DOS And Unix Essay Research Paper Compare free essay sample

DOS And Unix Essay, Research Paper Compare and Contrast Microsoft DOS with UNIX As is implicative of its name, an operating system ( OS ) is a aggregation of plans that operate the personal computing machine ( Personal computer ) . Its primary intent is to back up plans that really do the work one is interested in, and to let viing plans to portion the resources of the computing machine. However, the OS besides controls the interior workings of the computing machine, moving as a traffic director which controls the flow of informations through the system and initiates the starting and fillet procedures, and as a agency through which package can entree the hardware and system package. In add-on, it provides modus operandis for device control, provides for the direction, programming and interaction of undertakings, and maintains system unity. It besides provides a installation called the user interface which issues bids to the system package. Utilities are provided for pull offing files and paperss created by users, development of plans and package, pass oning between users with other computing machine systems and pull offing user demands for plans, storage infinite and precedence. There are a figure of different types of runing systems with changing grades of complexness. A system such as DOS can be comparatively simple and minimalistic, while others, like UNIX, can be slightly more complicated. Some systems run merely a individual procedure at a clip ( DOS ) , while other systems run multiple procedures at one time ( UNIX ) . In world, it is non possible for a individual processor to run multiple procedures at the same time. The processor of the computing machine runs one procedure for a short period of clip, so is switched to the following procedure and so on. As the processor executes 1000000s of instructions per second, this gives the visual aspect of many procedures running at one time. User plans are normally stored on a difficult disc and demand to be loaded into memory before being executed. This presents the demand for memory direction, as the memory of the computing machine would necessitate to be searched for a free country in which to burden a users plan. When the user was finished running the plan, the memory consumed by it would necessitate to be freed up and made available for another user when required ( CIT ) . Procedure programming and direction is besides necessary, so that all plans can be executed and run without struggle. Some plans might demand to be executed more often than others, for illustration, printing. Conversely, some plans may necessitate to be temporarily halted, so restarted once more, so this introduces the demand for inter-program communicating. In modern runing systems, we speak more of a procedure ( a part of a plan in some phase of executing ( CIT, 3 ) ) than a plan. This is because merely a part of the plan is loaded at any one clip. The remainder of the plan sits waiting on the disc until it is needed, thereby salvaging memory infinite. UNIX users speak of the operating system as holding three chief parts: the meat, the shell and the file system. While DOS users tend non to utilize the term meat and merely sometimes use the term shell, the footings remain relevant. The meat, besides known as the ? Real Time Executive? , is the low-level nucleus of the OS and is loaded into memory right after the burden of the BIOS whenever the system is started. The meats handles the transportation of informations among the assorted parts of the system, such as from difficult disc to RAM to CPU. It besides assigns memory to the assorted system-level procedures that occur whenever the computing machine does anything. The meat is besides responsible for scheduling the CPU? s operations and for allowing the shell entree the CPU ( PC Mag, 1 ) . The shell is the seeable user interface to the OS and is a plan that loads on top of the operating system and offers users commands that lets them entree the OS. Strictly talking, the shell is an input public-service corporation that offers entree to the operating system. Technically talking, the shell, being a separate plan, is non a portion of the OS at all. In the UNIX universe a figure of shells are available, among them the Korn shell, the C-shell, the Bourne shell and the Bourne Again shell ( yes, truly ) . In DOS, the criterion shell is COMMAND.COM, once more nil more than a plan. As different versions of command.com came with different versions of DOS, each added new bids and new things that could be done by the user. For illustration, DOS 4? s COMMAND.COM added the /P