How to get to Jining coal mine staff training center
Publish: 2021-04-25 07:31:36
1. On Jingqi Road, you can take a bus to Anshan cable group
2. It's not easy to study now
3. Cats make money.
4. The company is legal
5. Hello,
that's fake. Now I don't know who Nakamoto is. Don't read the Internet. Thank you
that's fake. Now I don't know who Nakamoto is. Don't read the Internet. Thank you
6. People's daily news on May 4, according to comprehensive media reports, recently, a bitcoin blackmail virus named "CTB Locker" has exploded. The virus extorts ransom from users by remotely encrypting their computer files. Users' files can only be opened after paying ransom. According to foreign media reports, the originator of the virus is Russian hacker bogchev, the FBI's most wanted reward for cyber criminals, and has not yet been brought to justice.
7. LAN composition
1. Features of LAN:
small distribution range, less investment, simple configuration, etc., with the following features:
1. High transmission rate: generally 1Mbps -- 20MBps, optical fiber high-speed network up to 100Mbps, 1000Mbps
2. Support a variety of transmission media
3. Communication processing is usually completed by network card
4. Good transmission quality and low bit error rate
5. Regular topology< Second, the composition of LAN:
LAN is generally composed of server, user workstation and transmission medium
1. Server:
running network 0s, providing hard disk, file data and printer sharing services, is the core of network control
from the application point of view, more than 486 compatible computers with higher configuration can be used as file servers, but in order to improve the overall performance of the network, especially the system stability of the network, it is better to choose a dedicated server
at present, there are three common NOS: Netware, UNIX and windows NT<
Netware:
popular versions v3.12, v4.11 and V5.0 have low hardware requirements, similar application environment to DOS, perfect technology, reliable support for a variety of workstations and protocols, suitable for LAN operating system, and good performance as file server and print server
UNIX:
a typical 32-bit multi-user NOS is mainly used in super minicomputers and mainframes. At present, the commonly used version is UNIX sur4.0. Support network file system services, provide data applications, powerful, difficult to master, complex commands, launched by at & T and SCO companies
Windows NT Server 4.0:
a complete platform system for distributed graphics applications, with interface similar to Win95, easy to install and manage, and integrated with internet network management tools, has a broad prospect
servers are divided into file servers, print servers, database servers, web servers, FTP servers, e-mail servers, etc
Network 0s is developing towards supporting a variety of communication protocols, network cards and workstations< 2. Workstation: it can have its own 0s and work independently; By running workstation network software, access to server shared resources, common DOS workstation, Windows 95 workstation< Network card: connect the workstation server to the network, realize resource sharing and mutual communication, data conversion and electrical signal matching< (1) speed: 10Mbps, 100Mbps
(2) bus type: ISA / PCI
(3) transmission medium interface:
single port: BNC (thin cable) or RJ-45 (twisted pair)
4. Transmission medium: Twisted pair, coaxial cable, optical fiber, etc<
(1) twisted pair (TP):
more than one pair of twisted pair is encapsulated in an insulating jacket, and each pair is twisted to rece interference. UTP can be divided into unshielded twisted pair (UTP) and shielded twisted pair (STP). UTP in LAN can be divided into three categories, four categories, five categories and super five categories
take amp company as an example:
Category 3: 10Mbps, thin skin, Cat3 on the skin, category 3 on the box, 305m / box, 400 yuan / box
category 4: few used in network
category 5: (super category 5) 100Mbps, 10Mbps, thick skin, dense turns, CAT5 on the skin, category 5 on the box, 305m / box, 600-700 yuan / box (each 100m, connected with 4 repeaters, Maximum 500m)
wiring sequence: normal: white orange white green blue white blue white green white brown
12345678
Jilian: white green white orange brown white brown orange white blue
12345678
STP: same as UTP, outsourcing aluminum foil, STP twisted pair is required for network procts of apple and IBM, with high speed and high price<
(2) coaxial cable:
consists of a hollow outer cylindrical conctor and an inner conctor located on the central axis, and the two conctors are separated by insulating materials
according to the diameter, it can be divided into thick cable and thin cable
thick cable: long transmission distance, high performance, but high cost. It is used in large LAN trunk lines and requires terminators at both ends
a. the thick cable is connected to the external transceiver
B. the transceiver and network card are connected by AUI cable
C. the network card must have AUI interface: each 500m segment, 100 users, 4 repeaters up to 2500m, minimum 2.5m between transceivers, maximum 50m of transceiver cable
thin cable: short transmission distance, relatively cheap, T-shaped head, connected with BNC network card, with 50 ohm terminal resistor installed at both ends
each segment is 185m, with 4 repeaters, the maximum is 925m, each segment has 30 users, and the minimum is 0.5m between T-heads. According to the transmission band, it is divided into baseband and broadband transmission
baseband: digital signal, which takes up the whole channel and can transmit one signal at the same time
broadband: it transmits signals of different frequencies< Optical fiber:
(3) optical fiber:
based on the optical principle, the optical transmitter generates a light beam, changes the electrical signal into an optical signal, and then leads the optical signal into the optical fiber. At the other end, the optical receiver receives the optical signal from the optical fiber, and converts it into an electrical signal, which is decoded and then processed. It is divided into single-mode fiber and multi-mode fiber. The insulation has good confidentiality
