple programs, and what that memory area contains can be swapped or exchanged on demand. Virtual memory provides

2604-503: A program does not interfere with memory already in use by another program. Since programs time share, each program must have independent access to memory. Cooperative memory management, used by many early operating systems, assumes that all programs make voluntary use of the kernel 's memory manager, and do not exceed their allocated memory. This system of memory management is almost never seen any more, since programs often contain bugs which can cause them to exceed their allocated memory. If

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2728-408: A program fails, it may cause memory used by one or more other programs to be affected or overwritten. Malicious programs or viruses may purposefully alter another program's memory, or may affect the operation of the operating system itself. With cooperative memory management, it takes only one misbehaved program to crash the system. Memory protection enables the kernel to limit a process' access to

2852-440: A program tries to access memory that is not accessible memory, but nonetheless has been allocated to it, the kernel is interrupted (see § Memory management ) . This kind of interrupt is typically a page fault . When the kernel detects a page fault it generally adjusts the virtual memory range of the program which triggered it, granting it access to the memory requested. This gives the kernel discretionary power over where

2976-470: A significant amount of CPU time. Direct memory access (DMA) is an architecture feature to allow devices to bypass the CPU and access main memory directly. (Separate from the architecture, a device may perform direct memory access to and from main memory either directly or via a bus.) When a computer user types a key on the keyboard, typically the character appears immediately on the screen. Likewise, when

3100-684: A solid state machine designed with a microprocessor. In the US the earliest models such as the Altair 8800 were often sold as kits to be assembled by the user, and came with as little as 256 bytes of RAM , and no input/output devices other than indicator lights and switches, useful as a proof of concept to demonstrate what such a simple device could do. As microprocessors and semiconductor memory became less expensive, microcomputers grew cheaper and easier to use. All these improvements in cost and usability resulted in an explosion in their popularity during

3224-402: A specific moment in time. Hard real-time systems require exact timing and are common in manufacturing , avionics , military, and other similar uses. With soft real-time systems, the occasional missed event is acceptable; this category often includes audio or multimedia systems, as well as smartphones. In order for hard real-time systems be sufficiently exact in their timing, often they are just

3348-557: A time, although they can often be modified with software or hardware to concurrently serve more than one user. Microcomputers fit well on or under desks or tables, so that they are within easy access of users. Bigger computers like minicomputers , mainframes , and supercomputers take up large cabinets or even dedicated rooms. A microcomputer comes equipped with at least one type of data storage, usually RAM . Although some microcomputers (particularly early 8-bit home micros) perform tasks using RAM alone, some form of secondary storage

3472-508: A time, by turning them over and notching a hole for the write protect sensor. The first disk operating systems for the Apple II were DOS 3.1 and DOS 3.2, which stored 113.75 KB on each disk, organized into 35 tracks of 13 256-byte sectors each. After about two years, DOS 3.3 was introduced, storing 140 KB thanks to a minor firmware change on the disk controller that allowed it to store 16 sectors per track. (This upgrade

3596-417: A user moves a mouse , the cursor immediately moves across the screen. Each keystroke and mouse movement generates an interrupt called Interrupt-driven I/O . An interrupt-driven I/O occurs when a process causes an interrupt for every character or word transmitted. Devices such as hard disk drives , solid-state drives , and magnetic tape drives can transfer data at a rate high enough that interrupting

3720-453: A variation of the classic reader/writer problem . The writer receives a pipe from the shell for its output to be sent to the reader's input stream. The command-line syntax is alpha | bravo . alpha will write to the pipe when its computation is ready and then sleep in the wait queue. bravo will then be moved to the ready queue and soon will read from its input stream. The kernel will generate software interrupts to coordinate

3844-418: Is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers . In the personal computer market, as of September 2024 , Microsoft Windows holds a dominant market share of around 73%. macOS by Apple Inc. is in second place (15%), Linux is in third place (5%), and ChromeOS

Apple II - Misplaced Pages Continue

3968-562: Is remote direct memory access , which enables each CPU to access memory belonging to other CPUs. Multicomputer operating systems often support remote procedure calls where a CPU can call a procedure on another CPU, or distributed shared memory , in which the operating system uses virtualization to generate shared memory that does not physically exist. A distributed system is a group of distinct, networked computers—each of which might have their own operating system and file system. Unlike multicomputers, they may be dispersed anywhere in

4092-484: Is a change away from the currently running process. Similarly, both hardware and software interrupts execute an interrupt service routine . Software interrupts may be normally occurring events. It is expected that a time slice will occur, so the kernel will have to perform a context switch . A computer program may set a timer to go off after a few seconds in case too much data causes an algorithm to take too long. Software interrupts may be error conditions, such as

