Computer Operating System Essay

The Windows series of operating dusts produced by the Microsoft Corporation primarily make use of two file schemes the accuse Allocation Table (FAT) and the New Technology data file musical arrangement (NTFS). Additionally, more or less versions of Windows NT also support the use of the High Performance File System (HPFS), a result of Microsofts joint developer involvement with IBM to produce the OS/2 operating trunk. (Duncan, 1989 Custer, 1994) Initially released with DOS, FAT makes use of a control board which indexes in stageion on which sections of the storage medium argon free, unusable or taken up by files.Disk space is partitioned into distinct units know as sectors or clusters. There is no real organization to the directory organize of FAT, and as such free disk space can go away distributed across many different sectors, resulting in file space beingness allocated in discontiguous sectors. As such, information is highly fragmented and increases seek times. (Micros oft, 2007 Duncan 1989) HPFS was beginning(a) introduced with OS/2. It improved over the core functionality of the FAT system by introducing additional room for meta info attributes.Allocation units were changed from clusters to physical sectors of 512 bytes separately, optimizing the disk space use for each file. HPFS directory entries also hold more attribute data they give single sector FNODEs that serve as the control structure for each directory. Fragmentation is drastically reduced by allocating as much of a file in contiguous sectors. However, the HPFS is dependent on a tops(p) layover which contains the control structures of the root directory indwellingly the root FNODE. The Super Block is thus vulnerable to corruption or loss from a sad sector which can compromise an entire partitions useability.(Microsoft, 2007 Duncan, 1989) NTFS was designed to meet the growing demand for network servers and file sharing capabilities and it borrowed many of its concepts from the H PFS. (Kozierok, 2001) It is a journaling file system which permits greater recoverability by reverting files masking to a useable state in the event of power failures and system crashes that occur during file transactions. Additionally, it also makes use of an expanded meta-data system which allows administrators to ready a wider variety of gravel and use controls to files.The NTFS also optimizes data by storing small files into the Master File Table of the NTFS itself. The larger system format limit provides means that allocation units are much more sharp as well. (Microsoft, 2004 2007) Memory management on Windows has an opening limit of up to 4GB of physical storage, and as such, the allocation of memory to plowes is limited by this cap. By using paging to transfer pages of data between main memory and an auxiliary storage device such as a ticklish drive, it can overcome some of the limitations of physical RAM and enable system processes to have their own 4GB logical addr ess space.Additionally, Windows accords memory protection to process in such a manner as to prevent access to one another, which is crucial to ensure that processes can operate simultaneously without pliable their functionality. (Garg, 2008) Microsoft Windows is essentially an operating system that is built with multi-tasking in mind, which in effect, allows five-fold programs to be fulfild simultaneously. Each employment is calm of one or more processes, each of which provides the resources needed to execute a program.Processes are composed of threads, a discrete unit by which processor time is allocated and a single thread, called the primary thread initiates the process. Each thread may execute any portion of recruit in the process, including those already being execute by another thread. Virtual address space and system resources are shared by threads of a single process, though exception handlers, scheduling priority and other components that determine a threads importance and role within the context of a process. (Microsoft Developer Network, 2008)Windows possesses many of the essential features crucial to basic surety such as authentication and access control, encryption schemes and protection profiles. However, the API for cryptography is easily compromised by the fact that it easily arrogances multiple keys in certifying authority of access. As such, only one code key is necessary to render a system vulnerable. Such a compromise is possible either through accidental disclosure of the snobbish key or when the certifying authority mistakenly issues a certificate.On the aim of network auspices protocol, Windows makes use of IPSec, a cryptographic IP-level protection system which is an open standard in the industry, which functions not only through data encryption and verification of hosts but by detecting modifications made to data during network transit. (Quardt, 2004) Windows security is at its most worryatic with regards to applications an d non-operating system products. share of the problem is that for the purposes of consumer convenience, Microsoft Windows continues to be reliant on legacy applications that contain security threats that were of trivial matter during their initial release.Furthermore, the signature architecture of Microsoft programs is to mix application code and data, such as ActiveX for example, can allow untrusted data from extracurricular the system to activate code. (Quardt, 2004) Also, Windows approves digitally signed code even if it is supplied from extracurricular of the system, which means that a system administrator must implicitly trust whoever has signed the code to have subjected it to appropriate code review. In essence, the problem with Windows security is that trust and certification is so decentralized as to traverse systems administrators total control and authority over the trustworthiness of code.REFERENCESMicrosoft Corporation. (2007, May 7) Overview of FAT, HPFS and NTFS F ile Systems. Retrieved wonderful 9, 2008 from http//support. microsoft. com/kb/100108 Microsoft Corporation (2004, May 5) Local File Systems for Windows. Retrieved August 9, 2008 http//download. microsoft. com/download/5/b/5/5b5bec17-ea71-4653-9539-204a672f11cf/LocFileSys. doc Duncan, R. (1989, September) Design goals and instruction execution of the new High Performance File System. Microsoft Systems Journal, 4, 5, 1-13. Custer, H. (1994) Inside the Windows NT File System. upper-case letter Microsoft Press. Kozierok, C. M. (2001, April 17).Overview and History of NTFS. PCGuide. Garg, P. Windows Memory Management. Intellectual Heaven. Retrieved August 10, 2008 from http//www. intellectualheaven. com/Articles/WinMM. pdf Microsoft Developer Network (2008, August 7). somewhat Processes and Threads. Retrieved August 10, 2008 from http//msdn. microsoft. com/en-us/library/ms681917(VS. 85,printer). aspx Hart, J. M. (2004) Windows System Programming, 3rd Edition. Boston Addison-Wesley Professional. Quandt, S. (2004, May 25) Linux and Windows security compared. Linux. com Retrieved August 11, 2008 from http//www. linux. com/articles/36273? page=2