OPERATING SYSTEM FUNCTIONALITY

1. Whenever user sends a request, primary search for the data will be done in RAM. If the

information is available, it will be given to the user

2. Otherwise, secondary search will be done in hard disk and copy of that info will be placed in

RAM before giving that to the user

3. The request and response between RAM and hard disk is called I/O operation

4. Files with more size will be fitted into RAM using swapping (flushing old data – Least Recently

Used algorithm)

Questions:

1. Why to copy data to RAM?

a. It will give benefit for next users who are requesting for same data. Accessing

information from memory is always faster than accessing it from disk

2. What happens if data size is more than RAM size?

a. Data will be splitted based on the RAM size and swapping will takes place (In windows,

this is called paging)

3. How the data will be managed in RAM?

a. Using Least Recently Used (LRU) algorithm

Note: The primary goal of DBA is to reduce response time there by increasing performance and also

avoiding I/O (all these 3 are interlinked)

Note: Any request and response between memory and disk is called I/O

USER

RAM

HARD DISK