Linux-chapter 0 (basic computer knowledge)

1. Five computer components: memory, arithmetic logic unit, control unit, and input/output device.

The cpu contains some small instruction sets, including the precision instruction sets (ARM) and complex instruction sets (AMD and intel)

The chipset is divided into nanqiao (interface responsible for slow speed, hard disk, Nic, usb) North Bridge (fast speed, cpu, memory, graphics card)

2. External frequency: the speed at which the cpu can exchange data with external components. A multiplier that is used internally by the cpu to accelerate the performance.

The bus of the North Bridge is called the system bus. The supported frequency is the speed of the front-end bus. The number of digits transmitted each time is the bus width (32/64), and the bus bandwidth is the product of the two. the amount of data that the cpu can process each time is called the word group size. The word group size is divided into 32-bit and 64-bit based on the cpu design.

Cpu level i386, i586, i686, x86_64, with downward compatibility

3. memory, the main component of the personal computer memory is dynamic random access to Memory DRAM (divided into SDRAM, DDRSDRAM), mainly considering frequency, bandwidth, capacity

Dual-channel design, the cpu external frequency and memory external frequency are best the same, DRAM Memory uses SRAM as Level 2 cache,

BOIS is a program that is written into an internal chip of the dead child motherboard. It can also record data when there is no power, that is, ROM

4. the graphics card (VGA) determines the screen resolution and color depth, sometimes embedded with a 3D acceleration chip GPU

5. Hard Disk (disk, mechanical arm, Head, spindle motor) Sector-track-Cylinder

Interface: IDE interface, SATA interface, and SCSI interface. Usually there is a buffer memory on the hard disk, about 16 Mb, speed, desktop 7200 RPM, notebook 5600 rpm

CMOS: The main function is to record the important parameters on the motherboard, such as the system time, cpu voltage and frequency, the addresses of various I/O and IRQ (on the motherboard, the oil battery)

6. Operating System

Kernel: allocates and manages resources related to computer systems, such as cpu and memory. The kernel layer is directly written based on hardware specifications.

System Call: a full set of development interfaces provided by the system. developers can develop the interfaces following the accepted system call parameters.

Application: refer to the interface provided by the operating system for compiling