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
HP-UX is Hewlett Packard Enterprise's proprietary implementation of the Unix operating system, based on UNIX System V and first released in 1984. Recent versions support the HP 9000 series of computer systems, based on the PA-RISC instruction set architecture, HP Integrity systems, based on Intel's Itanium architecture. Earlier versions of HP-UX supported the HP Integral PC and HP 9000 Series 200, 300, 400 computer systems based on the Motorola 68000 series of processors, as well as the HP 9000 Series 500 computers based on HP's proprietary FOCUS architecture. HP-UX was the first Unix to offer access control lists for file access permissions as an alternative to the standard Unix permissions system. HP-UX was among the first Unix systems to include a built-in logical volume manager. HP has had a long partnership with Veritas Software, uses VxFS as the primary file system, it is one of six commercial operating systems that have versions certified to The Open Group's UNIX 03 standard. HP-UX 11i offers a common root disk for its clustered file system.
HP Serviceguard is the cluster solution for HP-UX. HP Global Workload Management adjusts workloads to optimize performance, integrates with Instant Capacity on Demand so installed resources can be paid for in 30-minute increments as needed for peak workload demands. HP-UX offers operating system-level virtualization features such as hardware partitions, isolated OS virtual partitions on cell-based servers, HP Integrity Virtual Machines on all Integrity servers. HPVM supports guests running on HP-UX 11i v3 hosts – guests can run Linux, OpenVMS 8.4 or HP-UX. HP supports online VM guest migration, where encryption can secure the guest contents during migration. HP-UX 11i v3 scales as follows: 256 processor cores 8 TB main memory 32 TB maximum file system 16 TB maximum file size 128 million ZB—16 million logical units each up to 8ZB. "HP-UX 11i v3". Retrieved 2017-10-31; the 11i v2 release introduced kernel-based intrusion detection, strong random number generation, stack buffer overflow protection, security partitioning, role-based access management, various open-source security tools.
HP classifies the operating system's security features into three categories: data and identity: Release 6.x introduced the context dependent files feature, a method of allowing a fileserver to serve different configurations and binaries to different client machines in a heterogeneous environment. A directory containing such files had its suid bit set and was made hidden from both ordinary and root processes under normal use; such a scheme was sometimes exploited by intruders to hide malicious data. CDFs and the CDF filesystem were dropped with release 10.0. HP-UX operating systems supports a variety of PA-RISC systems; the 11.0 added support for Integrity-based servers for the transition from PA-RISC to Itanium. HP-UX 11i v1.5 is the first version. On the introduction of HP-UX 11i v2 the operating system supported both of these architectures. HP-UX 11i supports HP Integrity Servers of HP BL server blade family; these servers use the Intel Itanium architecture. HP-UX 11i v2 and 11i v3 support HP's CX series servers.
CX stands for carrier grade and is used for telco industry with -48V DC support and is NEBS certified. Both of these systems are discontinued. HP-UX supports HP's RX series of servers. Prior to the release of HP-UX version 11.11, HP used a decimal version numbering scheme with the first number giving the major release and the number following the decimal showing the minor release. With 11.11, HP made a marketing decision to name their releases 11i followed by a v for the version. The i was intended to indicate the OS is Internet-enabled, but the effective result was a dual version-numbering scheme. 1.0 First release for HP 9000 Series 500. HP-UX for Series 500 was different that HP-UX for any other HP machines, as it was layered atop a Series 500 specific operating system called SUNOS. 1.0 AT&T System III based. Support for the HP Integral PC; the kernel runs from ROM. 2.0 First release for HP's early Motorola 68000-based workstations 5.0 ROM-based AT&T System V for the HP Integral PC. Distinct from a HP-UX 5.x for Series 200/300.
