1,270 views
3 votes
3 votes
Can any one please explain , Why the compile time and load time address-binding generate identical logical and physical address but execution time binding generate different logical and physical address?

1 Answer

1 votes
1 votes

Logical address: Address generated by CPU

Physical address: Addresses seen by memory-management unit.

Compile time binding:-
we assume that a range of memory location will always be available(which is sufficient for the program) and absolute code is generated. So whatever addresses CPU generates(like pointer addresses etc.) are same as what is seen by memory-management unit.

Load time binding:-
A better version of memory utilization is to delay binding till the load time so that the memory is not used by the program sitting on disk. For this the code generated in relocatable format.

Execution time binding:-
Its where binding is delayed till execution time. In this case the CPU generates an address, and do all manipulation on generated address but whenever there is an actual memory access this address is transformed by adding the value of relocatable register, let us say R, to this address. So logical address range is 0-LIM while physical address space is R-(R+LIM)(here LIM is limit)..

Ex-
Consider swapping if you swapped a program with load time binding you need to swap it back to the same location(as all addresses in the instructions were bidden according to this address) while in execution time binding you can swap back any process to any place because you only need to change the value in the relocatable register and it will just work fine. Hence increasing memory utilization.

edited by

Related questions

0 votes
0 votes
0 answers
1
SSR17 asked Feb 8
186 views
we have 8 pages (each side 32B) to store in physical memory of 2^32 bits how many bits are required to identify each page , according to me 3 bits are required but that i...
0 votes
0 votes
2 answers
4
Unique_999 asked Aug 17, 2023
293 views
Can Any explain the relationship between The “ Word Size “ and “ Logical Address Space “