HGST was a manufacturer of hard disk drives, solid-state drives, external storage products and services. It was a subsidiary of Hitachi, formed through its acquisition of IBM's disk drive business, it was acquired by Western Digital in 2012, but required to operate autonomously from the remainder of the company due to conditions imposed by Chinese regulators. However, in October 2015, Chinese regulators permitted Western Digital to begin wider integration of HGST into its main business. By 2018, the HGST brand had been phased out, with its remaining products now marketed under the Western Digital name. Hitachi Global Storage Technologies was founded on January 6, 2003, as a merger of the hard disk drive businesses of IBM and Hitachi. Hitachi paid IBM US$2.05 billion for its HDD business. On March 8, 2012, Western Digital acquired Hitachi Global Storage Technologies for $3.9 billion in cash and 25 million shares of WD common stock valued at $0.9 billion. The deal resulted in Hitachi, Ltd. owning 10 percent of WD shares outstanding, reserving the right to designate two individuals to the board of directors of WD.
Citing antitrust concerns, China's Ministry of Commerce required HGST to operate autonomously from Western Digital, restricting outright integration between the companies' operations. As a result, HGST continued to operate independently with its own product lines and product development; as part of the deal, Western Digital agreed to trade assets with Toshiba, with Toshiba receiving assets for the production of 3.5-inch hard drives, in exchange for a Toshiba factory in Thailand for producing 2.5-inch drives. In November 2013, HGST announced. In September 2014, the company announced a 10 TB helium drive, which uses shingled magnetic recording to improve density. In October 2015, the Chinese Ministry of Commerce issued a decision allowing Western Digital to begin integrating HGST into its main business. WD was required to maintain the HGST sale team for at least two more years. In 2018, Western Digital announced that it was phasing out its HGST brand and that all of its remaining product lines will henceforth be marketed under the Western Digital brand.
Ultrastar – Enterprise-class line of 3.5-inch and 2.5-inch HDDs with SCSI, Fibre Channel, SAS, SATA interfaces. Deskstar – Desktop-class line in 3.5-inch form factor with SATA interfaces. Travelstar – Mobile-class line in 2.5-inch form factor with SATA interfaces. Endurastar – Ruggedized line in 2.5-inch form factor with PATA or SATA interfaces for automotive applications. Cinemastar – 3.5-inch and 2.5-inch form factors, optimized for consumer electronics applications requiring quiet operation and streaming support. LifeStudio products, announced in 2010 but now discontinued, were external hard drives that combine photo organization software, a 3D Wall for displaying content, a connected USB Flash key. G-Technology external storage products, acquired in 2009, are sold to Apple Macintosh communities, including users of multimedia content such as Final Cut Pro digital audio/video production professionals. Touro family of cloud storage backup products. Hitachi-LG Data Storage – joint venture of Hitachi and LG.
Hitachi Data Systems – manufacturer of modular enterprise storage systems and services
Linux is a family of free and open-source software operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is packaged in a Linux distribution. Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include Debian and Ubuntu. Commercial distributions include SUSE Linux Enterprise Server. Desktop Linux distributions include a windowing system such as X11 or Wayland, a desktop environment such as GNOME or KDE Plasma. Distributions intended for servers may omit graphics altogether, include a solution stack such as LAMP; because Linux is redistributable, anyone may create a distribution for any purpose. Linux was developed for personal computers based on the Intel x86 architecture, but has since been ported to more platforms than any other operating system.
Linux is the leading operating system on servers and other big iron systems such as mainframe computers, the only OS used on TOP500 supercomputers. It is used by around 2.3 percent of desktop computers. The Chromebook, which runs the Linux kernel-based Chrome OS, dominates the US K–12 education market and represents nearly 20 percent of sub-$300 notebook sales in the US. Linux runs on embedded systems, i.e. devices whose operating system is built into the firmware and is tailored to the system. This includes routers, automation controls, digital video recorders, video game consoles, smartwatches. Many smartphones and tablet computers run other Linux derivatives; because of the dominance of Android on smartphones, Linux has the largest installed base of all general-purpose operating systems. Linux is one of the most prominent examples of open-source software collaboration; the source code may be used and distributed—commercially or non-commercially—by anyone under the terms of its respective licenses, such as the GNU General Public License.
