Transcript Introduction - UW Courses Web Server

Chapter 1:
Introduction to Operating Systems
Joe McCarthy
CSS 430: Operating Systems - Introduction
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Outline
• Questions from last time?
• Updates
• Introduction to Operating Systems (Ch 1)
– Overview & History
– Process management
– Memory Management
– File System Management
• Informal Linux Lab orientation (UW1-320)
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Updates
• Updated syllabus page (http://bit.ly/css430B)
– Shared Discussion Board (Sections A & B)
– Slides posted from last time (“Overview” link)
– Will merge/create class homepage by Monday
• Shifted MW evening office hours:
– Old: 5:00-5:30pm, UW2-317
– New: 7:45-8:15pm, UW1-220 (and/or UW2-317)
• Best to email ahead of time
• Chapter 2, Assignment 1: next time
– http://courses.washington.edu/css430/prog/prog1.html
– “Program 1” via “Homework Assignments” on main CSS
430 page
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Chapter 1: Introduction
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What Operating Systems Do
Computer-System Organization
Computer-System Architecture
Operating-System Structure
Operating-System Operations
Process Management
Memory Management
Storage Management
Protection and Security
Distributed Systems
Special-Purpose Systems
Computing Environments
Open-Source Operating Systems
CSS 430: Operating Systems - Introduction
Material derived, in part, from
Operating Systems Concepts with Java, 8th Ed.
© 2009 Silberschatz, Galvin & Gagne
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What is a computer system?
CSS 430: Operating Systems - Introduction
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What is a computer system?
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What is an Operating System?
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What is an Operating System?
• OS is a resource allocator
– Manages resources efficiently & efficiency, resolves conflicts
• OS is a control program
– Controls execution of programs, operations of devices
• No universally accepted definition
– “Everything a vendor ships when you order an operating system”
CSS 430: Operating Systems - Introduction
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What is an Operating System?
• OS is a resource allocator
– Manages resources efficiently & efficiency, resolves conflicts
• OS is a control program
– Controls execution of programs, operations of devices
• No universally accepted definition
– “Everything a vendor ships when you order an operating system”
• Kernel vs. system program vs. application program?
CSS 430: Operating Systems - Introduction
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What is an Operating System?
• OS is a resource allocator
– Manages resources efficiently & efficiency, resolves conflicts
• OS is a control program
– Controls execution of programs, operations of devices
• No universally accepted definition
– “Everything a vendor ships when you order an operating system”
• Kernel: “The one program running at all times on the computer”
– Everything else is either a system program (ships with the OS)
or an application program
CSS 430: Operating Systems - Introduction
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What is an Operating System?
• OS is a resource allocator
– Manages resources efficiently & efficiency, resolves conflicts
• OS is a control program
– Controls execution of programs, operations of devices
• No universally accepted definition
– “Everything a vendor ships when you order an operating system”
• Kernel: “The one program running at all times on the computer”
– Everything else is either a system program (ships with the OS)
or an application program
• Bootstrap program?
CSS 430: Operating Systems - Introduction
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What is an Operating System?
• OS is a resource allocator
– Manages resources efficiently & efficiency, resolves conflicts
• OS is a control program
– Controls execution of programs, operations of devices
• No universally accepted definition
– “Everything a vendor ships when you order an operating system”
• Kernel: “The one program running at all times on the computer”
– Everything else is either a system program (ships with the OS)
or an application program
• Bootstrap program is loaded at power-up or reboot
– Typically stored in firmware (ROM or EEPROM)
– Initializes all aspects of system, loads OS kernel and starts execution
CSS 430: Operating Systems - Introduction
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What is an Operating System?
• OS is a resource allocator
– Manages resources efficiently & efficiency, resolves conflicts
• OS is a control program
– Controls execution of programs, operations of devices
• No universally accepted definition
– “Everything a vendor ships when you order an operating system”
• Kernel: “The one program running at all times on the computer”
– Everything else is either a system program (ships with the OS)
or an application program
• Bootstrap program is loaded at power-up or reboot
– Typically stored in firmware (ROM or EEPROM)
– Initializes all aspects of system, loads OS kernel and starts execution
• OS desiderata?
CSS 430: Operating Systems - Introduction
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What is an Operating System?
• OS is a resource allocator
– Manages resources efficiently & efficiency, resolves conflicts
• OS is a control program
– Controls execution of programs, operations of devices
• No universally accepted definition
– “Everything a vendor ships when you order an operating system”
• Kernel: “The one program running at all times on the computer”
– Everything else is either a system program (ships with the OS)
or an application program
• Bootstrap program is loaded at power-up or reboot
– Typically stored in firmware (ROM or EEPROM)
– Initializes all aspects of system, loads OS kernel and starts execution
• OS desiderata: effective, efficient, easy-to-use
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Computer System Components
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Computer Hardware
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Computer system operation
• CPU & I/O devices can execute concurrently
• Each device controller
– is in charge of a particular device type
– has a local buffer
• CPU moves data from/to main memory to/from local buffers
– Device I/O is from the device to local buffer of controller
• Device controller informs CPU that it has finished its operation by
causing an interrupt
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Interrupt handling: motivation
“…on a fully saturated 100 Mb/s Ethernet link
with an average packet size of 512 bytes, the
network adapter may generate over 20,000
interrupts per second.
