A piece of real personal experience, to those lost friends [Post]

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Title: A piece of real personal experience, to those lost friends [Post]
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A piece of real personal experience, to those lost friends [Post]

I have been writing a real-time operating system kernel over the past few days. I will make it public later, hoping to do my part for the development of domestic it. Recently, I have seen that many students and friends have no direction, so I wrote my experiences and shared them with you. I hope I can help my friends who just like me a little bit.

In a twinkling of an eye, I have been studying and working in the IT industry for more than seven years. During this period, I used Web pages, MIS, databases, applications, communication software, hardware drivers, and protocol stacks, now we have developed the operating system kernel and IC-related development, which has taken a lot of detours and suffered a lot.

Me
It is a three-stream University, and most people in the same city do not know it. Because the school is not good, it is not expected to find a good job by the reputation of the school. All hopes are pinned on your own efforts.
I started my study during my pre-school holiday. I remember that the first book I bought was "Computer Basics dos3.0". Don't be scared. In fact, dos6.22 was popularized at that time, I saw it in the bookstore.
Dos4.0, 5.0, and 6.0 books. I thought they were 4, 5, and 6 books like English. I remember looking for dos1.0 everywhere. Now I think I did not find it. :) I have finished school before I started school.
Pascal, at that time there was no computer or anyone who could ask for advice. I didn't even have the concept of a program, so I had to memorize the code and write it on paper. I had a 486 instance until I was a sophomore, before that
I can't remember how many programs I wrote with paper, but I only know that the longest I wrote over 30 pages with an A4 draft paper, my C language, C ++, and VC are all started under such conditions. So the condition is:
I hope that my experience will give my students with a little confidence. My first computer was in my brother-in-law's machine room. I was so excited that I could never miss it.
In win3.1 of the Chinese version, I saw a ghost in my dos knowledge. I was so worried that I could not recover the word when I accidentally turned it into a full screen, I am a machine
I broke it. The first C language program is the classic helloworld. After a few weeks of adjustment, there were very few opportunities for connecting to the computer, and no books told me that the development environment (tc2.0) needs to be set up,
At the beginning, I did not know how to compile the program. I was very intelligent and changed the extended program name from .cto .exe.

I finished C and x86 compilation, data structure, and C ++ in my freshman year. Because the energy is spent on self-study, the first and fourth courses are highlighted. This is good for the three types of schools, and the same is true for the 10 or 20 courses. However, as far away as you can say, I am so hard at all. It can be seen how rigid computer education is in our country.

Large
I was prepared to study VC and BC, but it was difficult to choose between them. Later I chose VC. Instead, I only chose two books in the bookstore. VC was 6 yuan cheaper. No one can work hard in my class. I learned day and night, and I had plans for my career.
This is especially true after the computation. Many times my father taught me in the middle of the night to say that I am not dying. I have always felt that my foundation is poor, my memory is not good, and my conditions are not good.
So I think it is only a little more time to catch up with others. Many of my friends later said that I had the talent to learn computer, which left me speechless. I used 486, 16 M memory, 1 GB hard disk, and the configuration of the students
Both are p166mmx. I have installed a Windows
NT4.0 needs an all-night program. It takes nearly two hours to compile a program generated by the bc5.0 wizard. My monitor is a second-hand program. The radiation is very high, and the boot screen Sparks. It looks cool :), there is one
The program has been written for too long. I thought that the background of the white editor had changed to purple. I thought that the monitor was broken and later I found that my eyes could not work, but it was strange to say that, today, my eyesight is still 1.5.
Trace. But the broken machine has been with me for two years, and I have learned VC, Delphi, and sqlserver. Later, the machine was used for typing for my aunt. According to her, she was playing happily one day.
The smoke was drilled out of the monitor with a flame in it before it went to life.