The Unix operating system was conceived and implemented in 1969, at AT&T's Bell Laboratories in the United States by Ken Thompson, Dennis Ritchie, Douglas McIlroy, Joe Ossanna. First released in 1971, Unix was written in assembly language, as was common practice at the time. In a key pioneering approach in 1973, it was rewritten in the C programming language by Dennis Ritchie; the availability of a high-level language implementation of Unix made its porting to different computer platforms easier. Due to an earlier antitrust case forbidding it from entering the computer business, AT&T was required to license the operating system's source code to anyone who asked; as a result, Unix grew and became adopted by academic institutions and businesses. In 1984, AT&T divested itself of Bell Labs; the GNU Project, started in 1983 by Richard Stallman, had the goal of creating a "complete Unix-compatible software system" composed of free software. Work began in 1984. In 1985, Stallman started the Free Software Foundation and wrote the GNU General Public License in 1989.
By the early 1990s, many of the programs required in an operating system were completed, although low-level elements such as device drivers and the kernel, called GNU/Hurd, were stalled and incomplete. Linus Torvalds has stated that if the GNU kernel had been available at the time, he would not have decided to write his own. Although not released until 1992, due to legal complications, development of 386BSD, from which NetBSD, OpenBSD and FreeBSD descended, predated that of Linux. Torvalds has stated that if 386BSD had been available at the time, he would not have created Linux. MINIX was created by Andrew S. Tanenbaum, a computer science professor, released in 1987 as a minimal Unix-like operating system targeted at students and others who wanted to learn the operating system principles. Although the complete source code of MINIX was available, the licensing terms prevented it from being free software until the licensing changed in April 2000. In 1991, while attending the University of Helsinki, Torvalds became curious about operating systems.
Frustrated by the licensing of MINIX, which at the time limited it to educational use only, he began to work on his own operating system kernel, which became the Linux kernel. Torvalds began the development of the Linux kernel on MINIX and applications written for MINIX were used on Linux. Linux matured and further Linux kernel development took place on Linux systems. GNU applications replaced all MINIX components, because it was advantageous to use the available code from the GNU Project with the fledgling operating system. Torvalds initiated a switch from his original license, which prohibited commercial redistribution, to the GNU GPL. Developers worked to integrate GNU components with the Linux kernel, making a functional and free operating system. Linus Torvalds had wanted to call his invention "Freax", a portmant
Microsoft Windows is a group of several graphical operating system families, all of which are developed and sold by Microsoft. Each family caters to a certain sector of the computing industry. Active Windows families include Windows Embedded. Defunct Windows families include Windows Mobile and Windows Phone. Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces. Microsoft Windows came to dominate the world's personal computer market with over 90% market share, overtaking Mac OS, introduced in 1984. Apple came to see Windows as an unfair encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh. On PCs, Windows is still the most popular operating system. However, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones.
In 2014, the number of Windows devices sold was less than 25 %. This comparison however may not be relevant, as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows show one third market share, similar to that for end user use; as of October 2018, the most recent version of Windows for PCs, tablets and embedded devices is Windows 10. The most recent versions for server computers is Windows Server 2019. A specialized version of Windows runs on the Xbox One video game console. Microsoft, the developer of Windows, has registered several trademarks, each of which denote a family of Windows operating systems that target a specific sector of the computing industry; as of 2014, the following Windows families are being developed: Windows NT: Started as a family of operating systems with Windows NT 3.1, an operating system for server computers and workstations. It now consists of three operating system subfamilies that are released at the same time and share the same kernel: Windows: The operating system for mainstream personal computers and smartphones.
The latest version is Windows 10. The main competitor of this family is macOS by Apple for personal computers and Android for mobile devices. Windows Server: The operating system for server computers; the latest version is Windows Server 2019. Unlike its client sibling, it has adopted a strong naming scheme; the main competitor of this family is Linux. Windows PE: A lightweight version of its Windows sibling, meant to operate as a live operating system, used for installing Windows on bare-metal computers, recovery or troubleshooting purposes; the latest version is Windows PE 10. Windows IoT: Initially, Microsoft developed Windows CE as a general-purpose operating system for every device, too resource-limited to be called a full-fledged computer. However, Windows CE was renamed Windows Embedded Compact and was folded under Windows Compact trademark which consists of Windows Embedded Industry, Windows Embedded Professional, Windows Embedded Standard, Windows Embedded Handheld and Windows Embedded Automotive.
