Network Operating Systems Essay Example for Free

Network Operating Systems Essay Multi tasking is when the operating system seems to be performing two or more tasks at the same time, i.e. MS Word and MS Access, however these tasks are not actually running simultaneously as they are actually resident in memory processor is actually switching between tasks at a very high speed, therefore each user sees their own task as having priority. One disadvantage can be that the more programs that are run by the user, the more memory that is required. Multi Tasking can be split into two categories, co-operative and pre-emptive. Co-operative is when the process currently controlling the CPU must offer a balanced share of the CPU to all other processes, hence Co-operative, as all processes must co-operate for it to work properly. Subsequently an MUOS will allow two or more users a share of the system resources at the same time. The use of the resources must be spread evenly between the requirements of the users so that a problem with one user does not become a problem between all users. Examples of co-operative multi tasking would be Windows 3x and Macintosh. Pre-emptive is when the applications are forced to share the CPU whether they want to or not and examples of this are Windows 95, NT and UNIX. How print sharing operates? NOS A print server allows multiple users access to a single printer. A print server will also give you information on the use of the printer. All print jobs are sent to a Network Printer, controlled by the server, where they will wait in turn to be printed. For example, you can: See how many people are using the printer; Set limits to the usage; Give higher priority to some workstations, allowing them to print before others; See who is currently printing or; See when your print job is coming up. MUOS The Multi-User Operating System Linux uses a printing system called LPD, which constantly runs as a background process and acts as a spooler for files when they are required to be printed. Spooling (Simultaneous Peripheral Operations On-Line) is where all input/output of non-shareable devices is redirected to an intermediate shareable device. This is done, for example to stop other processes queuing for long periods of time to access a certain device. The most common form of spooling would be print spooling, where documents are printed at the printers own rate after being loaded into an intermediate shareable area (buffer).) is where all input/output of non-shareable devices is redirected to an intermediate shareable device. This is done, for example to stop other processes queuing for long periods of time to access a certain device. The most common form of spooling would be print spooling, where documents are printed at the printers own rate after being loaded into an intermed iate shareable area (buffer). System Failure and Robustness On a MUOS, data must be backed up on a regular basis, as if the server goes down then all unsaved work or data on the network is lost. It is therefore necessary to make a hard copy of all-important data. It is also important to have a recovery disc made upon installation. However, on a Network Operating System there is a system failure then only the unsaved data on the actual client is lost and not across the entire Network. The clients will still be almost fully operational without the server itself. A Multi-User Operating System tends to be a lot more robust than a Network Operating System. It is widely recognised that windows in particular is very unpredictable at times and is prone to fatal errors. This is not the case with the likes of Unix or Linux. Application, file sharing and file locking File sharing is a very important part of a Network Operating System. Users will continuously need to access and share the same files across a network and giving them usernames and passwords can do this. However if two or more users were to try and access the same file (for example, a Word document) at the same time and both users on the Network had read and write access, then only one user would be granted access at a time and the other would be denied. This concept is known as File Locking. This could be looked upon as a basic traffic system, if you like, where as soon as one user has access to a file then the red light is switched on. Then, when the first user has finished with the particular file, the green light shows and the second user is free to access the data. In a Multi User Operating System, you would find a different method known as NFS (Network File System). This is a where the server or Network Administrator can control which users can have which type of access to diffe rent applications or files at specific times. Comparison Architecture Clients A Network Operating System uses a Graphical User Interface, as it is part of the Microsoft Windows family, which are all GUIs. This makes the Operating System much easier to use in many ways such as being more user friendly and easier to learn. However a Multi-User Operating System like Unix for example would use a Command Line Interface. This has its good and bad points being that the user has greater level of control over commands; the System is more stable and does not use excessive system resources. On the other hand, the users would  have to familiarise themselves with a lot of commands which can be time consuming. Both have the Kernel as the heart of the Operating System. This is the part of the operating system that loads first, and it remains in main memory and typically, is responsible for memory management, I/O system management, file system management, process and task management and scheduling, and disk management. The Kernel is essentially the nucleus of the operating system that provides basic services for all other components of the operating system. For each process, the Kernel holds a process identifier, the user identity and the size and location of the process. A Network Operating System and a Multi-Use r Operating System will normally operate using Thick and Thin clients respectively: Thin Client: No hard disk on client Connected to a server Applications run on server Data stored on server Mouse, Video, Keyboard etc. through which you can access server Can support sound, CD-ROM etc. Thick Client: Client has own hard disk Client has storage space Client can have own applications stored ETC. Basically the opposite of Thin clients A Network Operating System can support many hundreds of clients across a Local Area Network as can a Multi User