The IBM RT PC ( RISC Technology Personal Computer ) is a family of workstation computers from IBM introduced in 1986. These were the first commercial computers from IBM that were based on a reduced instruction set computer (RISC) architecture. The RT PC uses IBM's proprietary ROMP microprocessor , which commercialized technologies pioneered by IBM Research 's 801 experimental minicomputer (the 801 was the first RISC). The RT PC runs three operating systems: AIX , the Academic Operating System (AOS), and Pick .
73-445: The RT PC's specifications were regarded as "less than impressive" compared to contemporary workstations by its competitors in that particular market, although the product was deemed deserving of "a healthy amount of respect", particularly with the prospect of IBM as "a serious competitor" who, despite having a product whose performance was an estimated 18 months behind other vendors, would potentially be able to catch up quickly by applying
146-549: A LAN TCP/IP interface. One of the novel aspects of the RT design was the use of a microkernel . The keyboard, mouse, display, disk drives and network were all controlled by a microkernel, called Virtual Resource Manager (VRM), which allowed multiple operating systems to be booted and run at the same time. One could "hotkey" from one operating system to the next using the Alt-Tab key combination. Each OS in turn would get possession of
219-428: 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
292-554: A IBM 9309 Rack Enclosure; this a first generation RS/6000 server running AIX. These units were configured by IBM as experimental "NSS" ("Network Switching Subsystem") routers, and used on the NSFnet T3 backbone in the early/mid-90s. Produced since 1994 until the time were the RS/6000 line was rebranded to System P. The Model N40 was a PowerPC-based laptop developed and manufactured by Tadpole Technology in conjunction with IBM. It
365-645: 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
438-585: 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
511-484: 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,
584-565: A large cabinet that would have been positioned alongside the RT PC. The 5080 was used with a 1,024- by 1,024-pixel IBM 5081 display. The 6152 Academic System was a PS/2 Model 60 with a RISC Adapter Card, a Micro Channel board containing a ROMP, its support ICs, and up to 8 MB of memory. It allowed the PS/2 to run ROMP software compiled for the AOS. AOS was downloaded from a RT PC running AOS, via
657-442: 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
730-447: 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,
803-455: 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
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#1732771831647876-405: A phone number (via a modem) in case of serious failure with the machine. Early advertisements and documentation called the service processor "System Guard", (or SystemGuard ) although this name was apparently dropped later on, roughly around the same time that the simplified RS/6000 name was adopted for the computer line itself. Late in the RS/6000 cycle, the service processor was "converged" with
949-503: 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
1022-408: 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
1095-440: 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
1168-470: 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
1241-468: A special board slot for the processor card, as well as machine-specific RAM cards. Each machine had one processor slot, one co-processor slot, and two RAM slots. There were three versions of the processor card: All RT PCs supported up to 16 MB of memory. Early models were limited to 4 MB of memory because of the capacity of the DRAM ICs used, later models could have up to 16 MB. I/O
1314-402: 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
1387-417: 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
1460-532: A variant of the PL/I programming language, which proved troublesome during the migration to AIX v3. AIX v2 included full TCP/IP networking support, as well as SNA , and two networking file systems: NFS , licensed from Sun Microsystems , and IBM Distributed Services (DS). DS had the distinction of being built on top of SNA, and thereby being fully compatible with DS on the IBM midrange AS/400 and mainframe systems. For
1533-453: 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
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#17327718316471606-418: 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
1679-562: 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
1752-484: 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
1825-541: Is a family of RISC -based Unix servers , workstations and supercomputers made by IBM in the 1990s. The RS/6000 family replaced the IBM RT PC computer platform in February 1990 and is the first computer line to see the use of IBM's POWER and PowerPC based microprocessors. In October 2000, the RS/6000 brand was retired for POWER-based servers and replaced by the eServer pSeries . Workstations continued under
1898-422: 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