The following Windows families are no longer being developed: Windows 9x: An operating system that targeted consumers market. Discontinued because of suboptimal performance. Microsoft now caters to the consumer market with Windows NT. Windows Mobile: The predecessor to Windows Phone, it was a mobile phone operating system; the first version was called Pocket PC 2000. The last version is Windows Mobile 6.5. Windows Phone: An operating system sold only to manufacturers of smartphones; the first version was Windows Phone 7, followed by Windows Phone 8, the last version Windows Phone 8.1. It was succeeded by Windows 10 Mobile; the term Windows collectively describes any or all of several generations of Microsoft operating system products. These products are categorized as follows: The history of Windows dates back to 1981, when Microsoft started work on a program called "Interface Manager", it was announced in November 1983 under the name "Windows", but Windows 1.0 was not released until November 1985.
Windows 1.0 was to achieved little popularity. Windows 1.0 is not a complete operating system. The shell of Windows 1.0 is a program known as the MS-DOS Executive. Components included Calculator, Cardfile, Clipboard viewer, Control Panel, Paint, Reversi and Write. Windows 1.0 does not allow overlapping windows. Instead all windows are tiled. Only modal dialog boxes may appear over other windows. Microsoft sold as included Windows Development libraries with the C development environment, which included numerous windows samples. Windows 2.0 was released in December 1987, was more popular than its predecessor. It features several improvements to the user memory management. Windows 2.03 changed the OS from tiled windows to overlapping windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple's copyrights. Windows 2.0
Dell is an American multinational computer technology company based in Round Rock, United States, that develops, sells and supports computers and related products and services. Named after its founder, Michael Dell, the company is one of the largest technological corporations in the world, employing more than 145,000 people in the U. S. and around the world. Dell sells personal computers, data storage devices, network switches, computer peripherals, HDTVs, printers, MP3 players, electronics built by other manufacturers; the company is well known for its innovations in supply chain management and electronic commerce its direct-sales model and its "build-to-order" or "configure to order" approach to manufacturing—delivering individual PCs configured to customer specifications. Dell was a pure hardware vendor for much of its existence, but with the acquisition in 2009 of Perot Systems, Dell entered the market for IT services; the company has since made additional acquisitions in storage and networking systems, with the aim of expanding their portfolio from offering computers only to delivering complete solutions for enterprise customers.
Dell was listed at number 51 in the Fortune 500 list, until 2014. After going private in 2013, the newly confidential nature of its financial information prevents the company from being ranked by Fortune. In 2015, it was the third largest PC vendor in the world after Lenovo and HP. Dell is the largest shipper of PC monitors worldwide. Dell is the sixth largest company in Texas by total revenue, according to Fortune magazine, it is the second largest non-oil company in Texas – behind AT&T – and the largest company in the Greater Austin area. It was a publicly traded company, as well as a component of the NASDAQ-100 and S&P 500, until it was taken private in a leveraged buyout which closed on October 30, 2013. In 2015, Dell acquired the enterprise technology firm EMC Corporation. Dell traces its origins to 1984, when Michael Dell created Dell Computer Corporation, which at the time did business as PC's Limited, while a student of the University of Texas at Austin; the dorm-room headquartered company sold IBM PC-compatible computers built from stock components.
Dell dropped out of school to focus full-time on his fledgling business, after getting $1,000 in expansion-capital from his family. In 1985, the company produced the first computer of its own design, the Turbo PC, which sold for $795. PC's Limited advertised its systems in national computer magazines for sale directly to consumers and custom assembled each ordered unit according to a selection of options; the company grossed more than $73 million in its first year of operation. In 1986, Michael Dell brought in Lee Walker, a 51-year-old venture capitalist, as president and chief operating officer, to serve as Dell's mentor and implement Dell's ideas for growing the company. Walker was instrumental in recruiting members to the board of directors when the company went public in 1988. Walker retired in 1990 due to health, Michael Dell hired Morton Meyerson, former CEO and president of Electronic Data Systems to transform the company from a fast-growing medium-sized firm into a billion-dollar enterprise.
