1 operating systems foundations students

8/14/2019 1 Operating Systems Foundations Students

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K Sathyababu Dept of CSE NIT Rour

Operating SystemFoundations

Department of Computer Science & EngineeringNational Institute of Technology Rourkela.

Presented by

Korra Sathya Babu


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K Sathyababu Dept of CSE NIT R

Basic Computing

Computer Components

CPU, Memory, I/O, Interconnection and respective

software

Why OS ?

Before OS ?


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Operating System An Operating System is a layer of software on a bare machine

that supports two functions

User friendliness

Resource management

Example:

OS-X, Windows, Linux, BSD,

.......(Desktop, Server)

Symbian, JavaOS (Cell phones)

Vx Works, pSOS (real-time)

.......


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Mill of an Analytical Engine


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The Atanasoff-Berry Computer the First Electronic

Computer - John Atanasoff and Clifford Berry


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Z3- Konrad ZuseGerman engineer, Konrad Zuse Z3very sophisticated for its time utilized the binary number system and handle floating-

point arithmeticuse relays because they were more readily available


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COLOSSUS Alan Turing

COLOSSUS - electronic

machine to decode the

Geheimfernschreiber cipher

comprised 1,800 vacuumtubes


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The Harvard MARK I Computer- Howard Aiken and Grace Hopper

Harvard Mark 1 Computer


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The ENIAC I Computer

J Presper Eckert and John Mauchly

U.S. Army PhotoThe ENIAC, in BRL building 328


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1944 AD to 1952 AD

The First Stored Program Computer -- EDVAC


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Punched Card


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Serial Processing

No operating system

Machines run from a console with display lights, toggle

switches, input device, and printer

Schedule time

Setup included loading the compiler, source program,

saving compiled program, and loading and linking

This had two main problems

Scheduling

Setup time


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Batch Processing

Early batch system

bring cards to 1401

read cards to tape

put tape on 7094 which does computing

put tape on 1401 which prints output


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Structure of a typical FMS job 2nd generation

Batch jobs are set up so they can be run to completion without human interaction,

so all input data is preselected through scripts or command-line parameters. This is

in contrast to "online" or interactive programs which prompt the user for such input.


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4004 Microprocessor Family


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From 3rd Generation OS

Small Scale Integration of transistors on asingle chip

OS/360 (1964) for IBM MainframeSystem/360

OS/360 was a group of batch processingOS The direct access storage devices were

made as a prerequisite for the operation of

OS/360 More resources: http://www.beagle-ears.com/lars/engineer/comphist/ibm360.htm#opsys
http://www.beagle-ears.com/lars/engineer/comphist/ibm360.htmhttp://www.beagle-ears.com/lars/engineer/comphist/ibm360.htm


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Multiprogramming System

three jobs in memory 3rd generation


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Spooling

simultaneous peripheral operations on-line refers

to putting jobs in a buffer, a special area in

memory or on a disk where a device can access

them when it is ready.

Spooling is useful because devices access data

at different rates. The buffer provides a waiting

station where data can rest while the slower

device catches up.


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Time Sharing Systems (Multitasking)

Users demand for quick response

A derivative of Multiprogramming

First General purpose time sharing system CTSS (Compatible Time Sharing System)developed by MIT

The term time-sharing is no longer commonlyused, having been replaced by simplymultitasking.


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UNIX

Dennies Ritche with Ken Thompson in 1971

Multics renamed as UNIX PDP 11/20

UNIX first written in Assembly level Language

Various versions of UNIX (V1 to V7) confined to MIT 1979 UNIX development developed into two camps

System V model by AT & T

BSD (Berkeley Software Distribution) by University of

California Two Models diverged into different implementations

Linux by Linus Torvolds


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MAC evolution

Doug Engelbart of Stanford GUI with

windows, icons, mouse, menus etc

XEROX PARC machines used GUI

Steve Jobs Apple started Apple with

GUI (Lisa)

Jobs second attempt Machintosh was agreat success becos of Userfriendlyness


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MS Windows evolution

Inspired by MACs success goes for GUI based MS-DOS

Produced GUI based Shell running on MS-DOS (85 to 95)

1995 MS Windows plans for free standing OS still booting with MS DOS.

1998 MS comes with higher version of MS Win 95, MS Windows 98 (16 bit)

MS Win NT (New Technology) was rewritten from scatch

Designer of Win NT was David Cutler (designer of VAX VMS OS). Majorityof VMS ideas were in Win NT (VAX sued MS)

