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Adobe creates some plugins, such as Adobe Camera Raw, but third-party companies develop most plugins, according to Adobe's specifications. Some are free and some are commercial software. Most plugins work with only Photoshop or Photoshop-compatible hosts, but a few can also be run as standalone applications.
There are various types of plugins, such as filter, export, import, selection, color correction, and automation. The most popular plugins are the filter plugins also known as a 8bf plugins , available under the Filter menu in Photoshop. Filter plugins can either modify the current image or create content. Below are some popular types of plugins, and some well-known companies associated with them:. Adobe Camera Raw also known as ACR and Camera Raw is a special plugin, supplied free by Adobe, used primarily to read and process raw image files so that the resulting images can be processed by Photoshop.
Upon loading Photoshop, a sidebar with a variety of tools with multiple image-editing functions appears to the left of the screen. These tools typically fall under the categories of drawing ; painting ; measuring and navigation ; selection ; typing ; and retouching.
These can be expanded to reveal similar tools. In some newer versions hovering along the tools gives a small Video glimpse of the tool. Photoshop includes a few versions of the pen tool. The pen tool creates precise paths that can be manipulated using anchor points. The free form pen tool allows the user to draw paths freehand, and with the magnetic pen tool, the drawn path attaches closely to outlines of objects in an image, which is useful for isolating them from a background.
The Clone Stamp tool duplicates one part of an image to another part of the same image by way of a brush. The duplication is either in full or in part depending on the mode. The user can also clone part of one layer to another layer. The Clone Stamp tool is useful for duplicating objects or removing a defect in an image. Photoshop provides an array of shape tools including rectangles, rounded rectangles, ellipses, polygons and lines.
These shapes can be manipulated by the pen tool, direct selection tool etc. In addition, Photoshop provides its own shapes like animals, signs and plants. The eyedropper tool selects a color from an area of the image that is clicked, and samples it for future use. Selection tools are used to select all or any part of a picture to perform cut, copy, edit, or retouching operations. The crop tool can be used to select a particular area of an image and discard the portions outside the chosen section.
This tool assists in creating a focus point on an image and unnecessary or excess space. The crop tool is in the tools palette, which is located on the right side of the document. By placing the cursor over the image, the user can drag the cursor to the desired area. Once the Enter key is pressed, the area outside the rectangle will be cropped. The area outside the rectangle is the discarded data, which allows for the file size to be decreased.
The slice and slice select tools, like the crop tool, are used in isolating parts of images. The slice tool can be used to divide an image into different sections, and these separate parts can be used as pieces of a web page design once HTML and CSS are applied. The move tool can be used to drag the entirety of a single layer or more if they are selected.
Alternatively, once an area of an image is highlighted, the move tool can be used to manually relocate the selected piece to anywhere on the canvas. The marquee is a tool that can make selections that are a single row, single column, rectangular and elliptical. This tool can also crop an image; it allows for better control. In contrast to the crop tool, the marquee tool allows for more adjustments to the selected area before cropping.
The only marquee tool that does not allow cropping is the elliptical. Although the single row and column marquee tools allow for cropping, they are not ideal, because they only crop a line. The rectangular marquee tool is the preferred option. Once the tool has been selected, dragging the tool across the desired area will select it. The selected area will be outlined by dotted lines, referred to as "marching ants". To set a specific size or ratio, the tool options bar provides these settings.
Before selecting an area, the desired size or ratio must be set by adjusting the width and height. Any changes such as color, filters, location, etc. To crop the selection, the user must go to the image tab and select crop.
The lasso tool is similar to the marquee tool, however, the user can make a custom selection by drawing it freehand. The regular lasso tool allows the user to have drawing capabilities. Photoshop will complete the selection once the mouse button is released. The user may also complete the selection by connecting the end point to the starting point. The "marching ants" will indicate if a selection has been made.
The polygonal lasso tool will draw only straight lines, which makes it an ideal choice for images with many straight lines. Unlike the regular lasso tool, the user must continually click around the image to outline the shape. To complete the selection, the user must connect the end point to the starting point just like the regular lasso tool. Magnetic lasso tool are considered the smart tool. It can do the same as the other two, but it can also detect the edges of an image once the user selects a starting point.