3.x HP 9000 Series 600/800 only. Note: 2.x/3.x were developed in parallel with 5.x/6.x, so, for example, 3.x was contemporary with 6.x. The two lines were united at HP-UX 7.x. 6.x Support for HP 9000 Series 300 only. Introduced sockets from 4.3BSD. This version introduced the above-discussed context dependent files, which were removed in release 10 because of their security risks. 7.x Support for HP 9000 Series 300/400, 600/700 /800 HP systems. Provided OSF/Motif. 8.x Support for HP 9000 Series 300/400 600/700/800 systems. Shared libraries introduced. 9.x 9.00, 9.02, 9.04, 9.01, 9.03, 9.05, 9.07, 9.08, 9.09, 9.09+, 9.10. These provided support for the HP 9000 800 systems. Introduced System Administration Manager; the Logical Volume Manager was presented in 9.00 for the Series 800. 10.0 This major release saw a convergence of the operating system between the HP 9000 Series 700 and Series 800 systems, dropping suppor
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
OpenVMS is a closed-source, proprietary computer operating system for use in general-purpose computing. It is the successor to the VMS Operating System, produced by Digital Equipment Corporation, first released in 1977 for its series of VAX-11 minicomputers; the 11/780 was introduced at DEC's Oct. 1977 annual shareholder's meeting. In the 1990s, it was used for the successor series of DEC Alpha systems. OpenVMS runs on the HP Itanium-based families of computers; as of 2019, a port to the x86-64 architecture is underway. The name VMS is derived from virtual memory system, according to one of its principal architectural features. OpenVMS is a proprietary operating system. OpenVMS is a multi-user, multiprocessing virtual memory-based operating system designed for use in time-sharing, batch processing, transaction processing; when process priorities are suitably adjusted, it may approach real-time operating system characteristics. The system offers high availability through clustering and the ability to distribute the system over multiple physical machines.
This allows the system to be tolerant against disasters that may disable individual data-processing facilities. OpenVMS contains a graphical user interface, a feature, not available on the original VAX-11/VMS system. Prior to the introduction of DEC VAXstation systems in the 1980s, the operating system was used and managed from text-based terminals, such as the VT100, which provide serial data communications and screen-oriented display features. Versions of VMS running on DEC Alpha workstations in the 1990s supported OpenGL and Accelerated Graphics Port graphics adapters. Enterprise-class environments select and use OpenVMS for various purposes including mail servers, network services, manufacturing or transportation control and monitoring, critical applications and databases, environments where system uptime and data access is critical. System up-times of more than 10 years have been reported, features such as rolling upgrades and clustering allow clustered applications and data to remain continuously accessible while operating system software and hardware maintenance and upgrades are performed, or when a whole data center is destroyed.
Customers using OpenVMS include banks and financial services and healthcare, network information services, large-scale industrial manufacturers of various products. As of mid-2014, Hewlett-Packard licensed the development of OpenVMS to VMS Software Inc.. VMS Software will be responsible for developing OpenVMS, supporting existing hardware and providing roadmap to clients; the company has a team of veteran developers that developed the software during DEC's ownership. In April 1975, Digital Equipment Corporation embarked on a hardware project, code named Star, to design a 32-bit virtual address extension to its PDP-11 computer line. A companion software project, code named Starlet, was started in June 1975 to develop a new operating system, based on RSX-11M, for the Star family of processors; these two projects were integrated from the beginning. Gordon Bell was the VP lead on its architecture. Roger Gourd was the project lead for the Starlet program, with software engineers Dave Cutler, Dick Hustvedt, Peter Lipman acting as the technical project leaders, each having responsibility for a different area of the operating system.
The Star and Starlet projects culminated in the VAX 11/780 computer and the VAX-11/VMS operating system. The Starlet name survived in VMS as a name of several of the main system libraries, including STARLET. OLB and STARLET. MLB. Over the years the name of the product has changed. In 1980 it was renamed, with version 2.0 release, to VAX/VMS. With the introduction of the MicroVAX range such as the MicroVAX I, MicroVAX II and MicroVAX 2000 in the mid-to-late 1980s, DIGITAL released MicroVMS versions targeted for these platforms which had much more limited memory and disk capacity. MicroVMS kits were released for VAX/VMS 4.4 to 4.7 on TK50 tapes and RX50 floppy disks, but discontinued with VAX/VMS 5.0. In 1991, VMS was renamed to OpenVMS as an indication for its support of "open systems" industry standards such as POSIX and Unix compatibility, to drop the hardware connection as the port to DIGITAL's 64-bit Alpha RISC processor was in process; the OpenVMS name first appeared after the version 5.4-2 release.
The VMS port to Alpha resulted in the creation of a second and separate source code libraries for the VAX 32-bit source code library and a second and new source code library for the Alpha 64-bit architectures. 1992 saw the release of the first version of OpenVMS for Alpha AXP systems, designated OpenVMS AXP V1.0. The decision to use the 1.x version numbering stream for the pre-production quality releases of OpenVMS AXP caused confusion for some customers and was not repeated in the next platform port to the Itanium. In 1994, with the release of OpenVMS version 6.1, feature parity between the VAX and Alpha variants was achieved. This was the so-called Functional Equivalence release, in the marketing materials of the time; some features were missing however, e.g. based shareable images, which were implemented in versions. Subsequent version numberings for the VAX and Alpha variants of the product have remaine
Solaris (operating system)
Solaris is a Unix operating system developed by Sun Microsystems. It superseded their earlier SunOS in 1993. In 2010, after the Sun acquisition by Oracle, it was renamed Oracle Solaris. Solaris is known for its scalability on SPARC systems, for originating many innovative features such as DTrace, ZFS and Time Slider. Solaris supports SPARC and x86-64 servers from Oracle and other vendors. Solaris is registered as compliant with the Single UNIX Specification. Solaris was developed as proprietary software. In June 2005, Sun Microsystems released most of the codebase under the CDDL license, founded the OpenSolaris open-source project. With OpenSolaris, Sun wanted to build a user community around the software. After the acquisition of Sun Microsystems in January 2010, Oracle decided to discontinue the OpenSolaris distribution and the development model. In August 2010, Oracle discontinued providing public updates to the source code of the Solaris kernel turning Solaris 11 back into a closed source proprietary operating system.