Operating System. Protocols and Internetworking In order for a Network Operating System to send or receive data, the data must be broken down into packets by a method called a protocol. Windows NT uses the IPX/SPX, NetBEUI, and TCP/IP protocols for network communication. Netware uses IPX/SPX. UNIX, Linux, and the Internet all use TCP/IP. While different protocols usually cannot talk directly with each other, most Network Operating Software can understand more than one protocol. This also adds the possibility of Internetworking for most Network operating Systems as they can communicate freely over different Networks unlike MUOS. Both types of operating system (NOS and MUOS) have built-in TCP/IP networking, for communications across all forms of networks, and between all forms of computers. Other Protocols and the respective layers of the OSI models at which they operate are shown here: Application Telnet, HTML Presentation SMB, NCP Session NETBIOS (NETBEUI) Transport TCP Network IP. TCP/IP, IPX/SPX Data Link Ethernet Physical Radio Scalability: Multi User Operating Systems are far more scalable because they can run on literally every hardware platform, from the slowest hardware to the worlds fastest. Additionally, most UNIX operating systems support more than one processor, so a machine configured with 4 processors can support many more users than a machine with one processor of the same type. Security: Security measures are very important on any Operating System. On a Network operating System such as Win 2000 server it would be fairly easy to install some sort of security software (Firewall) such as one of the Norton Internet Security packages. Anti-virus software is also readily available and very widely used. With a Multi-User Operating System such as Unix, there are a number of security tools available to download as Freeware that perform a vast array of different tasks relating to security. Hardware requirements: the Typical Hardware requirements for installing two different Operating Systems (Linux and windows 2000 server) are shown here below (minimum and recommended): MUOS (Linux) Minimum Requirements 200 MHZ Processor required 32MB RAM 650MB Hard Drive CD-ROM Network Card NOS (Windows 2000 Server) Minimum Requirements Pentium compatible 133MHZ or faster 128MB RAM 2GB Hard Drive 1GB Free Recommended Requirements Pentium II 200MHZ 256 MB RAM 9GB Hard Drive 2GB Free CD Rom Network Card Costs: Financially, Multi-User a Operating System would be much more viable than a Network Operating System due to the fact that the MUOS can use dumb Terminals, which basically means that the majority of the hardware and more importantly software is on the actual server i.e. the clients (workstations) have only the essential components needed to operate. These would include  Keyboard, Mouse, monitor etc. however in the event of having a very large Network this could in effect end up equally as costly as a Network Operating System. Role of Network Administrator The role of a network administrator in large companies and consulting firms may be only managing network servers, adding users, and adding printers. However, most network administrators also do some desktop support as well as controlling network addresses, protocols used, and the network interfaces because these are all obviously network components. The network administrator will also control routing, name resolution, and assignment of TCP and UDP socket numbers because, again, these are all pretty clearly network specific components. In small companies, day-to-day network administration is often not a full time job and is assigned as a part-time task to someone in the office. To troubleshoot a network you must understand things, such as: how individual PCs work, general networking concepts, and product specific features. A network administrator is a manager: not of people but of computing resources. A network administrator is creating and managing user accounts, installing and maintaining print services, ensuring that the network is running smoothly and that the computers are running efficiently, maintaining the integrity of the network, handling user complaints, and so forth. Users would be allowed access to system resources by means of a user account, which would be set up and then users would be allocated a username and password(s). This would allow the Network Administrator to set different security levels for different clients and users. For example, within a company or Business, you would have different levels of access for different levels of staff members with management having access to more resources and data than perhaps an office junior etc. A network administrator should be able to manage resources by doing the following: Creating, managing and utilizing Windows 2000 shared folders Using the Distributed File System to provide easy access to network resources Using the Windows 2000 events logs to monitor system and application activities Using the Task Manager to observe and monitor resources Using the System Monitor in the Performance tool to optimize performance Using security policies to protect data and system integrity Using auditing to track security events The Network Administrator is also responsible for budgeting decisions regarding the Network itself. This would involve very closely monitoring each and every client, making decisions on whether new hardware or software is required and when. Any Firewalls or Antivirus software would also have to be updated continuously. Bibliography http://www.north.ecasd.k12.wi.us/Departments/TCS/Web%20Pages/Powerpoints/IT%20Essentials%202%20NOS%20chpt%206%203-03.ppt http://www.pctechguide.com/29network.htm#Client-Server http://www.webopedia.com/TERM/N/network.html http://www.microsoft.com/windows2000/server/default.asp http://www.k12.hi.us/~tethree/95-96/landesign/G02/WHAT.html http://compnetworking.about.com/cs/networknos/index.htm http://suned.sun.com/US/catalog/courses/EC-425.html http://www.microsoft.com/windows2000/server/evaluation/business/overview/scalable/default.asp http://www.devdaily.com/unix/edu/UnixSysAdmin/node2.shtml http://www.linksys.com/edu/nos.asp http://www-personal.umd.umich.edu/~salmadra/common.htm http://linux.oreillynet.com/pub/a/linux/2000/07/20/LinuxAdmin.html http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/introint.htm#xtocid2 http://www.cert.org/tech_tips/unix_security_checklist2.0.html http://www.cert.org/tech_tips/usc20_full.html#A13 Dick, David (2002) The P.C. Support Handbook. Kirkintilloch: Dumbreck Publishing

