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CHAPTER 1: INTRODUCTION TO OS - Coggle Diagram
CHAPTER 1: INTRODUCTION TO OS
TYPES OF OS
REAL-TIMME
HYBRID
INTERACTIVE /TS
Faster turnaround that BS
slower than RTS
provide fast turnaround when debugging prog
TS(time sharing) software developed for OS
QUANTUM
: task given time to execute so all work smoothly
task can be from single user or diff user
ADV
task get same oppoturnity each
chances of duplication of software is less
cpu idle time can be reduced
DIS
EMBEDDED
BATCH
takes similar jobs, with same requirement, group them into batches.
sort jobs with similar needs
ADV
processor know how long the job will be when in que
idle time for batch is less
can be shared by multiple users
easy to manage large work repeatedly.
DIS
Comp operator should know the system
hard to debug
costly
if any job fails, other job need to wait for unknown period
EVOLUTION OF OPERATING SYSTEM
OBJECT ORIENTED DESIGN
OPEN SOURCE & CLOSED SOURCE
COMPUTING ENVIRONMENT
WHAT IS AN OS
USER POV
WORKSTATIONS
MAINFRAME
other users access through other terminal
PC
SINGLE USER:
-monopolize resource
maximize work
COMPUTER SYSTEM
USERS
people, machines, comp
APPLICATION PROGRAMS
ways in system resources are used
to solve computing problem for various users
OS
control and coordinate hardware among
various
apps programs for
various
user
HARDWARE
cpu, memory, devices
provide computing resources
control who and how system is used
manage all hardware and software
software (program),hardware (component)
provide user environment where user can execute program in convenient and efficient manner
a program hat act as intermediary between a user of a computer and the hardware of the computer
SYSTEM POV
RESOURCES ALLOCATOR
OS is the manager thatof resources, they allocate and manage resource
CONTROL PROGRAM
-manage the execution of user program
-prevent error, improper computer usage
KERNEL
one program running all the time on the comp
SUBSYSTEM MANAGER
WORK CLOSELY WITH OTHER MANAGER
monitor resources continuously
enforce policies determine who get what and how much
allocate and delocate resource when appropriate
MEMORY MANAGER
MAIN MEMORY
RAM
TASK:
preserve space in MM occupied by OS
check validity and legality if memory space request
set up memory tracking table
usage by sections, need in multiuser env
deallocate memory to reclaim it
PROCESSOR MANAGER
track process status (program execution)
CPU
TASK:
L1:
HANDLE JOB AS THEY ENTER SYSTEM
, Job scheduler
L2:
MANAGE EACH PROCESS WITHIN JOB
, process scheduler
3.DEVICE MANAGER
KEYBOARD, PRINTER, MODEM, DISK DRIVE
TASK:
choose the most efficient resource allocation method based on schedule policy
allocate device
start device operation
deallocate device
4.FILE MANAGER
PROGRAM FILES, DATA FILE, COMPILERS
TASK:
Enforce user/program resource access restrictions predetermined access policies
control user modification restrictions
allocating resources
open and close file
5.NETWORK MANAGER
NETWORK COMM PROTOCOLS
convenient way to share resources, control user access