switch to DEL to verify each omission, and DOS 5? s COMMAND.COM provided the ability to screen the end product of the DIR bid. HISTORY An acronym for disc operating system, the term DOS can mention to any operating system, but is most frequently used as stenography for MS-DOS. Originally developed by Microsoft for IBM, MS-DOS was the criterion operating system for IBM-compatible computing machines. The initial version of DOS was slightly unsophisticated and resembled another operating system called CP/M. Subsequent versions have become progressively sophisticated, nevertheless DOS remains a 16-bit operating system without support for multiple users or multitasking. The earliest signifiers of DOS were rough and utilized merely a few bids, but as computing machines became more advanced, so did DOS. By maintaining up with engineering, DOS was implemented into more? user friendly? runing systems. However, as more sophisticated runing systems were released, DOS became less of import. ? Today, hackers involved with the latest OS trends gag that DOS stands for? Dad? s Operating System? ? ( Comerford, 23 ) . In 1980, IBM asked the Microsoft Corporation to bring forth the operating system for its first personal computing machine, the IBM Personal computer. Prior to this, a company called Seattle Computer Products had sold an operating system called 86-DOS to Microsoft. Microsoft hired the writer of 86-DOS, Tim Paterson, in April of 1981 to modify the system, and renaming it MS-DOS ( Microsoft Disk Operating System ) , it was released with the IBM Personal computer. Thereafter, most makers of personal computing machines licensed MS-DOS as their operating system ( Brittanica, 1 ) . Restrictions of the early Personal computer? s hardware were a large influence on MS-DOS. Although the 8088 theoretical account computing machine had a 1Mb reference infinite, IBM decided to apportion the first 640K of this to RAM, and the remainder to ROMs, picture boards and other things. Consequently, MS-DOS was set up to back up plans whose maximal size was 640K. Version 1.0 of DOS was released along with the IBM Personal computer in August 1981. It occupied 12K of the systems 640K of memory, was slightly compatible with CP/M and, much like CP/M, supported merely a individual directory. By contrast, even the first version of UNIX had a full hierarchical file system. In add-on, Version 1.0 supported merely a 160K individual sided 51/4-inch floppy floppy. Version 1.1 was released by Microsoft in October 1982 and supported double sided 320K floppies. Aside from repairing some bugs, this release was similar to Version 1.0. Releases such as 1.1, in which the figure to the left of the denary point is the same as the old version depict comparatively minor alterations from the old release. By contrast, Version 2.0 was mostly a new system. In March 1983, IBM introduced the PC/XT, its first personal computing machine with a difficult disc. It came with a new discrepancy of MS-DOS, Version 2.0. In this version, Microsoft incorporated many thoughts from the UNIX system for which it was besides a seller. For illustration, integrating minor alterations, the MS-DOS file system was taken mostly from UNIX. In add-on, the shell was improved, and Version 2.0 supported a new floppy floppy format, the 360K every bit good as user installable device drivers, print spooling, system constellation and memory direction. At this point, Microsoft disk operating system was established as the dominant operating system in Personal computer market. In August 1984, IBM released its first 286 bit based Personal computer, the PC/AT. The PC/AT supported memory up to 16 Mb and had the ability to run multiple plans at one time. However, the version of MS-DOS that shipped with the PC/AT was 3.0, which supported neither of these. Rather, it ran the PC/AT in a manner that simulated the 8088, merely faster. Since the PC/AT came with a 1.2Mb disc thrust, battery backup clock, and constellation information in the CMOS, support for these devices was added. What # 8217 ; s more, difficult discs larger that 10Mb were now supported. In add-on, the bid processor ( shell ) was removed from the operating system and made into a separate plan. In November 1984, 3.0 was replace by 3.1 which provided the first support for networking. In 1987, IBM came out with the PS/2 line of Personal computer which shipped with MS-DOS 3.3, supplying support for both 720K and 1.44Mb 31/3 floppy disc thrusts. With Version 4.0, Microsoft added the DOS shell, a bill of fare driven shell instead than the old keyboard driven 1s. In add-on, it now provided support for difficult thrusts larger than 32 