Question

What is the capacity of a disk with two platters, 10,000 cylinders, an average of 400 sectors per track, and 512 bytes per sector?
What is the use of cache memory? Explain the concepts of cache hit and cache miss.

Answer 1

Answer:

The capacity of the disk is "40 GB".

Explanation:

Given value:

$\to \text{cylinder}= 10,000\\\\\to \frac{sector}{track} = 400\\\\\to \frac{bytes}{sector} = 512$

$\text{Calculating the size of track} = \frac{bytes}{sector} \times \frac{sector}{track}$

                                            $= 512 \times 400 \\\\ = 204,800 \ \ Or \ \ 200 \ K$

$\text{Calculating the size of surface} = \frac{byte}{track} \times \ cylinder$

                                               $= 2000 \ K \times 10,000 \\\\ = 20, 000,000 \ K$

$\text{Calculating the capacity of a disk} = \frac{byte}{surface} \times \frac{surface}{disk}$

                                                     $= 20, 000,000 \ K \times 2 \\\\ = 40, 000,000 \ K \\\\= 40 \ GB$

Cache memory is often used to speed up the runtime. It will enable us to improve performance unless we can store information, that is retrieved constantly in memory space.

• Hit Cache: when the Processor relates to representing database data, Cache Hit results.
• Miss Cache: when this Processor responds to a non-present cache data, this will trigger its miss of cache.
• It doesn't have to retrieve the Main Memory through secondary storage.