Internal memory is a familiar name mentioned. However, there are many factors involved. Let’s find out what the computer’s internal memory is and how many types there are.
What is computer internal memory?
Computer memory holds the data and instructions needed to process the raw data and produce output at the output device. Computer memory is divided into many small parts called cells. Each cell has a unique address that varies from 0 to memory size minus one.
How many types of computer memory are there?
Computer memory is of two types: Volatile (RAM) and Non-volatile (ROM). Secondary memory (hard disk) is called non-memory storage.
However, if we classify memory on behalf of space or location, it comes in four categories:
- Register memory
- Main memory
- Extra memory
Registered memory is the smallest and fastest memory in a computer. It is not part of main memory and resides in the CPU as registers, which are the smallest data holding element.
A temporary register holds frequently used data, instructions, and memory addresses to be used by the CPU. They hold the instructions currently being processed by the CPU. All data is required to pass through registers before it can be processed. So they are used by the CPU to process user inputted data.
The register holds a small amount of data about 32 bits to 64 bits. The speed of the CPU depends on the number and size (number of bits) of the registers built into the CPU. Registry can be of different types based on their intended use. Some of the widely used Registers include Accumulator or AC, Data Register or DR, Address Register or AR, Program Counter (PC), I/O Address Register, etc.
Types and functions of computer registers:
Is a 16-bit register, used to store operands (variables) to be operated by the processor. It temporarily stores data being transmitted to or received from an external device.
Program counter (PC)
It holds the address of the next instruction’s memory location, which will be fetched after the current instruction is completed. So it is used to maintain the execution path of different programs and thus execute the programs one by one, when the previous instruction is completed.
It is a 16-bit register. It stores the instruction taken from main memory. So it is used to hold the code to be executed. The control device receives the instruction from the Instruction Register, then decodes and executes it.
A 16-bit register, used to store system-generated results. For example, the result generated by the CPU after processing is stored in the AC register.
A 12-bit register that stores the address of a memory location where instructions or data are stored in memory.
I/O Address Register
Its job is to specify the address of a particular I/O device.
I/O buffer registers:
Its job is to exchange data between the I/O module and the CPU.
Cache memory is high-speed memory, small in size but faster than main memory (RAM). CPU can access it faster than the main memory. So it is used to synchronize with a high-speed CPU and improve its performance.
The cache can only be accessed by the CPU. It can be a reserve part of main memory or a storage device outside the CPU. It contains data and programs used frequently by the CPU. So it ensures that the data is immediately available to the CPU whenever the CPU needs this data. In other words, if the CPU finds the required data or instructions in the cache, it does not need to access main memory (RAM). Therefore, by acting as a buffer between RAM and CPU, it speeds up system performance.
Types of Cache
L1: Is the first level of cache memory, called Level 1 cache or L1 cache. In this type of cache, a small amount of memory is present inside the CPU itself. If a CPU has four cores (quad core cpu), then each core will have its own level 1 cache. Since this memory is in the CPU, it can operate at the same CPU speed. The size of this memory ranges from 2KB to 64KB. L1 cache also has two types of cache: Instruction cache, which stores instructions requested by the CPU, and data cache, which stores data requested by the CPU.
L2: This cache is called level 2 cache or L2 cache. This level 2 cache can be inside the CPU or outside the CPU. All CPU cores can have separate level 2 cache, or they can share one L2 cache with each other. In case it is outside the CPU, it is connected to the CPU by a very high speed bus. The memory size of this cache ranges from 256 KB to 512 KB. In terms of speed, they are slower than L1 caching.
L3: It is called level 3 cache or L3 cache. This cache is not present in all processors; some high-end processors may have this type of cache. This cache is used to enhance the performance of level 1 and level 2 cache. It is located outside the CPU and is shared by all cores of the CPU. Its memory capacity ranges from 1 MB to 8 MB. Although it is slower than L1 and L2 cache, it is faster than Random Access Memory (RAM).