1971-896: 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
2044-443: 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
2117-499: 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,
2190-473: 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
2263-435: 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 ,
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2336-542: 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
2409-504: 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
2482-551: The PowerPC 604e -based Deep Blue supercomputer that beat world champion Garry Kasparov at chess in 1997, and the POWER3 -based ASCI White which was the fastest supercomputer in the world during 2000–2002. Many RS/6000 and subsequent pSeries machines came with a service processor, which booted itself when power was applied and continuously ran its own firmware, independent of the operating system. The service processor could call
2555-420: 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
2628-410: 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
2701-474: 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
2774-689: The RS/6000 brand until 2002, when new POWER-based workstations were released under the IntelliStation POWER brand. The first RS/6000 models used the Micro Channel bus, later models used PCI . Some later models conformed to the PReP and CHRP standard platforms, which were co-developed with Apple and Motorola , with Open Firmware . The plan was to enable the RS/6000 to run multiple operating systems such as Windows NT , NetWare , OS/2 , Solaris , Taligent , AIX and Mac OS but in
2847-629: The RT PC was introduced in January 1986, it competed with several workstations from established providers: the Apollo Computer Domain Series 3000 , the DEC MicroVAX II , and Sun Microsystems Sun-3 . In 1987, "The NSF starts to implement its T1 backbone between the supercomputing centers with 24 RT-PCs in parallel implemented by IBM as ‘parallel routers’. The T1 idea is so successful that proposals for T3 speeds in
2920-505: The RT inferior to other computers. The performance of the RT, in comparison with other contemporaneous Unix workstations , was not outstanding. In particular, the floating point performance was poor, and was scandalized mid-life with the discovery of a bug in the floating point square root routine. With the RT system's modest processing power (when first announced), and with announcements later that year by some other workstation vendors, industry analysts questioned IBM's directions. AIX for
2993-596: The RT was IBM's second foray into UNIX (its first was PC/IX for the IBM PC in September 1984.) The lack of software packages and IBM's sometimes lackluster support of AIX, in addition to sometimes unusual changes from traditional, de facto UNIX operating system standards, caused most software suppliers to be slow in embracing the RT and AIX. The RT found its home mostly in the CAD / CAM and CATIA markets, with some inroads into
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3066-538: 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
3139-576: The backbone begin. Internet History of 1980s The National Science Foundation Network (NSFNET) was the forerunner of the Internet . From July 1988 to November 1992, the NSFNET's T1 backbone network used routers built from multiple RT PCs (typically nine) interconnect by a Token Ring LAN. This entry incorporates text from the RT/PC FAQ . RS/6000 The RISC System/6000 ( RS/6000 )
3212-545: The company's renowned technological capabilities. Given such performance limitations, the RT PC had little commercial success as a result. IBM responded by introducing the RS/6000 workstations in 1990, which used a new IBM-proprietary RISC processor, the POWER1 . All RT PC models were discontinued by May 1991. Two basic types were produced: a floor-standing desk-side tower (IBM 6150), and a desktop (IBM 6151). Both types featured
3285-453: 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
3358-471: 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
3431-523: The end only IBM's Unix variant AIX was used and supported on RS/6000. Linux is widely used on CHRP based RS/6000s, but support was added after the RS/6000 name was changed to eServer pSeries in 2000. The RS/6000 family also included the POWERserver servers, POWERstation workstations and Scalable POWERparallel supercomputer platform. While most machines were desktops, desksides, or rack-mounted, there were laptop models too. Famous RS/6000s include
3504-422: 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
3577-639: The graphical user interfaces, AIX v2 came with the X10R3 and later the X10R4 and X11 releases of the X Window System from MIT , together with the Athena widget set . Compilers for C and Fortran programming languages were available. Some RT PCs were also shipped with the Academic Operating System (AOS), an IBM port of 4.3BSD Unix to the RT PC. It was offered as an alternative to AIX ,
3650-410: 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
3723-493: 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