It detects by examining the color pixels as the cursor moves over the desired area. Closing the selection is the same as the other two, which should also should display the "marching ants" once the selection has been closed.
The quick selection tool selects areas based on edges, similarly to the magnetic lasso tool. The difference between this tool and the lasso tool is that there is no starting and ending point.
For this reason, the selected area can be added onto as much as possible without starting over. By dragging the cursor over the desired area, the quick selection tool detects the edges of the image. The "marching ants" allow the user to know what is currently being selected. Once the user is done, the selected area can be edited without affecting the rest of the image.
One of the features that makes this tool especially user friendly is that the SHIFT key is not needed to add more to the selection; by default, extra mouse clicks will be added to the selection rather than creating a new selection.
The magic wand tool selects areas based on pixels of similar values. One click will select all neighboring pixels of similar value within a tolerance level set by the user. If the eyedropper tool is selected in the options bar, then the magic wand can determine the value needed to evaluate the pixels; this is based on the sample size setting in the eyedropper tool. This tool is inferior to the quick selection tool which works much the same but with much better results and more intuitive controls.
The user must decide what settings to use or if the image is right for this tool. The Eraser tool erases content based on the active layer. If the user is on the text layer, then any text across which the tool is dragged will be erased. The eraser will convert the pixels to transparent, unless the background layer is selected. The size and style of the eraser can be selected in the options bar. This tool is unique in that it can take the form of the paintbrush and pencil tools.
In addition to the straight eraser tool, there are two more available options — background eraser and magic eraser. The background eraser deletes any part of the image that is on the edge of an object.
This tool is often used to extract objects from the background. The magic eraser tool deletes based on similar colored pixels. It is very similar to the magic wand tool. This tool is ideal for deleting areas with the same color or tone that contrasts with the rest of the image. Using simple combinations of keys video layers can easily be modified, with other features such as adding text and creating animations using single images.
With the Extended version of Photoshop CS5, 2D elements of an artwork can easily become three-dimensional with the click of a button. Extrusions of texts, an available library of materials for three-dimensional, and even wrapping two-dimensional images around 3D geometry. Third-party plugins have also been added to the most recent version of Photoshop where technologies such as the iPad have integrated the software with different types of applications. Applications like the Adobe Eazel painting app allows the user to easily create paintings with their fingertips and use an array of different paint from dry to wet in order to create rich color blending.
The program will feature cloud syncing with other devices and a simpler interface than the desktop version. The plug-in allows users to remove noise without the side-effect of over-sharpening, add grain, and even perform post-crop vignetting.
From version Artists can add color, adjust the shape or rotate the angles of imported models, or design original 3D models from scratch. The Color Replacement Tool allows the user to change the color, while maintaining the highlights and shadows of the original image, of pieces of the image. By selecting Brushes and right clicking, the Color Replacement Tool is the third option down. What is important to note with this tool is the foreground color.
The foreground color is what will be applied when painting along the chosen part of the image with the Color Replacement tool. Photoshop and derivatives such as Photoshopped or just Shopped have become verbs that are sometimes used to refer to images edited by Photoshop, [47] or any image manipulation program. The same happens not only in English but as the Portuguese Wikipedia entry for image manipulation attests, even in that language, with the trademark being followed by the Portuguese verb termination -ar, yielding the word "photoshopar" to photoshop.
Such derivatives are discouraged by Adobe [6] because, in order to maintain validity and protect the trademark from becoming generic , trademarks must be used as proper nouns. Photoshop's naming scheme was initially based on version numbers, from version 0. Adobe published 7 major and many minor versions before the October introduction of version 8. In February Adobe donated the source code of the 1. The first Photoshop CS was commercially released in October as the eighth major version of Photoshop.
Photoshop CS increased user control with a reworked file browser augmenting search versatility, sorting and sharing capabilities and the Histogram Palette which monitors changes in the image as they are made to the document. Match Color was also introduced in CS, which reads color data to achieve a uniform expression throughout a series of pictures.
Photoshop CS2, released in May , expanded on its predecessor with a new set of tools and features. It included an upgraded Spot Healing Brush, which is mainly used for handling common photographic problems such as blemishes, red-eye, noise, blurring and lens distortion. One of the most significant inclusions in CS2 was the implementation of Smart Objects, which allows users to scale and transform images and vector illustrations without losing image quality, as well as create linked duplicates of embedded graphics so that a single edit updates across multiple iterations.
