2.1.5 Identify the need for persistent storage
Non-volatile slower memory with a much higher storage capacity for permanent storage
Relatively slow and cheap memory that may be written to and can be considered non-volatile similar to the Read Only Memory (ROM).
The contents of the memory are not wiped if power is lost, therefore persistent, the very reason why secondary memory storage referred as persistent storage.
Secondary memory has high storage capacity compared to primary memory.
Data is moved to secondary from primary to clear up space when primary is full
Secondary memory is a computer memory that is non-volatile and persistent in nature and is not directly accessed by a computer/processor (CPU).
Persistent storage is needed to store data in a non-volatile device during and after the running of the program.
Secondary memory consists of all persistent storage devices e.g. flash drives, hard disks (HDD), magnetic tapes and other types of internal/external storage media that cannot be accessed directly by the CPU.
Is accessed only by the primary or main memory and is later transported to the processor.
Is slower than primary memory but can store and retain data even if the computer is not connected to electrical power.
Has substantial storage capacities, ranging from some megabytes to several terabytes of storage space within single memory.
When you turn on the power to a computer, the first program that runs is usually a set of instructions kept in the computer’s read-only memory (ROM).
This code examines the system hardware to ensure that everything is functioning properly.
This power-on self test (POST) checks the CPU, memory, and basic input-output systems (BIOS) for errors and stores the result in a special memory location.
Once the POST has successfully completed, the software loaded in ROM (firmware) will begin to activate the computer’s disk drives.
In most modern computers, when the computer activates the hard disk drive, it finds the first piece of the operating system: the bootstrap loader.
The bootstrap loader is a small program that has one function: it loads the operating system into memory and allows it to begin operation.
It sets up the small driver programs that interface with and control the various hardware subsystems of the computer.
Volatile memory is faster than non-volatile memory;
Volatile memory is cheaper than non-volatile memory;
Some non-volatile memory can only be written a limited number of times;
Some non-volatile memory requires special hardware to be written;
Non-volatile memory retains its data without power;