Windows XP- History




History

In the mid-1980s, Microsoft and IBM cooperated to develop the OS/2 operating system, which was written in assembly language for single-processor Intel 80286 systems. In 1988, Microsoft decided to make a fresh start and to develop a "new technology" (or NT) portable operating system that supported both the OS/2 and POSIX application-programming interfaces (APIs).

 In October 1988, Dave Cutler, the architect of the DEC VAX/VMS operating system, was hired and given the charter of building this new operating system. Originally, the team planned for NT to use the OS/2 API as its native environment, but during development, NT was changed to use the 32-bit  Windows API (or Win32 API), reflecting the popularity of Windows 3.0. The first versions of NT were Windows NT 3.1 and Windows NT 3.1 Advanced Server. (At that time, 16-bit Windows was at version 3.1.)

Windows NT version 4.0 adopted the Windows 95 user interface and incorporated Internet web-server and web-browser software. In addition, user-interface routines and all graphics code were moved into the kernel to improve performance, with the side effect of decreased system reliability. Although previous versions of NT had been ported to other microprocessor architectures, the Windows 2000 version, released in February 2000, discontinued support for other than Intel (and compatible) processors due to marketplace factors.

Windows 2000 incorporated significant changes over Windows NT. It added Active Directory (an X.500-based directory service), better networking and laptop support, support for plug-and-play devices, a distributed file system, and support for more processors and more memory. In October 2001, Windows XP was released as both an update to the Windows 2000 desktop operating system and a replacement for Windows 95/98. In 2002, the server versions of Windows XP became available (called Windows .Net Server). Windows XP updates the graphical user interface (GUI) with a visual design that takes advantage of more recent hardware advances and many new ease-of-use features.

Windows XP- History

 Numerous features have been added to automatically repair problems in applications and the operating system itself. Windows XP provides better networking and device experience (including zero-configuration wireless, instant messaging, streaming media, and digital photography/video), dramatic performance improvements both for the desktop and large multiprocessors, and better reliability and security than even Windows 2000. Windows XP uses a client-server architecture (like Mach) to implement multiple operating-system personalities, such as Win32 API and POSIX, with user-level processes called subsystems.

 The subsystem architecture allows enhancements to be made to one operating-system personality without affecting the application compatibility of any others. Windows XP is a multiuser operating system, supporting simultaneous access through distributed services or through multiple instances of the graphical user interface via the Windows terminal server. The server versions of Windows XP support simultaneous terminal server sessions from Windows desktop systems.

The desktop versions of terminal server multiplex the keyboard, mouse, and monitor between virtual terminal sessions for each logged-on user. This feature, called fast user switching, allows users to preempt each other at the console of a PC without having to log off and onto the system. Windows XP is the first version of Windows to ship a 64-bit version. The native NT file system (NTPS) and many of the Win32 APIs have always used 64- bit integers where appropriate—so the major extension to 64-bit in Windows XP is support for large addresses. There are two desktop versions of Windows XP. Windows XP Professional is the premium desktop system for power users at work and at home. For home users migrating from Windows 95/98, Window's XP Personal provides the reliability and ease of use of Windows XP, but lacks the more advanced features needed to work seamlessly with Active Directory or rim POSIX applications. The members of the Windows .Net Server family use the same core components as the desktop versions but add a range of features needed for 22.2 Design Principles 785 uses such as webserver farms, print/file servers, clustered systems, and, large datacenter machines. The large datacenter machines can have up to 64 GB of memory and 32 processors on IA32 systems and 128 GB and 64 processors on IA64 systems.



