20120319150304Lecture 3 - Operating System and History

7/23/2019 20120319150304Lecture 3 - Operating System and History

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CSNB113: SystemAdministration

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3rdTopic: The need for anoperating system // history

of operating systems


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Remember:Booting - III

As soon as a BR is fo!nd on one of de"ices scannedby the BI#S$ the contro% is passed to this de"ice$ andthe %ocation of the operating system is &na"igated& to'(A BR essentia%%y is a pointer to a specific

%ocation/address on the specific dis) dri"e'*

At that %ocation on the dri"e$ a basic programloaderneeds to be fo!nd'If this is not the case$ the boot process fai%s

This program loaderthen %oads the kernelof theoperating system'

The )erne% in t!rn %oads the operating systemandits app%ications'


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Simp%e %oader

A simp%e program loaderco!%d a%so be !sed$ and +as !sed in the ear%y days ofcomp!ters$ ,!st to %oad a program and r!n it'DOS(is) #perating System* is act!a%%y a program %oader'

This method +or)s$ b!t not too +e%%:

Then only one single programcan r!n at a time' #ne cannot open more than one&+indo+&$

#ne cannot !se more than one app%ication

#n%y one usercan !se the machine$ and if (s*he does not !se it$ it +i%% ha"e toremain id%e

.hen this program or app%ication gets &st!c)&$ the machine is &dead& and needs a&hard reset&

That is +hy the concept of &operating system& +as in"ented:

A kernelto a%%ocate and contro% reso!rces

A system to contro% the running of programs$ starting and stopping them

A n!mber of system programsto ca%c!%ate time$ manage !sers$ manage printers$manage the disp%ay$ manage the net+or) connections$ notify !sers$ etc'


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#perating Systems:Batch processing

In the "ery beginning$ the tas) to r!n more than one program +asdone by r!nning strict%y one after the other$ so-ca%%ed Batchprocessing' The programs +ere read from punchcards:


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#perating Systems:!%tics and ni0

ater$ at Be%% abs (AT2T*$ it +as p%anned to ha"e asystem for multiple applicationsfor multipleusers'

(Read .hat&s In A Name on p'3 of the te0tboo) for

the detai%s'*

The res!%t +as &Unix&' It ran for the first time in 1454$de"e%oped by Ken Thompsonand Dennis Ritchie'Both a%so de"e%oped the programming language C

aro!nd this time'ni0 +as a h!ge s!ccess$ many companies paid forthe %icenses$ prod!ced their o+n "ersions$ and o+nutilities'


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6en and ennis(and i%bert*


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Commercia% S!ccess

ni0 +as a big s!ccess$ AT2T cashed a %ot of%icensing fees'

7or b!siness this +as o)ay'

7or academia it +as not: #n%y rich !ni"ersities and schoo%s co!%d afford

the licensing fees

#ften$ a program needs some modification in a

research en"ironment' B!t the programsources+ere !s!a%%y not inc%!ded$ somodifications co!%d not be done by the !sers$the academicians$ the researchers


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7ree Soft+are 7o!ndation

Richard Stallman$ a researcher in the Artificia%Inte%%igence ab of assach!setts Instit!te ofTechno%ogy (IT*$ +as con"inced that sharingsoft+are +as he%pf!%$ and changingit +as

necessary for contin!o!s progress'8e s!ggested to re-+rite a%% proprietaryni0!ti%ities !nder a licensethat a%%o+s to e0change$modify and re-distrib!te the so!rce code free%y'

8e fo!nded the ree Soft!are oundation(7S7*for this p!rpose in 149'


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7ree Soft+are

The ree Soft!are oundationde"e%oped four essentialfreedoms:

The freedom to runthe program$ for any p!rpose (freedom ;*'

The freedom to studyho+ the program +or)s$ and changeit toma)e it do +hat yo! +ish (freedom 1*'

The freedom to redistributecopies so yo! can he%p yo!r neighbor(freedom


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S!ccesses and 7ai%!res

The ree Soft!are oundationachie"ed its p!rposes$ most ofthem' A compilerbecame a"ai%ab%e$ an editor$ a shell$ and a%%other too%s and !ti%ities'

="erything +as %icensed !nder a %icense that gi"es the fo!rfreedoms to a%% !sers' B!t nobody is a%%o+ed to remo"e this

%icense from the soft+are that they distrib!te or se%%' So these >freedoms remain +ith the soft+are fore"er'

The %icense is ca%%ed #eneral $ublic %icense(?@*

ailure&

The &fai%!re& +as the %ac) of an operating system kernel' Thetoolsa%% a"ai%ab%e !nder ?@$ it sti%% needed a proprietary%icense for a )erne%'


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in!s and in!0

The prob%em &)erne%& +as so%"ed in an !ne0pected manner' A st!dent atni"ersity of 8e%sin)i in 7in%and +anted to !se the po+er of the Unix'shellonhis @ersona% Comp!ter at home' (In the 149;-s affordab%e comp!ters hadbeen introd!ced by IB and trademar)ed as $Cs' They +ere a%most a%%r!nning DOS- is) #perating System$ in princip%e a program %oader +ith abasic command prompttoo%'*

%inus Tor"alds$ that st!dent$co!%d !se a%% the !ti%ities offered !nder #$%$b!t the )erne% +as missing' So he too) the initiati"e to +rite one himse%f$ andhad it p!b%ished !nder the same %icense'

7ina%%y$ a complete operating system+ith )erne% and !ti%ities +asa"ai%ab%e !nder a 7ree Soft+are %icense' Since most ni0 "ersions had beennamed +ith some -i0 or simi%ar at the end$ %i)e AI$ 8@-$ IRI$ ini0$ So%aris$

it +as no s!rprise that this ne+ one +as ca%%ed %inux'


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in!0 and ?@-istrib!tions

in!s (in!0* act!a%%y being the )erne% &on%y&$ thecomp%ete and correct pict!re of a comp%eteoperating system sho!%d inc%!de the #(U(?N is Not ni0 read .hat&s In A Name on p'15

of the te0tboo) for the detai%s'*Since both )erne% and ?N !ti%ities are a"ai%ab%e as7ree Soft+are$ many organisations$ companies andindi"id!a%s started to distrib!te their preferred sets

of programs as %inux Distributions' The mostfamo!s are Red 8at$ S!se$ b!nt!' #thers areebian$ ?entoo$ S%ac)+are'


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in!s and ?N/in!0


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References

http://en'+i)ipedia'org/+i)i/Comp!terprogramminginthep!nchedcardera

Te0tboo)$ p'3

Te0tboo)$ p'15

http://+++'fsf'org/

http://en'+i)ipedia'org/+i)i/in!sTor"a%ds

Documents

20120319150304Lecture 3 - Operating System and History