7/25/2019 Operasys Hw Week4

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SCHOOL OF TECHNOLOGYCollege of Engineering

1stSemester, A.Y. 2015 - 201

O!er"ting S#stem $O%E&ASY'Home(or) *ee) +

Com!lete te follo(ing ome(or) for smission efore 0/.00 "m

Trs"# Agst t2015.

1. Consider a multiprogramming system with degree 5. Assume that eachprocess spends 40% of its time waiting for I/O. hat will !e the C"#

utili$ation

C"# utili$ation & 1 ' pn

C"# utili$ation & 1 ( 0.45

&0.)*)+,

-he total C"# #tili$ation is 0.)*)+,.

. A computer has of A2 of which the operating system occupies 5,

2. -he processes are all 1* 2! and ha3e the same characteristics. If the

goal is ))% utili$ation what is the maimum I/O time that can !e tolerated

-here is enough room to hold 14 programs in its main memory. -he

process has p num!er of I/O then p14 is the pro!a!ility that they are

all waiting for I/O. e can get the 3alue of p if we e6uate p14 to 0.01 7

p14 &0.018. -he answer that we get is 0.+. 9o p=0.72 therefore we can

tolerate the process up to +% I/O wait.