Frequently Asked Questions

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Ans: Mach The Mach operating system traces its ancestry to the Accent operating system developed at Carnegie Mellon University (CMU) (Rashid and Robertson [1981]). Mach's communication system and philosophy are derived from Accent, but many other significant portions of the system (for example, the virtual memory system, task and thread management) were developed from scratch (Rashid [1986], Tevanian et al. [1989], and Accetta et al. [1986]). The Mach scheduler was described in detail by Tevanian et al. [1987a] and Black [1990]. view more..
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Ans: IBM OS/360 The longest line of operating-system development is undoubtedly that of IBM computers. The early IBM computers, such as the IBM 7090 and the IBM 7094, are prime examples of the development of common I/O subroutines, followed by development of a resident monitor, privileged instructions, memory protection, and simple batch processing. These systems were developed separately, often by each site independently. As a result, IBM was faced with many different computers, with different languages and different system software. view more..
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Ans: MULTICS The MULTICS operating system (Corbato and Vyssotsky [1965], Organick [1972]) was designed at MIT as a natural extension of CTSS. CTSS and other early time-sharing systems were so successful that they created an immediate desire to proceed quickly to bigger and better systems. As larger computers became available, the designers of CTSS set out to create a time-sharing utility. Computing service would be provided like electrical power. Large computer systems would be connected by telephone wires to terminals in offices and homes throughout a city. The operating system would be a time-shared system running continuously with a vast file system of shared programs and data. view more..
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Ans: History In the mid-1980s, Microsoft and IBM cooperated to develop the OS/2 operating system, which was written in assembly language for single-processor Intel 80286 systems. In 1988, Microsoft decided to make a fresh start and to develop a "new technology" (or NT) portable operating system that supported both the OS/2 and POSIX application-programming interfaces (APIs). view more..
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Ans: Access Matrix Our model of protection can be viewed abstractly as a matrix, called an access matrix. The rows of the access matrix represent domains, and the columns represent objects. Each entry in the matrix consists of a set of access rights. Because the column defines objects explicitly, we can omit the object name from the access right. The entry access(/,/) defines the set of operations that a process executing in domain Dj can invoke on object . view more..
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Ans: Election Algorithms Many distributed algorithms employ a coordinator process that performs functions needed by the other processes in the system. These functions include enforcing mutual exclusion, maintaining a global wait-for graph for deadlock detection, replacing a lost token, and controlling an input or output device in the system. If the coordinator process fails due to the failure of the site at which it resides, the system can continue only by restarting a new copy of the coordinator on some other site. The algorithms that determine where a new copy of the coordinator should be restarted are called election algorithms. Election algorithms assume that a unique priority number is associated with each active process in the system. For ease of notation, we assume that the priority number of process P, is /. To simplify our discussion, we assume a one-to-one correspondence between processes and sites and thus refer to both as processes. view more..
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Ans: Reaching Agreement For a system to be reliable, we need a mechanism that allows a set of processes to agree on a common value. Such an agreement may not take place, for several reasons. First, the communication medium may be faulty, resulting in lost or garbled messages. Second, the processes themselves may be faulty, resulting in unpredictable process behavior. The best we can hope for in this case is that processes fail in a clean way, stopping their execution without deviating from their normal execution pattern. In the worst case, processes may send garbled or incorrect messages to other processes or even collaborate with other failed processes in an attempt to destroy the integrity of the system. view more..
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Ans: Atomicity We introduced the concept of an atomic transaction, which is a program unit that must be executed atomically. That is, either all the operations associated with it are executed to completion, or none are performed. When we are dealing with a distributed system, ensuring the atomicity of a transaction becomes much more complicated than in a centralized system. This difficulty occurs because several sites may be participating in the execution of a single transaction. The failure of one of these sites, or the failure of a communication link connecting the sites, may result in erroneous computations. Ensuring that the execution of transactions in the distributed system preserves atomicity is the function of the transaction coordinator. Each site has its own local transaction coordinator, which is responsible for coordinating the execution of all the transactions initiated at that site. view more..