The company dropped the PC's Limited name in 1987 to become Dell Computer Corporation and began expanding globally. In June 1988, Dell's market capitalization grew from $30 million to $80 million from its June 22 initial public offering of 3.5 million shares at $8.50 a share. In 1992, Fortune magazine included Dell Computer Corporation in its list of the world's 500 largest companies, making Michael Dell the youngest CEO of a Fortune 500 company ever. In 1993, to complement its own direct sales channel Dell planned to sell PCs at big-box retail outlets such as Wal-Mart, which would have brought in an additional $125 million in annual revenue. Bain consultant Kevin Rollins persuaded Michael Dell to pull out of these deals, believing they would be money losers in the long run. Margins at retail were thin at best and Dell left the reseller channel in 1994. Rollins would soon join Dell full-time and become the company President and CEO. Dell did not emphasize the consumer market, due to the higher costs and unacceptably low-profit margins in selling to individuals and households.
While the industry's average selling price to individuals was going down, Dell's was going up, as second- and third-time computer buyers who wanted powerful computers with multiple features and did not need much technical support were choosing Dell. Dell found an opportunity among PC-savvy individuals who liked the convenience of buying direct, customizing their PC to their means, having it delivered in days. In early 1997, Dell created an internal sales and marketing group dedicated to serving the home market and introduced a product line designed for individual users. From 1997 to 2004, Dell enjoyed steady growth and it gained market share from competitors during industry slumps. During the same period, rival PC vendors such as Compaq, Gateway, IBM, Packard Bell, AST Research struggled and left the market or were bought out. Dell surpassed Compaq to become the largest PC manufacturer in 1999. Operating costs made up only 10 percent of Dell's $35 billion in revenue in 2002, compared with 21 percent of revenue at Hewlett-Packard, 25 percent at Gateway, 46 percent at Cisco.
In 2002, when Compaq merged with Hewlett Packard, the newly combined Hewlett Packard took the top spot but struggled and Dell soon regained its lead. Dell grew the fastest in the early 2000s. Dell attained an
Fujitsu Ltd. is a Japanese multinational information technology equipment and services company headquartered in Tokyo, Japan. In 2015, it was the world's fourth-largest IT services provider measured by IT services revenue. Fortune named Fujitsu as a Global 500 company. Fujitsu chiefly makes computing products, but the company and its subsidiaries offer a diversity of products and services in the areas of personal computing, enterprise computing, including x86, SPARC and mainframe server products, as well as storage products, telecommunications, advanced microelectronics, air conditioning, it has 140,000 employees and its products and services are available in over 100 countries. Fujitsu is listed on the Tokyo Stock Exchange and is a constituent of the Nikkei 225 and TOPIX indices. Fujitsu is the second oldest IT company after IBM and before Hewlett Packard, established on June 20, 1935, under the name Fuji Telecommunications Equipment Manufacturing, as a spin-off of the Fuji Electric Company, itself a joint venture between the Furukawa Electric Company and the German conglomerate Siemens, founded in 1923.
Despite its connections to the Furukawa zaibatsu, Fujitsu escaped the Allied occupation of Japan after the Second World War unscathed. In 1954, Fujitsu manufactured Japan's first computer, the FACOM 100 mainframe, in 1961 launched its second generation computers the FACOM 222 mainframe; the 1968 FACOM230 "5" Series marked the beginning of its third generation computers. Fujitsu offered mainframe computers from 1955 until at least 2002 Fujitsu's computer products have included minicomputers, small business computers and personal computers. In 1955, Fujitsu founded Kawasaki Frontale as a company football club. In 1967, the company's name was changed to the contraction Fujitsū. Since 1985, the company fields a company American football team, the Fujitsu Frontiers, who play in the corporate X-League, have appeared in 7 Japan X Bowls, winning two, winning two Rice Bowls. In 1971, Fujitsu signed an OEM agreement with the Canadian company Consolidated Computers Limited to distribute CCL's data entry product, Key-Edit.
Fujitsu joined both ICL who earlier began marketing Key-Edit in the British Commonwealth of countries as well as in both western and eastern Europe. Mers Kutt, inventor of Key-Edit and founder of CCL, was the common thread that led to Fujitsu’s association with ICL and Gene Amdahl. In 1986, Fujitsu and The Queen's University of Belfast business incubation unit established a joint venture called Kainos, a held software company based in Belfast, Northern Ireland. In 1990, Fujitsu acquired 80% of the UK-based computer company International Computers Limited for $1.29 billion. In September 1990, Fujitsu announced the launch of a new series of mainframe computers which were at that time the fastest in the world. In July 1991, Fujitsu acquired more than half of the Russian company KME-CS. In 1992, Fujitsu introduced the world's first 21-inch full-color plasma display, it was a hybrid, based upon the plasma display created at the University of Illinois at Urbana-Champaign and NHK STRL, achieving superior brightness.