I got a chance to practice in a computer research institute during my junior year holiday. Instead of volunteering, I spent two months working.
I didn't get a penny. However, these two months have helped me a lot in my development, and I learned more about society. When I first went there, I certainly knew nothing about it. Where I got familiar with the network, I learned Delphi and
Oracle. I got a good review from my serious work. I started to work with an elders on projects, which gave me my income when I was a junior or senior, I found two more senior students.
I am a part-time job in MIS. Although I don't have a lot of money, I am very satisfied with more than 1000 of my students. I finally used my own money to change my computer. I started looking for a job in my senior year.
There are already many (of course, it's very naive to think about it now). I started to hear my parents want to go to that research institute, and I hope I can go to that department after my internship, but I don't know why I ended up failing, such units are relatively bureaucratic,
In my breath, I got to work as a team leader for MIS in a part-time company. I have done various MIS jobs from my junior year to one year of graduation, from gas, tobacco factory, public security, railway, food to colleges and universities,
I have a lot of money to do and work hard. I often work overtime and stay up late, from talking to the customer about requirements to designing, coding, testing, and delivery. At that time, I felt very fulfilled and I felt pretty good. Now I think it's really great.
Superficial.

Students who have just started their jobs can easily be misled. Various development tools are dazzling and very important to the company. However, such work will always be a low-level development.
. Don't tell me how important and difficult a system analysis is. Do you think that designing your own demands is System Analysis and Design? How many companies in China can do well?
I am an ISO9000 internal auditor and have been trained many times in rational, obtained four certificates, and another company asked me to do CMM. I have heard a lot of this, but a lot of things have changed.
Nature, a company can be standardized without Passing ISO9000 or CMM. I am now working in a foreign company with decades of history, and the management in it is not comparable to that in Chinese enterprises. As a graduate
Students who have never entered the society before can hardly grasp system analysis and design in a short time. object-oriented and UML are just a tool. The key is people's ideas, it's not that you are familiar with C ++,
Rose can make a good design. On the contrary, if you have a high quality, you can use C to write programs that are more modular than others who use C ++.

In other words, domestic software development
There is a strange circle in the development industry. Many people think VC> Delphi>
VB is really funny. I have developed these software. To put it bluntly, they are all tools. You should choose which one to use based on the application's needs, rather than the upper layer. If you use a development tool
If you choose "face", it means you are very simple. If there are layers, these tools are not hierarchical, because they are used as system APIs, and Microsoft's friends won't remember how many of them
The API or several classes will think you are amazing. You will always be their customers, and they value the money in your pockets. I have also worked on the system kernel, and I have encapsulated many APIs, so I will not pay attention to them.
Customers who use these APIs for secondary development, unless they can make their own unique designs.

Some people think that C ++>
C makes people laugh at it. You may as well inquire about it. Now, several operating system kernels are written in C ++, and several real-time systems use C ++, of course, I am not saying that C ++ is not good, but the current
C ++ cannot match C in the kernel and real-time system. c ++ is suitable for application system development. So my point is not what tools and languages you use, but what do you do?
. Your design reflects your technical level.

After doing this for a year, I felt very depressed. Most of my work was done by skilled workers, and I could not see much improvement in my personal technology. Therefore, I decided to leave the city to go to Shanghai for better development, and planned to give up my previous MIS transfer to the communication industry.

