Central Processing Unit (CPU)
Definition: Central processing unit (CPU) is a large-scale integrated circuit, which is the computing core and control core of a computer.
Functions: interpret computer instructions and process data in computer software.
Main frequency: Main frequency is the CLOCK frequency of the CPU, which is short for the frequency of the CPU operation (the number of synchronous pulses within 1 second). The unit is Hz. Generally speaking, the higher the main frequency, the faster the CPU speed, due to the internal structure of the different, not all clock frequency CPUs are the same performance.
External frequency: the operating frequency of the system bus, the working clock frequency of the EXCHANGE of data, and instructions between the CPU and the external (motherboard chipset).
Frequency doubling: frequency doubling refers to the multiple of the difference between the CPU external frequency and the main frequency.
The relation of the three is: main frequency = external frequency X times
Cache: High-speed switched storage. CPU caches are divided into level 1, Level 2, and level 3 caches, namely L1, L2, and L3.
Memory bus speed: Generally equal to the external frequency of the CPU, refers to the communication speed between the CPU and the level 2 (L2) cache and RAM memory.
Address bus width: Determines the physical address space that the CPU can access.
CPU Companies: The most well-known CPU companies are "Intel" and "AMD", both in the news and online. In addition, "IBM" also has CPU products.
Definition: Internal memory is one of the most important parts in the computer. It is the bridge of communication with CPU. All programs in a computer are run in internal memory, so the performance of internal memory has a great impact on the computer.
Function: Memory, also known as Memory, is used to temporarily store computing data in the CPU and data exchanged with external Memory such as hard disk.
Capacity: Storage capacity of the memory (unit: KB MB GB)
1. SIMM memory before 1988
2. EDO DRAM memory 1991-1995
3. SDRAM memory after 1995
4. Rambus DRAM Memory 1998
DDR memory is more commonly known as memory
8. DDR4 now
An external device
Definition: External memory refers to the memory other than computer memory and CPU cache, this kind of memory can normally retain data after a power failure (unlike memory loss data).
Common external storage floppy disk: ①U disk ② hard disk ③ tape storage ④ CD storage
Basic disk parameters
Capacity: The capacity is the most important parameter of a hard disk. The capacity determines how much data can be stored in the hard disk. The unit is MB, GB, TB, or PB.
Rotational speed: The rotational speed of a disk is the number of revolutions per minute (unit: RPM). A higher rotational speed increases the speed of data storage and reading. Common hard disks range from 5400 RPM to 7200 RPM. The rotational speed of a hard disk on a server can reach 15000 RPM.
Transmission rate: Transmission rate. The data transfer rate of a disk refers to the data read/write speed of a disk.
Cache: The disk cache is used to solve the problem that the read/write speeds at the front and rear levels of the system do not match, thus improving the disk read/write speed.
Disk Interface Type
IDE interface: hard disk interface specification, using ATA technical specification
SCSI interface: High-speed data transfer technology for small computers
SATA port: The Serial ATA port is hot-swappable and increases the transmission rate. Transmission speed: SATA2=3.0Gb/s SATA3=6.0Gb/s
SAS interface: Serial Attached SCSI, compatible with SATA
Currently, SATA and SAS ports are the mainstream hard disk ports.
Storage's new favorite: solid-state drives
Definition: Solid State Drives (SSDS), Solid State Drives (SSDS) are hard Drives made of Solid State electronic memory chip arrays, composed of control units and storage units (FLASH chips, DRAM chips).
And traditional mechanical hard disk difference
Appearance: SATA SSD interface and traditional 2.5-inch mechanical disk appearance are basically the same.
Speed: SSDS can read and write far faster than traditional mechanical drives.
Weight: Solid-state drives are light because they lack the heavy metal parts and discs found in mechanical hard drives.
Power consumption: A mechanical disk drives the disk with a motor, and a solid-state disk uses much less energy to run than a mechanical disk.
Size: SATA solid-state disks have the same size as mechanical disks, but other solid-state disks, such as mSATA, NGFF(M.2), and PCIE, are much smaller than mechanical disks.
Noise: Solid-state drives run without any noise because they don't need the disk to rotate and only run with electricity.
Earthquake-resistant: Traditional SOLID-state drives (SSDS) can work well even in unstable environments because they have mechanical movement and the magnetic head is very close to the disk.
Capacity: SSD capacity is generally small
Price: SOLID-state drives are much more expensive than mechanical drives.
Life: SOLID-state drives (SSDS) flash memory have a limited number of erasures, which is one of the reasons many people complain about their short life. Solid-state drives that run on a typical home computer tend to last longer than the computer or are replaced with a new product before they run out of life, so it doesn't matter much. However, working in a high reading and writing environment requires longevity.
Data irretrievable: Once a solid-state drive (SSD) is damaged, its data cannot be recovered. Even if a mechanical drive is broken, its data is still on the disk, and a lot of data can be recovered.