14 Difference Between Primary And Secondary Memory With Examples

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What Is Primary Memory?

All types of computer memories that are directly accessed by the processor using data bus are referred to as Primary memory. Primary memory can also be referred to as Main memory or Internal memory, however in most cases, primary memory refers to system RAM.

RAM, or random access memory, consists of one or more memory modules that temporarily store data while a computer is running. RAM is volatile memory, meaning it is erased when the power is turned off. Therefore, each time you start up your computer, the operating system must be loaded from secondary memory (such as a hard drive) into the primary memory, or RAM. Similarly, whenever you launch an application on your computer, it is loaded into RAM.

As soon as a computer starts, primary memory loads all running applications, including the base operating system (OS), user interface and any user-installed and running software utility. A program/application that is opened in primary memory interacts with the system processor to perform all application-specific tasks.

RAM, An Example of Primary Memory

The operating system and applications are loaded into primary memory, since RAM can be accessed much faster than storage devices. In fact, the data can be transferred between CPU and RAM more than a hundred times faster than between the CPU and the hard drive. By loading data into RAM, programs can run significantly faster and are much more responsive than if than constantly accessed data from secondary memory.

Examples of primary memory:

  • RAM
  • ROM
  • Cache memory
  • PROM
  • EPROM
  • Registers etc.

What You Need To Know About Primary Memory

  1. Primary memory is the main memory of the computer which is used to store data or information temporarily.
  2. Primary memory can also be referred to as Main memory or Internal memory.
  3. The primary memory is majorly volatile in nature. Data or information stored in the main memory is temporarily stored and there is high risk of data loss of data in case of power failure.
  4. In primary memory, data is directly accessed by the processing unit and it resides in the main memory until processing.
  5. Primary memory is an internal memory.
  6. Information and data is stored in semiconductor chips, so they have a limited storage capacity.
  7. Primary memory holds only those data or instructions which the computer is currently processing allowing the processor to access running applications and services that are stored temporarily in a specific memory address.
  8. It is very fast in interacting with microprocessor.
  9. The primary memory is generally available in small sizes, usually between 500MB to 32GB.
  10. Primary memory can be accessed by the data bus.
  11. Primary memory is costlier than secondary memory.
  12. Data and information is stored and operated uniformly.
  13. Information stored in primary devices cannot be moved from one computer to another.
  14. Examples of primary memory: RAM, ROM, Cache memory, PROM, EPROM, Registers etc.

What Is Secondary Memory?

Secondary memory refers to external storage devices that are used to store data or information permanently. It allows a user to store data that may be instantly and easily retrieved, transported and used by applications and services.

Unlike primary memory, secondary memory is not accessed directly by the CPU. Instead, data accessed from secondary memory is first loaded into RAM and is then sent to the processor. The RAM plays an important intermediate role, since it provides much faster data access speeds than secondary memory. By loading software programs and files into primary memory, computers can process data much more quickly.

Secondary Memory

While secondary memory is much slower than primary memory, it also has substantial storage capacities, ranging from megabytes to several terabytes of storage space within single memory. For example, a computer may have a one terabyte hard drive, but only 16 gigabytes of RAM. That means the computer has roughly 64 times more secondary memory than primary memory.

More importantly, secondary memory is non-volatile, meaning it can store and retain its data, even if the computer is not connected to electric power. Therefore, secondary memory is used to store “permanent data,” such as the operating system, applications, and user files.

Examples of secondary memory  

  • Magnetic Tapes
  • Optical Disc
  • Floppy Disks
  • Flash memory (USB drives)
  • CDs
  • DVDs
  • Paper Tape
  • Punched cards etc

What You Need To Know About Secondary Memory

  1. Secondary memory refers to external storage devices that are used to store data or information permanently.
  2. Secondary memory can also be referred to as Backup memory, Auxiliary memory or External memory.
  3. The secondary memory is non-volatile memory in nature; which means information is stored permanently with no data loss in case of power failure.
  4. In secondary memory, information is stored in external storage devices and they cannot be directly accessed by the processing unit.
  5. Secondary memory is an external memory.
  6. Information and data is stored in magnetic and optical memories.
  7. Secondary is persistent in nature. Instructions are transferred to the main memory first and then re-routed to the central processing unit.
  8. It is relatively slow in interacting with the microprocessor.
  9. These memories are generally available in large sizes, from 200GB to Terabytes.
  10. Secondary memory is accessed by I/O channels.
  11. Secondary memory is less costly when compared to primary memory.
  12. Data and information is not uniformly stored and retrieved.
  13. Information stored in secondary memory can easily be transferred from one computer to another.
  14. Examples of secondary memory include: Magnetic Tapes, Optical Disc, Floppy Disks, Flash memory (USB drives), CDs, DVDs, Paper Tape, Punched cards etc.

Also Read: Difference Between Registers And Memory

Difference Between Primary And Secondary Memory In Tabular Form

BASIS OF COMPARISON PRIMARY MEMORY SECONDARY MEMORY
Description Primary memory is the main memory of the computer which is used to store data or information temporarily. Secondary memory refers to external storage devices that are used to store data or information permanently.
Alternative Name Main memory or Internal memory. Backup memory, Auxiliary memory or External memory  
Nature The primary memory is majorly volatile in nature.   The secondary memory is non-volatile memory in nature.  
Access In primary memory, data is directly accessed by the processing unit and it resides in the main memory until processing.   In secondary memory, information is stored in external storage devices and they cannot be directly accessed by the processing unit.  
Category Primary memory is an internal memory.   Secondary memory is an external memory.  
Storage Information and data is stored in semiconductor chips, so they have a limited storage capacity.   Information and data is stored in magnetic and optical memories.  
Processing Of Data Primary memory holds only those data or instructions which the computer is currently processing allowing the processor to access running applications and services that are stored temporarily in a specific memory address. Secondary is persistent in nature. Instructions are transferred to the main memory first and then re-routed to the central processing unit.  
Speed It is very fast in interacting with microprocessor.   It is relatively slow in interacting with the microprocessor.  
Capacity The primary memory is generally available in small sizes, usually between 500MB to 32GB. These memories are generally available in large sizes, from 200GB to Terabytes.
Access Component Primary memory can be accessed by the data bus. Secondary memory is accessed by I/O channels.
Cost Primary memory is costlier than secondary memory. Secondary memory is less costly when compared to primary memory.
Storage Of Information & Data Data and information is stored and operated uniformly. Data and information is not uniformly stored and retrieved.
Information Transfer Information stored in primary devices cannot be moved from one computer to another. Information stored in secondary memory can easily be transferred from one computer to another.
Examples RAM, ROM, Cache memory, PROM, EPROM, Registers etc.   Magnetic Tapes, Optical Disc, Floppy Disks, Flash memory (USB drives), CDs, DVDs, Paper Tape, Punched cards etc.

Also Read: Difference Between Cache Memory And Virtual Memory