Write
I can't help but mention my girlfriend here. We met her half a year before coming to Shanghai. she was an intern in our company when she was a senior. The company sent her to write documents for me, and our feelings grew fast. She told me a lot of things. Her house was originally
Her mother loves playing cards, lost millions, and owes a lot of debt to her first batch of nouveau riche during reform and opening up. She has a boyfriend, but she has no feelings for him, he only gave her mother more than 20 thousand yuan, and then forced her to write
Her boyfriend betrayed her and beat her more than once. Now she is forced to get married, or she will pay back the money. This person is still a college teacher! Her mother spent her father's tuition because she was in arrears.
She cannot get her diploma. Her mother is ill and needs money now. I took out some of my savings and received some money from my friends, I paid her tuition and prescribed medical treatment for her mother. (later I learned that I didn't know the money for medical treatment.
I don't even know if her mother is ill, but she can't ). At this time, my family knew something and resolutely opposed me to be with her. Her old boyfriend also tried to destroy me. However, we
We decided to leave this sad city early and leave our house alone. Due to the rush of time, I only prepared 4000 yuan, and her only a few hundred yuan was required by her mother. I bought three tickets, one at noon.
The two are for the night. At noon, my family sent me to the ship and they got off the ship as soon as they left, she and I took the night boat and left the city where I lived with her for many years. All they took was debt. Not here
We are both stubborn and reluctant to bother our classmates and friends. It was half past six in the evening when we arrived in Shanghai. We didn't know where to go. We found a hotel with 20 yuan worth of money. This room didn't even have a window,
The weather in February was so hot that the room was very stuffy. The next day, we started to rent a house. Because we didn't have much money, we basically walked. It took us a week and I don't know how many laps I found in Pudong.
A 400-piece house, but we all
I don't know about Shanghai, but I have to pay for three times and half a month of intermediary fees. After I bought some pots and pans, we only paid 800 yuan for our work, and we have not yet completed our work, we have to pay 800 yuan for the first month.
Salary: to save money, we cook on our own. It takes only two yuan to buy food every day. She enjoys it very much (or she is willing to go hungry frequently in College ), I can't bear to see how easy it is to use. Her old male
Friends did not let her go, often called to harass, and came to Shanghai to see her, but also said a lot of threatening her words, she was too kind, said he had helped her before, after all, tell me not to be familiar with him. In the future
I tried to wait for an interview notice. I originally wanted to quickly find a mis company to solve the problem, but she insisted that I should not give up on my own ideals. Finally, I found a communication company, 4000
Even though I cannot keep up with the price offered by MIS, I am still able to survive in Shanghai. She also found a job. She cried when she went to work on the first day. This was the first time she came to Shanghai to shed tears. I felt very uncomfortable and touched.

As a brand-new industry, I have reduced myself to zero. The VC, Delphi, and database I have learned are not useful. I have never touched on embedded systems, protocols, and signaling.
Knowledge. I knew that I had not left the door, so I tried my best to study hard. I considered myself a fresh graduate, and I finally got familiar with it over the past six months.
I was recognized by the company and received a higher salary. In the days that followed, we spent less than 10 thousand yuan on our friends and finally got on track. At this moment, my girlfriend told me that she wanted to study
Student, I am also very supportive, so she resigned at home to prepare for the exam.

In addition, I would like to thank my project manager for being a product manager of a large communication company,
I learned a lot from him and gave me a lot of selfless help. At work, he gives me plenty of space and trust. Remember that the company has arranged for me to maintain an Access Server software,
Because the amount of code is not too small (50 thousand lines), and the materials and documents are not complete, I am very difficult to maintain, so I want to redo it again, the company leaders do not support it, he may think the workload is too heavy, but he strongly supports it.
In private, he asked me to let me do it, And he squeezed time for my maintenance work. With his support, I spent half a year completing the software for accessing the server, and
And implements a relatively complete TCP/IP protocol stack. Here I learned about embedded system design, driver development, TCP/IP, and a lot of communication knowledge. I spent a year finally getting myself from the MIS
Development has moved to the communication industry and gained a firm foothold. I have developed a lot of direct hardware operations, and I am no longer constrained by Microsoft's operating systems, VC and delhpi development tools. I finally see another
A blank sky.

I like to stick to the root of the problem when I do things. With the development going deeper, software development and hardware are getting closer and closer, and the lack of hardware knowledge creates obstacles for my development, and the chip
The technology is basically in the hands of foreign companies. This is a huge constraint on system-level design. The first profit (and often the most lucrative profit) for a new product) it is often used by IC companies such
Intel and Motorola make money, and domestic manufacturers can only get some soup. Therefore, I am determined to solve my hardware technical barriers and intend to leave the communications industry and enter the relevant fields of icdesign.

