Central Processing Unit (CPU)

CPU stands for Central Processing Unit.
It contains a control unit that operates each device in the computer and controls normal operation.
It contains an arithmetic unit that processes various computational data.
It contains registers for temporarily storing data.
It contains an arithmetic logic unit and performs computational functions.
It determines computer performance and the type of system.
- It determines the type of computer.
- It determines computer performance.

Execution Unit (EU)
The execution unit is the unit that executes each instruction in a microprocessor.
The execution unit consists of the ALU (Arithmetic Logic Unit), the control unit (CU), and registers.
The ALU performs arithmetic operations, such as addition and comparison, as well as logical operations, and stores intermediate results in registers.

Instruction Unit
The instruction unit controls instructions fetched from memory so that they can be executed correctly by the execution unit.
At this time, the control unit ensures that the ALU and registers operate correctly.

Addressing Unit
The addressing unit creates memory or input/output addresses when the CPU reads data from, or writes data to, memory or input/output devices.

Bus Interface Unit
The bus interface unit connects the microprocessor to the outside through the address, data, and control buses.

Cache Memory

Cache memory is one type of buffer memory temporarily used inside the CPU.

Understanding Cache Memory

A cache is a temporary storage device located between two devices with different speeds. It improves the speed of data access between devices and improves processing speed during repeated access.

When cache is not applied

Run a program called TEST.EXE.
Load TEST.EXE from (1) auxiliary storage, such as a hard disk, into (3) main memory.
When the program exits, the program loaded in (3) disappears.
Run the same program again.
The program is loaded from (1) into (3) again. In this case, the user must wait each time while the program is read from (1).

When cache is applied

Run TEST.EXE.
While the program is loaded from (1) into (3), it is also written to (2).
When the program exits, the program loaded in (3) disappears. However, what was stored in (2) is not erased.
Run the same program again.
This time, the program is loaded from (2), not from (1). From the perspective of (3), the same program is being loaded, but the first time it was loaded from slower auxiliary storage. From the second time onward, repeated loading occurs from faster cache memory, which improves speed.

Clock (Operating Frequency)

A clock is a unit that represents CPU speed. A clock refers to the time it takes for a waveform to move once in one second, and CPU speed changes depending on the amount of data processed during that time.
It is written in Hz. In general, the higher the clock value, the faster the performance.
However, if only the clock is raised to improve performance, power consumption increases and heat generation can become severe, so this must also be considered.

Clock and FSB

A clock is an electrical rhythm that oscillates at a fixed cycle and is generated by the motherboard’s clock generator to operate the CPU and other devices. It is expressed in MHz (megahertz).

1 Hz is a clock that oscillates once per second, and a CPU basically processes one instruction per clock.

It is used as a unit for expressing the speed of the CPU and the system.

FSB (Front Side Bus) is another name for the clock generated by the motherboard’s clock generator and supplied to each device. It is also called the external clock. The CPU and devices inside the computer operate according to the clock speed supplied by the clock generator. However, the CPU does not use the supplied clock as-is. It uses “clock doubling” to increase that speed several times before using it.

Core

A core is the central part of the processing circuit built into the central processing unit. In the past, when computers were not as widespread, it was natural for one CPU to have one core.
However, dual-core processors with two cores appeared in 2005, making multi-core processors popular in general PCs. Later, processors with four, six, and even eight cores appeared.

A dual-core processor can reduce work that a single core would have processed in two steps to one step. Therefore, it has the advantage of improving overall processing efficiency.

Virtualization Support

Virtualization support, simply put, means running another operating system inside an operating system. For example, it is a technology that allows Linux or another operating system to run inside Windows, just as a program runs after Windows starts. Intel CPUs support virtualization under the name “VT-x”, and AMD CPUs under the name “AMD-V”. To build a cloud environment with servers, it is essential to check whether the CPU supports virtualization.

Types of CPUs

CPU Types by Data Processing Capacity

Classification according to the amount of data that can be processed simultaneously.
The width of the bus, which is the path that transfers data.
8 bits is the minimum unit of data processed by a computer.
Development progressed from 8088 (8-bit) to 80286 (16-bit), 80386 (32-bit), and Pentium (64-bit).

ARM

Licensed products from companies such as Apple and Samsung.
ARM chips are small, generate less heat, and consume less power. They do not require a cooling fan. However, they have tended to be limited to specialized uses.