Karl Benz automotive storage blockchain

1. Karl Friedrich Benz (November 25, 1844 - April 4, 1929), one of the founders of the famous German Daimler Benz Automobile Company and one of the pioneers of modern automobile instry, is known as "father of automobile" and "originator of automobile". Maybe it's the currency named after him!

2.

Carl? Born in Karlsruhe in western Germany, Benz studied in Karlsruhe until he graated from technical college

In 1864, Karl? After graating from school, Benz entered the Karlsruhe machinery factory. In 1866, he entered the vengiesel steam engine company in fulzheim. In 1871, Ritter invested in the construction hardware factory by using Benz's technology. However, Benz and Ritter, who made the engine, disagreed and decided to leave the factory and concentrate on studying the gas engine

In 1877, when he learned that the patent of Otto's four stroke engine had been approved, he switched to the research of two-stroke fixed engine, and completed the first prototype in 1878. In 1879, he built a practical engine. In 1882, he obtained the patent of battery ignition mode and governor. In 1882, he moved to Mannheim and founded Mannheim gas engine company. In 1883, he was hired to the company of Lodz and eslinger, and changed the company into Benz? Mannheim gas company. In 1884, the patent of Otto four stroke engine was suspended. In 1886, it soon obtained the patent of magnetic ignition four stroke gas engine. In 1885, Benz demonstrated the engine at the Antwerp World Expo in Belgium, and won praise. Since then, full of confidence, he refitted the gasoline engine and began to build cars

In the autumn of 1885, Benz successfully carried out the real vehicle test in Mannheim factory. The patent of tricycle was obtained on January 29, 1886, marking the birth of the first gasoline engine car in the world. In 1986, 100 years later, Mercedes? Mercedes Benz held a 100th anniversary celebration, inviting engineers and technicians from all over the world to gather to celebrate the centennial

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6.

driving route: the whole journey is about 40 meters

starting point: cruise center terminal

1. Starting from the starting point, drive 40 meters to the terminal

Terminal: cruise center terminal

7. 1、 Fill in the blanks
1, software system driver system 2, general file directory file, special file symbol link file
3, multi-user and multi task 4, operator range
5, batch real-time virtual asynchrony 6, current directory of root directory
7, command body operation option command parameter 8, external device
9 Mount MNT 10, root user-r root system administrator
11, file name subdirectory name and its pointer (inode number) 12, peripheral device (input / output) I / O
13, shell script user definition 14, user indicator
15, / dev / HDB 16, instruction translator
17, / user / bin 18, pipeline 19 6 20, three
21, NFS 22, samba 23, smbd 24, turn on / off server
25, $26, peripheral 27, system administrator