Mb. A major new release, MS-DOS Version 5.0 was shipped in April 1991. Although this was the first version that made any serious usage of the drawn-out memory, it still had the limitations that plans could non transcend 640K. However, it had the ability to locate most of MS-DOS itself in drawn-out memory, so about 600K of the lower 640K was now available for user plans. Version 5.0 besides came with a utile Aid public-service corporation, to help new users. For the first clip, MS-DOS was sold in shops to the populace ( old versions were merely sold to computing machine sellers who delivered them with their machines ) ( CIT, 1-3 ) . The MS-DOS 6 household provided more memory direction for applications such as Microsoft Windows. In add-on, newer public-service corporations were provided for disk-defragmentation, file compaction, file backups and anti-virus checking. Other fluctuations of MS-DOS exist, such as PC-DOS by IBM, DOS-V, Dr. DOS and others. There is even a FREE DOS available on the Internet as an MS-DOS ringer. Although it can still be found on many computing machines, MS-DOS is technically an disused operating system, being replaced by Microsoft Windows. For personal computing machines, MS-DOS is a individual user, individual tasking operating system. Single user means merely one individual uses the computing machine at a clip. Single tasking means that it basically runs one application plan at a clip, and has no built-in support for running more than one application plan at the same time ( CIT, 2 ) . If we want to look at the basic DOS operating system itself, there is no demand to look further than three system files, command.com, Io.sys and ( in DOS6.x and before ) Msdos.sys. These files are important in DOS versions up to 6.22. Io.sys represents the lowest degree of the interface and contains the modus operandis necessary for interfacing the OS with the system? s BIOS. It implements MS-DOS as seen by the hardware and has default drivers for console show and keyboard, pressman, consecutive communications, clock, and a boot disc thrust. Msdos.sys handles the higher-level modus operandis such as change overing bids from applications into instructions for Io.sys. It implements MS-DOS as seen by application plans. It supports file and record direction, memory direction, character device input and end product, executing of other plans, and entree to a real-time clock ( CIT, 3 ) . Both of these files are in the root directory, and both are hidden from position by default. The thought is that you are non suppose to see them, so that you wear? Ts do anything destructive to them ( such as canceling them ) . They are besides read-only so that they can? t be deleted by chance. Command.com is the shell plan which interprets user bids, presents the shell prompt, and conta Immigration and Naturalization Services a set of internal bids. The remainder of MS-DOS consists of a figure of public-service corporation plans. Although DOS had cornered the Personal computer market, UNIX was still dominant on the larger workstations. The birth of UNIX in 1969 provided the universe with its first modern operating system. An synergistic multi-user operating system, UNIX was ab initio developed by coders for their ain usage. Working for Bell Laboratories, Ken Thompson and Dennis Ritchie created UNIX as an operating system for the PDP-7 computing machine. Designed as a simplification of an operating system named Multics, UNIX was developed in Assembly linguistic communication, a crude computing machine linguistic communication specific to one type of machine ( Osiris, 1 ) . However, Thompson developed a new scheduling linguistic communication? B? which Ritchie enhanced to? C? , and in 1973 this was used to rewrite UNIX which lended the OS portability ( Linux Intl. , 1 ) . The original design doctrine for UNIX was to administer functionality into little parts, the plans ( Theochem, 1 ) . In this manner, functionality could be achieved by uniting the little parts ( plans ) in new ways. Furthermore, if a new plan were to look, it could be integrated into the system. UNIX was slow to catch on exterior of academic establishments but shortly was popular with concerns every bit good. The first five versions were portion of an internal research attempt of Bell Labs, and it was non until the 6th version, called UNIX Timesharing Sixth Edition V, that UNIX was widely distributed ( Osiris, 1 ) . Relatively recent developments are graphical interfaces ( GUI ) such as MOTIF, X Windows and Open View. UNIX has two major versions. One, jointly developed by UNIX Systems Laboratories ( USL ) and by AT A ; T research workers together