When
However, I understand that if I have little knowledge about hardware, no IC company will be kind enough to hire someone like me for training. Therefore, I must lay a solid foundation and learn some relevant knowledge to prepare for the future. Just
Like I started to switch from MIS to communication, I have read a lot of books on communication and used a radius billing sorting desk for an ISP, in this context, the communication company gave me this opportunity. Me
Systems are designed in communication companies, with many PCB
Layout hardware staff, I usually pay attention to learning from them. Because I am working on software, I am embarrassed to read hardware materials from the company, so I had to watch the hardware materials at home, I have been working overtime for a year since I first came to Shanghai.
I want to squeeze out time to study. I usually go to bed around half past five. I started to work early the next day at. If there are not many people on the subway
I also read books. Of course, learning will not be smooth sailing. I have accumulated some questions that I really don't understand and asked the hardware staff. Their help has made my learning progress much faster, because I learned it by myself without human resources, me
Half of the time is
I am very glad that I have such a learning environment. In the next year, I learned how to view the hardware schematic and how to simplify it.
Single Hardware Design
(There is still a small gap in analog circuits). This is the case. When you work on software, others always think that you are a software developer and others start learning hardware.
I may not agree that a friend of  also told me that a person cannot finish learning everything. I also understand this, but I hope I can do better. But when you are familiar with hardware, people will think you are
I knew everything about software and hardware, and my colleagues became familiar with it. At this time, I can take the hardware materials to the company, and no one will be surprised. What makes me proud is that I have done it through my own efforts.
An IAD (Softswitch terminal device) system solution, including software and hardware selection, design, and so on.
I am very pleased that the solution has been recognized by the company and colleagues.

Technology
Skills complement each other. When my hardware has made some progress, my software design has also been greatly improved. I can understand the problem from a deeper level, the CPU used for accessing the server is Motorola.
Powerpc860, familiar friends all know that 860 QMC and the batch data transmission of software usually adopt the BD table method. Hardware staff are used to driving the data.
A fixed BD table is used. Data is copied from the BD table to the user buffer or from the user buffer every time data is received or sent.
BEI to the BD table, because of the deep understanding, I re-implemented this process myself, using the dynamic BD table method, the driver receives data from a network port, submit the software to me for layer-3 switching, from another
Interface sent out, no
There is a copy. This design greatly improves the performance and makes the system indicators close to the theoretical value. The combination of software and hardware has brought my design level to a certain level. I am writing this operating system. After compilation, I will
Decompile the code into an assembly, find out the unoptimized code, and then adjust it in the C program. For example, many CPUs do not have special multiplication commands, so we should all know that a multiplication operation is performed on such CPUs.
Regular operations often consume a large number of instruction cycles. Some friends may say that I know that I will try to avoid using the X number, but things are often not that simple. You know
How is the subscript operation of arrays in C language implemented? Take a closer look at the disassembly code and you will understand that the C compiler sometimes produces displacement commands, but sometimes uses Multiplication
Implementation, the two are often very different, so you can understand these problems to improve the system performance to the extreme. I will not talk about these issues much more. If you are interested, you can discuss them later.

Words
To put it a little farther, I sincerely hope that my friends who are more deeply engaged in software will have the opportunity to learn hardware and other
Related Knowledge, especially for underlying development and embedded design. This is of great help to improve the software technology. No
You only know a lot of things, but you don't know why. My point is in my current IC company proj ect.
The manager is also verified. He told us that the software manager for the 802.11 chip product is
The design of the chip hardware was originally made of software, and now we are working on IC. There are many similar examples, but this is not very popular in China.