4216-422: Is difficult to define, but has been called "the layer of software that manages a computer's resources for its users and their applications ". Operating systems include the software that is always running, called a kernel —but can include other software as well. The two other types of programs that can run on a computer are system programs —which are associated with the operating system, but may not be part of

4340-896: Is in fourth place (2%). In the mobile sector (including smartphones and tablets ), as of September 2023 , Android's share is 68.92%, followed by Apple's iOS and iPadOS with 30.42%, and other operating systems with .66%. Linux distributions are dominant in the server and supercomputing sectors. Other specialized classes of operating systems (special-purpose operating systems), such as embedded and real-time systems, exist for many applications. Security-focused operating systems also exist. Some operating systems have low system requirements (e.g. light-weight Linux distribution ). Others may have higher system requirements. Some operating systems require installation or may come pre-installed with purchased computers ( OEM -installation), whereas others may run directly from media (i.e. live CD ) or flash memory (i.e. USB stick). An operating system

4464-806: Is normally desirable. In the early days of home micros, this was often a data cassette deck (in many cases as an external unit). Later, secondary storage (particularly in the form of floppy disk and hard disk drives) were built into the microcomputer case. Although they did not contain any microprocessors, but were built around transistor-transistor logic (TTL), Hewlett-Packard calculators as far back as 1968 had various levels of programmability comparable to microcomputers. The HP 9100B (1968) had rudimentary conditional (if) statements, statement line numbers, jump statements ( go to ), registers that could be used as variables, and primitive subroutines. The programming language resembled assembly language in many ways. Later models incrementally added more features, including

4588-443: Is only a single application running, at least conceptually, so there is no need to prevent interference between applications) and OS services are accessed via simple library calls (potentially inlining them based on compiler thresholds), without the usual overhead of context switches , in a way similarly to embedded and real-time OSes. Note that this overhead is not negligible: to the direct cost of mode switching it's necessary to add

4712-534: Is sometimes called the first generation of microcomputers. Many companies such as DEC , National Semiconductor , Texas Instruments offered their microcomputers for use in terminal control, peripheral device interface control and industrial machine control. There were also machines for engineering development and hobbyist personal use. In 1975, the Processor Technology SOL-20 was designed, which consisted of one board which included all

4836-499: Is supported by most UNIX systems. MINIX was a stripped-down version of UNIX, developed in 1987 for educational uses, that inspired the commercially available, free software Linux . Since 2008, MINIX is used in controllers of most Intel microchips , while Linux is widespread in data centers and Android smartphones. The invention of large scale integration enabled the production of personal computers (initially called microcomputers ) from around 1980. For around five years,

4960-473: Is that they do not load user-installed software. Consequently, they do not need protection between different applications, enabling simpler designs. Very small operating systems might run in less than 10 kilobytes , and the smallest are for smart cards . Examples include Embedded Linux , QNX , VxWorks , and the extra-small systems RIOT and TinyOS . A real-time operating system is an operating system that guarantees to process events or data by or at

5084-435: Is the part of the operating system that provides protection between different applications and users. This protection is key to improving reliability by keeping errors isolated to one program, as well as security by limiting the power of malicious software and protecting private data, and ensuring that one program cannot monopolize the computer's resources. Most operating systems have two modes of operation: in user mode ,

Apple II - Misplaced Pages Continue

5208-606: Is trademarked with square brackets as Apple ][ , then, beginning with the IIe, as Apple // . The Apple II was a major advancement over its predecessor, the Apple I , in terms of ease of use, features, and expandability. It became one of several recognizable and successful computers during the 1980s and early 1990s, although this was mainly limited to the US. It was aggressively marketed through volume discounts and manufacturing arrangements to educational institutions, which made it

5332-559: The Apple II J-Plus (Japan). In these models, Apple made the necessary hardware, software and firmware changes in order to comply to standards outside of the US. The Apple II Plus was followed in 1983 by the Apple IIe, a cost-reduced yet more powerful machine that used newer chips to reduce the component count and add new features, such as the display of upper and lowercase letters and a standard 64 KB of RAM. The IIe RAM

5456-399: The BASIC programming language (HP 9830A in 1971). Some models had tape storage and small printers. However, displays were limited to one line at a time. The HP 9100A was referred to as a personal computer in an advertisement in a 1968 Science magazine, but that advertisement was quickly dropped. HP was reluctant to sell them as "computers" because the perception at that time was that

5580-492: The CP/M (Control Program for Microcomputers) was the most popular operating system for microcomputers. Later, IBM bought the DOS (Disk Operating System) from Microsoft . After modifications requested by IBM, the resulting system was called MS-DOS (MicroSoft Disk Operating System) and was widely used on IBM microcomputers. Later versions increased their sophistication, in part by borrowing features from UNIX. Apple 's Macintosh

