9. OCR GCSE (J277) 1.2 The need for secondary storage

Summary

In this video, Craig explores the essential role of secondary storage in computer systems. He explains the three types of storage: primary (immediate memory like RAM and ROM), secondary (non-volatile storage such as hard drives), and tertiary (long-term backup and archiving). Secondary storage is crucial for retaining data when power is off, providing semi-permanent storage, and enabling data backup and archiving. The video also highlights the process of data transfer during startup and shutdown, emphasizing the need for reliable storage solutions to maintain data integrity and accessibility.

Takeaways

• 😀 Storage in a computer system is categorized into three types: primary, secondary, and tertiary.
• 💾 Primary storage includes immediate memory accessed by the processor, such as registers, cache, ROM, and RAM.
• 🔒 ROM (Read-Only Memory) is non-volatile but cannot be altered, while RAM (Random Access Memory) is volatile and loses data when powered off.
• 🖥️ Secondary storage is crucial for holding programs and data not currently in use, typically involving hard disk drives and other writable media.
• 🛡️ Secondary storage is necessary because ROM is read-only and RAM is volatile, ensuring data is stored when the power is turned off.
• 🔄 Secondary storage allows for semi-permanent storage of data that can be modified and includes backup and archival functions.
• 🗄️ Tertiary storage refers to long-term data backup and archiving but is not included in the GCSE specification.
• 🚀 During startup, the CPU retrieves initial instructions from ROM before loading the operating system and software from secondary storage into RAM.
• 📦 When shutting down, any data currently in use must be saved back to secondary storage to prevent loss, as RAM cannot retain data without power.
• 🔑 In summary, secondary storage is essential for managing data and programs when the computer is powered off due to the limitations of ROM and RAM.

Q & A

What are the three broad terms of storage in a computer system?

The three broad terms of storage in a computer system are primary storage, secondary storage, and tertiary storage.

What is included in primary storage?

Primary storage includes the registers, cache, ROM, and RAM that the processor has immediate access to.

Why is secondary storage necessary?

Secondary storage is necessary because ROM is read-only and cannot be changed, while RAM is volatile and loses data when power is turned off.

What types of media are considered secondary storage?

Secondary storage media includes hard disk drives and other drives on the computer system.

What is the purpose of tertiary storage?

Tertiary storage is used for longer-term backup or archiving of files, keeping backups in case the main data file is lost or corrupt.

What components are highlighted in the video as important internal components of a computer system?

The important internal components highlighted are ROM, the CPU, RAM, and a hard drive.

What happens when you first turn on your computer?

When you first turn on your computer, the CPU receives power and gets its initial startup instructions from the bootstrap contained in the ROM.

What happens to data and instructions when a computer is shut down?

When a computer is shut down, all instructions and data currently in use must be stored safely on a secondary storage device, since they cannot be kept in RAM or ROM.

Why can't instructions and data be stored in RAM when the power is off?

Instructions and data cannot be stored in RAM when the power is off because RAM is volatile and cannot hold data without power.

Can you summarize the main reasons why secondary storage is needed?

Secondary storage is needed for the storage of programs and data when power is turned off, for semi-permanent storage of data that can change, for backing up data files, and for archiving data files.