Transcript Starting Up Operating Systems

COSC1078 Introduction to
Information Technology
Lecture 17
Operating Systems
James Harland
[email protected]
Lecture 17: Operating Systems
Intro to IT
Introduction to IT
1-4 Introduction, Images, Audio, Video
5-6 Computer Fundamentals
Assignment 1, WebLearn Test 1
7 Review
8 Operating Systems
WebLearn Test 2
9 Operating Systems
Assignment 2
10 Internet
11 Internet Security
WebLearn Test 3
12 Future of IT
Assignment 3, Peer and Self Assessment
Lecture 17: Operating Systems
Intro to IT
Overview
 Questions?
 Assignment 2
 Operating Systems
 Questions?
Lecture 17: Operating Systems
Intro to IT
Assignment 2
 Now in the Learning Hub
 Assumes you are using Audacity
 If not, please see me asap
 Seems a lot, but shouldn’t be too hard once you have
Audacity and your files
 CD task requires CD reading software
Windows: ImgBurn www.imgburn.com
Mac: Burn, Toast
Linux: ImgBurn via Wine, or K3B, Brasero, Nero, …
Lecture 17: Operating Systems
Intro to IT
Initial State When Turned On
Processor
00
Program
Counter
Memory
00 Bootstrap
Disk
ROM
Program
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Load Bootstrap Program
Processor
00
Program
Counter
Memory
00 Bootstrap
Disk
ROM
Program
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Bootstrap program loads OS
Processor
00
Program
Counter
Memory
00 Bootstrap
Disk
ROM
Program
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Bootstrap program loads OS
Processor
00
Program
Counter
Memory
00 Bootstrap
Disk
ROM
Program
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Bootstrap program has loaded OS
Processor
AA
Memory
Disk
00 Bootstrap
ROM
AA
RAM
Program
Program
Counter
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
OS takes over execution
Processor
AA
Memory
Disk
00 Bootstrap
ROM
AA
RAM
Program
Program
Counter
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Starting Up Operating Systems
Processor
AA
Memory
Disk
00 Bootstrap
ROM
AA
RAM
Program
Program
Counter
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Starting Up Operating Systems
Processor
AA
Memory
Disk
00 Bootstrap
ROM
AA
RAM
Program
Program
Counter
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Starting Up Operating Systems
Processor
AA
Memory
Disk
00 Bootstrap
ROM
AA
RAM
Program
Program
Counter
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Multiple boot scenario …
Processor
00
Program
Counter
Memory
00 Bootstrap
Disk
ROM
Program
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Multiple boot scenario …
Processor
00
Program
Counter
Memory
00 Bootstrap
Disk
ROM
Program
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Multiple boot scenario …
Processor
00
Program
Counter
Memory
00 Bootstrap
Disk
ROM
Program
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Multiple boot scenario …
Processor
00
Program
Counter
Memory
00 Bootstrap
Disk
ROM
Program
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Processes
Lecture 17: Operating Systems
Intro to IT
Processes
A program is a static set of
instructions
A processes is the execution
of a program, which changes
state over time.
Lecture 17: Operating Systems
Intro to IT
Processes Executing in Context
Processor
CC
Memory
00
Program
Counter
Disk
ROM
RAM
CC
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Processes Executing in Context
Processor
DD
Memory
00
Program
Counter
Disk
ROM
RAM
CC
DD
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Processes Switching
Ready
Scheduler maintains
process table
Ready
Waiting
Lecture 17: Operating Systems
Intro to IT
Processes Switching
Lecture 17: Operating Systems
Intro to IT
Interrupts
 Signals to the CPU
 Often generated by timing circuits
 CPU reacts by jumping to appropriate memory
location
 Dispatcher
 selects a ready process
 resets timing circuit
 starts process
 CPUs often designed to switch process states
efficiently
Lecture 17: Operating Systems
Intro to IT
Processes Executing in Context
Processor
BB
Program
Counter
Memory
00
BB
Disk
ROM
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Processes Executing in Context
Processor
BB
Program
Counter
Memory
00
BB
Disk
ROM
RAM
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Processes Executing in Context
Processor
FF
Memory
00
Program
Counter
Disk
ROM
RAM
FF
Instruction
Register
Lecture 17: Operating Systems
Intro to IT
Interrupts
 Provide mechanism to switch processes
 CPU doesn’t have to wait for I/O transfers
 Switching leads to faster throughput
 `Save document’ means CPU does something
else while the save takes place
Lecture 17: Operating Systems
Intro to IT
Conclusion
 Work on Assignment 2
 Web Quizzes and Web Test 2
 Finish reading book!
Lecture 17: Operating Systems
Intro to IT