Existentialism In The Early 19th Century :: essays research papers

Existentialism in the Early 19th Century Major Themes Because of the diversity of positions associated with existentialism, the term is impossible to define precisely. Certain themes common to virtually all existentialist writers can, however, be identified. The term itself suggests one major theme: the stress on concrete individual existence and, consequently, on subjectivity, individual freedom, and choice. Moral Individualism Most philosophers since Plato have held that the highest ethical good is the same for everyone; insofar as one approaches moral perfection, one resembles other morally perfect individuals. The 19th-century Danish philosopher Sà ¸ren Kierkegaard, who was the first writer to call himself existential, reacted against this tradition by insisting that the highest good for the individual is to find his or her own unique vocation. As he wrote in his journal, â€Å"I must find a truth that is true for me . . . the idea for which I can live or die.† Other existentialist writers have echoed Kierkegaard's belief that one must choose one's own way without the aid of universal, objective standards. Against the traditional view that moral choice involves an objective judgment of right and wrong, existentialists have argued that no objective, rational basis can be found for moral decisions. The 19th-century German philosopher Friedrich Nietzsche further contended that the individual must decide which situations are to count asmoral situations. Subjectivity All existentialists have followed Kierkegaard in stressing the importance of passionate individual action in deciding questions of both morality and truth. They have insisted, accordingly, that personal experience and acting on one's own convictions are essential in arriving at the truth. Thus, the understanding of a situation by someone involved in that situation is superior to that of a detached, objective observer. This emphasis on the perspective of the individual agent has also made existentialists suspicious of systematic reasoning. Kierkegaard, Nietzsche, and other existentialist writers have been deliberately unsystematic in the exposition of their philosophies, preferring to express themselves in aphorisms, dialogues, parables, and other literary forms. Despite their antirationalist position, however, most existentialists cannot be said to be irrationalists in the sense of denying all validity to rational thought. They have held that rational clarity is desirable wherever possible, but that the most important questions in life are not accessible to reason or science. Furthermore, they have argued that even science is not as rational as is commonly supposed. Nietzsche, for instance, asserted that the scientific assumption of an orderly universe is for the most part a useful fiction. Choice and Commitment Perhaps the most prominent theme in existentialist writing is that of choice. Humanity's primary distinction, in the view of most existentialists, is the freedom to choose.