Win NT 4.0 able to kill DOS to a great extent

Early 1999 Win NT 5.0 (successor of Win 98 and Win NT) - renamed asWindows 2000 (but failed)

Came out with another version of Win 98 called Win ME

2001- slightly upgraded version of Win 2000 called Win XP released (had 6years run)

2007 Win Vista successor to XP released


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Other major contenders in PC

World

Unix strongest in network and enterprise servers

Linux becoming alternative to Windows

FreeBSD is also another popular derivative of UNIX

UNIX also strong on workstations powered by highperformance RISC chips

X Windows systems (X11)

Gnome or KDE run on top of X11 giving windows orMac look for UNIX

Network operating systems Real time operating systems

Distributed operating systems


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Review

Transparency, distributed

control

Resource Sharing90sDistributed

Real time schedulingMeet deadline80sReal Time

Time slice, round robin

scheduling

Good Response Time70sTime Sharing

Program Priorities and

preemption

Resource Utilization70sMultiprogramming

Spooling, Turn around timeCPU idle time60sBatch processing

Key conceptsPrime concernPeriodOS Class

C t H d R i


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Computer Hardware Review

(Basic Computer Components)

Components of a simple personal computer


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Processor


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(Pipelining)

(a) A three-stage pipeline

(b) A superscalar CPU


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C H d R i


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(Disks)

Structure of a disk drive


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Computer Hardware Review (5)

One base-limit pair and two base-limit pairs


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Computer Hardware Review (6)

(a) Steps in starting an I/O device and getting interrupt

(b) How the CPU is interrupted

(a) (b)


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Computer Hardware Review (Bus)

Structure of a large Pentium system


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Software

System S/w Application S/w

System Development

ProgramsSystem Mgmt Programs

Operating Systems

Device Drivers

System Utilities

Loaders

Linkers

Translators

Word Processors

Presentation tools

Spread Sheets

DBMS

Editors

-Backups

-Virus Protection

-Disks

-Compiler

-Interpreter

- Assembler


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Review of Last Class

Various computing Strategies were covered

(Serial processing, batch processing,

Multiprogramming, Multitasking, Real time,

Distributed) Since Operating System is in between a user and

bare machine, we have given an overview of

basic components of a computer

Also we have gone through software divisions


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Booting

ROM BIOScontains low level S/w including to read keyboard, write onscreen and do disk I/O and other

Now a days even stored in Flash RAMs

Process of Booting

Scans ISA and PCI buses to check if all devices are connected

RAM, keypad and other devices are responding or not

Checks for boot device in CMOS memory (first from floppy, CD-ROMthen disk for software configure)

The 1st Sector from boot device is read to memory and executed

This program examines partition tables for active partitions

Then second boot loader is read from that partition

The loader reads the OS from that partition and starts it

The OS then queries BIOS to get the configuration details

For each device the OS checks to see if it has device drivers

On Finding the device drivers the OS loads them into kernel

Then initialize the tables and performs background processes and startsthe shell


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Shell

Users physical interaction

Different types of shells of different

operating systems

Benefit of shell


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Instruction Execution

Fetch Cycle

Decode Cycle

Operand Fetch Cycle

Execute CycleFour cycles are called Instruction Cycle orComputer Cycle.

Interrupt Cycle


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Interrupts

External (H/w and I/O Interrupts)

Internal (page fault, segment fault,

exception handling and other S/w

interrupts)

Interrupts may be sync or async


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System Calls It is a method by which user programs

makes a request to Operating Systems System Calls vary from OS to OS

Only System Call enters the Kernel and

Procedure calls do not

Explanation with example of read

instruction


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Goals of an OS

Efficiency (high throughput)

Convenience (user friendliness, good service,

support for new programming languages etc.)

Scalability (Ability to involve) (Plug & play)

Reliability (support applications, secure

them, recover when failure etc.)

Portability (machine independent)


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Functions of an OS

Process Management

Memory Management

File Management

Device Management

Protection Management

User Interface


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Different Operating Systems Mainframe OS (oriented towards processing many jobs

at a time)

Server OS (serve multiple users at once over a networkallow sharing of resources)

Multiprocessor OS (load sharing towards other systems)

Personal Computer OS (focus on providing good serviceto single user)

Handheld Computer OS (or PDA OS supports smallnumber of functionalities)

Embedded OS (run on microcontrollers to providespecific applications)

Sensor Node OS Real-Time OS (oriented for fast responses)

Smartcard OS ()


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OS Structures

Monolithic Kernel

Layered Systems

Microkernel

Client Server Model

Virtual Machines

Exokenels


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Monolithic approach

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