os

1. Ca) Define Cper ating system
Ope TatinqSystem : A
between use3
in
and
system
kernel It is compute pooqsam at
y passive
disk
|C6) Diffesentiate between
block
3 It doesn't
Besouice allocate
qeneoally has
proqTam
must
proqrams and comput es hadunse
control poogam
() What is
-or4 of system
When CPU
pooqsam that acts
3 It Tesides in secondary mem-271t
and Kevne)
S-toe d om
have a contoo)
Save
S tepe |
eXecution into its PcB
comp lete contool ovci
progtam and process
Step 2i
Switch ime is pue
the state of
woTK while switching
contezt Switching?
5witches to another
3y Tt
y A paoqam in execution
"block
an
Process
coTe of a
progam is in execution and is
being Joaded into main me mo7y
Load saved state foom Scheduled
compute's
evenything
pvoceSS
has itS own
media'
ereated when
(d) piffetentiate process and Thzead
process, the system
conto]
PoocesS
cuÝTent(s undey
oveohead,the system does no
PcG context
us e f
entity

2. 27 ProcesS tahes moe time to
terminate
ProceSS
3> Takes more time fo
cTeation
-
poocesSes that
efficienty
Waiting time
while watting
19 in eIeutionA
(+) Define waiting time
ce) what ie deqsee of
The dequee of moltiploguamming describes
-short
a
TAT efes to time
Teady 4ueue fos
me?
() what is convoy
convey effect
Tefevs to
mimimum
shortes ob
single -POOceSSer
taken
douwn ouing
Pooce sses behin d
to few
effeet?
terminate
2) Thread tahes less time
A segment of
Multiproqra mming
Thread
37 Tahes
and TAT
Teady quele unil
by
pöoceSs of
Ch† which scheduling lgoi thm
eTeation
slower
total time
system
phen omenon f
Lwaiinq time- t
erecution
less time fo%
maximum
Can
that
a
til|
accomn odat e
pöoces
qets
Sin ce
long poocesS leods to
optional
a poocess spends
noiof
Pooce sSes in System
CPU
it enters
Co mpletfon.
whi ch entie o.5 slows
jo b Fist (sTF) scheduling olgonthm qtues
qjves
qives minîmum aveaq e waiting
to convoy cffeet
s e e
mp

3. ooirfesentiote preemptive and"preemptive schedulinq.
Preemptive scheduling
IY T thís, des oudces ate
pocesS -fo a
|D) ProcesS can
i0 between
Supe0.tral. .
J> What is
Concument
may
in data
accesS
lead to Tace
be intetBupted
Race condition?
allocated7On ce ze 5o¯NCeS
Jimited timc a piocCS5, he pooces5 hos it
Sig
Kó What is puopose of
Non- pyecm ptíve schedul ing.
in
positive If S is negatíve
perfomed
nal Cs )
ovdealy fashion
condition Race Condition may lead to inconsiçle
Se maphore accessed bonly thaough
opetatlons.
Siqnal c): Incoements value off
til it complet
tes its hust time Do
switches to waitnq state
3
deadlock?
27 PooceSS Can't be int e dupted
until it teminates itself o7
its time is up:
uait(): Decrements value of its amqument
wait C) and smal?
allocated to
2 standard automic
3eo, th en
its aqumers
A Set of blockd pocess each hsdin
5, if it is
opevati on is
resoudce
Ye Souce held by amother proceSS
to shae dota not
and waiting to acquite

4. myjwhat is
Safestate ?
pocesS es wthout
Thé state of
system is
called
Safestate
i .
alloate all
TeSouices
enteving înto dodelocs
MsDiffexentiate Tnternal oud E*ternal Foagment
Inter
nal
Fragmentation
y In Internal Fvaqmentation
fixed Sized memo, blocks
appointed to
Squate
PocesS
block
27Solution for this
measte
P What is
The
ces
requested byall
Page
binding )?
Due to flexibili:ty a sinqle function
7 This is
ifomation Temains
9) Diffeventiate
an
loqicaleage
27 It
o7ihat is advantage of dynamic bindinq (execution time
putpose
is
Page
also
vistual
is best ft2y 5oluton
faqe an d
[*ternal Foagmentation
method
7Variab le sized memory blocks
Page or
Tun time.
of Page table
puzpose of pagetable is to store mappinq between
viTtual addzesses and physical addsesses
ixed -length
5quaTC meassTe appointed to
called memoy
c
Frame
vailab le before Tun
7 This
frame
Can
tem
fo
frame
Foame
IS
thi s is Paqing
also
handle different
time
Py It is iyed length bloch of
CentiguouS bloct of vitual memDoy RAM
called memoay
physical poqe or page
types of obje ct at