Mozi Essay

When did he live and what was his historical significance? Mozi, also pronounce as Mo Di, was a philosopher born in Tengzhou, Shandong Province of China from 470-400 BCE. He founded the school of Mohism, which rivaled arguably to Confucianism and Daoism. While there is much mystery to his life and origins, speculations points that Mozi was schooled in Confucianism in his early years. He thought Confucianism emphasize too much contribution to celebrations and funerals which he felt were unfavorable to the livelihood and production of common people. Mozi believed that society should be led by the wise and the virtuous, and as people, we should work to save each other. He sought a world of jian’ai or â€Å"impartial care† which is aim to give a moral guide to social behavior; that is to say, no matter the relationship between a person, every individual should equally care for one another. Although, despite contention that all people deserve equal concern, elements of Mozi thought may have provided a corrective to some, but not supported as such to economic equality or status equality. During the Warring States Period, Mohism was actively developed and practiced in many states, but fell out of favor when the legalist of Qin Dynasty came to power. Mohist and Mohism values were tarnished when Emperor Qin ordered the burning of books and burying of scholars. Furthermore, Mohism further declined when Confucianism became the dominant â€Å"school of thought† during the Han Dynasty. Though Mozi’s school faded into obscurity after the Warring States period, Mohism was studied again two millennia after his death. Since almost nobody had seize the texts during the last two thousand years, there was much difficulty deciphering the it. As a result, Mohism became the hardest philosopher within the hundred â€Å"school of thoughts† to study. In addition, Mozi has been place in China’s history as an important figure of philosophy. His passion was for the good of the people, without concern of personal gain nor even of his life or death.

A Brave New World by Aldous Huxley - 545 Words

In Aldous Huxley’s â€Å"Brave New World,† there is a forceful religious connotation. Huxley’s uses of biblical allusions emphasize the inborn necessity of spiritual belief, in even the most neutral society. By assimilating religious references into the population, specific characters, and science, he successfully illustrates the absolute need for the religion in any society The culture of â€Å"Brave New World† is full of religious symbolism, indicating the demand for a spiritual belief in a community. As first seen on page 21, this population uses the terms â€Å"Ford,† and â€Å" Our Ford Above,† to commend to a position of authority over others. This saying is further followed by the ceremonial action of the â€Å"T†, which is similar to the cross, without the upper portion. Another example of how religion is interwoven through the story line is found on page 70. Bernard is present at his weekly solidarity service, during which a g roup all chants, â€Å"I drink to the Greater Being† and then drinks the soma from the â€Å"Loving Cup.† Meanwhile, a cup of soma-laced ice cream is passed around the circle. This is very similar to how modern day Christians honor Jesus Christ, by drinking the wine and eating the bread. Huxley successfully exhibits how the necessity for the belief is present in even the most mundane cultures. Next, Huxley uses religious references to show the inherent beliefs in â€Å"Brave New World† is liable for the characters nonchalantly playing biblical roles. For instance, Bernard plays theShow MoreRelatedA Brave New World by Aldous Huxley668 Words   |  3 PagesIn Brave New World, there are similarities that have a deeper meaning that we can understand. There are personal effects in Aldous Huxley life that contribute to what he has written in the book. 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The hero in the novel, a â€Å"savage† named John, is Huxley’s main focal point. It is through his eyes and mind that the reader sees what’s going on. Now when I read this novel, I began to think, â€Å"Could this perfect, conformed world actuallyRead MoreA Brave New World by Aldous Huxley1684 Words   |  7 Pagesimperfect world and is usually only a hopeful dream. These types of worlds can greatly be described in detail through the world of science fiction. Aldous Huxley was an English writer who lived during a time when war and chaos were engulfing the world. His works reflect his view and thoughts on a dystopia, which is a false utopia, and describes what could occur in possible governments of the world. The ability to understand and dive into the thoughts of the author is what make s world literatureRead MoreA Brave New World by Aldous Huxley614 Words   |  2 Pagesthem truly happy. What if someone were to tell you that what you thought was true happiness was all an illusion. 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