Basic components of a computer
Computer divided into five components are: a controller, the arithmetic unit, memory, input and output devices. The controller CPU = + operator
CPU (brain)
Controller
Control the entire operation of the computer
Operator
Arithmetic and logic operations
Memory
A computer storage unit is called binary 1bit, 8bit = 1Bytes called a byte, 1024Bytes = 1KB, 1024KB = 1MB, 1024MB = 1GB, 1024GB = 1TB, 1024TB = 1PB.
Memory ROM: read-only memory (non-write), generally is programmed at the factory, then no longer be modified, the general store (basic input output system) BIOS program, which is generally used to start the computer, or for treating the underlying device control
Understanding computers 1 and 0 (low and high)
Main memory / memory (memory brain)
Pros: Fast
Disadvantages: small capacity, power disappears
External memory / hard disk
Advantages: large capacity, power failure will not erase
Cons: Slow
Process start computer
- Power on the computer
- BIOS running, detect hardware: CPU, memory, hard drives, etc.
- BIOS reads the parameters in the CMOS memory, select the boot device, etc.
- Reading the contents of the first sector from the boot device
- The partition information into BootLoader read enable loading module, the operating system boot
- The operating system asks BIOS, to obtain configuration information. For each device will check whether there is a device driver, and if not, the system will require users to install a device driver, with all of the device drivers, operating systems, they will be transferred to the kernel, then the initial relevant form ( as the process table)
I（input）/O(output)设备
input device
Input information, such as a keyboard, mouse
Output Device
Output information, such as display, printer
In order to understand the content of the following
32 and 64
The computer reads a 32-bit or 64-bit binary number (1 or 0 bit is called)
32 and the installation package is essentially the same number of bits, but to a different computer 64
Digit speed results in the speed of installation software, and the 32-bit 64-bit computer can not install the installation package
Multi-core CPU
cpu "brain, a brain the same time can only do one thing at a time to complete the multi-core CPU more thing
There will be no more than 8-10 core essential difference for us
Infix expression, postfix expression
bus
Connecting the computer hardware (CPU / memory / input / output)
Mechanical works hard
Have mechanical hard disk by a magnetic storage data, 0 is a magnetic degaussing 1
Robot: reading data, a head end of the robot arm is
Track: storing data
Sector:
1. The robot reads the contents of a sector of disposable
2. The disk is divided, a plurality of disc sectors into one (area)
The average seek (track) time
Time to reach the robot track: 5ms
The average delay time (mechanical arm to find time data)
In the hard disk 7200r / min for example
The average delay time:
7200/60=120(r/s)
1/120 = 0.0083 (s / r) = 8.3 (ms / r)
8.3 / 2 = 4.15 (ms / r)
The average seek time to find the average data + average latency time =
SSD (presence or absence of an electrical capacitor is determined by 0/1)
No mechanical arm, to save time
What is the programming language
python programming language, humans and computer communication medium
What is programming?
Programming: Programmers based syntax of a programming language in their brains want the computer to do written to a file, so the result is programming a bunch of files, this pile of documents that program.
Before programming need to learn grammar + keyword (phrase)
Write a bunch of files in a programming language (that is, after writing a file, the file is in python syntax and phrases)
Why programming?
The computer is like a man's slave, the purpose is to make computer programming help people work, and thus replace human
What is the file
The concept of virtual information is stored file, the file is provided by the operating system, use it to store information
What is the operating system
Computer hardware and the operating system is located between the application software, which is a control program coordinated management of computer resources and software resources. It complicated hardware operation, a package into a simple interface, for people to use.
What is the application procedure
Go to the operating system, and the rest are software applications. It is located above the operating system, by interacting with the operating system, to help people complete the work.
What is the use operating system specific
Operating system and hardware interaction and simplify the complex operations of the hardware
Three major components of the computer
software
operating system
Hardware (cpu / memory / external memory)
Hardware and operating systems, hardware interacts with the operating system and the hardware interact
Start the application
1. Double-click qq (qq found at the location where the hard disk) CPU Xianxiang memory fetch command issued (CPU + memory)
2. Memory qq instruction fetch operation from the hard disk (hard disk)
3. Run qq controller analyzes the instruction and informs the operator of the work (controller)
4.运算器进行一系列的算术运算和逻辑运算打开qq,并从硬盘读取qq的代码至内存（运算器+内存+硬盘）
5.计算机在内存中运行qq的代码（内存）
6.如果此时从qq好友接收一个文件并下载，该文件将会永久保存在硬盘中
7.关闭qq时CPU向内存发出关闭qq的指令，内存关闭qq并清理内存中qq的代码