Report on Multi User Operating Systems Essay Example for Free

Report on Multi User Operating Systems EssayResources sharing Concepts of Resource SharingA multi exploiter in operation(p) transcription abide support more that star exploiter at a beat, this means that multiple users can sh are the same ashes resources simultaneously. The users of a multi user operating constitution can share both hardware and software resources, the operating system carries out mingled routines to manage all the deales that the users are running. List of shared resources * Hardware primeval processing unit Power, hammer in, Hard drive, Peripherals (printer, Scanner, CD ROM) former(a) peripherals whitethorn be made available in a MUOS for users who require them (Floppy disk drive, Speakers, Head Phones, tv put up Cameras etc. )* Software Scheduler Software ( makeed to manage and prioritise businesss). Batch JobSome processes take a persistent time to complete and can often disturb new(prenominal) computer tasks that are important. A Batch J ob is a file that does not require any user interaction, so it is set up to run a number of processes at a later time, often late at night. integrity example is overnight maintenance at a bank when they update all the accounts so it volition not disrupt the other processes during the day.Multi-Tasking Concepts of multi-taskingMulti tasking is when the operating system switches between tasks at a really high speed, it can roughtimes seem as though it is performing more than one task at a time. For example, a user could be printing and typing at the same time, and perceive to a CD. Many users can access the same resources at (what appears to be) the same time. One disadvantage of this is that it requires a great deal of retentiveness and the processes may run slower.The two types of multi-tasking are co-operative and pre-emptive* Pre-emptive This is when the applications are forced to infract up the CPU after a certain length of time so that the other processes nark an equal share of CPU time. (time-sliced).* Co-operative multi-tasking is when it is the current running tasks responsibility to share the CPU to the other processes. One task must finish before the other starts. It is called Co-operative because all the tasks must co-operate for this type of processing to reverse and there is no time limit on each task. (Round Robin). Advantages / DisadvantagesAn advantage of Pre-emptive multi-tasking is that some important tasks may be allocated a more time slices so it will not be stalled by other smaller tasks.A disadvantage of both types of multi-tasking is that it requires a crowing amount of memory to work properly. ambit Processing Concepts of background / highlight processingWhen a task will require a long time to process and requires no user input e.g. downloading a large file from the internet, it can be processed later when the computer is not processing other tasks. Background processing is often apply in banks and businesses to process the customers accounts at the end of each day, the operating system can be left to run the process overnight or when the CPU is not currently universe used by a task that requires a great deal of processing. Unix command to run background processingControl-Z = ply process running in backgroundbg = Continue process at backgroundControl-C = move foreground process to backgroundFg = move the process to foreground Example of a background processIf you need to run a large print job, e.g. printing out one hundred copies of aWorkbook for a group of students, it can be set as a background process and will that use CPU power when other tasks are not running.Types of Multi-User Operating SystemMulti-Processor More than one CPUMulti user operating systems can sometimes have more that one processor. In some expensive operating systems it is possible to connect more CPUs to the system and have them work together to ply tasks.Multiprocessing can significantly reduce the time taken to execute eac h process. An operating system with multiple processors can perform different tasks separately or a task can be split up and processed by different CPUs. Advantages / DisadvantagesAn advantage is that multi processing systems can be truly speedy at completing tasks.A disadvantage is that this type of system is very expensive.Time-SlicedAs multi user operating systems share resources, different processes can require different amounts of time. It is possible and to interrupt a large process so that a smaller process to be completed. If you were using a time disappearance system then the processor will switch between processes at timed intervals (Pre-emptive). The amount of time allocated to each process is called a time slice. The length of time attached for each time-slice is allocated by a program called a scheduler. An advantage is that larger or more important processes may be given more time slices than a smaller task so it can be completed, however this could likewise be a d isadvantage if there are many users executing smaller tasks as they will take longer to be finished.DistributedThe distributed system is where a number of systems are connected through a Local Area Network. This can be more powerful than a single processor system and it is capable of online sharing.Hardware ComponentsProcessor The CPU is the brain of the operating system. It responds to and processes and instructions that control the computer. The control unit of measurement in a CPU controls everything which happens within, the ALU does calculations and is responsible for decision making and the accumulator stores the last data that was decoded for future(a) processes. There are various registers within the CPU, they are the instruction register, which holds the instruction that is being decoded, the program forebode stores what part of the program we have reached, the memory address register points to the location where data is being fetched or pen and the memory data register is a storage area for data that is currently being transferred between the memory and the CPU. The Fetch-Decode-Execute Cycle has three important stages.* FETCH The CPU collects an instruction from the RAM* decode The control unit figures out what to do with it.* EXECUTE The instruction is carried out The speed of an FDE cycle depends on how fast the processor is (the length of time it takes for the signals to be sent to the control bus, and how many T-cycles each fictionalisation instruction takes to execute.MemoryRandom Access Memory is sometimes known as main memory. RAM is volatile, which means it loses all the stored information when the power is cut off. Some computers also use virtual memory, which is stored in the hard drive but acts like RAM, this is much slower than physical memory. Another type of memory is Read Only Memory (ROM) which can be written to but cannot be erased.Data reposition whatsiss Floppy disk can be written to and erased, 1.44Mb CD ROM Can be w ritten to but not erased, 700Mb Hard subscribe to stores many Gigabytes, can be written to and erased Zip Drive can be written to and erased, 100 250MbTerminals Dumb Terminal A dumb terminal has no processing capabilities as they have no memory or processor of their own, it has only a monitor, keyboard and mouse. They are connected to a central processor. Intelligent Terminal An intelligent terminal contains memory and a CPU and is a standalone artifice. It only has to connect to the central processor when needed. Command to find terminal type terminfo foreplay / Output DevicesDumb Terminal Input keyboard and mouse. Output monitorIntelligent Terminal Input keyboard, mouse, scanner, suffer screen. Output monitor, printer, speakersSoftware ComponentsKernelThe Kernel is the heart of the operating system, the lowest level or the central part. Communication with the hardware is through the kernel. In multi user operating systems it is the kernels job to keep each process and user separate and to organize access to the system hardware, including CPU, memory, disk and other I/O devices.Device HandlersA device is any piece if hardware that is used in an operating system. A device handler is a piece of software within the operating system that communicates with the devices and tells them what to do. This is part of the operating system that is responsible for servicing requests of the device request queue.Spoolers (Simultaneous peripheral operations on-line)Spooling is used when data is waiting to go to an output device after it has been processed. The data is placed into a queue so that the CPU can process something else instead of having to slow down to the speed of the output device. Spoolers are used on primarily old devices e.g. old printers that can only handle one job at a timeUser InterfaceThis is how the user can view the data within the operating system. The main types of user interfaces are the graphical user interface e.g. Windows and Command d riven interface e.g. MS DOS and meter UNIX. The CDI was more complicated to use than a GUI as you would have to know certain commands to do very basic tasks.BibliographyIndexhttp//physinfo.ulb.ac.be/cit_courseware/opsys/ostart.htmhttp//electronics.howstuffworks.com/operating-system1.htmhttp//physinfo.ulb.ac.be/cit_courseware/opsys/ostart.htmhttp//www.canberra.edu.au/sam/whp/unix-cmd.htmlhttp//cm.bell-labs.com/