I have some experiences
I will share with you that only after I have done my job well will I learn the technologies that are less relevant to my work, so that my boss will not be disgusted, in the entry stage, I usually don't ask senior people
But ask some friends with relatively low qualifications, such as students who have just graduated, because they will often tell you in detail
However, senior people usually think that your question is too simple, so the answer is very simple. I am sorry to ask more questions. And so on
After a certain technical level, I will ask them, and they can give you a deeper answer. In addition, some of my friends said that I had a better chance. They also hoped that they could do a new job. Unfortunately, they did not have a chance.
Smile, I have the opportunity to understand people should know, I was not born in any it family :) no one will promote me all the way, all the ways are from
My mother died early. My stepmother (I called her aunt) looked at me and tried to come over. Once she saw that I was still writing programs for 30 years, she said that I could learn from the hard work of wood like me.

Me
The ultimate goal is IC rather than PCB, so my next preparation begins to learn about icdesign. The same
I did not understand the icdesign, and I had to rely on myself for the next step. I bought a lot of related books and checked a lot on the Internet.
Materials, I spent a lot of time learning VHDL, and used software for some simple design and simulation (No
ASIC, only for FPGA). With the deep learning, I gradually understand the basic process of IC design.
The hardships of this road. At this time, I was ready to change jobs. I submitted my resume to an industry-renowned icdesign company and passed a long interview (more than four hours ). Everything else
I am satisfied, but my salary is not satisfactory. I also understand the reason, because I am a newcomer to this industry and I have no experience, I reset myself again. My boss asked me if I could accept it for more than 6000 months.
He also acted according to the rules. Think about my friends in the communication industry, basically all of them have an annual salary of more than 0.1 million yuan, and the monthly salary of over yuan is also everywhere. My friends have also introduced me to me.
I was hesitant about how to choose a less-paid company. I love my career and yearn for my pursuit, but I am also an ordinary person, I also need to support my family. I also want to buy a house and buy a car a little earlier. Life
It gave me a difficult problem.

Einstein said at the age of 63, "if a person has never achieved the greatest scientific achievement before the age of 30, then he will never have it ." This sentence gave me a lot
I am 26 years old in terms of pressure and vibration, and I am only four years away from the last 30 years. I have to pay close attention to the precious time of the past few years and strive to reach the highest technical peak. For this ideal, in order to be closer to your dream,
I chose this IC company, and I understand that my salary is almost the same as the number of graduate students I just came in, but I have to endure it for future development, and everything has to start over again. Changing the industry is a very painful process,
In particular, switching from a proud position to a strange position, it is unacceptable to drill out of the warm quilt and jump into the ice water. In the original communication company, I was the only one who raised my salary five times in two years.
Employees, companies, and colleagues have given me great recognition, and I am often entrusted with important responsibilities at work. But now it's all in the past, in the new company
I am just a newcomer, and no one knows or cares about my past achievements. I decided to start over and think of myself
For new students, I should use my own efforts to get the company's approval. It is very painful to enter a new industry. I told myself that I must endure all this. Although there are many temptations outside, I cannot accept the choice.
Make yourself easy to put
Discard.

I have been working in this new company for more than a month. It started to be very difficult and now I have adapted to it. First
At the end of the month, the team
Leader talked to me and said that I am one of the best new employees and I am very pleased. This is definitely an affirmation of my efforts. I would like to thank my girlfriend for her great support and encouragement.
Dancing, she encouraged me every time when I was shaken, and made me stick to my own ideals. When I first came to Shanghai, she told me not to barely go.
I am doing mis. This time, she gave me the temptation to withstand a monthly salary of over. Without her, I may not be able to get my grades today. The current company has its own operating system, its own CPU, DSP and other chips. Here I
I am very happy to learn the most advanced technologies in the world. Our design and development do not depend entirely on other people's hardware and systems. After my work is on the right track, I plan to learn new knowledge and realize my ideal.

In the next two years, I have set several goals for myself:
I. Strive to do my job well and get the approval of the company and colleagues in terms of work;
2. Learn IC hardware design knowledge, consult with colleagues, and use all opportunities to practice more;
3. Implement the main part of my real-time operating system, complete the TCP/IP protocol stack module, and release the source code for free;
4. Marry my girlfriend and buy a small house. This is the most important thing, because I understand that my career can come back,
Precious feelings are hard to be recovered.