with Bell Labs, generically known as System V, is the commercial version and is the most widely distributed by major makers. The 2nd, developed by the University of Berkley and Berkley Software Distribution ( BSD ) , is the educational version and is wholly focused on research. The USL version is now on its 4th release, or SVR4, while BSD? s latest version is 4.4. However, there are many different versions of UNIX besides these two. The operating system has been licensed to several makers who in bend developed their ain versions of UNIX, based on System V or BSD, but adding new features. Most versions of UNIX developed by package companies are derived from one of the two groupings and, recent versions of UNIX really incorporate characteristics from both of them. However, UNIX has had an unregulated history with over 200 versions ( Berson, 16 ) bing today. The UNIX system is made up of three primary constituents, the meat, the shell, and the public-service corporations ( which includes the file system ) . The cardinal portion of the OS, the meat is the first plan to get down when the system is turned on and the last plan to make anything when the system is halted. In add-on to scheduling undertakings, it manages data/file entree and storage, enforces security mechanisms and performs all hardware entree. The name? KERNEL? represents the fact that it is a plan designed as a cardinal karyon, around which other maps of the system were added. The bosom of the operating system, it non merely interacts straight with the system? s hardware, but presents each user with a prompt, interprets bids typed by a user, executes user bids and supports a usage environment for each user. The two most common shells are the Bourne shell, default for the System V, and the C-shell used chiefly with the BSD version ( Osiris, 1 ) . The utilities consist of file direction ( rm, cat, cubic decimeter, rmdir, mkdir ) , user direction ( passwd, chmod, chgrp ) , process direction ( kill, PS ) and printing ( LP, troff, Pr ) . In order to obtain a basic apprehension of the UNIX operating system, it is necessary to touch upon several of the chief features that have permitted it to stay competitory through the old ages. 1. Advanced Administration of Processes UNIX has a procedure director known as Process Scheduler, which handles the allocation of clip to each of the procedures harmonizing to the precedence it was assigned. 2. Multiprocessing Many UNIX discrepancies allow the usage of assorted processors to put to death user undertakings. This agencies that UNIX has support for symmetric processing, with which it can take advantage of the fact that there are two or more Central processing units in the machine. 3. File Management The hierarchal files system that UNIX runs, every bit good as file entree control and directory control have served as theoretical accounts for the bulk of modern runing systems such as MS-DOS, OS/2 and even Windows NT. 4. Utilities Access For the UNIX operating system, each of the machines devices, whether it be a difficult thrust, pressman, modem, etc. is seen as a file. Thus, entree to any device is carried out as entree to a file. This is possible through the fact that UNIX differentiates between sorts of files. In fact, the procedures themselves are seen as files, which permits the constitution of another of import Unix characteristic, interprocess communicating. 5. Virtual Memory The fact that UNIX has practical memory allows the figure of procedures being executed to necessitate more memory than exists in the machine. 6. Graphic Interface Although non precisely a fresh feature of UNIX, most versions now have a in writing interface. 7. Interplatform Support This is another characteristic that was added to UNIX which lends the capableness to put to death plans from other platforms ( DOS and Windows ) , within the UNIX environment. 8. Network The usual UNIX communications protocol is TCP/IP. This allows discrepancies of UNIX based runing systems to communicate between themselves or with other platforms ( Osiris, 1-2 ) . Contrast Both DOS and UNIX present a figure of similarities, several of which shall be addressed here. First, both systems are synergistic, intending that the shell nowadayss a prompt and delaies for the user to come in a bid. After the return or enter key is pressed, the shell processes the bid and when the bid is finished, the shell re-displays the prompt. Second, DOS batch files and UNIX book files can be used which can hive away normally used bids in a file, which when executed, runs each bid as though it has been typed from the bid line. A sequence of bids can be executed by put to