Adobe responded to feedback from the professional media industry by implementing non-destructive editing as well as the producing and modifying of Bit High Dynamic Range HDR images, which are optimal for 3D rendering and advanced compositing.
FireWire Previews could also be viewed on a monitor via a direct export feature. Image Warping makes it easy to digitally distort an image into a shape by choosing on-demand presets or by dragging control points. The File Browser was upgraded to Adobe Bridge, which functioned as a hub for productivity, imagery and creativity, providing multi-view file browsing and smooth cross-product integration across Adobe Creative Suite 2 software.
Camera Raw version 3. Photoshop CS2 brought a streamlined interface, making it easier to access features for specific instances. In CS2 users were also given the ability to create their own custom presets, which was meant to save time and increase productivity. CS3 improves on features from previous versions of Photoshop and introduces new tools. One of the most significant is the streamlined interface which allows increased performance, speed, and efficiency.
There is also improved support for Camera RAW files which allow users to process images with higher speed and conversion quality. The Black and White adjustment option improves control over manual grayscale conversions with a dialog box similar to that of Channel Mixer. There is more control over print options and better management with Adobe Bridge. The Clone Source palette is introduced, adding more options to the clone stamp tool.
Other features include the nondestructive Smart Filters, optimizing graphics for mobile devices, [53] Fill Light and Dust Busting tools. CS3 Extended includes everything in CS3 and additional features. It also provides the ability to hot-add supported hardware. Windows Server Enterprise is also the required edition to issue custom certificate templates.
Windows Server Datacenter is designed [25] for infrastructures demanding high security and reliability. Windows Server is available for IA, Itanium, and x64 processors.
It supports a maximum of 32 physical processors on IA platform or 64 physical processors on x64 and IA hardware. The Datacenter edition, like the Enterprise edition, supports 8-node clustering.
Clustering increases availability and fault tolerance of server installations by distributing and replicating the service among many servers. This edition supports clustering with each cluster having its own dedicated storage, or with all cluster nodes connected to a common SAN. Windows Compute Cluster Server CCS , released in June , is designed for high-end applications that require high performance computing clusters.
It is designed to be deployed on numerous computers to be clustered together to achieve supercomputing speeds. Each Compute Cluster Server network comprises at least one controlling head node and subordinate processing nodes that carry out most of the work. It ties nodes together with a powerful inter-process communication mechanism which can be complex because of communications between hundreds or even thousands of processors working in parallel.
The application programming interface consists of over functions. A job launcher enables users to execute jobs to be executed in the computing cluster. Windows Storage Server , a part of the Windows Server series, is a specialized server operating system for network-attached storage NAS. Launched in at Storage Decisions in Chicago, it is optimized for use in file and print sharing and also in storage area network SAN scenarios.
It is only available through Original equipment manufacturers OEMs. Windows Storage Server NAS equipment can be headless , which means that they are without any monitors, keyboards or mice, and are administered remotely. Such devices are plugged into any existing IP network and the storage capacity is available to all users. Multiple such NAS servers can be clustered to appear as a single device, which allows responsibility for serving clients to be shared in such a way that if one server fails then other servers can take over often termed a failover which also improves fault-tolerance.
Windows Storage Server can also be used to create a Storage Area Network , in which the data is transferred in terms of chunks rather than files, thus providing more granularity to the data that can be transferred. This provides higher performance to database and transaction processing applications.
Single instance storage SIS scans storage volumes for duplicate files, and moves the duplicate files to the common SIS store. The file on the volume is replaced with a link to the file.
Windows Storage Server R2 provides an index-based, full-text search based on the indexing engine already built into Windows server. Windows Storage Server can be promoted to function as a domain controller; however, this edition is not licensed to run directory services. It can be joined to an existing domain as a member server. Windows Small Business Server SBS is a software suite which includes Windows Server and additional technologies aimed at providing a small business with a complete technology solution.
SBS has the following design limitations, mainly affecting Active Directory: [30]. Windows Home Server was announced on January 7, , at the Consumer Electronics Show by Bill Gates and is intended to be a solution for homes with multiple connected PCs to offer file sharing, automated backups, and remote access.