Following that, in 2011 the Solaris 11 kernel source code leaked to BitTorrent. However, through the Oracle Technology Network, industry partners can still gain access to the in-development Solaris source code. Source code for the open source components of Solaris 11 is available for download from Oracle. In 1987, AT&T Corporation and Sun announced that they were collaborating on a project to merge the most popular Unix variants on the market at that time: Berkeley Software Distribution, UNIX System V, Xenix; this became Unix System V Release 4. On September 4, 1991, Sun announced that it would replace its existing BSD-derived Unix, SunOS 4, with one based on SVR4; this was identified internally as SunOS 5, but a new marketing name was introduced at the same time: Solaris 2. The justification for this new overbrand was that it encompassed not only SunOS, but the OpenWindows graphical user interface and Open Network Computing functionality. Although SunOS 4.1.x micro releases were retroactively named Solaris 1 by Sun, the Solaris name is used exclusively to refer only to the releases based on SVR4-derived SunOS 5.0 and later.
For releases based on SunOS 5, the SunOS minor version is included in the Solaris release number. For example, Solaris 2.4 incorporates SunOS 5.4. After Solaris 2.6, the 2. was dropped from the release name, so Solaris 7 incorporates SunOS 5.7, the latest release SunOS 5.11 forms the core of Solaris 11.4. Although SunSoft stated in its initial Solaris 2 press release their intent to support both SPARC and x86 systems, the first two Solaris 2 releases, 2.0 and 2.1, were SPARC-only. An x86 version of Solaris 2.1 was released in June 1993, about 6 months after the SPARC version, as a desktop and uniprocessor workgroup server operating system. It included the Wabi emulator to support Windows applications. At the time, Sun offered the Interactive Unix system that it had acquired from Interactive Systems Corporation. In 1994, Sun released Solaris 2.4, supporting both SPARC and x86 systems from a unified source code base. On September 2, 2017, Simon Phipps, a former Sun Microsystems employee not hired by Oracle in the acquisition, reported on Twitter that Oracle had laid off the Solaris core development staff, which many interpreted as sign that Oracle no longer intended to support future development of the platform.
While Oracle did have a large layoff of Solaris development engineering staff, development continues today of which Solaris 11.4 was released in 2018. Solaris uses a common code base for the platforms it supports: i86pc. Solaris has a reputation for being well-suited to symmetric multiprocessing, supporting a large number of CPUs, it has been integrated with Sun's SPARC hardware, with which it is marketed as a combined package. This has led to more reliable systems, but at a cost premium compared to commodity PC hardware. However, it has supported x86 systems since Solaris 2.1 and 64-bit x86 applications since Solaris 10, allowing Sun to capitalize on the availability of commodity 64-bit CPUs based on the x86-64 architecture. Sun has marketed Solaris for use with both its own "x64" workstations and servers based on AMD Opteron and Intel Xeon processors, as well as x86 systems manufactured by companies such as Dell, Hewlett-Packard, IBM; as of 2009, the following vendors support Solaris for their x86 server systems: Dell – will "test and optimize Solaris and OpenSolaris on its rack and blade servers and offer them as one of several choices in the overall Dell software menu" Intel Hewlett Packard Enterprise – distributes and provides software technical support for Solaris on BL, DL, SL platforms Fujitsu SiemensAs of July 2010, Dell and HP certify and resell Oracle Solaris, Oracle Enterprise Linux and Oracle VM on their respective x86 platforms, IBM stopped direct support for Solaris on x64 kit.