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#17327718316473796-418: 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
3869-404: 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
3942-431: 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
4015-507: The keyboard, mouse and display. Both AIX version 2 and the Pick operating system were ported to this microkernel. Pick was unique in being a unified operating system and database, and ran various accounting applications. It was popular with retail merchants, and accounted for about 4,000 units of sales. The primary operating system for the RT was AIX version 2. Much of the AIX v2 kernel was written in
4088-400: 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
4161-408: 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
4234-534: The one used on the AS/400 machines. POWER machines typically ran AIX . Solaris, OS/2 and Windows NT were also ported to PowerPC. Later Linux was also used. Some AIX systems support IBM Web-based System Manager . Some models were marketed under the RS/6000 POWERstation and POWERserver names. The early lines were based on an IBM proprietary Micro Channel architecture ; the same architecture that
4307-408: 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
4380-421: 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
4453-418: 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
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#17327718316474526-744: The scientific and educational areas, especially after the announcement of AOS and substantial discounts for the educational community. The RT running the Pick OS also found use as shopping store control systems, given the strong database, accounting system and general business support in the Pick OS. The RT also did well as an interface system between IBM's larger mainframes, due to its SNA and DS support, and some of its point-of-sale terminals, store control systems, and machine shop control systems. Approximately 23,000 RTs were sold over its lifetime, with some 4,000 going into IBM's development and sales organizations. Pick OS sales accounted for about 4,000 units. When
4599-400: 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
4672-400: 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
4745-442: 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
4818-547: The system. Problems with reading unaligned data on the RT forced an incompatible protocol change, leading to version 10 in late 1985. Personal Computer World said "it's hard to see what you get with the 6150 that you can't get by combining any other Unix box to run multi-user applications, with a cheap AT clone to run single-user PC applications". Many thought that the RT was part of IBM's Personal Computer line of computers. This confusion started with its initial name, "IBM RT PC". Initially, it seemed that even IBM thought that it
4891-447: The usual RT PC operating system , to US universities eligible for an IBM educational discount. AOS added a few extra features to 4.3BSD, notably NFS , and an almost ANSI C -compliant C compiler . A later version of AOS existed that was derived from 4.3BSD-Reno, but it was not widely distributed. The RT forced an important stepping-stone in the development of the X Window System, when a group at Brown University ported X version 9 to
4964-473: 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
5037-591: Was a high-end Personal Computer given the initially stunning lack of support that it received from IBM. This could be explained by the sales commission structure the IBM gave the system: salesmen received commissions similar to those for the sale of a PC. With typically configured models priced at $ 20,000, it was a hard sell, and the lack of any reasonable commission lost the interest of IBM's sales force. Both MIT 's Project Athena and Brown University 's Institute for Research in Information and Scholarship found
5110-518: Was provided by eight ISA bus slots. Storage was provided by a 40 or 70 MB hard drive, upgradeable to 300 MB. External SCSI cabinets could be used to provide more storage. Also standard were a mouse and either a 720×512 or 1024×768 pixel-addressable display, and a 4 Mbit/s Token Ring network adapter or 10BASE2 Ethernet adapter. For running CADAM , a computer-aided design (CAD) program, an IBM 5080 or 5085 graphics processor could be attached. The 5080 and 5085 were contained in
5183-476: Was released on 25 March 1994, priced at US$ 12,000. The internal batteries could power the system for 45 minutes only and an external battery pack that lasted for 4 hours was available for this reason. 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
5256-406: 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
5329-474: Was used in the high end PS/2 x86 desktop line. MCA-based lines were produced until 1999. These workstations were marketed under the PowerStation name. This type was for Xstations, IBM's line of X terminal . The 380, 390, and 39H servers correspond to the 3AT, 3BT, and 3CT workstations. The 7016-730 model was a version of 7013-530 model, but with licensed by Silicon Graphics graphics card. Uses
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