Intended use was for building firewall, VPN caching servers and similar appliances. Availability of the original version ended May 28, Availability of R2 ended March 5, End of extended support was July 14, all variants except Storage Server [9] , and End of Licence was May 28, R2 and original. All variants continued to receive Critical security updates until the end of extended support: [37]. While many features of the bit variant of Windows XP were brought over into Windows XP Professional x64 Edition, other limitations imposed by constraints such as only supporting bit drivers, and support for bit programs being dropped led to incompatibilities with the bit Windows XP editions available.
Among the improvements are many of the same updates that were provided to Windows XP users with Service Pack 2. Features that are added with Service Pack 1 include:. A full list of updates is available in the Microsoft Knowledge Base. Service Pack 2 for Windows Server was released on March 13, This was followed by build , known as Beta 2 Refresh.
The final build is Microsoft has described Service Pack 2 as a "standard" service pack release containing previously released security updates, hotfixes, and reliability and performance improvements.
Service Pack 2 also adds Windows Server Scalable Networking Pack SNP , [48] which allows hardware acceleration for processing network packets, thereby enabling faster throughput. Windows Server R2 is an updated release of Windows Server , which contains a copy of Windows Server SP1 on one CD and a host of optionally installed new features on another disc, similar to Microsoft Plus!
New features of Windows Server R2 include: [51]. On July 13, , Windows Server 's mainstream support expired and the extended support phase began.
During the extended support phase, Microsoft continued to provide security updates; however, free technical support, warranty claims, and design changes are no longer being offered. Although Windows Server is unsupported, Microsoft released an emergency security patch in May for the OS as well as other unsupported versions of Windows including Windows Vista and Windows 7 RTM without a service pack , to address a vulnerability that was being leveraged by the WannaCry ransomware attack.
Anonymous users from managed to compile the Windows Server source code, as well as a Twitter user who posted videos of the process on YouTube proving that the code was genuine, [57] but was removed from the platform on copyright grounds by Microsoft. The leak was incomplete as it was missing the Winlogon source code and some other components.
Microsoft issued a statement stating that it was investigating the leaks. From Wikipedia, the free encyclopedia. Server operating system by Microsoft released in This article has multiple issues.
Please help improve it or discuss these issues on the talk page. Learn how and when to remove these template messages. This article's lead section may be too short to adequately summarize the key points. Please consider expanding the lead to provide an accessible overview of all important aspects of the article.
October This article needs additional citations for verification. They are designed to operate on small machines with less autonomy e. They are very compact and extremely efficient by design and are able to operate with a limited amount of resources. 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. Such an event-driven system switches between tasks based on their priorities or external events, whereas 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 [ further explanation needed ].
Early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the s, such as resident monitor functions that could automatically run different programs in succession to speed up processing.
Operating systems did not exist in their modern and more complex forms until the early s. When personal computers became popular in the s, operating systems were made for them similar in concept to those used on larger computers. In the s, 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 plugboards.
These were special-purpose systems that, for example, generated ballistics tables for the military or controlled the printing of payroll checks from data on punched paper cards. After programmable general-purpose computers were invented, machine languages consisting of strings of the binary digits 0 and 1 on punched paper tape were introduced that sped up the programming process Stern, In the early s, a computer could execute only one program at a time.
Each user had sole use of the computer for a limited period and would arrive at a scheduled time with their program and data on punched paper cards or punched tape. The program would be loaded into the machine, and the machine would be set to work until the program completed or crashed. Programs could generally be debugged via a front panel using toggle switches and panel lights. It is said that Alan Turing was a master of this on the early Manchester Mark 1 machine, and he was already deriving the primitive conception of an operating system from the principles of the universal Turing machine.
Later machines came with libraries of programs, which would be linked to a user's program to assist in operations such as input and output and compiling generating machine code from human-readable symbolic code. This was the genesis of the modern-day operating system. However, machines still ran a single job at a time. At Cambridge University in England, the job queue was at one time a washing line clothesline from which tapes were hung with different colored clothes-pegs to indicate job priority.