5704-504: The INT assembly language instruction is available. The syntax is INT X , where X is the offset number (in hexadecimal format) to the interrupt vector table . To generate software interrupts in Unix-like operating systems, the kill(pid,signum) system call will send a signal to another process. pid is the process identifier of the receiving process. signum is

5828-566: The instruction set of its custom TTL processor was the basis of the instruction set for the Intel 8008 , and for practical purposes the system behaves approximately as if it contains an 8008. This is because Intel was the contractor in charge of developing the Datapoint's CPU, but ultimately CTC rejected the 8008 design because it needed 20 support chips. Another early system, the Kenbak-1 ,

5952-420: The transistor in the mid-1950s, mainframes began to be built. These still needed professional operators who manually do what a modern operating system would do, such as scheduling programs to run, but mainframes still had rudimentary operating systems such as Fortran Monitor System (FMS) and IBSYS . In the 1960s, IBM introduced the first series of intercompatible computers ( System/360 ). All of them ran

6076-549: The Altair itself was only a mild commercial success, it helped spark a huge industry. By 1977, the introduction of the second microcomputer generation as consumer goods , known as home computers , made them considerably easier to use than their predecessors because their predecessors' operation often demanded thorough familiarity with practical electronics. The ability to connect to a monitor (screen) or TV set allowed visual manipulation of text and numbers. The BASIC language, which

6200-541: The Apple II could boot into the CP/M operating system and run WordStar , dBase II , and other CP/M software. With the release of MousePaint in 1984 and the Apple II GS in 1986, the platform took on the look of the Macintosh user interface, including a mouse. Much commercial Apple II software shipped on self-booting disks and does not use standard DOS disk formats. This discouraged the copying or modifying of

6324-686: The Apple II series looked similar, featuring much clean white space and showing the Apple rainbow logo prominently. For several years up until the late 1980s, Apple used the Motter Tektura font for packaging, until changing to the Apple Garamond font. Apple ran the first advertisement for the Apple II, a two-page spread ad titled "Introducing Apple II", in BYTE in July 1977. The first brochure,

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6448-639: The Apple logo on the casing was represented using rainbow stripes, which remained a part of Apple's corporate logo until early 1998. The earliest Apple IIs were assembled in Silicon Valley , and later in Texas; printed circuit boards were manufactured in Ireland and Singapore . An external 5 + 1 ⁄ 4 -inch floppy disk drive, the Disk II , attached via a controller card that plugged into one of

6572-410: The CPU for every byte or word transferred, and having the CPU transfer the byte or word between the device and memory, would require too much CPU time. Data is, instead, transferred between the device and memory independently of the CPU by hardware such as a channel or a direct memory access controller; an interrupt is delivered only when all the data is transferred. If a computer program executes

6696-474: The CPU to re-enter supervisor mode , placing the kernel in charge. This is called a segmentation violation or Seg-V for short, and since it is both difficult to assign a meaningful result to such an operation, and because it is usually a sign of a misbehaving program, the kernel generally resorts to terminating the offending program, and reports the error. Windows versions 3.1 through ME had some level of memory protection, but programs could easily circumvent

6820-524: The Disk II became available in 1978, tape-based Apple II software essentially disappeared from the market. The initial price of the Disk II drive and controller was US$ 595, although a $ 100 off coupon was available through the Apple newsletter "Contact". The controller could handle two drives and a second drive (without controller) retailed for $ 495. The Disk II single-sided floppy drive used 5.25-inch floppy disks ; double-sided disks could be used, one side at

6944-623: The IBM PC itself was widely imitated, as well as the term. The component parts were commonly available to producers and the BIOS was reverse engineered through cleanroom design techniques. IBM PC compatible "clones" became commonplace, and the terms "personal computer", and especially "PC", stuck with the general public, often specifically for a computer compatible with DOS (or nowadays Windows). Monitors, keyboards and other devices for input and output may be integrated or separate. Computer memory in

7068-657: The IIc itself will accept between 12 V and 17 V DC, allowing third parties to offer battery packs and automobile power adapters that connected in place of the supplied AC adapter. The Apple II GS , released on September 15, 1986, is the penultimate and most advanced model in the Apple II series, and a radical departure from prior models. It uses a 16-bit microprocessor, the 65C816 operating at 2.8 MHz with 24-bit addressing, allowing expansion up to 8 MB of RAM. The graphics are significantly improved, with 4096 colors and new modes with resolutions of 320×200 and 640×400. The audio capabilities are vastly improved, with

