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(Define Deadlock, Describe the life cycle of a process, (Differentiate…

- - - - Mutual exclusion condition .A resource cannot be used by more than process
      - Hold and wait condition. Each thread while waiting for another
      - No preemption condition. Thread can only release resources voluntarily. No OS can force the thread to release
      - Circular wait condition . Two or more processes from a circular chain where each proces waits for a resource that the next process in the chain holds
      - All four condition must occur before the deadlock happens
      - There will be no deadlock if at least one of the conditions unhold
      - Identify the method for handling deadlock
        
        3 ways to deal with deadlock
        
        Use a protocol to prevent or avoid deadlock, ensuring the system never enter a deadlock state
        
        Allow the system to enter a deadlock state .
        
        Ignore the problem altogether and pretend that deadlock never occur in the system
        
        Deadlock Prevention
        
        Mutual Exclusion. Must hold for non sharable resources
        
        Hold and Wait . Process request a resource , it does not hold any other resources
        
        No preemption. Already been allocated
        
        Circular Wait . Never hoids is to impose a total ordering of all resources type and to require that each process requests resources in an increasing order of enumeration
        
        Deadlock Avoidance
        
        Prevents by restraining how request can be made
        
        Restraint ensure that a least one of the necessary condition for deadlock cannot occur and, hence that deadlock cannot hold
        
        Deadlock Solution
        
        Non-blocking synchronization algorithm. Threads competing for a shared resources do not have their execution indefinitely postponed by mutual exclusion . Next , its look free if there is guaranteed system wide progress; wait free if there is also guaranteed per thread progress
        
        Serializing tokens.A concept in concurrency control arising from the ongoing development of DragonFly BSD . According to Matthew Dillion , they are most akin to SPLs, except token works across multiple CPUs , while SPLs only work within a single CPU`s domin
        
        Lock free and wait free algorithm.Structures guarantee the progress of at least one thread when executing multithreaded procedures , thereby helping you avoid deadlock.
        
        Resource hierarchy solution. Its not always practical , especially when the list of required resources is not completely known in advance
- - - - Terminates
      - Switches from waiting to ready
      - Switches from running to waiting state
      - Switches from running to ready state
    - -  Consider the case of two processes that share a
        data
      - It is preemptive so that while one process
        is updating the data
      - the second process then
        tries to read the data
      - which are in an
        inconsistent state.
  - - -  The input devices is used to provide information (or data) to the computer system: Keyboard (typing text), mouse (pointing), scanning (scanning of paper documents), microphone, etc..
  - - - Processes alternate between these two states
        
        followed by
        an I/O burst
        
        another CPU burst,
        then another I/O burst, and so on
        
        Process execution begins with a CPU burst
        
        the final CPU burst ends with a system request to terminate execution
      - The durations of CPU bursts may vary greatly from
        process to process and from computer to computer
      - Process execution consists of a cycle of CPU execution and
        I/O wait.(multiprogramming)
      - An I/O-bound program typically has many short CPU
        bursts
      - Whenever the CPU becomes idle, the operating system must select one of
        the processes in the ready queue to be executed
      - A CPU-bound program might have a few long
        CPU bursts
      - Note that the ready queue is not necessarily a first-in, first-out (FIFO) queue
- - - - CPU time (or CPU usage, process time) is the amount
        of time for which a central processing unit(CPU) was used for processing instructions of a computer program, as opposed to, for example, waiting for input/output (I/O)
        operations.
      - The CPU time is often measured in clock ticks or seconds.
      - CPU time is also mentioned as percentage of the CPU's capacity at any given time on multi-tasking environment.
      - That helps in figuring out how a CPU’s computational
        power is being shared among multiple computer programs.
    - - Random access memory (RAM) is a form of computer data storage.
      - A random access device allows stored data to be accessed in any order in very nearly the same amount of time for any storage location or size of memory device.
      - Memory devices (such as floppy discs, CDs and DVDs) can access the storage data only in a predetermined order, because of mechanical design limitations; the time to access a given part of the device varies significantly due to its physical location.
      - Memory: Virtual Memory
        
        virtual memory is a memory management technique developed for multitasking kernels.
        
        This technique virtualizes a computer architecture's various forms of computer data storage allowing a program to be designed as though there is only one kind of memory "virtual" memory, which behaves like directly addressable read/write memory (RAM).
    - - The term "disk space" is an amount of computer storage space on random-access memory devices, such as on a hard drive, floppy or USB flash drive
      - Disk space units are commonly measured in large numbers of bytes, such as Kilobytes, Megabytes, and Gigabytes, with each unit 1024x times larger than the previous unit.
      - As storage devices have been created in other shapes, the term "disk space" has still been used to refer to areas of permanent storage on various storage devices.
    - - In communication networks, such as Ethernet or packet radio, throughput or network throughput is the average rate of successful message delivery over a communication channel.
      - This data may be delivered over a physical or logical link, or pass through a certain network node.
- - - - one joule per second