What is the need of different types of memories in a computer? Explain. Explain the role of
RAM, ROM and cache memory in a computer? Differentiate between PROM and EPROM.
Answers
1) What is the need of different types of memories in a computer? Explain.
Ans. Memory is the most essential element of a computing system because without it computer can't perform simple tasks. Computer memory is of two basic type – Primary memory(RAM and ROM) and Secondary memory(hard drive,CD,etc.).
2) Explain the role of
RAM, ROM and cache memory in a computer?
Ans. There are two main types of memory within the computer. Random Access Memory is volatile and Read Only Memory is non-volatile, Volatile memory loses its data when the power is turned off. RAM memory chips provides a form of memory that offers the same access time for allocations within it. The time it takes to fetch a program instruction that affects the speed at which an application can run. Having a bigger amount of RAM means that there will be more space for more instructions, which means that the amount of time spent swapping pages in and out of RAM will reduce.
ROM does not lose its data when the power supply is off, so it can be used to store data and instructions that are required for when you next turn on the computer.
There is one other type of memory which is a fast memory that is used as a data buffer between the Computer and the RAM, which is called Cache memory. Internal cache is located inside the computer chip and external memory is also on the motherboard but not within the computer chip. Cache memory is needed because it is the communication between CPU and RAM. The CPU works in Megahertz and RAM works in nanoseconds.
Internal memory generally refers to main memory (RAM), however it may also refer to ROM and flash memory. Internal memory typically refers to chips rather than disks and tapes. It is used to store data program needed for current progressing. After processing the finishing output is stored in the memory for further processing if needed, before it is permanently stored in the external storage.
Internal memory can be referred to as either ROM, or RAM.
Read-only memory because it is static memory, which retains information when powered off, and Random-access memory because it is dynamic memory which loses its information immediately when the power is turned off.
3) Differentiate between PROM and EPROM.
Ans. 1. PROM is not reusable.
While EPROM is reusable multiple times.
2. PROM is inexpensive.
While it is costlier than PROM.
3. The processes of PROMS is irreversible, means it’s memory is permanent.
Whereas EPROM’s processes can be reversed.
4. The storage endurance of PROM is high.
While EPROM’s storage endurance of PROM is less than PROM.
5. PROM is totally sheathed during a plastic cowl.
While EPROM is boxed in during a rock crystal window so the ultraviolet radiation rays will transfer through it.
6. PROM is the type of ROM is written only.
While EPROM is also the type of ROM is read and written optically.
7. If there’s miscalculation or error or bug while writing on PROM, it becomes unusable.
Whereas if there’s miscalculation or error or bug while writing on EPROM, it will still be used once more.
8. PROM is the older version of EPROM.
While EPROM is modern version of PROM.
9. PROM is better than EPROM in terms of flexibility and scale.
While EPROM have less flexibility and scalability.
10. In PROM, bipolar transistor is used.
While in EPROM, MOS transistor is used.
Answer:
Processor is much faster than the main memory.
As a result, the processor has to spend much of its time waiting while
instructions and data are being fetched from the main memory.
Major obstacle towards achieving good performance.
Speed of the main memory cannot be increased
beyond a certain point.
Cache memory is an architectural arrangement
which makes the main memory appear faster to the
processor than it really is.
Cache memory is based on the property of
computer programs known as “locality of
reference”.
Analysis of programs indicates that many
instructions in localized areas of a program are
executed repeatedly during some period of time,
while the others are accessed relatively less
frequently.
These instructions may be the ones in a loop, nested loop or few procedures
calling each other repeatedly.
This is called “locality of reference”.
Temporal locality of reference:
Recently executed instruction is likely to be executed again very soon.
Spatial locality of reference:
Instructions with addresses close to a recently instruction are likely
to be executed soon.
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