7192-606: The Macintosh until terminating the II GS in December 1992 and the IIe in November 1993. The last II-series Apple in production, the IIe card for Macintoshes , was discontinued on October 15, 1993; having been one of the longest running mass-produced home computer series, the total Apple II sales of all of its models during its 16-year production run were about 6 million units (including about 1.25 million Apple II GS models) with

7316-710: The Platinum IIe and II GS . Unlike the IIe IIc and II GS , the IIc Plus came only in one version (American) and was not officially sold anywhere outside the US. The Apple IIc Plus ceased production in 1990, with its two-year production run being the shortest of all the Apple II computers. Although not an extension of the Apple II line, in 1990 the Apple IIe Card, an expansion card for the Macintosh LC ,

7440-702: The SMP80/08, which used the Intel 8008 microprocessor. The SMP80/08, however, did not have a commercial release. After the first general-purpose microprocessor, the Intel 8080 , was announced in April 1974, Sord announced the SMP80/x, the first microcomputer to use the 8080, in May 1974. Virtually all early microcomputers were essentially boxes with lights and switches; one had to read and understand binary numbers and machine language to program and use them (the Datapoint 2200

7564-538: The application program, which then interacts with the user and with hardware devices. However, in some systems an application can request that the operating system execute another application within the same process, either as a subroutine or in a separate thread, e.g., the LINK and ATTACH facilities of OS/360 and successors . An interrupt (also known as an abort , exception , fault , signal , or trap ) provides an efficient way for most operating systems to react to

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7688-439: The attention of more software developers. As the industry matured, the market for personal computers standardized around IBM PC compatibles running DOS , and later Windows . Modern desktop computers, video game consoles , laptops , tablet PCs , and many types of handheld devices , including mobile phones , pocket calculators , and industrial embedded systems , may all be considered examples of microcomputers according to

7812-566: The computer's expansion slots (usually slot 6), was used for data storage and retrieval to replace cassettes. The Disk II interface, created by Steve Wozniak , was regarded as an engineering masterpiece for its economy of electronic components. Rather than having a dedicated sound-synthesis chip, the Apple II had a toggle circuit that could only emit a click through a built-in speaker; all other sounds (including two, three and, eventually, four-voice music and playback of audio samples and speech synthesis) were generated entirely by software that clicked

7936-453: The computer's memory. Various methods of memory protection exist, including memory segmentation and paging . All methods require some level of hardware support (such as the 80286 MMU), which does not exist in all computers. In both segmentation and paging, certain protected mode registers specify to the CPU what memory address it should allow a running program to access. Attempts to access other addresses trigger an interrupt, which causes

8060-711: The computer's speed. Rod Holt designed the Apple II's power supply. He employed a switched-mode power supply design, which was far smaller and generated less unwanted heat than the linear power supply some other home computers used. The original Apple II was discontinued at the start of 1981, superseded by the Apple II+ . The Apple II Plus, introduced in June 1979, included the Applesoft BASIC programming language in ROM. This Microsoft -authored dialect of BASIC, which

8184-465: The definition given above. By the early 2000s, everyday use of the expression "microcomputer" (and in particular "micro") declined significantly from its peak in the mid-1980s. The term is most commonly associated with the most popular 8-bit home computers (such as the Apple II , ZX Spectrum , Commodore 64 , BBC Micro , and TRS-80 ) and small-business CP/M -based microcomputers. In colloquial usage, "microcomputer" has been largely supplanted by

8308-471: The details of how interrupt service routines behave vary from operating system to operating system. However, several interrupt functions are common. The architecture and operating system must: A software interrupt is a message to a process that an event has occurred. This contrasts with a hardware interrupt — which is a message to the central processing unit (CPU) that an event has occurred. Software interrupts are similar to hardware interrupts — there

8432-504: The end of the rail – and read and execute code from sector 0. The code contained in there would then pull in the rest of the operating system. DOS stored the disk's directory on track 17, smack in the middle of the 35-track disks, in order to reduce the average seek time to the frequently used directory track. The directory was fixed in size and could hold a maximum of 105 files. Subdirectories were not supported. Most game publishers did not include DOS on their floppy disks, since they needed

8556-422: The environment. Interrupts cause the central processing unit (CPU) to have a control flow change away from the currently running program to an interrupt handler , also known as an interrupt service routine (ISR). An interrupt service routine may cause the central processing unit (CPU) to have a context switch . The details of how a computer processes an interrupt vary from architecture to architecture, and

8680-419: The expansion hardware sold for the other machines in the series. The original Apple II has the operating system in ROM along with a BASIC variant called Integer BASIC . Apple eventually released Applesoft BASIC , a more advanced variant of the language which users can run instead of Integer BASIC. The Apple II series eventually supported over 1,500 software programs. When the Disk II floppy disk drive

