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kumpulan 9, Kumpulan 9 :fire: - Coggle Diagram

- - - - Printer: when a print job is issued, the spooler take care of it, sending it to the printer if it is not busy, or stoking it on disk otherwise
  - - - If it is, information used directly from the cache (fast)
        
        If not, data copied to cache and used there
    - - Cache management important design problem
        
        Cache size and replacement policy
- - - - Monolithic Architecture Characteristics
        
        1 source code
        
        1 program generated
        
        no structured
      - What is Monolithic Architecture
        
        Design to handle mulitple related task.They're typically complex applications that encompass several tighly coupled functions.
    - - Example
    - - Shared kernal spaced
      - The monolithic kernel is a static single binary file (means only one file to run)
      - Highly efficient and good performance (because all the services are implemented under the same adress space)
    - - Inflexible (Difficult to isolate the source of bug and other error, if any service fails entire system will fail)
      - No hidden information (Can easily damaged from errant and malicious code because all code executes unrestricted acess to the system)
      - Chaotic
      - Difficult to understand
      - To add any new service, the entire operating system needs to be modified by the user
  - - - Windows XP, Linux, Windows 2000 implement some
        level of layering.
    - - Each layer communicates ONLY with those immediately above and below it (Therefore, user process's request may need to pass through many layer before it is services)
      - Lower-level layers provide services to high-level layer using interfaces that hide thier implementation
    - - Issues related to higher/lower layers
      - Sluggish operation mode on application
      - More risk of breakdown
      - Data overheat
    - - Flexibility
      - Scalability
      - Simplicity
      - Portability
      - Modularity
    - - There can be N number of layers, each buid on top of lower layers. The bottom layer (layer 0), is the hardware; the highest (layer N) is the user interface
      - Example
        
        Layered System (6 layers)
        
        MS-DOS (4 layers)
  - - - I/O servers
      - memory server
      - process server
    - - Limit the code executedin privileged mode and to allow easy modifications and extensions
    - - Components above microkernel communicate directly with one another, although using message that pass through the microkernel itself
      - Microkernel validate messages, passes them between the components and grants access to hardware
      - Example
        
        C-DAC Microkernel
        
        Mach
        
        Window NT
        
        Chorus
- - - - Commands OS to execute certain task
    - - Used by users to control hardware
    - - Controls and coordinate hardware
    - - Provide basic computing resources
  - - - Manage all resources
    - - Controls execution of program
- - - - summary
        There is ONE main
        CPU capable of
        executing general-purpose instruction
        set, including
        instructions from user
        processes.
      - On a single-processor
        system
        
        ◦ there is ONE main CPU capable of executing a generalpurpose instruction set, including instructions from user
        processes.
        ◦ Almost all systems have other special-purpose processors
        as well.
      - Special-purpose
        processor
        
        ◦ Run a limited instruction set and do not run user processes.
        ◦ Sometimes managed by the operating system
      - Special-purpose processors are low-level components built into the hardware.
        
        The OS cannot communicate with these processors; they do their jobs
        autonomously
        
        Having special purpose microprocessors does not make a single-processor
        system become a multiprocessor.
        
        If there is only one general-purpose CPU, then the system is a single-processor
        system.
    - - summary
        Is a kind of processing
        system where two
        or more processors
        work together to
        process more than one program at one
        time
      - also known as
        Parallel system or tightly coupled systems
      - advantages
        
        Increased throughput
        
        by increasing the number of processors, we
        expect to get more work done in less time.
        
        When 1 task is done cooperatively by
        multiple processors, works can be done faster
        and less error.
        
        Economy of scale
        
        Multiprocessor systems can cost less than
        equivalent multiple single-processor systems,
        because they can share peripherals, mass
        storage, and power supplies.
        
        If several programs operate on the same set
        of data, it is cheaper to store those data on
        one disk and to have all the processors share
        them.
        
        Inreased reliability
        
        If functions can be distributed properly
        among several processors, then the failure of
        one processor will not halt the system, only
        slow it down.
        
        If we have 10 processors and 1 fails, then
        each of the remaining nine processors can
        'help' do the work of the failed processor.
        Thus, the entire system runs only 10 percent
        slower, rather than failing altogether.
    - - summary
        It consists of two or more individual
        systems that are tied together and share
        the same storage space, also closely
        attached through a LAN network. It makes
        use of multiple CPU's to complete a
        specific task.
      - Clustering is usually used to provide high-availability service; that is,
        service will continue even if one or more systems in the cluster fail.
        
        High availability is generally obtained by adding a level of redundancy in
        the system.
        
        A layer of cluster software runs on the cluster nodes. Each node can
        monitor one or more of the others (over the LAN).]
        
        If the monitored machine fails, the monitoring machine can take
        ownership of its storage and restart the applications that were running
        on the failed machine.
        
        The users and clients of the applications see only a brief interruption of a
        service.
      - Clustering structure
        
        asymmetrically
        all machine work monitoring each other
        
        asymmetrically
        One machine work another standby