deathing the file which contains the bid ( s ) . Third, the handling of files in both DOS and UNIX is simplified by utilizing wild-card characters to fit files which match specific forms. Besides, with both runing systems, users can custom-make and command the behaviour of the shell by utilizing particular variables that the shell supports, such as the prompt ( 20,1 ) . In add-on, both systems make usage of? pipes? whose symbol is a perpendicular saloon ( | ) . With this convention, the end product from one bid becomes the input for another bid. Several unsimilarities are deserving observing. As was antecedently mentioned, DOS is a individual user, individual undertaking operating system. Its user interface is non instance sensitive, which means that bids may be typed in either upper instance, lower instance or a combination of the two. UNIX nevertheless, is a multi-user, multi-task OS. Non-interactive undertakings which do non necessitate keyboard input can be run in the background as a separate undertaking while the user continues working with other synergistic plans ( 20,1 ) . Differing from DOS, its user interface is instance sensitive, intending that merely upper or lower instance bids must be used. APPLICATIONS A ; COMPUTER TYPES Whereas DOS has been used chiefly on Personal computers and standalone computing machines, UNIX can be run on single- or multi-user computing machines of all sizes with a broad scope of microprocessors ( Flynn A ; McHoes 319 ) . UNIX is the widely supported operating system in the field of computing machine scientific discipline, used extensively in concern every bit good as educational establishments. Conversely, DOS is used chiefly in concerns with older computing machine systems. BENEFITS A ; DISADVANTAGES The major advantage that DOS has over UNIX is its basic simpleness. Between this and the unsophisticated bids presented by the user interface, it is a comparatively simple OS to larn. DOS besides has the advantage of leting the user to make an environment tailored purely for the peculiar undertaking they wish to carry through. In add-on, one can custom-make DOS to accommodate the current hardware. This can be accomplished with bids such as day of the month, clip, prompt, way, set, assign and subst. Unlike DOS, UNIX? s chief characteristic is that it is a multi-user system, intending more than one user can utilize the machine at a clip when supported via terminuss provided by a series or web connexion. Offering true pre-emptive multi-tasking, UNIX can run more than one plan at a clip with a CPU that services all applications every bit. In add-on, it has a hierarchal directory construction which supports the organisation and care of files. Other advantages are that it has been in the market for a figure of old ages, and is hence considered a stable merchandise. Besides, due to the fact that the meat is in? C? , UNIX works in merely about every machine in the market, one time once more, doing it a portable system with a aggregation of really powerful public-service corporations. Besides, there are many applications developed for DOS and UNIX which fall into the class of? shareware? available via the Internet ( 8,1 ) . As with advantages, both DOS and UNIX have their portion of disadvantages. It can be said that DOS has two chief drawbacks. Since MS-DOS was originally written for a peculiar household of microprocessors, it displays an unbelievable deficiency of flexibleness and limited ability to run into the demands of coders and experient users ( Flynn A ; McHoes, 265 ) . UNIX besides has several really distinguishable disadvantages. First, novitiate users find its bids are about deep which is interpreted as being non- ? user-friendly? . Second, the fact that there exist so many versions of the operating system means that package manufacturers must do several versions of their applications to cover the greatest figure of possible users. Third, UNIX is a big operating system, and depending on the figure of services installed and the maps used, infinite used on a difficult thrust may change from 20 Mb to 300 Mb ( Osiris, 1 ) . Benson, Alex. Client/Server Architecture. Gainesville: U P of Florida, 1992. Comelford, Richard. ? Operating Systems go Head to Head? , IEEE Spectrum. Dec 1993, pp 23-25. Flynn, Ida M. , and Ann M. McHoes. Understanding Operating Systems. Second erectile dysfunction. Boston: PWS, 1997. Greenfield, Larry. Unix: The User? s Guide. University of Deuselldorf. [ Accessed 3 September 1998 ] . *http: //www. Theochem.uni-duesseldorf.de/docu/user-guide* Introduction to UNIX. University of Guadalajara. 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