Solaris 2.5.1 included support for the PowerPC platform, but the port was canceled before the Solaris 2.6 release. In January 2006, a community of developers at Blastwave began work on a PowerPC port which they named Polaris. In October 2006, an OpenSolaris community project based on the Blastwave efforts and Sun Labs' Project Pulsar, which re-integrated the relevant parts from Solaris 2.5.1 into OpenSolaris, announced its first official source code release. A port of Solaris to the Intel Itanium architecture was announced in 1997 but never brought to market. On November 28, 2007, IBM, Sine Nomine Associates demonstrated a preview of OpenSolaris for System z running on an IBM System z mainframe under z/VM, called Sirius
AIX is a series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms. Released for the IBM RT PC RISC workstation, AIX now supports or has supported a wide variety of hardware platforms, including the IBM RS/6000 series and POWER and PowerPC-based systems, IBM System i, System/370 mainframes, PS/2 personal computers, the Apple Network Server. AIX is based on UNIX System V with 4.3BSD-compatible extensions. It is one of six commercial operating systems that have versions certified to The Open Group's UNIX 03 standard; the AIX family of operating systems debuted in 1986, became the standard operating system for the RS/6000 series on its launch in 1990, is still developed by IBM. It is supported on IBM Power Systems alongside IBM i and Linux. AIX was the first operating system to have a journaling file system, IBM has continuously enhanced the software with features such as processor and network virtualization, dynamic hardware resource allocation, reliability engineering ported from its mainframe designs.
Unix started life at AT&T's Bell Labs research center in the early 1970s, running on DEC minicomputers. By 1976, the operating system was in use at various academic institutions, including Princeton, where Tom Lyon and others ported it to the S/370, to run as a guest OS under VM/370; this port would grow out to become UTS, a mainframe Unix offering by IBM's competitor Amdahl Corporation. IBM's own involvement in Unix can be dated to 1979, when it assisted Bell Labs in doing its own Unix port to the 370. In the process, IBM made modifications to the TSS/370 hypervisor to better support Unix, it took until 1985 for IBM to offer its own Unix on the S/370 platform, IX/370, developed by Interactive Systems Corporation and intended by IBM to compete with Amdahl UTS. The operating system offered special facilities for interoperating with PC/IX, Interactive/IBM's version of Unix for IBM PC compatible hardware, was licensed at $10,000 per sixteen concurrent users. AIX Version 1, introduced in 1986 for the IBM RT PC workstation, was based on UNIX System V Releases 1 and 2.
In developing AIX, IBM and Interactive Systems Corporation incorporated source code from 4.2 and 4.3 BSD UNIX. Among other variants, IBM produced AIX Version 3, based on System V Release 3, for their POWER-based RS/6000 platform. Since 1990, AIX has served as the primary operating system for the RS/6000 series. AIX Version 4, introduced in 1994, added symmetric multiprocessing with the introduction of the first RS/6000 SMP servers and continued to evolve through the 1990s, culminating with AIX 4.3.3 in 1999. Version 4.1, in a modified form, was the standard operating system for the Apple Network Server systems sold by Apple Computer to complement the Macintosh line. In the late 1990s, under Project Monterey, IBM and the Santa Cruz Operation planned to integrate AIX and UnixWare into a single 32-bit/64-bit multiplatform UNIX with particular emphasis on running on Intel IA-64 architecture CPUs. A beta test version of AIX 5L for IA-64 systems was released, but according to documents released in the SCO v. IBM lawsuit, less than forty licenses for the finished Monterey Unix were sold before the project was terminated in 2002.
In 2003, the SCO Group alleged that IBM had misappropriated licensed source code from UNIX System V Release 4 for incorporation into AIX. IBM maintains that their license was irrevocable, continued to sell and support the product until the litigation was adjudicated. AIX was a component of the 2003 SCO v. IBM lawsuit, in which the SCO Group filed a lawsuit against IBM, alleging IBM contributed SCO's intellectual property to the Linux codebase; the SCO Group, who argued they were the rightful owners of the copyrights covering the Unix operating system, attempted to revoke IBM's license to sell or distribute the AIX operating system. In March 2010, a jury returned a verdict finding that Novell, not the SCO Group, owns the rights to Unix. AIX 6 was announced in May 2007, it ran as an open beta from June 2007 until the general availability of AIX 6.1 on November 9, 2007. Major new features in AIX 6.1 included full role-based access control, workload partitions, enhanced security, Live Partition Mobility on the POWER6 hardware.
