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I tried to give answers to the following questions in this section : |
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What is Memory Management and what is it needed for? |
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Memory is a part of the computer system where volatile information can be stored.
It is a much faster storage medium than disks or tapes are, but it can only serve
as intermediate storage place because the information is lost when the power
supply is off. |
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When the CPU is executing programs it has to get the commands from somewhere,
and it must be provided with space to store the results. For the sake of
efficiency, only memory is capable of playin the role of a storage medium
for the CPU. |
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Memory Management is needed when a program is to be executed. The
Memory Manager then gives the process the requested amount of memory and
makes sure that no other process is allowed to change the content of this
memory section (Otherwise the result could be data corruption:
one program saving data back to disk which has been changed from outside). |
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The process of giving memory exclusively to a certain program is called
memory allocation. The process of freeing that part of memory
again and to make it usable for the next process(es) is called
memory deallocation accordingly. |
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Logical organisation of memory |
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In order to make it accessible every memory cell has got an
address. It is given as a hexadecimal number. Looking at
this address it is possible for us to treat memory as a
single stack of cells, starting with zero and rising up to the
total amount of memory:
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Figure: Logical stack of 1 MB of system memory (divided into 8 parts of 125 KB each) |
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What ways of memory allocation are there? |
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| Early systems | ||||||||||||||||||||||||||||||||||||
| Recent systems |