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Ans: Concurrency Control We move next to the issue of concurrency control. In this section, we show how certain of the concurrency-control schemes discussed in Chapter 6 can be modified for use in a distributed environment. The transaction manager of a distributed database system manages the execution of those transactions (or subtransactions) that access data stored in a local site. Each such transaction may be either a local transaction (that is, a transaction that executes only at that site) or part of a global transaction (that is, a transaction that executes at several sites). Each transaction manager is responsible for maintaining a log for recovery purposes and for participating in an appropriate concurrency-control scheme to coordinate the conciirrent execution of the transactions executing at that site. As we shall see, the concurrency schemes described in Chapter 6 need to be modified to accommodate the distribution of transactions. view more..
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Ans: Features of Real-Time Kernels In this section, we discuss the features necessary for designing an operating system that supports real-time processes. Before we begin, though, let's consider what is typically not needed for a real-time system. We begin by examining several features provided in many of the operating systems discussed so far in this text, including Linux, UNIX, and the various versions of Windows. These systems typically provide support for the following: • A variety of peripheral devices such as graphical displays, CD, and DVD drives • Protection and security mechanisms • Multiple users Supporting these features often results in a sophisticated—and large—kernel. For example, Windows XP has over forty million lines of source code. view more..
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Ans: Implementing Real-Time Operating Systems Keeping in mind the many possible variations, we now identify the features necessary for implementing a real-time operating system. This list is by no means absolute; some systems provide more features than we list below, while other systems provide fewer. • Preemptive, priority-based scheduling • Preemptive kernel • Minimized latency view more..
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Ans: VxWorks 5.x In this section, we describe VxWorks, a popular real-time operating system providing hard real-time support. VxWorks, commercially developed by Wind River Systems, is widely used in automobiles, consumer and industrial devices, and networking equipment such as switches and routers. VxWorks is also used to control the two rovers—Spirit and Opportunity—that began exploring the planet Mars in 2004. The organization of VxWorks is shown in Figure 19.12. VxWorks is centered around the Wind microkernel. Recall from our discussion in Section 2.7.3 that microkernels are designed so that the operating-system kernel provides a bare minimum of features; additional utilities, such as networking, file systems, and graphics, are provided in libraries outside of the kernel. This approach offers many benefits, including minimizing the size of the kernel—a desirable feature for an embedded system requiring a small footprint view more..
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Ans: Mutual Exclusion In this section, we present a number of different algorithms for implementing mutual exclusion in a distributed environment. We assume that the system consists of n processes, each of which resides at a different processor. To simplify our discussion, we assume that processes are numbered uniquely from 1 to n and that a one-to-one mapping exists between processes and processors (that is, each process has its own processor). view more..
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Ans: Event Ordering In a centralized system, we can always determine the order in which two events occurred, since the system has a single common memory and clock. Many applications may require us to determine order. For example, in a resourceallocation scheme, we specify that a resource can be used only after the resource has been granted. A distributed system, however, has no common memory and no common clock. Therefore, it is sometimes impossible to say which of two events occurred first. The liappened-before relation is only a partial ordering of the events in distributed systems. Since the ability to define a total ordering is crucial in many applications, we present a distributed algorithm for exterding the happened-before relation to a consistent total ordering of all the events in the system. view more..
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Ans: Types of System Calls System calls can be grouped roughly into five major categories: process control, file manipulation, device manipulation, information maintenance, and communications. In Sections 2.4.1 through 2.4.5, we discuss briefly the types of system calls that may be provided by an operating system. view more..
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Ans: Overview of Mass-Storage Structure In this section we present a general overview of the physical structure of secondary and tertiary storage devices. view more..
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Ans: Atomic Transactions The mutual exclusion of critical sections ensures that the critical sections are executed atomically. That is, if two critical sections are executed concurrently, the result is equivalent to their sequential execution in some unknown order. Although this property is useful in many application domains, in many cases we would like to make sure that a critical section forms a single logical unit of work that either is performed in its entirety or is not performed at all. An example is funds transfer, in which one account is debited and another is credited. Clearly, it is essential for data consistency either that both the credit and debit occur or that neither occur. Consistency of data, along with storage and retrieval of data, is a concern often associated with database systems. Recently, there has been an upsurge of interest in using database-systems techniques in operating systems. view more..
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Ans: Programmer Interface The Win32 API is the fundamental interface to the capabilities of Windows XP. This section describes five main aspects of the Win32 API: access to kernel objects, sharing of objects between processes, process management, interprocess communication, and memory management. view more..




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