AIX 7.1 was announced in April 2010, an open beta ran until general availability of AIX 7.1 in September 2010. Several new features, including better scalability, enhanced clustering and management capabilities were added. AIX 7.1 includes a new built-in clustering capability called Cluster Aware AIX. AIX is able to organize multiple LPARs through the multipath communications channel to neighboring CPUs, enabling high-speed communication between processors; this enables multi-terabyte memory address range and page table access to support global petabyte shared memory space for AIX POWER7 clusters so that software developers can program a cluster as if it were a single system, without using message passing. AIX administrators can use this new capability to cluster a pool of AIX nodes. By default, AIX V7.1 pins kernel memory and includes support to allow applications to pin their kernel stack. Pinning kernel memory and the kernel
Z/OS is a 64-bit operating system for IBM mainframes, produced by IBM. It is the successor to OS/390, which in turn followed a string of MVS versions. Like OS/390, z/OS combines a number of separate, related products, some of which are still optional. Z/OS offers the attributes of modern operating systems but retains much of the functionality originating in the 1960s and each subsequent decade, still found in daily use. Z/OS was first introduced in October 2000. Z/OS supports stable mainframe systems and standards such as CICS, COBOL, IMS, DB2, RACF, SNA, IBM MQ, record-oriented data access methods, REXX, CLIST, SMP/E, JCL, TSO/E, ISPF, among others. However, z/OS supports 64-bit Java, C, C++, UNIX APIs and applications through UNIX System Services – The Open Group certifies z/OS as a compliant UNIX operating system – with UNIX/Linux-style hierarchical HFS and zFS file systems; as a result, z/OS hosts a broad range of open source software. Z/OS can communicate directly via TCP/IP, including IPv6, includes standard HTTP servers along with other common services such as FTP, NFS, CIFS/SMB.
Another central design philosophy is support for high quality of service within a single operating system instance, although z/OS has built-in support for Parallel Sysplex clustering. Z/OS has a Workload Manager and dispatcher which automatically manages numerous concurrently hosted units of work running in separate key-protected address spaces according to dynamically adjustable goals; this capability inherently supports multi-tenancy within a single operating system image. However, modern IBM mainframes offer two additional levels of virtualization: LPARs and z/VM; these new functions within the hardware, z/OS, z/VM — and Linux and OpenSolaris support — have encouraged development of new applications for mainframes. Many of them utilize the WebSphere Application Server for z/OS middleware. From its inception z/OS has supported tri-modal addressing. Up through Version 1.5, z/OS itself could start in either 31-bit ESA/390 or 64-bit z/Architecture mode, so it could function on older hardware albeit without 64-bit application support on those machines.
IBM support for z/OS 1.5 ended on March 31, 2007. Now z/OS only runs in 64-bit mode. Application programmers can still use any addressing mode: all applications, regardless of their addressing mode, can coexist without modification, IBM maintains commitment to tri-modal backward compatibility. However, increasing numbers of middleware products and applications, such as DB2 Version 8 and above, now require and exploit 64-bit addressing. IBM markets z/OS as its flagship operating system, suited for continuous, high-volume operation with high security and stability. Z/OS is available under standard license pricing as well as via IBM Z New Application License Charges and "IBM Z Solution Edition," two lower priced offerings aimed at supporting newer applications. U. S. standard commercial z/OS pricing starts at about $125 per month, including support, for the smallest zNALC installation running the base z/OS product plus a typical set of optional z/OS features. Z/OS introduced Variable Workload License Charges and Entry Workload License Charges which are sub-capacity billing options.
VWLC and EWLC customers only pay for peak monthly z/OS usage, not for full machine capacity as with the previous OS/390 operating system. VWLC and EWLC are available for most IBM software products running on z/OS, their peaks are separately calculated but can never exceed the z/OS peak. To be eligible for sub-capacity licensing, a z/OS customer must be running in 64-bit mode, must have eliminated OS/390 from the system, must e-mail IBM monthly sub-capacity reports. Sub-capacity billing reduces software charges for most IBM mainframe customers. Advanced Workload License Charges is the successor to VWLC on mainframe models starting with the zEnterprise 196, EAWLC is an option on zEnterprise 114 models. AWLC and EAWLC offer further sub-capacity discounts. Within each address space, z/OS permits the placement of only data, not code, above the 2 GB "bar". Z/OS enforces this distinction for performance reasons. There are no architectural impediments to allowing more than 2 GB of application code per address space.
IBM has started to allow Java code running on z/OS to execute above the 2 GB bar, again for performance reasons. Starting with z/OS version 2 release 3, code may be placed and executed above the 2 GB "bar"; however few z/OS services may be invoked from above the "bar". Memory is obtained as "Large Memory Objects" in multiples of 1 MB. There are three types of large memory objects: Unshared – where only the creating address space can access the memory. Shared – where the creating address space can give access to specific other address spaces. Common – where all address spaces can access the memory. Generation Data Group is a special type of file used by IBM's mainframe operating system z/OS; the actual GDG is a description of how many generations of a file are to be kept and how old the oldest generation must be at least before it is deleted. Whenever a new generation is created, the system checks whether one or more obso