Primary Storage: Immediate memory accessible by the processor.
Includes:
Registers
Cache
ROM (Read-Only Memory)
RAM (Random Access Memory)
Secondary Storage: Media for storing programs and data not in active use.
Includes:
Hard Disk Drives (HDD)
Other drives
Tertiary Storage: Long-term backup or archiving of files.
Backups: Kept in case main data files are lost or corrupted.
Archives: Data moved from main files to free up space.
Note: Tertiary storage is not included in GCSE specifications.
Importance of Secondary Storage
ROM Characteristics:
Read-only
Cannot be changed
Limited size
RAM Characteristics:
Volatile memory
Loses data when power is off
Functions of Secondary Storage
Stores programs and data when power is off.
Provides semi-permanent data storage that can change.
Ensures backing up of data files.
Facilitates archiving of data files.
Computer System Components
Key Components:
ROM
CPU (Central Processing Unit)
RAM
Hard Drive
Computer Startup Process
Bootstrapping:
CPU receives initial startup instructions from ROM when powered on.
Loading Software/Data:
Operating systems and applications stored on secondary storage are loaded into RAM for quick access.
Shutdown Process
Data Storage:
On shutdown, current instructions/data must be safely stored:
ROM: Not suitable due to size and read-only nature.
RAM: Cannot hold data without power.
Solution: Transfer to secondary storage (e.g., hard drive) which is non-volatile and writable.
Recap
Need for Secondary Storage:
ROM limitations and RAM volatility necessitate secondary storage for various data management tasks including storing data when power is off, and for backup and archival purposes.