Operating System (CS - 308)
Chapter 1 - New Vocabulary

Historical overview :

- Simple batch system - Time_sharing systems - Parallel systems
- Multiprogrammed batched  - Personal-computer systems - Distributed systems
systems - Real-time systems
New Vocabulary :
 
- Turn around time - Spooling - Job pool - Response time
- Process - Job - Throughput - Fault - tolerant
- Interrupt - RJE - Front - End - Back - End
       
Simple batch system
  • Normally read a stream of seperate jobs (from a card reader, for example), each with its own control cards. The computer no longer had to wait for human operation.
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    Time-sharing systems
  • Were developed to provide interactive use of a computer system at a reasonable cost.  A time-shared system use CPU scheduling and multiprogamming to provide each user with a small portion of a time shared computer.  Each user has at least one seperate program in the memory.
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    Parallel systems
  • Have more than one processor in close communication, sharing the computer busy, the clock, sometimes memory or peripheral devices.
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    Multiprogrammed batched systems
  • Several jobs are kept in the memory at one time.  The operating system simply swithes to and executes another job.  When a job needs to wait, the CPU is switched to another job, and so on.  This will increase CPU utilization, and decrease the total time needed to execute the jobs.
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    Personal-Computer systems
  • They are micro computers that are considerably smaller and less expensive than mainframe system.  The I/O devices have certainly changed, with panels of switches and card readers replace with typewriterlike keyboards and mice.  Line printers and card punches have succumbed to display screens and to small, fast printers.
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    Distributed systems
  • In this kind of system, the processors don't share memory or the clock.  Each processor has its own local memory, and the processors communicate with one another through various communication lines, such as high-speed buses or telephone lines.
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    Real-time systems
  • It has a limitation of a time between the input and output system.  It is used when there are rigrid time requirements on the operation of a processor or the flow of data, and thus is often used as a control device in a dedicated application.
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    Turnaround time
  • The delay time between job submission and job completion
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    Spooling (Simultaneous Peripheral Operation On-Line)
  • In essense, use the disk as a huge buffer, for reading as far as ahead as possible on the input devices, and for storing the output file until the output devices are able accept them.
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    Job pool
  • Spooling will generally result in several jobs that have already been read waiting on disk, ready to run.  A pool of jobs on disk alows the operating system to select which job to run next, to increase CPU utilization.
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    Response Time
  • The time in which user submits the command and then waits for the result.
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    Process
  • An active program is ready in the memory
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    Job
  • Job is a unit of work; a series of tasks to be performed by the computer.  It consists of one or more programs executed in sequence to accomplish a specific function.
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    Throughput
  • An amount of job done.  The number of programs that CPU has executed in a time.
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    Fault-tolerant (Graceful degradation)
  • The ability to continue providing services proportional to the level of surviving hardware.
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    Interrupt
  • called by input or output devices.
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    RJE (Remode - Job - Entry)
  • In older batch systems, small processors, located at some distance from the main CPU, were used to run card readers and line printers and to transfer these jobs to and from the main computer.
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    Front-End
  • Mini computer acts as a buffer between the terminals and the main CPU, allowing the main CPU to handle lines and blocks of character, instead of individual characters.
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    Back-End
  • Slave processor receives a sequence of requests from the main CPU and implement its own disk queue and scheduling algorithm.
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    Email to: dtnguyen@neiu.edu

    Chapter 1 - New Vocabulary Page
    Created by Doan Nguyen
    Last Update March 26, 1999