8804-623: The features of the later model Apple IIc ) and the Apple IIe Platinum (a modernized case color to match other Apple products of the era, along with the addition of a numeric keypad ). Some of the feature of the IIe were carried over from the less successful Apple III , among them the ProDOS operating system. The Apple IIc was released in April 1984, billed as a portable Apple II because it could be easily carried due to its size and carrying handle, which could be flipped down to prop

8928-636: The first computer in widespread use in American secondary schools, displacing the early leader Commodore PET . The effort to develop educational and business software for the Apple II, including the 1979 release of the popular VisiCalc spreadsheet , made the computer especially popular with business users and families. The Apple II computers are based on the 6502 8-bit processor and can display text and two resolutions of color graphics. A software-controlled speaker provides one channel of low-fidelity audio. A model with more advanced graphics and sound and

9052-452: The form of RAM , and at least one other less volatile, memory storage device are usually combined with the CPU on a system bus in one unit. Other devices that make up a complete microcomputer system include batteries, a power supply unit, a keyboard and various input/output devices used to convey information to and from a human operator ( printers , monitors , human interface devices ). Microcomputers are designed to serve only one user at

9176-410: The hardware checks that the software is only executing legal instructions, whereas the kernel has unrestricted powers and is not subject to these checks. The kernel also manages memory for other processes and controls access to input/output devices. The operating system provides an interface between an application program and the computer hardware, so that an application program can interact with

9300-493: The hardware only by obeying rules and procedures programmed into the operating system. The operating system is also a set of services which simplify development and execution of application programs. Executing an application program typically involves the creation of a process by the operating system kernel , which assigns memory space and other resources, establishes a priority for the process in multi-tasking systems, loads program binary code into memory, and initiates execution of

9424-418: The indirect pollution of important processor structures (like CPU caches , the instruction pipeline , and so on) which affects both user-mode and kernel-mode performance. The first computers in the late 1940s and 1950s were directly programmed either with plugboards or with machine code inputted on media such as punch cards , without programming languages or operating systems. After the introduction of

9548-404: The interrupt request, the operating system will: When the writing process has its time slice expired, the operating system will: With the program counter now reset, the interrupted process will resume its time slice. Among other things, a multiprogramming operating system kernel must be responsible for managing all system memory which is currently in use by the programs. This ensures that

9672-578: The introduction of the minicomputer , although Isaac Asimov used the term in his short story " The Dying Night " as early as 1956 (published in The Magazine of Fantasy and Science Fiction in July that year). Most notably, the microcomputer replaced the many separate components that made up the minicomputer's CPU with one integrated microprocessor chip . In 1973, the French Institut National de la Recherche Agronomique (INRA)

9796-431: The kernel—and applications—all other software. There are three main purposes that an operating system fulfills: With multiprocessors multiple CPUs share memory. A multicomputer or cluster computer has multiple CPUs, each of which has its own memory . Multicomputers were developed because large multiprocessors are difficult to engineer and prohibitively expensive; they are universal in cloud computing because of

9920-581: The late 1970s and early 1980s. A large number of computer makers packaged microcomputers for use in small business applications. By 1979, many companies such as Cromemco , Processor Technology , IMSAI , North Star Computers , Southwest Technical Products Corporation , Ohio Scientific , Altos Computer Systems , Morrow Designs and others produced systems designed for resourceful end users or consulting firms to deliver business systems such as accounting, database management and word processing to small businesses. This allowed businesses unable to afford leasing of

10044-571: The lines of the Commodore Datasette was never produced; Apple recommended using the Panasonic RQ309 in some of its early printed documentation. The uses of common consumer cassette recorders and a standard video monitor or television set (with a third-party RF modulator ) made the total cost of owning an Apple II less expensive and helped contribute to the Apple II's success. Cassette storage may have been inexpensive, but it

10168-489: The machine up into a typing position. Unlike modern portables , it lacked a built-in display and battery. It was the first of three Apple II models to be made in the Snow White design language , and the only one that used its unique creamy off-white color. The Apple IIc was the first Apple II to use the 65C02 low-power variant of the 6502 processor, and featured a built-in 5.25-inch floppy drive and 128 KB RAM, with

10292-400: The memory allocated to a different one. Around the same time, teleprinters began to be used as terminals so multiple users could access the computer simultaneously. The operating system MULTICS was intended to allow hundreds of users to access a large computer. Despite its limited adoption, it can be considered the precursor to cloud computing . The UNIX operating system originated as

10416-489: The memory it occupied more than its capabilities; instead, they often wrote their own boot loaders and read-only file systems. This also served to discourage "crackers" from snooping around in the game's copy-protection code, since the data on the disk was not in files that could be accessed easily. Microcomputer The abbreviation "micro" was common during the 1970s and 1980s, but has since fallen out of common usage. The term microcomputer came into popular use after