In 1993, Fujitsu formed a flash memory manufacturing joint venture with Spansion. As part of the transaction, AMD contributed its flash memory group, Fab 25 in Texas, its R&D facilities and assembly plants in Thailand and China. From February 1989 until mid-1997, Fujitsu built the FM Towns PC variant, it started as a proprietary PC variant intended for multimedia applications and computer games, but became more compatible with regular PCs. In 1993, the FM Towns Marty was released. Fujitsu agreed to acquire the 58 percent of Amdahl Corporation that it did not own for around $850 million in July 1997. In April 1997, the company acquired a 30 percent stake in GLOVIA International, Inc. an El Segundo, Calif. manufacturing ERP software provider whose software it had begun integrating into its electronics plants starting in 1994. In June 1999 Fujitsu's historical connection with Siemens was revived, when the two companies agreed to merge their European computer operations into a new 50:50 joint venture called Fujitsu Siemens Computers, which became the world's fifth-largest computer manufacturing company.
In April 2000, Fujitsu acquired the remaining 70% of GLOVIA International. In April 2002 ICL re-branded itself as Fujitsu. On March 2, 2004, Fujitsu Computer Products of America lost a class action lawsuit over hard disk drives with defective chips and firmware. In October 2004, Fujitsu acquired the Australian subsidiary of Atos Origin, a systems implementation company with around 140 employees which specialized in SAP. In August 2007, Fujitsu signed a £500 million, 10-year deal with Reuters Group under which Reuters outsourced the majority of its internal IT department to Fujitsu; as part of the agreement around 300 Reuters staff and 200 contractors transferred to Fujitsu. In October 2007, Fujitsu announced that it would be establishing an offshore development centre in Noida, India with a capacity to house 1,200 employees, in an investment of US$10 million. In October 2007, Fujitsu's Australia and New Ze
Disk partitioning or disk slicing is the creation of one or more regions on secondary storage, so that each region can be managed separately. These regions are called partitions, it is the first step of preparing a newly installed disk, before any file system is created. The disk stores the information about the partitions' locations and sizes in an area known as the partition table that the operating system reads before any other part of the disk; each partition appears to the operating system as a distinct "logical" disk that uses part of the actual disk. System administrators use a program called a partition editor to create, resize and manipulate the partitions.. Partitioning allows the use of different filesystems to be installed for different kinds of files. Separating user data from system data can prevent the system partition from becoming full and rendering the system unusable. Partitioning can make backing up easier. A disadvantage is that it can be difficult to properly size partitions resulting in having one partition with much free space and another nearly allocated.
This section describes the master boot record partitioning scheme, as used in DOS, Microsoft Windows and Linux on PC-compatible computer systems. As of the mid-2010s, most new computers use the GUID Partition Table partitioning scheme instead. For examples of other partitioning schemes, see the general article on partition tables; the total data storage space of a PC HDD on which MBR partitioning is implemented can contain at most four primary partitions, or alternatively three primary partitions and an extended partition. The Partition Table, located in the master boot record, contains 16-byte entries, each of which describes a partition; the partition type is identified by a 1-byte code found in its partition table entry. Some of these codes may be used to indicate the presence of an extended partition. Most are used by an operating system's bootloader to decide if a partition contains a file system that can be mounted / accessed for reading or writing data. A primary partition contains one file system.
In DOS and all early versions of Microsoft Windows systems, Microsoft required what it called the system partition to be the first partition. All Windows operating systems from Windows 95 onwards can be located on any partition, but the boot files must reside on a primary partition. However, other factors, such as a PC's BIOS may impose specific requirements as to which partition must contain the primary OS; the partition type code for a primary partition can either correspond to a file system contained within or indicate that the partition has a special use. The FAT16 and FAT32 file systems have made use of a number of partition type codes due to the limits of various DOS and Windows OS versions. Though a Linux operating system may recognize a number of different file systems, they have all used the same partition type code: 0x83. An HDD may contain only one extended partition, but that extended partition can be subdivided into multiple logical partitions. DOS/Windows systems may assign a unique drive letter to each logical partition.