By the late s, programs that one would recognize as an operating system were beginning to appear. In a May paper describing the system, George Ryckman noted:. The development of computer operating systems have materially aided the problem of getting a program or series of programs on and off the computer efficiently.
One of the more famous examples that is often found in discussions of early systems is the Atlas Supervisor , running on the Atlas in The Atlas team itself used the term "supervisor", [13] which was widely used along with "monitor". Brinch Hansen described it as "the most significant breakthrough in the history of operating systems.
These features were included or not included in application software at the option of application programmers, rather than in a separate operating system used by all applications. When a process is terminated for any reason, all of these resources are re-claimed by the operating system. In cooperation with the University of Minnesota, the Kronos and later the NOS operating systems were developed during the s, which supported simultaneous batch and timesharing use.
Like many commercial timesharing systems, its interface was an extension of the Dartmouth BASIC operating systems, one of the pioneering efforts in timesharing and programming languages. In the late s, Control Data and the University of Illinois developed the PLATO operating system, which used plasma panel displays and long-distance time sharing networks.
Plato was remarkably innovative for its time, featuring real-time chat, and multi-user graphical games. MCP also introduced many other ground-breaking innovations, such as being the first commercial implementation of virtual memory.
This proposal was declined by Burroughs management to protect its existing hardware production. From the late s through the late s, several hardware capabilities evolved that allowed similar or ported software to run on more than one system. Early systems had utilized microprogramming to implement features on their systems in order to permit different underlying computer architectures to appear to be the same as others in a series.
The enormous investment in software for these systems made since the s caused most of the original computer manufacturers to continue to develop compatible operating systems along with the hardware.
Notable supported mainframe operating systems include:. The first microcomputers did not have the capacity or need for the elaborate operating systems that had been developed for mainframes and minis; minimalistic operating systems were developed, often loaded from ROM and known as monitors. In the s, Apple Computer Inc. The introduction of the Intel CPU chip in October , [18] with bit architecture and paging capabilities, provided personal computers with the ability to run multitasking operating systems like those of earlier minicomputers and mainframes.
He would lead the development of the Windows NT operating system, which continues to serve as the basis for Microsoft's operating systems line. Steve Jobs , a co-founder of Apple Inc. While the project was highly successful in duplicating the functionality of various parts of UNIX, development of the GNU Hurd kernel proved to be unproductive. In , Finnish computer science student Linus Torvalds , with cooperation from volunteers collaborating over the Internet, released the first version of the Linux kernel.
It was soon merged with the GNU user space components and system software to form a complete operating system. Unix was originally written in assembly language. B was replaced by C , and Unix, rewritten in C, developed into a large, complex family of inter-related operating systems which have been influential in every modern operating system see History.
The name " UNIX " is a trademark of The Open Group which licenses it for use with any operating system that has been shown to conform to their definitions. Unix-like systems run on a wide variety of computer architectures.
They are used heavily for servers in business, as well as workstations in academic and engineering environments. The POSIX standard can be applied to any operating system, although it was originally created for various Unix variants. These operating systems are most commonly found on webservers , although they can also function as a personal computer OS. The Internet owes much of its existence to BSD, as many of the protocols now commonly used by computers to connect, send and receive data over a network were widely implemented and refined in BSD.
In , University of California, Berkeley installed its first Unix system. Over time, students and staff in the computer science department there began adding new programs to make things easier, such as text editors. When Berkeley received new VAX computers in with Unix installed, the school's undergraduates modified Unix even more in order to take advantage of the computer's hardware possibilities. Steve Jobs , upon leaving Apple Inc. Developers like Keith Bostic encouraged the project to replace any non-free code that originated with Bell Labs.
Unlike its predecessor, macOS is a UNIX operating system built on technology that had been developed at NeXT through the second half of the s and up until Apple purchased the company in early Since then, six more distinct "client" and " server " editions of macOS have been released, until the two were merged in OS X Prior to its merging with macOS, the server edition — macOS Server — was architecturally identical to its desktop counterpart and usually ran on Apple's line of Macintosh server hardware.
With Mac OS X v The server tools are now offered as an application. The Linux kernel originated in , as a project of Linus Torvalds , while a university student in Finland.
