Page 47 - Computer_Science_F5

Computer Science (d) Storage (Hard drive): This is the faster memory for efficient processing.
largest and slowest memory for In summary each type of memory within
permanent storage, like a library’s the hierarchy offers a trade-off between
back room where they keep extra the following performance parameters:
books and materials you do not see
(a) Speed: faster memory allows for
FOR ONLINE READING ONLY
typically smaller and more expensive.
on the main shelves. quicker access to data, but it is
By combining different memory
types, computer architects achieve (b) Size: larger memory holds more data,
a balance between speed, cost, and but it may be slower to access.
power consumption. Frequently (c) Cost: faster and smaller memories are
accessed data resides in faster, generally more expensive per unit of
more expensive memory, while storage compared to larger, slower
less frequently used data is stored memories.
in slower, cheaper memory options. CPU
This approach ensures efficient use
of resources and high performance
for your computer programs. Increasing Increasing Increasing
cost and storage
access speed Registers distance CPU capacity
Cache
Memory hierarchy and interfacing memory
Memory hierarchy optimises computer Main memory
performance by using various memory Flash/USB
(memory)
levels with distinct speeds and capacities, Secondary storage
ensuring the processor accesses data as Magnetic tapes
quickly as possible. Interfacing between (backup devices)
these levels manages data transfer, Figure 1.38: Computer memory hierarchy
starting from the fastest memory (cache
and registers) to the slower, larger Computer memory interfacing
storage levels. The computer memory hierarchy uses
various memory levels with distinct
Computer memory hierarchy speeds and capacities to optimise
The computer memory hierarchy, shown performance. The processor relies on
in Figure 1.38, uses multiple levels of the fastest available memory (cache
memory with different access times and registers) for data access, but these
and capacities. Faster memory, closer levels have limited capacity. Therefore,
to the processor, is smaller and more data must be copied from lower levels
expensive, while slower memory, further when needed by the processor. This
away, offers larger, and cheaper storage. communication between memory levels,
This design optimises performance as shown in Figure 1.39, is managed by
by storing frequently accessed data in memory hierarchy interfacing.

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Computer Science Form 5.indd 38 23/07/2024 12:32