comp229-slide-5 - Concordia university Department of...

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Lesson 5 - Introduction to operating systems 1 Concordia university Department of computer science System software – COMP229 Lesson 5 : Introduction to operating systems © Author : Kerly Titus
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Lesson 5 - Introduction to operating systems 2 Introduction to operating systems Contents 1. Categories of operating systems 3 2. Families of operating systems 15 3. Operating system components 29 4. Operating system services 46 5. Key points 57 6. References 59
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Lesson 5 - Introduction to operating systems 3 1. Categories of operating systems Batch systems Timesharing systems Client-server systems Multiprocessing systems Distributed systems Personal computer systems Handheld systems Real-time systems Pedagogic systems
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Lesson 5 - Introduction to operating systems 4 Categories of operating systems Multiprogrammed batch systems Characteristics. Non interactive OS used in the 1960s. Resident monitor. Interrupt processing. Device drivers. Job scheduler. Job control language interpreter. Memory management and protection. Resident monitor executes privileged instructions. ± Non resident monitor is in user space. Routines are loaded on request. Multiple jobs are loaded in memory. Some jobs wait in the disk job pool. Jobs execute without interruption. A job is only interrupted due to an error or an I/O operation. A new job is selected from memory to run while another job is blocked. A job example. $JOB $FTN . . . $LOAD $RUN . . . $END FORTRAN instructions Data
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Lesson 5 - Introduction to operating systems 5 Categories of operating systems Multiprogrammed batch systems •P r i n c i p l e s . – Program is written manually. – Program is coded on a punch card or is saved on a magnetic tape. – Program is given to an operator. – Operator groups common jobs that are inserted in a job queue. – Operator loads the specific job processing program in memory. – Job queue is saved on an input device. – Monitor loads the jobs from the input device and executes them. – Program listing and output are printed. Job Job queue Memory allocation Memory Job scheduler Processor •Flowchart of a traditional batch processing
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Lesson 5 - Introduction to operating systems 6 Categories of operating systems Timesharing systems Characteristics. – Users communicate interactively with the central computer. Input commands are sent through a console keyboard. Output results are received through a console screen. – Each user maintains a connection session through a virtual machine. – Sharing and protection of resources between users. – Each user session receives a fixed CPU time slice. A context switch occurs when the time slice expires. The interrupted user waits in a queue for the next time slice.
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This note was uploaded on 03/25/2010 for the course COMP COMP229 So taught by Professor Guy during the Spring '10 term at Concordia Canada.

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comp229-slide-5 - Concordia university Department of...

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