The operating system I have developed is a real-time embedded system that currently supports the following features:

A. Supports time slice rotation scheduling and priority-based scheduling, with a maximum of 64 priorities;
B. preemptible real-time kernel;
C. For ease of transplantation, the subject is implemented using standard C;
D. Very few Assembly codes, less than 100 lines;
E. Supports task management. Each task has an independent stack;
F. Currently, semaphore has been completed for Process Synchronization and communication, and message queue is being debugged;
G. Scheduled system call is implemented;
H. It can be simulated and debugged on Windows.
I plan to implement priority inversion protection, event flag, data pipe, memory management (previously implemented), and driver interfaces. After that, I will try my best to improve it, such as joining file systems, protocol stacks, and debugging interfaces. I hope my friends can give me their comments and suggestions. I am very grateful!

Postscript:
Just
As some friends have said, my experience may mislead some friends. Here I must explain it. I used to study too hard before I came to Shanghai. I often slept for more than three hours at night. I was 1 meter tall and I was only
108 (I am more than 130), and my family also said that I am desperate to survive 60 years old, but at that time I was too stubborn, I said to them as long as they can
It is enough for me to live for 50 years. At that time, my body was affected by my desperate efforts. One morning, my waist muscles suddenly suffered a severe pain and I fell into bed and couldn't stand up. Although I already pay attention to it, sometimes
It will cause a faint pain. Later, my girlfriend convinced me that I would not do this again after I came to Shanghai. I often quote my father's saying "the body is the capital of the revolution ".

And I also found that
I can stay up one or two nights. I have been working for three days and three nights at most once, but I haven't recovered for half a month. Is this not worth the candle? Learning should be a long-term process,
Like a marathon instead of a hundred meters sprint. I pay close attention to adjusting the learning and work intensity.
Some young friends feel that they should work hard, which worries me a lot. If my story can make you more interested in study and work, I will be very happy, but if it is misleading
Some friends will feel guilty if they make some effort that is not worth it.

Technology is not cheap. I used to change the industry because of my own interests, rather than the industry
Prejudice. I hope that my experience will not give a wrong orientation to my friends. I feel that I have always been developing towards a higher level of technology. In fact, it is very difficult for all walks of life to be top-notch. Even though the technology is not cheap
There is a high level. In any case, the threshold for IC creation is higher than that for Web pages, which is undeniable. All kinds of talents in the country are needed, but as an individual, the idea of hard work should still exist.
Industry, rather than staying at a superficial level.

I am a person who thinks I have self-knowledge. Maybe my biggest advantage is that I have many shortcomings.
:). Many twists and turns and errors in my story are caused by my shortcomings. I hope you can look at them with caution.
My experience should not be confused by my "rhetoric. I learned to do what I needed, which brought me endless troubles and greatly hindered my development. I remember that when I was a child, my grades were excellent, but later I learned
Severe!
As a result, my secondary school scores declined over and over again, and I didn't take an exam in any good school. When I was a child friend, my grades were similar to mine, but I didn't have this shortcoming. She went to Tsinghua, later, I went to the United States for further study.
It is not a better way to study theoretical science under the mentor. In addition, my learning methods are constantly improving. In the past, I learned too much about the quantity and time. In this way, learning is both bitter and inefficient.
I pay great attention to the efficiency and skills of learning. This is the shortcut for learning (not opportunistic, of course). For example, if you want to learn a relatively unfamiliar technology, ask experienced people if you have the necessary skills, no need to ask
More often, his casual words will give you a lot of help, or even more than a week of books. Learning with this idea will save you a lot of time. How happy is it? I have learned a lot over the years.
Things are messy because they are very blind at the beginning. Now I think it sounds so ridiculous. I waste a lot of time on some knowledge that I don't need to know deeply, after all, a person's energy is
Limitation. Many of my friends, like me, are carrying five styles. It is indeed a good input method, but it is definitely not worth it for a developer, your time should be spent in valuable places. Something like me
I have also done a lot of work, and I have memorized CCed and WPS commands and shortcuts. After DBASE basically exited the stage of history, I spent a lot of time learning how to use it. Therefore, my study lacks planning in the early stage.
A clear short-term objective and medium-term objective have only one ethereal long-term ideal. This is just like designing. A good design involves many processes from requirement abstraction to code. If you cannot get the requirement, you can start coding immediately.
.