single mode fiber: it uses laser as light source, has only one optical path, and has long transmission distance, more than 2km
multimode fiber: LED, low speed, short distance, within 2km< 3. Computer network software system:
4. Several working modes of LAN:
1. Special server structure: (server base)
also known as "workstation / file server" structure, which consists of several computer workstations and one or more file servers connected by communication lines to access server files, Shared storage devices
file servers naturally share disk files. It is enough for general data transmission, but when the database system and other complex application systems used by increasing users come, the server can no longer undertake such a task, because with the increase of users, there are more programs serving each user, and each program is a large file running independently, which makes users feel very slow, Therefore, the client / server mode is proced< 2. Client / Server Mode: (client / server)
one or several large computers centralize the management and access of the shared database, which is called server, while other application processing work is distributed to other computers in the network to form a distributed processing system, The ability of server to control and manage data has risen from file management to database management. Therefore, the server of C / S is also called database server. It focuses on data definition and access security, backup and restore, concurrency control and transaction management, and performs database management functions such as selective search and index sorting, It has enough ability to transfer the part of data that the user needs after processing, rather than the whole file, to the client through the network, which reces the transmission load of the network. C / S structure is the result of the combination of the development and universal application of database technology and the development of LAN technology< (peer to peer)
the topology of peer-to-peer network is the same as that of dedicated server and C / s. In the peer-to-peer network structure, there is no dedicated server, and each workstation can act as either a client or a server.
1. Features of LAN:
small distribution range, less investment, simple configuration, etc., with the following features:
1. High transmission rate: generally 1Mbps -- 20MBps, optical fiber high-speed network up to 100Mbps, 1000Mbps
2. Support a variety of transmission media
3. Communication processing is usually completed by network card
4. Good transmission quality and low bit error rate
5. Regular topology< Second, the composition of LAN:
LAN is generally composed of server, user workstation and transmission medium
1. Server:
running network 0s, providing hard disk, file data and printer sharing services, is the core of network control
from the application point of view, more than 486 compatible computers with higher configuration can be used as file servers, but in order to improve the overall performance of the network, especially the system stability of the network, it is better to choose a dedicated server
at present, there are three common NOS: Netware, UNIX and windows NT<
Netware:
popular versions v3.12, v4.11 and V5.0 have low hardware requirements, similar application environment to DOS, perfect technology, reliable support for a variety of workstations and protocols, suitable for LAN operating system, and good performance as file server and print server
UNIX:
a typical 32-bit multi-user NOS is mainly used in super minicomputers and mainframes. At present, the commonly used version is UNIX sur4.0. Support network file system services, provide data applications, powerful, difficult to master, complex commands, launched by at & T and SCO companies
Windows NT Server 4.0:
a complete platform system for distributed graphics applications, with interface similar to Win95, easy to install and manage, and integrated with internet network management tools, has a broad prospect
servers are divided into file servers, print servers, database servers, web servers, FTP servers, e-mail servers, etc
Network 0s is developing towards supporting a variety of communication protocols, network cards and workstations< 2. Workstation: it can have its own 0s and work independently; By running workstation network software, access to server shared resources, common DOS workstation, Windows 95 workstation< Network card: connect the workstation server to the network, realize resource sharing and mutual communication, data conversion and electrical signal matching< (1) speed: 10Mbps, 100Mbps
(2) bus type: ISA / PCI
(3) transmission medium interface:
single port: BNC (thin cable) or RJ-45 (twisted pair)
4. Transmission medium: Twisted pair, coaxial cable, optical fiber, etc<
(1) twisted pair (TP):
more than one pair of twisted pair is encapsulated in an insulating jacket, and each pair is twisted to rece interference. UTP can be divided into unshielded twisted pair (UTP) and shielded twisted pair (STP). UTP in LAN can be divided into three categories, four categories, five categories and super five categories
take amp company as an example:
Category 3: 10Mbps, thin skin, Cat3 on the skin, category 3 on the box, 305m / box, 400 yuan / box
category 4: few used in network
category 5: (super category 5) 100Mbps, 10Mbps, thick skin, dense turns, CAT5 on the skin, category 5 on the box, 305m / box, 600-700 yuan / box (each 100m, connected with 4 repeaters, Maximum 500m)
wiring sequence: normal: white orange white green blue white blue white green white brown
12345678
Jilian: white green white orange brown white brown orange white blue
12345678
STP: same as UTP, outsourcing aluminum foil, STP twisted pair is required for network procts of apple and IBM, with high speed and high price<
(2) coaxial cable:
consists of a hollow outer cylindrical conctor and an inner conctor located on the central axis, and the two conctors are separated by insulating materials
according to the diameter, it can be divided into thick cable and thin cable