He posted information about his project on a newsgroup for computer students and programmers, and received support and assistance from volunteers who succeeded in creating a complete and functional kernel. Because of its open license model, the Linux kernel code is available for study and modification, which resulted in its use on a wide range of computing machinery from supercomputers to smartwatches. Although estimates suggest that Linux is used on only 1.
Linux has superseded Unix on many platforms and is used on most supercomputers including the top Linux is also commonly used on other small energy-efficient computers, such as smartphones and smartwatches. Microsoft Windows is a family of proprietary operating systems designed by Microsoft Corporation and primarily targeted to Intel architecture based computers, with an estimated In , Windows 7 overtook Windows XP as the most common version in use.
Microsoft Windows was first released in , as an operating environment running on top of MS-DOS , which was the standard operating system shipped on most Intel architecture personal computers at the time. Windows ME , released in , was the last version in the Win9x family.
Later versions have all been based on the Windows NT kernel. In the past, Windows NT supported additional architectures. Server editions of Windows are widely used, however, Windows' usage on servers is not as widespread as on personal computers as Windows competes against Linux and BSD for server market share.
ReactOS is a Windows-alternative operating system, which is being developed on the principles of Windows — without using any of Microsoft's code. Some are still used in niche markets and continue to be developed as minority platforms for enthusiast communities and specialist applications. Yet other operating systems are used almost exclusively in academia, for operating systems education or to do research on operating system concepts.
A typical example of a system that fulfills both roles is MINIX , while for example Singularity is used purely for research. It was used mainly for research, teaching, and daily work in Wirth's group. Other operating systems have failed to win significant market share, but have introduced innovations that have influenced mainstream operating systems, not least Bell Labs' Plan 9.
The components of an operating system all exist in order to make the different parts of a computer work together. All user software needs to go through the operating system in order to use any of the hardware, whether it be as simple as a mouse or keyboard or as complex as an Internet component.
With the aid of firmware and device drivers , the kernel provides the most basic level of control over all of the computer's hardware devices. It manages memory access for programs in the RAM , it determines which programs get access to which hardware resources, it sets up or resets the CPU's operating states for optimal operation at all times, and it organizes the data for long-term non-volatile storage with file systems on such media as disks, tapes, flash memory, etc. The operating system provides an interface between an application program and the computer hardware, so that an application program can interact with 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 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. An interrupt also known as abort , exception , fault , signal [45] and trap [46] provides an efficient way for most operating systems to react to 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.
The details of how a computer processes an interrupt vary from architecture to architecture, and the details of how interrupt service routines behave vary from operating system to operating system. A software interrupt is a message to a process that an event has occurred. 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. Software interrupts may be error conditions, such as a malformed machine instruction.
Users can send messages to the kernel to modify the behavior of a currently running process. To generate software interrupts in Unix-like operating systems, the kill pid,signum system call will send a signal to another process.
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. Signals may be classified into 7 categories. Some computers require an interrupt for each character or word, costing 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.
Since the Intel , most [h] CPUs have received hardware interrupts through interrupt pins. When a computer user types a key on the keyboard, typically the character appears immediately on the screen. Likewise, when a user moves a mouse , the cursor immediately moves across the screen. If a device is setup to be a block device , then an interrupt will be generated following each data block transfer. To fulfill this service, a direct memory access DMA chip is installed on the motherboard.
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. When the writing process has its time slice expired, the operating system will: [74].
With the program counter now reset, the interrupted process will resume its time slice. Separate from the architecture, a device may have a DMA chip installed to perform direct memory access. Modern computers support multiple modes of operation. CPUs with this capability offer at least two modes: user mode and supervisor mode. In general terms, supervisor mode operation allows unrestricted access to all machine resources, including all MPU instructions.
User mode operation sets limits on instruction use and typically disallows direct access to machine resources.
CPUs might have other modes similar to user mode as well, such as the virtual modes in order to emulate older processor types, such as bit processors on a bit one, or bit processors on a bit one.
At power-on or reset, the system begins in supervisor mode. Once an operating system kernel has been loaded and started, the boundary between user mode and supervisor mode also known as kernel mode can be established. Supervisor mode is used by the kernel for low level tasks that need unrestricted access to hardware, such as controlling how memory is accessed, and communicating with devices such as disk drives and video display devices.