2. Term explanation
1. Lilo: Lilo (Linux loader), Lilo stands for Linux loader. Lilo is a program that runs at system startup and allows you to choose the operating system to boot your computer
2. Multiple file system: Linux system has a fixed hard disk drive to store the operating system and some user data. This file system is called root file system. At the same time, Linux also provides other removable auxiliary devices to store a large amount of data, with the help of the file system generated on each device to strengthen and simplify the huge file system. Because each auxiliary device has its own file system, they also have their own complete hierarchical file system structure with "root directory", and each file system is independent of each other. In Linux, other file systems can be "hung" on the root file system through mount instruction, making it a part of the root file system. When the file system is no longer used, it must be dismounted from the root file system by umount instruction
3. String of instructions: Linux allows users to combine multiple instructions together and logically regard them as a single instruction. The combination is implemented with braces or braces, and the two methods are different
1. Use braces "{}" to form a string of instructions. Use braces to enclose several instructions, followed by a semicolon ";", To indicate the end of the instruction
2. Use parentheses "()" to compose a string of instructions. The instructions enclosed in parentheses are restricted to be executed in the new child shell. After the completion of the sub shell composed of the instruction string, it will return to the situation before the execution of the sub shell. The instructions in the sub shell will not affect the original variables or change the original working directory
4. Shell script: shell script is a string of shell and operating system commands in a file, which can be reused. In essence, shell script is a simple combination of command line commands into a file. Shell is basically a command interpreter. It receives the user command and then calls the corresponding application.
5. Response:
6. RPM: RPM is the abbreviation of red hat package manager. Rpm is the installation and management program of software package developed by red hat company according to bogus (pmpms). Similar to the software such as uninstaller and CleanSweep on Windows platform, it is the management program for users to install and manage the application software package on Linux by themselves
7. Shell variable: a variable is the name of a storage unit in memory. When accessing a variable, it is like accessing the corresponding storage unit in memory. Shell variables are divided into environment variable and temporary variable
8. System call: all operating systems have some built-in functions in their kernel, which can be used to complete some system level functions. Such a function used by Linux system is called "system call". These functions represent a transformation from user space to kernel space. Each system call has a well-defined number, which is used to construct these system calls. The corresponding numbers and parameters of these system calls are sent to some registers when they are called. The number of a system call is actually a sequence number, indicating that it is in an array sys of the system_ call_ Symbolic links file: (symbolic links), which also has a file name, but its content is just a pointer to a file or directory. If you want to see its contents, you see the contents of the file or directory to which the pointer refers
10. TCP / IP: short for transmission control protocol / Internet protocol, which is also known as network communication protocol. It is the most basic protocol of Internet and the foundation of Internet. It consists of IP protocol of network layer and TCP protocol of transmission layer. TCP / IP defines how electronic devices connect to the Internet and how data is transmitted between them. The protocol adopts a four layer hierarchical structure, and each layer calls the network provided by its next layer to fulfill its own requirements. Generally speaking: TCP is responsible for finding the problem of transmission. When there is a problem, it will send out a signal to request retransmission until all data is safely and correctly transmitted to the destination. IP is an address for every computer on the Internet
11. Shell quotation marks: there are three kinds of shell quotation marks: single quotation mark, double quotation mark and inverted single quotation mark
single quotation mark: the data in it is completely regarded as a normal string, without any replacement.
double quotation mark: if the data in it has $and single quotation mark, it still retains the specific functions in the shell
inverted single quotation marks: use the instruction result to replace the string in it
12. Instruction substitution: in Linux, users are allowed to regard the standard output of an instruction as a string. Therefore, the instruction needs to be enclosed in inverted quotation marks. At this time, the shell executes the instruction first, and then replaces the instruction name string with the result of its standard output
13. PAM (pluggable authentication moles): PAM (pluggable authentication moles) is an authentication mechanism proposed by sun. By providing some dynamic link libraries and a set of unified API, it separates the service provided by the system from the authentication method of the service, so that the system administrator can flexibly configure different authentication methods for different services without changing the service program. At the same time, it is convenient to add new authentication methods to the system
14. Positional parameters: there are 10 positional parameters, which enable users to use arguments when executing shellscript. Its name is $0, $1, $2, $3, $4, $5, $6, $7, $8, $9. When an instruction is executed, the parameters following the instruction name are assigned to the corresponding positional parameters
15. TCP: transmission control protocol TCP is a connection oriented, reliable and byte stream based transport layer communication protocol. In the simplified computer network OSI model, it completes the functions specified by the fourth transport layer
16. DNS: a DNS server is a (domain name system or domain name service) domain name system or domain name service, which assigns domain name addresses and IP addresses to hosts on the Internet. When users use the domain name address, the system will automatically convert the domain name address to IP address. Domain name service is an internet tool to run domain name system. The server that performs domain name service is called DNS server, which answers the query of domain name service through DNS server
17. CSMA / CD: Carrier Sense Multiple Access / collision detection (CSMA / CD) is a carrier sense multiple access / collision detection method. In Ethernet, all nodes share the transmission medium. How to ensure that the transmission medium can provide transmission services for many nodes orderly and efficiently is the problem to be solved by the medium access control protocol of Ethernet< Http: Hypertext Transfer Protocol (HTTP) is the most widely used network protocol on the Internet. All www files must comply with this standard
19. Domain name: a domain name is the name of a computer or computer group on the Internet, which is composed of a series of names separated by dots. It is used to identify the electronic location of the computer (sometimes also referred to as the geographical location) ring data transmission< 3. Judgment ×× √√√ × √√√ ×× √√√ ×× √ × √ ××< 4. Question and answer
1 Describe ext3 file system of Linux
in ext2 format, each logical disk is divided into many blocks, and the number is very large. Each block is composed of 1024 units, and each unit is a byte
each byte holds a letter, a number or a symbol< br />2. The following is the file information using the $LS – l instruction. Please indicate:
in which part of the file system is the information saved? What is the significance of Indoc blocks<
"total 1 / DRW RW RW 1 Wang Wang 1565 OCT 24 12:40 cjbg"
total 1 means that there is only one file (namely cjig) in the folder (the upper directory of cjig)
/ D means that it is a directory, which means that the folder means
RW RW - means that all groups of permissions, that is, all the owners, members of the same group and other users have read and write permissions, but not execute permissions
1 indicates the number of inode nodes occupied by the file
Wang Wang indicates that the owner of the file (cjig) is Wang and its group is Wang
1565 indicates the file size
OCT 24 12:40, and the last modification time is OCT 24 12:40
cjig is the file name
3. Briefly describe the file users, operation permissions and permission changes of Linux operating system
1. There are three kinds of Linux operating system file users: owners, people in the same group, and other users
2. Permissions are divided into three groups: the first group is the permissions of the owner, the second group is the permissions of the same group, and the third group is the permissions of other users
each group consists of: r-readability; W-writable; X-executable, composed of three permissions. The X executable right of subdirectory means that the files in the directory can be used, that is, the CD can be transferred to the directory
the operation right or mode of the whole file can be represented by three octal numbers. This method is also called absolute mode
3. Chmod instruction is used to change the operation permission of one or a group of files
format 1: Chmod absolute mode file1 [File2] [file3]... - absolute mode
argument: absolute mode - that is, the operation permission is represented by a three digit octal number
filenames are separated by a space
format 2: Chmod symbolic mode file1 [File2] [file3]... -- symbol mode
argument: symbolic mode -- consists of three parts:
[who] OP permission
who -- user's identity: u-owner
g-with owner in the same group
o-other users
A-All of the users
op the act of operation:
+ - add one of permissions plus one right
- cancel one of permissions cancel one of permissions Interest
w-write right< br />x—

8. 1. False welding belongs to the problem of welding reliability, which may not be found completely by general visual inspection
it is suggested that a simple test fixture can be used for power on inspection
2. The phenomenon of unsound welding is a relatively abstract description
we need to continue to analyze the deep reasons, why it is not firm, empty welding, tin hole... Or other reasons
if the reason is clear, it can be checked by IPC general standard.

9. The actual frequency of ddd333 is 166MHz, the PC value is pc-2700, the single channel bandwidth is 2.7, the actual frequency of ddd400 is 200MHz, the PC value is pc-3200, the single channel bandwidth is 3.2
there is a gap between them, but it is not very big