Pyramid-shaped storage devices, abstract concepts of operating systems

Source: Internet
Author: User

Pyramid-shaped storage devices , Abstract concepts of operating systems

The system spends a lot of time on the book of data . Hardware Developer ( mostly the person who made the storage media ) to reduce the time cost of this data transfer , This is a way to reduce this time cost with medium-cache technology .

Cache is placed in the processor , and the processor in the register file directly to Exchange data , which greatly reduces the time cost of data transmission, The speed of the program can be increased several times . as a computer-engaged , a stake can be used to properly use the cache to store some of the data commonly used in the process of running the program , you can increase the speed of a program several times or even several orders of magnitude .

You think about it in the Web page,you're the first one to open a Web page,It could be slow .,But when you open the second time,,maybe hurry up.,It might be fun to open more times .,If you know how to check the cache,,you'll know that you've cached a lot of pictures of that page ..say this example,nothing special.,just wanted to tell you something about the cache..I want to tell you the importance of cache.

Shows the location of the hardware distribution , telling the cache .

Pyramid of storage devices

In today's computer systems,basically all of them are in a variety of storage devices.,These parking devices are presented in a distinct hierarchical structure,their specific size is larger.,The slower the speed(your hard drive has a large capacity,But what about speed??)so if they're presented in a graphic way, by capacity and speed,,looks like a pyramid(If you learn the book well,,is a what withxIncrease

Y Decrease the function , I am not good at maths , do not know how to describe , you understand ). Steal a picture

English version , how to do ? think about that function . , x getting bigger , y Decrease , x representative Capacity , y represents speed . Link Up .

Explain the diagram.:the left side means smaller, faster, but also more expensive storage devices,includes registers andL1-l3the Cache,and larger, slower, cheaper storage devices,including main memory,Betty Disk,and Remote Storage the usual sense,we use the storage device on the previous tier as the cache for the current device,likeL1the tell cache is a register, L2the cache isL1,etc..

OS is the manager of the hardware

The operating system is the software that helps us to control the hardware , It is like the middle of the application and the hardware program , play a role of translation between the two , the relationship such as :

OS operating system provides several concepts of our properties to represent hardware , such as processes , virtual memory , and files . the hardware devices they represent are as follows :

Can see that the file is i/o device abstract description i/o device collectively ? The process on this basis added the processor

What do you mean , for the operating system , the hardware is actually abstracted , for the os , file is I/O Equipment .



process is the operating system's abstract Span style= "font-family: Arial" > These states are referred to as the context of the process These states mainly include the pc, Register and current contents of main memory when os when switching between processes

In the process , but also by the computer World's great God introduced the concept of threading , no way to learn , I think of my high school , The math teacher said a word , If someone crosses , in Gauss 5 years old when he killed , Our maths textbook is at least half thin . ....

Virtual memory

For me this slag , What is to find your memory do not know , study together today , virtual memory is an abstract description , Physically , It contains the I/O device and main memory . Logically speaking, , virtual memory is described as virtual address space . represents the virtual address space for a process :

(After reading this picture I really do not know this figure to say what , can not understand )

The address here is incremented from top to bottom.,can see.The starting address is indicated in the figure,respectively for0x08048000 (bit)as well0x00400000 (bit),and then up is read-only code and data,Read and write Data,run-time heap,memory map interval for shared libraries,user stack and kernel virtual memory area.

A lot of the term, remember it's okay , take it slow . It's no use remembering this thing. . to really understand. .

program code and Data : The starting address of the content is 0x08048000, first the code , Then some global variables .

Heap : is a part of the area where the runtime can dynamically expand , and he can be used by malloc and Free This is the standard library function operation .

Shared libraries : Code and data that are used to hold shared libraries .

Stack : at the top of the user's virtual address space is the stack , and this part of the area is closely related to the execution of the function .

Kernel Virtual Storage Area : The kernel is part of the OS and the Linux kernel should have heard of it ? The kernel can be thought of as a process , Is always running while the computer is running , Therefore, this part of the memory area is not visible to the user program , It's not a popular word . .


File isI/OThe concept of device logic,He's actually a byte sequence .,also0and the1composed of some all theI/OEquipment,include disk,keyboard,Mouse,the display can be viewed as a file.


All the I/O devices are actually the concrete manifestation of the concept of the document . Na,e Network is actually a sound kind of , because in the end , He can also be seen as a series of byte sequences . the function of a network adapter is to input a bunch of byte sequences that are transmitted over the computation . , This may include pictures , text may even be code and so on .

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Pyramid-shaped storage devices, abstract concepts of operating systems

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