User mode, in contrast, is used for almost everything else. Application programs, such as word processors and database managers, operate within user mode, and can only access machine resources by turning control over to the kernel, a process which causes a switch to supervisor mode.
Typically, the transfer of control to the kernel is achieved by executing a software interrupt instruction, such as the Motorola TRAP instruction. The software interrupt causes the processor to switch from user mode to supervisor mode and begin executing code that allows the kernel to take control.
In user mode, programs usually have access to a restricted set of processor instructions, and generally cannot execute any instructions that could potentially cause disruption to the system's operation. In supervisor mode, instruction execution restrictions are typically removed, allowing the kernel unrestricted access to all machine resources. The term "user mode resource" generally refers to one or more CPU registers, which contain information that the running program isn't allowed to alter.
Attempts to alter these resources generally cause a switch to supervisor mode, where the operating system can deal with the illegal operation the program was attempting; for example, by forcibly terminating "killing" the program.
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 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 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 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 MMU , which doesn't 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 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. 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 a program tries to access memory that isn't in its current range of accessible memory, but nonetheless has been allocated to it, the kernel is interrupted in the same way as it would if the program were to exceed its allocated memory.
See section on memory management. Under UNIX this kind of interrupt is referred to as 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 a particular application's memory is stored, or even whether or not it has actually 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.
Windows Vista editions.Windows server 2012 standard memory limit free
Mainstream support ended on April 12, Extended support ended on April 12, [11] [12]. Windows Server is the second version of Windows Server operating system produced by Microsoft. It is part of the Windows NT family of operating systems and was released on April 24, An updated version , Windows Server R2, was released to manufacturing on December 6, Windows Server is based on the consumer operating system, Windows XP.
Windows Server is the follow-up to Windows Server, incorporating compatibility and other features from Windows XP. Unlike Windows , Windows Server 's default installation has none of the server components enabled, to reduce the attack surface of new machines.
Windows Server includes compatibility modes to allow older applications to run with greater stability. It was made more compatible with Windows NT 4. Windows Server brought in enhanced Active Directory compatibility and better deployment support to ease the transition from Windows NT 4.
Windows Server is the first server edition of Windows to support the IA64 and x64 architectures. The product went through several name changes during the course of development. When first announced in , it was known by its codename "Whistler Server"; it was named "Windows Server" for a brief time in mid, followed by "Windows.
NET Server" and "Windows. NET Server ". After Microsoft chose to focus the ". NET" branding on the. Windows Server was the first Microsoft Windows version which was thoroughly subjected to semi-automated testing for bugs with a software system called PREfast [17] developed by computer scientist Amitabh Srivastava at Microsoft Research. Microsoft co-founder Bill Gates stated that Windows Server was Microsoft's "most rigorously tested software to date.
Microsoft used Windows Server 's kernel in the development of Windows Vista. Windows Server comes in a number of editions, each targeted towards a particular size and type of business. NET technology. Domain controller and Terminal Services functionality are not included on Web Edition. However, Remote Desktop for Administration is available. Only 10 concurrent file-sharing connections are allowed at any moment.
NET Framework version 2. When using it for storage or as a back-end with another remote server as the front-end, CALs may still be required. Microsoft Windows Server Standard is aimed towards small to medium-sized businesses. Standard Edition supports file and printer sharing, offers secure Internet connectivity, and allows centralized desktop application deployment.
A specialized variant for the x64 architecture was released in April Windows Server Enterprise is aimed towards medium to large businesses. It also provides the ability to hot-add supported hardware. Windows Server Enterprise is also the required edition to issue custom certificate templates. Windows Server Datacenter is designed [25] for infrastructures demanding high security and reliability. Windows Server is available for IA, Itanium, and x64 processors. It supports a maximum of 32 physical processors on IA platform or 64 physical processors on x64 and IA hardware.
The Datacenter edition, like the Enterprise edition, supports 8-node clustering. Clustering increases availability and fault tolerance of server installations by distributing and replicating the service among many servers. This edition supports clustering with each cluster having its own dedicated storage, or with all cluster nodes connected to a common SAN. Windows Compute Cluster Server CCS , released in June , is designed for high-end applications that require high performance computing clusters.
