Assume that the OS is using a memory segmentation method, instructions are 1 wor
ID: 3593469 • Letter: A
Question
Assume that the OS is using a memory segmentation method, instructions are 1 word long, and each address in memory accesses only one word.
A segment table for a particular process is given below:
Segment Number
Size
Starting Address
0
3,000
13,000
1
4,000
7,000
2
1,000
20,000
3
500
6,000
4
10,000
30,000
Calculate a physical memory address for each of the following instructions. If the address cannot be calculated using the segment table, say why not.
segment #1, instruction #50
segment #2, instruction #900
segment #3, instruction #600
segment #5, instruction #800
Segment Number
Size
Starting Address
0
3,000
13,000
1
4,000
7,000
2
1,000
20,000
3
500
6,000
4
10,000
30,000
Explanation / Answer
As per given table of infirmation regarding segment number,size and respective starting address,physical adresses are calculated as follows:
1) segment-1,instruction 50:
In this segment the size is 4000 therefore,it contains instructions from (0-3999).
physical address for instruction-50 in segment-1
= 7000+50 = 7050
3) segment-2, instruction-900:
In this segment the size is 1000 therefore,it contains instructions from (0-999).
physical address for instruction-900 in segment-1= 20000 +900
= 20900
4) segment-3, instruction-600
In this segment the size is 500 therefore,it contains instructions from (0-499).
So that we can not find physical address for instruction-600 in segment-3