If each interrupt takes 15μsec, over 30% of the
processor time may be devoted to interrupt
handling.”
Profiling Interrupt Handler Performance through
Kernel Instrumentation
Branden Moore, Thomas Slabach, Lambert Schaelicke
Proceedings of the 21 st IEEE International Conference
on Computer Design, 2003
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Interrupt handling
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Interrupt handling
www.iti.uni-stuttgart.de/~radetzki/Seminar06/08_report.pdf
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Interrupt handling, with priorities
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Brief history of Operating Systems
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Batch systems
Multiprogramming
Time-sharing
Multiprocessing
Multi-computer systems
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Batch Systems
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Job: program + the data + control info
Programmers pass their jobs to an operator
The operator batches together jobs
OS transfers control from one job to another
Job output is sent back to the programmer
IBM 1402
CSS 430: Operating Systems - Introduction
IBM 1403
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Multiprogramming
• Several jobs are kept in main
memory a same time
• OS picks one of them to execute
• The job may have to wait for a
slow I/O operation to complete
• OS picks & executes another job
• OS Requirements:
– Job scheduling
– Memory management
IBM System/360
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Timesharing
• Timesharing (multitasking): CPU switches jobs
frequently so that multiple users can interact
with their jobs while they is running (interactive
computing)
– Response time should be < 1 second
– Each user has at least one program executing in
memory process
– If several jobs ready to run at the same time  CPU
scheduling
– If processes don’t fit in memory, swapping moves
them in and out to run
– Virtual memory allows execution of processes not
completely in memory
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Multiprocessing
Multiple CPUs, shared memory
(asymmetric or symmetric)
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Multiprocessing
Multiple CPUs, shared memory
(asymmetric or symmetric)
Advantage(s)?
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Multiprocessing
Multiple CPUs, shared memory
(asymmetric or symmetric)
Advantage(s)?
• Increased throughput
• Economy of scale
• Increased reliability
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Multi-processor vs. Multi-core
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Multi-processor vs. Multi-core
Multiple CPUs on separate chips
Multiple CPUs on same chip
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Multi-processor vs. Multi-core
Multiple CPUs on separate chips
Multiple CPUs on same chip
Advantage(s)?
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Multi-processor vs. Multi-core
Multiple CPUs on separate chips
Multiple CPUs on same chip
Advantage(s)?
More efficient
• Faster
• Less power
• Less heat
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Multi-computer Systems
Local Area Network (LAN)
(shared storage or
other peripherals)
Client-Server System
(e.g., WWW)
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How a Computer Works
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Instruction Execution Cycle
http://ocw.capilanou.ca/computing-science/breadth-topics-in-computingscience/course_files/programming/ProgrammableMachine.html
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Two modes of processing
• Why 2 modes?
• What causes shifts between modes?
• Why would a CPU need a timer?
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Process Management
• Activities an OS must perform?
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Process Management
• Activities an OS must perform:
– Creating and deleting user & system
processes
– Suspending and resuming processes
– Providing mechanisms for process
synchronization
– Providing mechanisms for process
communication
– Providing mechanisms for deadlock
handling
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Hierarchy of Memory
Variables:
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Hierarchy of Memory
Variables:
• Speed
• Cost
• Size
• Volatility
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Memory Performance
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Memory Management
• Activities OS must perform?
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Memory Management
• Activities OS must perform:
– Keeping track of which parts of
memory are currently being used
and by whom
– Deciding which processes (or parts
thereof) and data to move into and
out of memory
– Allocating and deallocating memory
space as needed
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File System Management
• Activities an OS must perform?
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File System Management
• Activities an OS must perform:
– Creating and deleting files & directories
– Primitives to manipulate files &
directories
– Mapping files onto secondary storage
– Backup files onto stable (non-volatile)
storage media
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Speaking of file systems …
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See your UW NetID in that list?
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Linux overview
• Basic commands
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Directories: cd, mkdir, ls
Manipulate files: cp, mv
Edit files: vi, pico, emacs
Help: man
Print: lpr -Puw1-320-p1
Compile: g++, javac
• Remote login:
– [email protected]
• More info:
– http://www.uwb.edu/css/facilities/unix
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For next time
• Readings
– Chapter 2: Operating System Structures
• Assignment 1
– Assigned (not due)
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