10540-408: The need to use it. A general protection fault would be produced, indicating a segmentation violation had occurred; however, the system would often crash anyway. The use of virtual memory addressing (such as paging or segmentation) means that the kernel can choose what memory each program may use at any given time, allowing the operating system to use the same memory locations for multiple tasks. If

10664-408: The open-source Android operating system (introduced 2008), with a Linux kernel and a C library ( Bionic ) partially based on BSD code, became most popular. The components of an operating system are designed to ensure that various parts of a computer function cohesively. With the de facto obsoletion of DOS , all user software must interact with the operating system to access hardware. The kernel

10788-628: The original II in terms of electronic functionality. There were small differences in the physical appearance and keyboard. RAM prices fell during 1980–81 and all II+ machines came from the factory with a full 48 KB of memory already installed. After the success of the first Apple II in the United States, Apple expanded its market to include Europe, Australia and the Far East in 1979, with the Apple II Europlus (Europe, Australia) and

10912-468: The parts of the computer system. The SOL-20 had built-in EPROM software which eliminated the need for rows of switches and lights. The MITS Altair just mentioned played an instrumental role in sparking significant hobbyist interest, which itself eventually led to the founding and success of many well-known personal computer hardware and software companies, such as Microsoft and Apple Computer . Although

11036-402: The peak occurring in 1983 when 1 million were sold. Unlike preceding home microcomputers, the Apple II was sold as a finished consumer appliance rather than as a kit (unassembled or preassembled). Apple marketed the Apple II as a durable product, including a 1981 ad in which an Apple II survived a fire started when a cat belonging to one early user knocked over a lamp. All the machines in

11160-421: The piping. Signals may be classified into 7 categories. The categories are: Input/output (I/O) devices are slower than the CPU. Therefore, it would slow down the computer if the CPU had to wait for each I/O to finish. Instead, a computer may implement interrupts for I/O completion, avoiding the need for polling or busy waiting. Some computers require an interrupt for each character or word, costing

11284-462: The rounded "a" of the logotype echoed the "bite" in the logo. This logo was developed simultaneously with an advertisement and a brochure; the latter being produced for distribution initially at the first West Coast Computer Faire . Since the original Apple II, Apple has paid high attention to its quality of packaging, partly because of Steve Jobs ' personal preferences and opinions on packaging and final product appearance. All of Apple's packaging for

11408-418: The same operating system— OS/360 —which consisted of millions of lines of assembly language that had thousands of bugs . The OS/360 also was the first popular operating system to support multiprogramming , such that the CPU could be put to use on one job while another was waiting on input/output (I/O). Holding multiple jobs in memory necessitated memory partitioning and safeguards against one job accessing

11532-405: The screen, with NTSC composite video output suitable for display on a TV monitor, or on a regular TV set by way of a separate RF modulator . The original retail price of the computer was US$ 1,298 (equivalent to $ 6,500 in 2023)(with 4 KB of RAM) and US$ 2,638 (equivalent to $ 13,300 in 2023) (with the maximum 48 KB of RAM). To reflect the computer's color graphics capability,

11656-525: The serial ports, mouse, and real-time clock. The IIe card could not, however, run software intended for the 16-bit Apple II GS . Mike Markkula , a retired Intel marketing manager, provided the early critical funding for Apple Computer. From 1977 to 1981, Apple used the Regis McKenna agency for its advertisements and marketing. In 1981, Chiat-Day acquired Regis McKenna's advertising operations and Apple used Chiat-Day. At Regis McKenna Advertising,

11780-436: The series, except the IIc, share similar overall design elements. The plastic case was designed to look more like a home appliance than a piece of electronic equipment, and the case can be opened without the use of tools. All models in the Apple II series have a built-in keyboard, with the exception of the II GS which has a separate keyboard. Apple IIs have color and high-resolution graphics modes , sound capabilities and

11904-400: The signal number (in mnemonic format) to be sent. (The abrasive name of kill was chosen because early implementations only terminated the process.) In Unix-like operating systems, signals inform processes of the occurrence of asynchronous events. To communicate asynchronously, interrupts are required. One reason a process needs to asynchronously communicate to another process solves

12028-400: The size of the machine needed. The different CPUs often need to send and receive messages to each other; to ensure good performance, the operating systems for these machines need to minimize this copying of packets . Newer systems are often multiqueue —separating groups of users into separate queues —to reduce the need for packet copying and support more concurrent users. Another technique

