7/25/2019 Operasys Hw Week4
1/1
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.