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MEMORY MANAGEMENT : EARLY SYSTEM Chapter 2
MEMORY MANAGER
TYPES OF MEMORY ALLOCATION SCHEMES: Single-User System
fie!"artiti#ns$ %ynami& "artiti#ns an! Rel#&ata'le
%ynami& "artiti#ns(
SINGLE- USER CONFIGURATION -The first mem#ry
all#&ati#ns&heme )#r*e! li*e this: Ea&h pr#gram t# 'e
pr#&esse! )as
l#a!e! in its entirety int# mem#ry an! all#&ate! as m+&h
as
ntig+#+s spa&e in mem#ry as it nee!e!(
The *ey)#r! here isentiretyandcontiguous(
SINGLE USER SYSTEMS ea&h +ser is gi,en a&&ess t# all
a,aila'lemain mem#ry f#r ea&h #'$ an! #'s are pr#&esse!
se.+entially$ #neafter the #ther( T# all#&ate mem#ry the
#perating system +ses a simplealg#rithm(
Algorithm to Load a Jo i! a Si!gl"-U#"r S$#t"m%
/( St#re first mem#ry all#&ati#n #f pr#gram int# 'ase
register(2( Set pr#gram +nter(0( Rea! first instr+&ti#n #f the
pr#gram(1( n&rement pr#gram +nter 'y n+m'er #f 'ytes in
instr+&ti#n(3( 4as the last instr+&ti#n 'een
rea&he!56(
f yes$ then st#p l#a!ing pr#gram(f N#$ then ntin+e )ith step
6(
6( s pr#gram +nter greater than mem#ry si7e5f yes$ then st#p
l#a!ing pr#gram(f N#$ then ntin+e )ith step 8(
8( L#a! instr+&ti#n in mem#ry(9( Rea! net instr+&ti#n #f
pr#gram(( G# t# step 1(
FI&E' PARTITIONS -The first attempt t# all#)
m+ltipr#gramming)as t# &reate fie! partiti#ns ;als# &alle!
stati& partiti#ns< )ithinthe main mem#ry = #ne partiti#n f#r
ea&h #'(
Main mem#ry is se&ti#ne! #ff$ )ith p#rti#ns assigne!
t#ea&h +ser(
On&e the system )as in #perati#n the partiti#ns
si7esremaine! stati&(
>Mem#ry is the primary an! f+n!amental p#)er$ )ith#+t
)hi&hthere +l! 'e n# #ther intelle&t+al #perati#n(?
=Sam+el
#hns#n ;/8-/891