12152-638: The software on the disks, and improved loading speed. The first Apple II computers went on sale on June 10, 1977 with a MOS Technology 6502 (later Synertek ) microprocessor running at 1.023  MHz , 4 KB of RAM , an audio cassette interface for loading programs and storing data, and the Integer BASIC programming language built into the ROMs . The video controller displayed 40 columns by 24 lines of monochrome, upper-case-only (the original character set matches ASCII characters 0x20 to 0x5F) text on

12276-529: The speaker at just the right times. The Apple II's multiple expansion slots permitted a wide variety of third-party devices, including Apple II peripheral cards such as serial controllers , display controllers, memory boards, hard disks, networking components, and real-time clocks . There were plug-in expansion cards – such as the Z-80 SoftCard – that permitted the Apple to use the Z80 processor and run

12400-442: The system and may also include accounting software for cost allocation of processor time , mass storage , peripherals, and other resources. For hardware functions such as input and output and memory allocation , the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or

12524-460: The team assigned to launch the Apple II consisted of Rob Janoff , art director, Chip Schafer, copywriter and Bill Kelley, account executive. Janoff came up with the Apple logo with a bite out of it. The design was originally an olive green with matching company logotype all in lowercase. Steve Jobs insisted on promoting the color capability of the Apple II by putting rainbow stripes on the Apple logo. In its letterhead and business card implementation,

12648-401: The term personal computer became generally used for microcomputers compatible with the IBM PC architecture ( IBM PC–compatible ). Operating system An operating system ( OS ) is system software that manages computer hardware and software resources, and provides common services for computer programs . Time-sharing operating systems schedule tasks for efficient use of

12772-452: The term " personal computer " or "PC", which specifies a computer that has been designed to be used by one individual at a time, a term first coined in 1959. IBM first promoted the term "personal computer" to differentiate the IBM PC from CP/M -based microcomputers likewise targeted at the small-business market, and also IBM's own mainframes and minicomputers. However, following its release,

12896-473: The world. Middleware , an additional software layer between the operating system and applications, is often used to improve consistency. Although it functions similarly to an operating system, it is not a true operating system. Embedded operating systems are designed to be used in embedded computer systems , whether they are internet of things objects or not connected to a network. Embedded systems include many household appliances. The distinguishing factor

13020-493: Was a striking exception, bearing a modern design based on a monitor, keyboard, and tape and disk drives). Of the early "box of switches"-type microcomputers, the MITS Altair 8800 (1975) was arguably the most famous. Most of these simple, early microcomputers were sold as electronic kits —bags full of loose components which the buyer had to solder together before the system could be used. The period from about 1971 to 1976

13144-509: Was also slow and unreliable. The Apple II's lack of a disk drive was "a glaring weakness" in what was otherwise intended to be a polished, professional product. Recognizing that the II needed a disk drive to be taken seriously, Apple set out to develop a disk drive and a DOS to run it. Wozniak spent the 1977 Christmas holidays designing a disk controller that reduced the number of chips used by a factor of 10 compared to existing controllers. Still lacking

13268-508: Was available, after some user-specific voice training it would recognize simple commands (Hit, stand). Bob Bishop's "Music Kaleidoscope" was a simple program that monitored the cassette input port and based on zero-crossings created color patterns on the screen, a predecessor to current audio visualization plug-ins for media players. Music Kaleidoscope was especially popular on projection TV sets in dance halls. Apple and many third-party developers made software available on tape at first, but after

13392-535: Was based on LSI chips with an Intel 8008 as peripheral controller (keyboard, monitor and printer), before adopting the Zilog Z80 as main processor. In late 1972, a Sacramento State University team led by Bill Pentz built the Sac State 8008 computer, able to handle thousands of patients' medical records. The Sac State 8008 was designed with the Intel 8008. It had a full set of hardware and software components :

13516-431: Was configured as if it were a 48 KB Apple II Plus with a language card. The machine had no slot 0, but instead had an auxiliary slot that could accept a 1 KB memory card to enable the 80-column display. This card contained only RAM; the hardware and firmware for the 80-column display was built into the Apple IIe. An "extended 80-column card" with more memory increased the machine's RAM to 128 KB. The Apple IIe

13640-474: Was easier to learn and use than raw machine language, became a standard feature. These features were already common in minicomputers , with which many hobbyists and early produces were familiar. In 1979, the launch of the VisiCalc spreadsheet (initially for the Apple II ) first turned the microcomputer from a hobby for computer enthusiasts into a business tool. After the 1981 release by IBM of its IBM PC ,

13764-489: Was entitled "Simplicity" and the copy in both the ad and brochure pioneered "demystifying" language intended to make the new idea of a home computer more "personal." The Apple II introduction ad was later run in the September 1977 issue of Scientific American . Apple later aired eight television commercials for the Apple II GS , emphasizing its benefits to education and students, along with some print ads. The Apple II