With DOS, Microsoft Windows, OS/2, a common practice is to use one primary partition for the active file system that will contain the operating system, the page/swap file, all utilities and user data. On most Windows consumer computers, the drive letter C: is assigned to this primary partition. Other partitions may exist on the HDD that may or may not be visible as drives, such as recovery partitions or partitions with diagnostic tools or data. Microsoft Windows 2000, XP, Windows 7 include a'Disk Management' program which allows for the creation and resizing of FAT and NTFS partitions; the Windows Disk Manager in Windows Vista and Windows 7 utilizes a 1 MB partition alignment scheme, fundamentally incompatible with Windows 2000, XP, OS/2, DOS as well as many other operating systems. On Unix-based and Unix-like operating systems such as Linux, macOS, BSD, Solaris, it is possible to use multiple partitions on a disk device; each partition can be formatted as a swap partition. Multiple partitions allow directories such as /boot, /tmp, /usr, /var, or /home to be allocated their own filesystems.
Such a scheme has a number of advantages: If one file system gets corrupted, the data outside that filesystem/partition may stay intact, minimizing data loss. Specific file systems can be mounted with different parameters e.g. read-only, or with the execution of setuid files disabled. A runaway program that uses up all available space on a non-system filesystem does not fill up critical filesystems. Keeping user data such as documents separate from system files allows the system to be updated with lessened risk of disturbing the data. A common minimal configuration for Linux systems is to use three partitions: one holding the system files mounted on "/", one holding user configuration files and data mounted on /home, a swap partition. By default, macOS systems use a single partition for the entire filesystem and use a swap file inside the file system rather than a swap partition. In Solaris, partitions are sometimes known as slices; this is a conceptual reference to the slicing of a cake into severa
An operating system 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 the system and may include accounting software for cost allocation of processor time, mass storage 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 executed directly by the hardware and makes system calls to an OS function or 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; the dominant desktop operating system is Microsoft Windows with a market share of around 82.74%. MacOS by Apple Inc. is in second place, the varieties of Linux are collectively in third place. In the mobile sector, use in 2017 is up to 70% of Google's Android and according to third quarter 2016 data, Android on smartphones is dominant with 87.5 percent and a growth rate 10.3 percent per year, followed by Apple's iOS with 12.1 percent and a per year decrease in market share of 5.2 percent, while other operating systems amount to just 0.3 percent.
Linux distributions are dominant in supercomputing sectors. Other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can only run one program at a time, while a multi-tasking operating system allows more than one program to be running in concurrency; this is achieved by time-sharing, where the available processor time is divided between multiple processes. These processes are each interrupted in time slices by a task-scheduling subsystem of the operating system. Multi-tasking may be characterized in co-operative types. In preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, such as Solaris and Linux—as well as non-Unix-like, such as AmigaOS—support preemptive multitasking. Cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking.
32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem. A multi-user operating system extends the basic concept of multi-tasking with facilities that identify processes and resources, such as disk space, belonging to multiple users, the system permits multiple users to interact with the system at the same time. Time-sharing operating systems schedule tasks for efficient use of the system and may include accounting software for cost allocation of processor time, mass storage and other resources to multiple users. A distributed operating system manages a group of distinct computers and makes them appear to be a single computer; the development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine; when computers in a group work in cooperation, they form a distributed system.
In an OS, distributed and cloud computing context, templating refers to creating a single virtual machine image as a guest operating system saving it as a tool for multiple running virtual machines. The technique is used both in virtualization and cloud computing management, is common in large server warehouses. Embedded operating systems are designed to be used in embedded computer systems, they are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources, they are compact and efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is an operating system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, it uses specialized scheduling algorithms so that a deterministic nature of behavior is achieved. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.
A library operating system 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 the application and configuration code to construct a unikernel: a specialized, single address space, machine image that can be deployed to cloud or embedded environments. Early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could automatically run different programs in succession to speed up processing. Operating systems did not exist in their more complex forms until the early 1960s. Hardware features were added, that enabled use of runtime libraries and parallel processing; when personal computers became popular in the 1980s, operating systems were made for them similar in concept to those used on larger computers. In the 1940s, the earliest electronic digital systems had no operating systems.
Electronic systems of this time were programmed on rows of mechanical switches or by jumper wires on plug boards. These were special-purpose systems that, for example, generated ballistics tables for the military or controlled the pri