It is designed to be deployed on numerous computers to be clustered together to achieve supercomputing speeds. Each Compute Cluster Server network comprises at least one controlling head node and subordinate processing nodes that carry out most of the work. It ties nodes together with a powerful inter-process communication mechanism which can be complex because of communications between hundreds or even thousands of processors working in parallel. The application programming interface consists of over functions.
A job launcher enables users to execute jobs to be executed in the computing cluster. Windows Storage Server , a part of the Windows Server series, is a specialized server operating system for network-attached storage NAS. Launched in at Storage Decisions in Chicago, it is optimized for use in file and print sharing and also in storage area network SAN scenarios.
It is only available through Original equipment manufacturers OEMs. Windows Storage Server NAS equipment can be headless , which means that they are without any monitors, keyboards or mice, and are administered remotely. Such devices are plugged into any existing IP network and the storage capacity is available to all users. Multiple such NAS servers can be clustered to appear as a single device, which allows responsibility for serving clients to be shared in such a way that if one server fails then other servers can take over often termed a failover which also improves fault-tolerance.
Windows Storage Server can also be used to create a Storage Area Network , in which the data is transferred in terms of chunks rather than files, thus providing more granularity to the data that can be transferred. This provides higher performance to database and transaction processing applications. Single instance storage SIS scans storage volumes for duplicate files, and moves the duplicate files to the common SIS store.
The file on the volume is replaced with a link to the file. Windows Storage Server R2 provides an index-based, full-text search based on the indexing engine already built into Windows server.
Windows Storage Server can be promoted to function as a domain controller; however, this edition is not licensed to run directory services. It can be joined to an existing domain as a member server. Windows Small Business Server SBS is a software suite which includes Windows Server and additional technologies aimed at providing a small business with a complete technology solution.
SBS has the following design limitations, mainly affecting Active Directory: [30]. Windows Home Server was announced on January 7, , at the Consumer Electronics Show by Bill Gates and is intended to be a solution for homes with multiple connected PCs to offer file sharing, automated backups, and remote access.
Intended use was for building firewall, VPN caching servers and similar appliances. Availability of the original version ended May 28, Availability of R2 ended March 5, End of extended support was July 14, all variants except Storage Server [9] , and End of Licence was May 28, R2 and original. All variants continued to receive Critical security updates until the end of extended support: [37]. While many features of the bit variant of Windows XP were brought over into Windows XP Professional x64 Edition, other limitations imposed by constraints such as only supporting bit drivers, and support for bit programs being dropped led to incompatibilities with the bit Windows XP editions available.
Among the improvements are many of the same updates that were provided to Windows XP users with Service Pack 2. Features that are added with Service Pack 1 include:. A full list of updates is available in the Microsoft Knowledge Base. Service Pack 2 for Windows Server was released on March 13, This was followed by build , known as Beta 2 Refresh. The final build is Microsoft has described Service Pack 2 as a "standard" service pack release containing previously released security updates, hotfixes, and reliability and performance improvements.
Service Pack 2 also adds Windows Server Scalable Networking Pack SNP , [48] which allows hardware acceleration for processing network packets, thereby enabling faster throughput. Windows Server R2 is an updated release of Windows Server , which contains a copy of Windows Server SP1 on one CD and a host of optionally installed new features on another disc, similar to Microsoft Plus!
New features of Windows Server R2 include: [51]. On July 13, , Windows Server 's mainstream support expired and the extended support phase began. During the extended support phase, Microsoft continued to provide security updates; however, free technical support, warranty claims, and design changes are no longer being offered.
Although Windows Server is unsupported, Microsoft released an emergency security patch in May for the OS as well as other unsupported versions of Windows including Windows Vista and Windows 7 RTM without a service pack , to address a vulnerability that was being leveraged by the WannaCry ransomware attack.
Anonymous users from managed to compile the Windows Server source code, as well as a Twitter user who posted videos of the process on YouTube proving that the code was genuine, [57] but was removed from the platform on copyright grounds by Microsoft. The leak was incomplete as it was missing the Winlogon source code and some other components.
Microsoft issued a statement stating that it was investigating the leaks. From Wikipedia, the free encyclopedia. Server operating system by Microsoft released in This article has multiple issues. Please help improve it or discuss these issues on the talk page. Learn how and when to remove these template messages.
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