Computer Scicen 1.2 part 1

What is Primary Storage?

Primary storage is high-speed, internal memory that the CPU can directly access. It includes RAM and ROM.

What is the need for primary storage?

Primary storage is needed to provide fast, direct access to the data and instructions required to run programsand start the computer.

What are some examples of Primary Storage

RAM and ROM

RAM ( random access memory )

Exam definition: RAM is volatile primary memory that stores data and instructions currently being used by the CPU.

Purpose: Stores the programs and data currently in use.

Volatile: Its contents are lost when the power is switched off.

Read and write: Data can be read from and written to RAM.

ROM ( read only memory )

Exam definition: ROM is non-volatile primary memory that stores the instructions needed to start up a computer.

Purpose: Stores start-up instructions, such as those used to boot the computer.

Non-volatile: Its contents are retained when the power is switched off.

Read-only: Its contents cannot normally be changed during everyday operation.

What are the differences between RAM and ROM?

RAM

Volatile

Stores data and instructions currently in use

Can be read from and written to

Contents are lost when power is off

ROM

Non-volatile

Stores start-up instructions

Normally read-only

Contents remain when power is off

What is virtual memory?

Virtual memory is a section of secondary storage used as additional memory when RAM is full.

Why is virtual memory needed?

Virtual memory is needed when RAM is full or nearly full. It uses part of secondary storage as extra memory, allowing data and programs that are not currently needed to be moved out of RAM so that other programs can run.

How virtual memory works

Data is transferred from RAM to secondary storage when RAM is full.

When that data is needed again, it is transferred back into RAM.

Virtual memory is slower than RAM because secondary storage is slower.

What is Secondary Storage?

Secondary storage is non-volatile storage used to save data, files and programs for long-term use.

Why is secondary storage needed?

Secondary storage is needed to store data and programs long-term. RAM is volatile, meaning its contents are lost when the computer is switched off, whereas secondary storage is non-volatile and retains data when the power is turned off. RAM has a limited capacity and stores data and instructions currently in use, whereas secondary storage generally has a larger storage capacity, allowing more data and programs to be stored.

Optical Storage

Definition: Optical storage uses a laser to read and write data on an optical disc.

Examples: CD, DVD and Blu-ray.

Advantages: Portable and relatively cheap to produce.

Disadvantages: Slower read/write speeds and lower storage capacity than many other storage types.

Uses: Distributing music, films and software

Magnetic Storage

Definition: Magnetic storage stores data by magnetising areas of a magnetic surface.

Examples: Hard disk drive (HDD) and magnetic tape.

Advantages: High storage capacity and low cost per unit of storage.

Disadvantages: HDDs have moving parts, making them vulnerable to physical damage; magnetic tape has slow access times.

Uses: Storing large amounts of data, backing up files and archiving data.

Solid state storage

Definition: Solid-state storage stores data electronically in flash memory and has no moving parts.

Examples: Solid-state drive (SSD), USB flash drive and SD card.

Advantages: Fast read/write speeds, durable and portable.

Disadvantages: Usually more expensive per gigabyte than magnetic storage.

Uses: Storing the operating system, applications and files in computers, phones and cameras.

which applications are solid state useful for?

1. Solid-state storage — SSDs, USB flash drives, SD cards

Best when speed, portability and durability are important.

Example: An SSD for a laptop because it has fast access speeds and no moving parts.

Which applications are optical useful for?

2. Optical storage — CDs, DVDs, Blu-ray discs

Best for distributing media or software and situations where removable discs are useful.

Example: Blu-ray for distributing films because it can store more data than a standard DVD.

Which applications are magnetic useful for?

3. Magnetic storage — HDDs, magnetic tape

Best when large capacity and low cost per GB are important.

Example: Magnetic tape for backing up huge amounts of data because it is cheap for long-term archiving.