5. censider -followinq set of processes, which
aTived in otde P,Pa, Pa, Pu, Ps, Ps at
and ssf, Piority (non- piecmp tive
scheduing olqpithms
ay Draw the
PIocesS
minimom avg waiting ti me?
P:
P
z
charts
FCFS;
on these
c calculate avq tnn aro un d time d which alqorith m would qivc
CPu
Bunst Time
2
az Gantt chatsi
P3
24
13
pTocesseS
b> Calculat e avetaq e waitìng timg
Round Robin (4 z loms) cPU
2
Pziozi ty
diff times Apply
Pu
65
e
18
assomed to have
PCS
P.
30
Azsival time.
2
|
Gantt

6. Poioity
Round Robin
FCFS
PoocesS
by Avetaqe waiting time
Pz
STE
-A
Pi
P,
Poocess
PG
P3
CPU
BT
4=10ms
| 2
3
4|
5
vezaqe
CPU BT
3
22
Agival
|2
TÉme
5
T-AT =
AVetaqe wai tning timc =
Arrival
tme
5
2.
32
5
Completion
Time
c}Avetaqe Tun Asound Time
2|
24
Compleion
|
13
18
64
Time
34
4420 t22+C24 66t66
30
TAT CT-At
20
222
62
66
66
5
36
t4
TAT
29
= 40 83
2|
wT = TAT-cpU
6|
65
A v 9 .
w a t i g
wT
A v TAT
Poioni

7. Avg
Prionity
PaocesS
PI
P
P5
P
P
TAT
Process
AVg
5
Round ßobini
6
cPU
Avq wai tin g tint e
BT
445+1)4 4+29 +68
12
BT
5
|2
3
2
4
6
Agvival
33-64
-time
3
4
2
46
22
:276G
Comple Hon
37
Compleon
time.
38
50
55
6+
|
0+6+y6 +5y t65t65
39
TAT
20
68
33
33
TAT
- 5|(66
Avg waiting time z 0t27 117t244 t3 2
51
68
66
2 7
2?
46
54
65
65
3433
3 2
WT

8. dy Lihich algoíthrn ubuld give
Shotrst 1o9 f1rs (51 )
is oplimnol
Solve 4he foll 3oblen using
To
T
Allocatiom
Bequest
5
lord
can the request
esou%ce vequest and
Atoilable
be
ajíven Requs t ,o, 6)
Go, AVnilable
Rquest
Requrst Availob te
O3
Necd
Poce ss T2; Request 2
+
3
min
Banke ss
o3
CAto)
qanted? Give
C
safety functions
3
Avcilable - Requrt
min huq Wti
alqosithm
-ANailable
3
aoives
worbot of
Ihis ereerles 8R -fn Ihvokes satety -fn
for a,o, o)
Solution using
-finis h leF|e|
2
Need,
w o r k
3

9. i: 4
As
Need, Wok (vrs)
wors=
finish =
Heedo
Need, Wok(No)
Safe
Needwoih ¢yes)
wonk woth tallocy
worh t alloc,
inish= r|T FTTJ
(o, 3,o) +(3,0,2)
Work =
Yes, vequest
B 2
s Woik CYes)
LNorK = woih Allo o
Process State:
Se quence 2
Waiting: Poocess (s
Tesminated:
is
Beady : Psoce 55 is
| 2 3
Psocess executes
3 4
Pxoces5
gdant ed
4' Descoibe Pocess States and PcB
i: 3
Need3 s Woih (Yes)
waitiog
Woak = Waok+ alloc3
43
T3, Ty, T,To
waiting
Wok z
Ne The PoocesS is
being cseated
Ronning: Instiueions
finis h |FTT
for
to
Need s Woh (No)
i=
changes state
has fiois hed
Need s Wosh (4es)
being ezecuted
finis h =
2
be
ezecutom.
3
Fr|TT
Some even t to oCUY
assned to
4
PõocessoT

10. Diaqtam of
task
new
to
Process stale i
admitted
Ilo o event
Accounting
Completion.
Process co
(Teady
The
Coto) Block)
interrupt
Pooce s5 stade- unning, waitinq ete
scheduling
for maion a550ciated wit h eoch paoress Calso) called
Waiting
cpU Teqisteis- contents of all pooces seS
Memo"y man aqement nto
sheduling info - m
ci tical
Pooqram counte- location of in stzction to
Satisfies all 3
thee
(Yuning
mext exeute
info CPU used, clock time
5 What are the 3 conditton 5 to bc
- Memoy alloceted
to ProcesS
tevminafed
time limits
exit
Emery allocated to
psocess
Conditions
o event wait
Ilo stutus info - I/o devices alloccted to Process.
List of open files.
Psoces s stode
Process Number
Condttions to be Satisfird
Psoqcam counter
Register
Memory urimts
List oF
elapsed sínce
Secti'on Pooblem? Explarn how Peteson's
OPen fil
stack,
M u t
Satisfied by any solution
s e c t
by any solution
Solution
Conttol Block CPe6):