13888-471: Was frequently cloned, both in the United States and abroad, in a similar way to the IBM PC. According to some sources (see below), more than 190 different models of Apple II clones were manufactured. Most could not be legally imported into the United States. Apple sued and sought criminal charges against clone makers in more than a dozen countries. Originally the Apple II used Compact Cassette tapes for program and data storage. A dedicated tape recorder along

14012-479: Was looking for a computer able to measure agricultural hygrometry . To answer this request, a team of French engineers of the computer technology company R2E, led by its Head of Development, François Gernelle , created the first available microprocessor-based microcomputer, the Micral N. The same year the company filed their patents with the term "Micro-ordinateur", a literal equivalent of "Microcomputer", to designate

14136-473: Was possible for software developers to create a DOS 3.2 disk which would also boot on a system with DOS 3.3 firmware. Later, double-sided drives, with heads to read both sides of the disk, became available from third-party companies. (Apple only produced double-sided 5.25-inch disks for the Lisa 1 computer). On a DOS 3.x disk, tracks 0, 1, and most of track 2 were reserved to store the operating system. (It

14260-420: Was possible, with a special utility, to reclaim most of this space for data if a disk did not need to be bootable.) A short ROM program on the disk controller had the ability to seek to track zero – which it did without regard for the read/write head's current position, resulting in the characteristic "chattering" sound of a Disk II boot, which was the read/write head hitting the rubber stop block at

14384-502: Was previously available as an upgrade, supported floating-point arithmetic, and became the standard BASIC dialect on the Apple II series (though it ran at a noticeably slower speed than Steve Wozniak's Integer BASIC). Except for improved graphics and disk-booting support in the ROM, and the removal of the 2k 6502 assembler to make room for the floating point BASIC, the II+ was otherwise identical to

14508-429: Was released in 1971. Like the Datapoint 2200, it used small-scale integrated transistor–transistor logic instead of a microprocessor. It was marketed as an educational and hobbyist tool, but it was not a commercial success; production ceased shortly after introduction. In late 1972, a French team headed by François Gernelle within a small company, Réalisations & Etudes Electroniques (R2E), developed and patented

14632-414: Was released in 1978, a new operating system, Apple DOS , was commissioned from Shepardson Microsystems and developed by Paul Laughton, adding support for the disk drive. The final and most popular version of this software was Apple DOS 3.3. Apple DOS was superseded by ProDOS , which supported a hierarchical file-system and larger storage devices. With an optional third-party Z80 -based expansion card ,

14756-477: Was released. Essentially a miniaturized Apple IIe computer on a card (using the Mega II chip from the Apple II GS ), it allowed the Macintosh to run 8-bit Apple IIe software through hardware emulation , with an option to run at roughly double the speed of the original IIe (about 1.8 MHz). However, the video output was emulated in software, and, depending on how much of the screen the currently running program

14880-491: Was the Apple IIc Plus introduced in 1988. It was the same size and shape as the IIc that came before it, but the 5.25-inch floppy drive had been replaced with a 3 + 1 ⁄ 2 -inch drive, the power supply was moved inside the case, and the processor was a fast 4 MHz 65C02 processor that actually ran 8-bit Apple II software faster than the II GS . The IIc Plus also featured a new keyboard layout that matched

15004-406: Was the first popular computer to use a graphical user interface (GUI). The GUI proved much more user friendly than the text-only command-line interface earlier operating systems had used. Following the success of Macintosh, MS-DOS was updated with a GUI overlay called Windows . Windows later was rewritten as a stand-alone operating system, borrowing so many features from another ( VAX VMS ) that

15128-486: Was the most popular machine in the Apple II series. It has the distinction of being the longest-lived Apple computer of all time—it was manufactured and sold with only minor changes for nearly 11 years. The IIe was the last Apple II model to be sold, and was discontinued in November 1993. During its lifespan two variations were introduced: the Apple IIe Enhanced (four replacement chips to give it some of

15252-524: Was trying to update in a single frame, performance could be much slower compared to a real IIe. This is due to the fact that writes from the 65C02 on the IIe Card to video memory were caught by the additional hardware on the card, so the video emulation software running on the Macintosh side could process that write and update the video display. But, while the Macintosh was processing video updates, execution of Apple II code would be temporarily halted. With

15376-470: Was user-installable as two PROMs on older controllers.) After the release of DOS 3.3, the user community discontinued use of DOS 3.2 except for running legacy software. Programs that required DOS 3.2 were fairly rare; however, as DOS 3.3 was not a major architectural change aside from the number of sectors per track, a program called MUFFIN was provided with DOS 3.3 to allow users to copy files from DOS 3.2 disks to DOS 3.3 disks. It

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