Of course, my studies and work have gained more or less over the years. Let me talk about some of my learning experiences. These methods may not be correct. I am constantly exploring and improving them. My Learning
XI and his work have relatively clear goals. I will not study a certain technology right away. I will consider a lot before the decision, including long-term development and personal route planning, the price and potential difficulties
Difficulties and solutions will be made clearer after the decision
Plan, including short-term, medium-term, and long-term resources available to you (including good books, materials, software and hardware environments, as well as experienced friends or teachers ), and how the transition from each stage to high
One-stage plan often goes smoothly in one learning stage, but it is usually difficult to perform different stages, such
Transfer basic knowledge to practice. In addition, I have my own methods to buy books. Currently, there are far fewer high-quality books than low-quality books in the world. For a strange technique, I often choose wrong when I buy a book for the first time, even if I buy one.
A good book, but its direction may not be suitable for you, so I usually first look for some introductions to this technology on the internet, with a little concept, I can buy another book that is relatively thin, relatively cheap, and with relatively extensive content. This is
The author is the best book written in China :). After reading it again, I will basically understand the key points of this technology. I will be more clear about buying books and making plans later.
. Otherwise, it is often difficult to find a good book at the beginning, and it is hard to learn it after I buy it. Sometimes I only find that it is a low-quality book or a relatively outdated technology. In addition, Let experienced people
It is usually a good choice.

Some of my friends want to learn communication and embedded development, but they always feel that they do not have a hardware or software environment.
Let's introduce how to establish such an environment. Of course, I only know how to study and work. Communication I made
It is a data network work, including TCP/IP, layer-2 and layer-3 switching, and has some knowledge about access networks, H.323, and SoftSwitch.
. These software and hardware environments can be built on PCs. You can even create a package on a PC without a network card.
A simulated network environment that includes multiple routers, access servers, VOIP gateways, network guard, hosts, and so on, and is quite similar to the actual network, of course, this requires you to have a clear network concept and a certain degree of network knowledge.
I am working hard to develop a set of software to simplify this process. Now that the experiment has been completed, I may integrate it into my operating system peripheral extension software.
. I can't use a simple statement to explain this method clearly. I can say that the general idea is on PC.
Implement a simulated NIC (anyone who knows how to implement the virtual Nic technology on a machine without a NIC in Windows should know
Then, Each simulated ENI corresponds to a virtual device, such as a router or host. You can also use third-party tools to complete some work, such as VMware. I am using a simulation Nic to do self
Developed by Alibaba Cloud. As for the embedded development environment, PC is a very large hardware platform, and the existing embedded operations
The operating system usually supports x86. You can perform development on it, boot through a floppy disk or use a virtual machine to load it. I tested it with VxWorks and ran Windows and
VxWorks systems. In addition, the DOS-compatible 16-bit simulation x86 environment on Windows also provides an excellent test environment for many operating systems.
Is implemented in this way. Linux is also widely used in embedded systems. It has a large amount of data on the Internet and is relatively easy to practice. At the same time, many complete embedded development environments support software simulation, such
Tornado, WinCE, etc.

Written at the end: this is a real and touching personal experience, and the lines between the lines are all fascinating. Maybe you have seen or
You are the embodiment of the hero in the article. I really think you are lucky and happy. I rarely published such "suspected" bumping articles. I accidentally opened the draft box when I opened my mailbox this morning,
I found it and looked at it for nearly a year. I don't want to talk about the origins of this article, but it is a real story. Hope to give courage to some people who are currently "confused"
For one direction, if you can really help them, the hero of this story will be very pleased!
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