11. Mu
tual Exclusion
section, then no
dotical sect ions.
proqoess i- If
and theve
PõocesS
erislS SUde
othe
1¢
3 Bounded Waiting: A bound must
that other
Petesona Solution;
follouing
wish to enter
enter their
pooceseS ahe
has made
ate
Two Psoce $5 solution
Alqorithm for P;
põoce s5 is exeuting in iHs coitic al Section
po ocesSes
-int turn
stuctue of P
do
qloba
pooce sses that
turn=is
Boolean flaql2]
whi le (tue)4
Vahia bles
allow ed
equest
execulig tn its caitical
can be
erecuting in
flaq G]- truej
e zist
tumj
flaqliJ= tuej
while(flag j] 4t turn =j)
Ilcaitical section
the (
to enter theí y cs after
flagliJ-falsej
the noof times
llxemainder section
while (flagl tt tun {);
enter
iical 5ection,then the sele ctio n of Poocess that will
itical secto

12. coN0rcness of Ate son's Soln
Poovable tht 3 cs (oitiealGec)requitemenls aYe net:
7 PoopesS
3 Bo onded
I7 Mutual exclusion is Poeseved
may
llcoiticol seclion
whi le 4oue;
|-Each p~oce55
Pi ent es cS ony ifs
-flaq]= falsc3
lsemaindes section
meed
6 Fo Sinq le instance vesousces usinq reso uNLe allocati on graph
attow á dead lock can bt avoided ? b> How deadlock can be deteted
and
Requises that system has Some addrtional
I
Resouce
Ieq - is Schisfied
allocation state
them
waiting 7eq is met
The dedloch -avoidance algotthm dyna mialy
declae maz no-of
circu lar wait condition:
tun i
by Dead Lock Detection;
to ensue that there Can
TesoudceS of each ty pe the it
allocation state is defincd by
allocated esourceS, and max demands
Palorlinto available
examines resourc&
mever he
mo.o f available
of P3ocesses
deadlocks do occur, 0.5 must detect and resolve
a p
Deadlock delection alqorithms, such as wait For
ether flaqlj]= false
ayDeadloch Avoidance:

13. yeph
o
qe
alqoníthm,Such as
27
used tp
esolve them
User inter face
Discuss o. S funetions and Services
Poqsam Execution
to
a file
37 I/o operations
-ceating and ddeting
Suspending and
Command-Line CcL), Gtaphical User Interfoc e Con)
-creating
mapping
identify deodloc bs,and
Aollback
poqam may
an Ilo Device
4 File- System Manipulatioy
Tes Uminq pioceSs eS.
57 Commu nicati ons:
and deleting files
Ales onto ma55
67 EroT Deteetion;
Processts may ¬xchanqe
- Debuqging -facilities.
Free Space
0s needs to be constartly
47 BesouTce Alocation;
and
1equive
sto rege
information
Multiple Processes Unmiag
o) Memony Manogement
Mutiple piocesses
by Mass storage Management
-Abot oAe
Qware of
conubsenlly
maage ment, stoage
Be cove
de alloc ting memoy
Possib le
aoe used
which may involv
ed0S
alloc a tion ,Piote tion

14. Manageoñt:
Buffeving, cachi ng, Speling, Divers
Dicuss how paqing
Paging isa stoage
There
hem seconday st ye
Aiges
Cach
woiks
me hunis
Mnmemy
. Mapping
4 prDcesSes in
So hat one pay
Irtiall all frornes
procesSes will qet
u5 considei size l6kb and
into
wit h help of
ale
mtin memoy
asedt
etive
Proces1o9
Pagc
Can b e
Page
Page3
Pagr
PageG
Page
pages
Foame siZe
System that is
poce s5 'n divided into pages
Pioqia
In the
fosm of
em pty
stoed in Coutiquay way
P, Pa,3, Pu
of
stored In one
these fore pages
Process
Foame:

15. afte? Some ime: Now
therefore other pages
place
Give n fact thet, we' ve
Pi
(n
P
memoy
Pi
P
Cons ider that, P, and P4
P
P3
P
Py
Py
available
stoung in diffetent places.
FoameS
ave
Can be
and
Paqing
Py
moved to waitin q state
become em
pty
(ooded in that
an d
empty
contiquous frames
piovde s fle xibili hy of

16. PI
P
P5
P3
Pa
Ps
Pr
Pr
Mainmeony
(pA6iNG6)