thick cable: long transmission distance, high performance, but high cost. It is used in large LAN trunk lines and requires terminators at both ends
a. the thick cable is connected to the external transceiver
B. the transceiver and network card are connected by AUI cable
C. the network card must have AUI interface: each 500m segment, 100 users, 4 repeaters up to 2500m, minimum 2.5m between transceivers, maximum 50m of transceiver cable
thin cable: short transmission distance, relatively cheap, T-shaped head, connected with BNC network card, with 50 ohm terminal resistor installed at both ends
each segment is 185m, with 4 repeaters, the maximum is 925m, each segment has 30 users, and the minimum is 0.5m between T-heads. According to the transmission band, it is divided into baseband and broadband transmission
baseband: digital signal, which takes up the whole channel and can transmit one signal at the same time
broadband: it transmits signals of different frequencies< Optical fiber:
(3) optical fiber:
based on the optical principle, the optical transmitter generates a light beam, changes the electrical signal into an optical signal, and then leads the optical signal into the optical fiber. At the other end, the optical receiver receives the optical signal from the optical fiber, and converts it into an electrical signal, which is decoded and then processed. It is divided into single-mode fiber and multi-mode fiber. The insulation has good confidentiality
single mode fiber: it uses laser as light source, has only one optical path, and has long transmission distance, more than 2km
multimode fiber: LED, low speed, short distance, within 2km< 3. Computer network software system:
4. Several working modes of LAN:
1. Special server structure: (server base)
also known as "workstation / file server" structure, which consists of several computer workstations and one or more file servers connected by communication lines to access server files, Shared storage devices
file servers naturally share disk files. It is enough for general data transmission, but when the database system and other complex application systems used by increasing users come, the server can no longer undertake such a task, because with the increase of users, there are more programs serving each user, and each program is a large file running independently, which makes users feel very slow, Therefore, the client / server mode is proced< 2. Client / Server Mode: (client / server)
one or several large computers centralize the management and access of the shared database, which is called server, while other application processing work is distributed to other computers in the network to form a distributed processing system, The ability of server to control and manage data has risen from file management to database management. Therefore, the server of C / S is also called database server. It focuses on data definition and access security, backup and restore, concurrency control and transaction management, and performs database management functions such as selective search and index sorting, It has enough ability to transfer the part of data that the user needs after processing, rather than the whole file, to the client through the network, which reces the transmission load of the network. C / S structure is the result of the combination of the development and universal application of database technology and the development of LAN technology< (peer to peer)
the topology of peer-to-peer network is the same as that of dedicated server and C / s. In the peer-to-peer network structure, there is no dedicated server, and each workstation can act as either a client or a server.
8. Depending on the nature of your server, the third one is not very cost-effective, but its stability and performance are good
the second one is that the speed of gigabit network card LAN will be better, and the cost performance is good
if you consider using the second solution for small LAN, but in the long run or if it is not bad, you can choose the third one
the second one is that the speed of gigabit network card LAN will be better, and the cost performance is good
if you consider using the second solution for small LAN, but in the long run or if it is not bad, you can choose the third one
9. Money, as a general equivalent, is the proct of the long-term development of commodity proction and exchange. A common misconception is that the meaning of money is limited to currency - notes and coins. From its basic meaning, money is not a specific thing or material, it has various forms
cash refers to the medium of exchange that can be put into circulation immediately. It is generally acceptable and can be used to purchase goods, goods, services or repay debts immediately
(the scope of use of cash is also attached: 1. 2. To pay employees' pension, funeral allowance, various labor insurance and welfare, and other personal expenses stipulated by the state. 3. Pay for personal services. 4. All kinds of prizes for science and technology, culture and art, sports, etc. given to indivials in accordance with state regulations. 5. Pay the price of purchasing agricultural and sideline procts and other materials from indivials. 6. Travel expenses that must be carried by the person on a business trip. 7. Sporadic expenses below the settlement starting point (1000 yuan). 8. Other expenses determined by the people's Bank of China to be paid in cash.)
cash refers to the medium of exchange that can be put into circulation immediately. It is generally acceptable and can be used to purchase goods, goods, services or repay debts immediately
(the scope of use of cash is also attached: 1. 2. To pay employees' pension, funeral allowance, various labor insurance and welfare, and other personal expenses stipulated by the state. 3. Pay for personal services. 4. All kinds of prizes for science and technology, culture and art, sports, etc. given to indivials in accordance with state regulations. 5. Pay the price of purchasing agricultural and sideline procts and other materials from indivials. 6. Travel expenses that must be carried by the person on a business trip. 7. