OPERATING SYSTEM.pptx

8/15/2019 OPERATING SYSTEM.pptx

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SYSTEM


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COMMON FEATURES

• Process management• Interrupts• Memory management• File system• Device drivers• Networking• Security• I / O


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SYSTEM• An operating system OS ! is system so"tware t#at

manages computer #ardware and so"tware resources andprovides common services "or computer programs$ %#eoperating system is a component o" t#e system so"tware in acomputer system$ Application programs usually re&uire anoperating system to "unction$

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%ime's#aring operating systems sc#edule tasks "or e(cientuse o" t#e system and may also include accounting so"tware"or cost allocation o" processor time) mass storage) printing)and ot#er resources$

• For #ardware "unctions suc# as input and outputand memory allocation) t#e operating system acts as anintermediary *etween programs and t#e computer #ardware)alt#oug# t#e application code is usually e+ecuted directly *yt#e #ardware and "re&uently makes system calls to an OS"unction or is interrupted *y it$ Operating systems are "oundon many devices t#at contain a computer , "rom cellular


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SYSTEM

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%ypes o" operating systems – 1Single' and multi'tasking – 2Single' and multi'user – 3Distri*uted – 4%emplated – 5-m*edded – 67eal'time –

8 i*rary


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SINGLE AND MULTITASKINGOPERATING SYSTEM

• A single'tasking system can only run one program at a time) w#ilea multi'tasking operating system allows more t#an one program to*e running in concurrency$ %#is is ac#ieved *y time's#aring) dividingt#e availa*le processor time *etween multiple processes t#at are

eac# interrupted repeatedly in time slices *y a task'sc#edulingsu*system o" t#e operating system$ Multi'tasking may *ec#aracteri9ed in preemptive and co'operative types$ In preemptivemultitasking) t#e operating system slices t#e :P; time and dedicatesa slot to eac# o" t#e programs$ ;ni+'like operating systems) e$g$)Solaris) inu+) as well as AmigaOS support preemptive multitasking$

:ooperative multitasking is ac#ieved *y relying on eac# process toprovide time to t#e ot#er processes in a de


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SINGLE AND MULTI USER• Single'user operating systems #ave no "acilities

to distinguis# users) *ut may allow multipleprograms to run in tandem$ A multi'user operating system e+tends t#e *asic concepto" multi'tasking wit# "acilities t#at identi"yprocesses and resources) suc# as disk space)*elonging to multiple users) and t#e systempermits multiple users to interact wit# t#esystem at t#e same time$ %ime's#aring operatingsystems sc#edule tasks "or e(cient use o" t#esystem and may also include accountingso"tware "or cost allocation o" processor time)mass storage) printing) and ot#er resources tomultiple users$


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• Distributed • A distri*uted operating system manages a group o" distinct

computers and makes t#em appear to *e a single computer$ %#edevelopment o" networked computers t#at could *e linked andcommunicate wit# eac# ot#er gave rise to distri*uted computing$Distri*uted computations are carried out on more t#an one mac#ine$0#en computers in a group work in cooperation) t#ey "orm adistri*uted system$

• Templated • In an OS) distri*uted and cloud computing conte+t) templating re"ers

to creating a single virtual mac#ine image as a guest operatingsystem) t#en saving it as a tool "or multiple running virtual mac#ines$

%#e tec#ni&ue is used *ot# in virtuali9ation and cloud computingmanagement) and is common in large server ware#ouses$

• Embedded • -m*edded operating systems are designed to *e used in em*edded

computer systems$ %#ey are designed to operate on small mac#ineslike PDAs wit# less autonomy$ %#ey are a*le to operate wit# a limitednum*er o" resources$ %#ey are very compact and e+tremely e(cient*y design$ 0indows :- and Mini+ 3 are some e+amples o" em*edded

operating systems$


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• Real-time• A real'time operating system is an operating system t#at

guarantees to process events or data wit#in a certains#ort amount o" time$ A real'time operating system may*e single' or multi'tasking) *ut w#en multitasking) it usesspeciali9ed sc#eduling algorit#ms so t#at a deterministicnature o" *e#avior is ac#ieved$ An event'driven systemswitc#es *etween tasks *ased on t#eir priorities or

e+ternal events w#ile time's#aring operating systemsswitc# tasks *ased on clock interrupts$• Library• A li*rary operating system is one in w#ic# t#e services

t#at a typical operating system provides) suc# asnetworking) are provided in t#e "orm o" li*raries$ %#eseli*raries are composed wit# t#e application andcon


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ISTORY OF OPERATING SYSTEMS• -arly computers were *uilt to per"orm a series o" single tasks) like a

calculator$ >asic operating system "eatures were developed in t#e

1=5?s) suc# as resident monitor "unctions t#at could automaticallyrun di@erent programs in succession to speed up processing$Operating systems did not e+ist in t#eir modern and more comple+"orms until t#e early 1=6?s$ ardware "eatures were added) t#atena*led use o" runtime li*raries) interrupts) and parallel processing$0#en personal computers *ecame popular in t#e 1=B?s) operatingsystems were made "or t#em similar in concept to t#ose used onlarger computers$

• In t#e 1=4?s) t#e earliest electronic digital systems #ad no operatingsystems$ -lectronic systems o" t#is time were programmed on rows o"mec#anical switc#es or *y Cumper wires on plug *oards$ %#ese werespecial'purpose systems t#at) "or e+ample) generated *allistics ta*les"or t#e military or controlled t#e printing o" payroll c#ecks "rom dataon punc#ed paper cards$ A"ter programma*le general purposecomputers were invented) mac#ine languages consisting o" stringso" t#e *inary digits ? and 1 on punc#ed paper tape! were introduced

t#at sped up t#e programming process Stern) 1=B1!$


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MAIN FRAMES• %#roug# t#e 1=5?s) many maCor "eatures were pioneered in t#e M s current main"rame operating systemsare distant descendants o" t#is original system and applications written"or OS/36? can still *e run on modern mac#ines$

• OS/36? also pioneered t#e concept t#at t#e operating system keeps tracko" all o" t#e system resources t#at are used) including program and dataspace allocation in main memory and


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#S&stems• ;ni+ was originally written in assem*ly language$ Jen %#ompson wrote >) mainly

*ased on >:P ) *ased on #is e+perience in t#e M; %I:S proCect$ > was replaced *y :)and ;ni+) rewritten in :) developed into a large) comple+ "amily o" inter'related

operating systems w#ic# #ave *een inKuential in every modern operating system $• %#e Unix-like "amily is a diverse group o" operating systems) wit# several maCor su*'

categories including System L)>SD) and inu+$ %#e name E;NI.E is a trademarko" %#e Open roup w#ic# licenses it "or use wit# any operating system t#at #as *eens#own to con"orm to t#eir deSD are popular in t#ese areas$

• Four operating systems are certiSD variant derived"romNe.%S%-P) Mac#) and Free>SD$

• ;ni+ interopera*ility was soug#t *y esta*lis#ing t#e POSI. standard$ %#e POSI.standard can *e applied to any operating system) alt#oug# it was originally created"or various ;ni+ variants$


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Linux• %#e inu+ kernel originated in 1==1) as a proCect o" inus %orvalds)

w#ile a university student in Finland$ e posted in"ormation a*out#is proCect on a newsgroup "or computer students andprogrammers) and received support and assistance "rom volunteersw#o succeeded in creating a complete and "unctional kernel$

• inu+ is ;ni+'like) *ut was developed wit#out any ;ni+ code) unlike>SD and its variants$ >ecause o" its open license model) t#e inu+kernel code is availa*le "or study and modi


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G''%le C(r'me OS• :#rome OS is an operating system *ased on t#e inu+

kernel and designed *y oogle$ It is developed out in t#e

open in t#e :#romium OS open source variant andoogle makes a proprietary variant o" it similar to t#esplit "or t#e :#rome and :#romium *rowser!$ Since:#romium OS targets computer users w#o spend most o"t#eir time on t#e Internet) it is mainly a we**rowser wit# limited a*ility to run local applications)t#oug# it #as a *uilt'in


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Mi)r's'*t +i!d',s

• Microso"t 0indows is a "amily o" proprietary operating systems designed*y Microso"t :orporation and primarily targeted to Intel arc#itecture *ased

computers) wit# an estimated BB$= percent total usage s#are on 0e*connected computers$ %#e latest version is 0indows 1?$• In 2?11) 0indows 8 overtook 0indows .P as most common version in use$• Microso"t 0indows was SD "or server market s#are$


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C'mp'!e!ts

• %#e components o" anoperating system all e+ist inorder to make t#e di@erentparts o" a computer worktoget#er$ All user so"tware

needs to go t#roug# t#eoperating system in order touse any o" t#e #ardware)w#et#er it *e as sim le as a

l


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• Kernel• 0it# t#e aid o" t#e


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• Memory management • Among ot#er t#ings) a multiprogramming operating system kernel must *e responsi*le "or

managing all system memory w#ic# is currently in use *y programs$ %#is ensures t#at aprogram does not inter"ere wit# memory already in use *y anot#er program$ Since programstime s#are) eac# program must #ave independent access to memory$

• :ooperative memory management) used *y many early operating systems) assumes t#at all

programs make voluntary use o" t#e kernel s memory manager) and do not e+ceed t#eirallocated memory$ %#is system o" memory management is almost never seen any more)since programs o"ten contain *ugs w#ic# can cause t#em to e+ceed t#eir allocated memory$I" a program "ails) it may cause memory used *y one or more ot#er programs to *e a@ectedor overwritten$ Malicious programs or viruses may purpose"ully alter anot#er program smemory) or may a@ect t#e operation o" t#e operating system itsel"$ 0it# cooperativememory management) it takes only one mis*e#aved program to cras# t#e system$

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Memory protection ena*les t#e kernel to limit a process access to t#e computer s memory$Larious met#ods o" memory protection e+ist) including memory segmentation and paging $All met#ods re&uire some level o" #ardware support suc# as t#e B?2B6 MM;!) w#ic# doesn te+ist in all computers$

• In *ot# segmentation and paging) certain protected mode registers speci"y to t#e :P; w#atmemory address it s#ould allow a running program to access$ Attempts to access ot#eraddresses trigger an interrupt w#ic# cause t#e :P; to re'enter supervisor mode ) placing t#e

kernel in c#arge$ %#is is called a segmentation violation or Seg'L "or s#ort) and since it is*ot# di(cult to assign a meaning"ul result to suc# an operation) and *ecause it is usually asign o" a mis*e#aving program) t#e kernel generally resorts to terminating t#e o@endingprogram) and reports t#e error$

• 0indows versions 3$1 t#roug# M- #ad some level o" memory protection) *ut programs couldeasily circumvent t#e need to use it$ A general protection "ault would *e produced) indicatinga segmentation violation #ad occurredH #owever) t#e system would o"ten cras# anyway$

https://en.wikipedia.org/wiki/Memory_managementhttps://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Memory_protectionhttps://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Memory_segmentationhttps://en.wikipedia.org/wiki/Paginghttps://en.wikipedia.org/wiki/80286https://en.wikipedia.org/wiki/Protected_modehttps://en.wikipedia.org/wiki/Supervisor_modehttps://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Segmentation_violationhttps://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/General_protection_faulthttps://en.wikipedia.org/wiki/General_protection_faulthttps://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Segmentation_violationhttps://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Supervisor_modehttps://en.wikipedia.org/wiki/Protected_modehttps://en.wikipedia.org/wiki/80286https://en.wikipedia.org/wiki/Paginghttps://en.wikipedia.org/wiki/Memory_segmentationhttps://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Memory_protectionhttps://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Kernel_(computer_science)https://en.wikipedia.org/wiki/Memory_management


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OPERATING SYSTEM.pptx