Computer Composition 1: Computer Composition

Computer Composition 1: Computer Composition

I,Motherboard:

The main board generally has BIOS chip, I/O control chip, key and panel control switch interface, expansion slot, main board and plug-in card DC power supply and other components.

Many important accessories, such as CPU, memory, video card, and chipset, are directly installed on the motherboard. They also support normal operation of hard disks, optical drives, and other carriers.

II,Register category:

1. General registers used to save variables and temporary results

2. program counter: saves the memory address of the next command to be retrieved (the address can be skipped)

3. Stack pointer: only the top of the current stack in the memory is used, and related input parameters, local variables, and temporary variables not in the General Register are saved.

4. Program status Register: (Program status word, PSW) contains the bar code bit, cpu priority, mode (user or kernel state), and other control bits. Generally, users read the entire PSW, but only write a small number of fields. PSW is very important in system calls and I/O.

Iii. processor (CPU) Evolution
1. Each Brand's cpu has its instruction set, which cannot be used across platforms
2. Read, decode, and execute-
3. multi-thread and multi-core chips: adding larger caches to cpu chips-increasing processing logic and multi-thread hyper-threading-multi-processor systems using multi-core chips (2 and 4 cores)
A process is a resource unit, a thread is the execution unit, and a cpu can only start one process. Therefore, multiple processes are real concurrency, while multiple threads are pseudo concurrency.
Intel multi-core: Each cpu contains a level-1 cache, and the communication between CPUs passes through the level-2 Cache. Sharing L2 requires more complex cache controllers.
Amd multi-core: second-level cache on each cpu, difficulty: Keeping L2 consistent
64-bit and 32-bit CPUs: 64-bit and 32-bit CPUs can be retrieved at a time
Cpu backward compatibility: 32-bit programs can run on 64-bit servers, but 64-bit programs cannot run on 32-bit servers.

 

Iv. Storage Classification:

Register: LI cache, which is integrated into the CPU
High-speed cache: L2 cache, which hits two clock cycles of the month
Primary storage: volatile, data loss caused by power failure. In addition to the primary RAM, there is also a ROM (ReadOnly Memory), EEPROM
Flash Memory (unlike disks (based on the magnetic mode), flash memory is based on the electrical mode), and Flash memory is inside the solid state disk (the electricity is faster than the Mechanical)
CMOS: It is volatile, but it has a battery drive. cmos stores the current time and date, and can also save the configuration of which is the boot disk, with little power consumption. An original battery can be used for several years.

 

V. Controller and multi-bus:

The I/O device has a controller. If a video card is used, a video card driver is required, which is related to the hardware of the manufacturer.

Bus:
1. North Bridge: PCI bridge, connected to high-speed devices, cpu, secondary high-speed cache, primary storage
2. South Bridge: ISA bridge, connecting to slow devices, printers, scsi, and mouse and keyboard

 

Vi. Operating System:

It is composed of the operating system kernel (running in the kernel state, managing hardware resources) and system calling (running in the user State), and the application software changes the competing state of hardware resources in an orderly manner.

Through system calls (implementation in the CPU is called a trap command), application software can switch from user to kernel to call hardware.

The software will frequently switch between the kernel and user States, so these two States cannot exist on the hard disk, but must exist on the register.

Differences from common software:
1. Large: linux, windows source code has 5 million lines
2. Longevity:

Development History:
1. 1940-1955: First Generation, vacuum tube and punch card (no operating system concept)
2. 1955-1965: Second Generation, transistor and Batch Processing System (saving many cards for batch operation by professionals)
3. 1965-1980: Third Generation, integrated circuit chip and multi-channel programming (system360 is the predecessor of the server)
Bell Labs, General Electric, MIT developed a unix System
4. 1980-today: the fourth generation of personal computers

VII. Computer startup process:

1. computer power-on
2. BIOS starts to run. Check hardware: hard disk with cpu memory
3. the BIOS reads the CMOS memory clock parameters and selects the boot device.
4. Read the content of the first sector from the Startup Device.
5. Read the boot loader module and start the operating system according to the partition information.
6. The operating system asks the BIOS to obtain the configuration information. For each device, check the driver. If there is a driver, call them into the kernel,
Then, start the relevant table (such as the progress table) and start the login program or GUI on the terminal.