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Topic 2: Memory and Process Management, image, image, image, image,…
Topic 2: Memory and Process Management
1) What is memory management :question:
Example:
Main Memory: RAM
CPU Registers
b) Involves taking segments of memory and assigning them to be used with other applications or moved in-between other portions of memory.
a) a software utility or term used to describe the process of managing computer memory in the computer.
c) Only the main memory and the registers can acess directly on CPU.
d) If have any instructions and data in execution or being used by the instructions, must be in either main memory or registers.
e)Registers accessible within “one cycle of CPU clock” a.k.a one tick.
f) Main memory is accessed using the memory bus.
Location :!?:
Memory is on the motherboard.
Registers are embedded in the CPU itself.
CPU works fast.
Memory access may take many cycles of CPU clock to complete work.
CPU have to wait since memory cannot give data for a short while. This is a waste of processor capability.
Add fast memory between the CPU and main memory, using “Cache”. This is a memory buffer that accomodate different speed between CPU and memory.
3) Hierarchy of memory organizations
there are 4 levels of memory hierarchy
each levels are divided based own the task; means each levels have their own function,
as for level 0 (or known as the lower level) have more excess where it is much faster than the other levels and uses small space due to its small capacity but more expensive than the other
the 4 level are divided into level 0-3: where each of them have their own specification
level 0- processor: superfast, super expensive, tiny capacity
level 3- mechanical hard drive: slow, cheap, large capacity
level 2 -SSD: average, priced personally, average capacity
level 1- RAM: faster, expensive, small capacity
4) MEMORY MANAGEMENT STRATEGIES
Placement
Best fit
concept: not wasting any space
all space must be filled or only have a least little space left unfilled
do entire search
keeps the list in order by size
Worst- fit
produce the largest leftover hole, which may be big enough to hold another process
do entire search
First -fit
don't do entire search
pick the first-largest space
Replacement
decide which memory pages to page out, sometimes called swap out, or write to disk, when a page of memory needs to be allocated
Fetch
used to determine which block is to be obtained next
2 type of fetch strategies:
Anticipatory Paging
Demand Paging
2) Function of memory manager :question:
b)can decide which processes and data to move into or/and out of memory.
c) Allocate and de-allocate memory space as needed.
a) can keep track of which parts of memory are currently being used and by whom.
SOLUTION :!?:
