Chapter 2 Data Manipulation Yonsei University 1 st Semester, 2015 Sanghyun Park.
Chapter 3 Operating Systems Introduction to CS 1 st Semester, 2015 Sanghyun Park.
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Transcript of Chapter 3 Operating Systems Introduction to CS 1 st Semester, 2015 Sanghyun Park.
Chapter 3Operating Systems
Introduction to CS
1st Semester, 2015 Sanghyun Park
Outline History of Operating Systems Operating System Architecture Coordinating the Machine’s Activities Handling Competition Among Processes (skipped) Security (skipped)
History of Operating Systems An Operating System (OS) controls and coordinates usage of a
machine’s __________ (CPU, memory, disks, …)
Single-processor machines in 1940s and 1950s Significant preparation of mechanical equipment to run a program Execution of a program → ____
Separation of users and equipments(introduction of computer operator concept) Submit program to operator to run,
along with any required ____ and special _________ Operator _____ program materials into machine’s mass storage Batch processing – the execution of jobs by collecting them in a single
_____, then executing them _______ further _________ with the user
Batch Processing
___ interaction with the program once submitted
Interactive Processing
What happens when we have multiple users? Time-_______ solution (time slices) In single-user systems usually called ___________
Software Classification
Application: spreadsheets, games, program development software
Utility: utility to format a disk, copy a file, utility to handle network communication
Operating system
Operating System Components
Shell: ________ between users and operating systems
Modern computers have a _____ shell
Window manager: component within the GUI shell
Kernel: ______ part of an OS
OS Kernel Software Components File manager
Coordinates use of machine’s mass _______
Device drivers Controls operation of machine’s ________ devices (printer, monitor, …)
Memory manager Coordinates machine’s use of main ________
Scheduler Determines which ________ is executed ______
Dispatcher Controls allocation of _____ slices to activities
Boot Strapping in OS
File Manager Keep ________ of files stored in secondary storage
_________ of each file Which users are allowed to access which files _________ space in secondary storage
Group files into a bundle called a __________ or folder
A directory may contain other directories called ____________
A chain of directories within directories is called a directory _____
Provide means to access files (open and manipulate files)
Memory Manager Charged with the task of coordinating the machine’s use of main
memory
Such duties are minimal in ‘one task at a ____’ environment The program for the current task is placed in main memory, executed,
and then replaced by the program for the next task
The duties are extensive in _________ or multitasking environment Many programs and blocks of data reside in main memory concurrently Allocate areas of memory for each program Fulfill memory requirements for programs Keep track of memory areas no longer occupied
Virtual Memory When total main memory required _______ actually available?
Memory manager creates _______ of additional memory space by ________ programs and data back and forth between main memory and secondary storage
Illusionary memory space is called _______ memory Memory requirements are allocated in units called ______
(page size < 4KB)
When a main memory of 256MB is required,but only 128MB is actually available? Memory manager _______ contents of pages in secondary storage When a page in secondary storage is needed for access,
_____ it in main memory If no space in main memory, _____ some other page no longer required
to secondary storage
Concept of a Process Distinction between a program and the activity of executing a program
Program static set of directions
Activity of executing a program dynamic activity known as a ________
Process state Current ________ in the program being executed (value of PC) _______ in other registers and associated memory cells
A single program can be associated with ___________ one process
In a time-sharing computer, processes _________ for time slices
It is the task of operating system to coordinate these processes
Process Administration (1/2) The tasks associated with process coordination are handled by the
_________ and _________ within OS kernel
Scheduler Maintains a block of information in main memory called _____________ When a new task is assigned to machine, creates a process for that
task by placing a new _____ in the process table Memory area assigned to process (from memory manager) Process priority Process status (ready, waiting for some event (I/O for example))
Determines which activity is executed first
Dispatcher Ensures that the scheduled processes are actually executed Divides time into time slices (quantum) Process __________
Process Administration (2/2)
At interrupt CPU completes current machine
_____, _______ current process state, and transfers control to an _________ handler
Interrupt handler is part of dispatcher
Dispatcher Selects a _____ process from the
process table (highest priority) _______ time circuit for the next
interrupt Allow selected process to ______
execution
Sometimes, the process time sliceis terminated ______ the timer expires(for example when executing I/O)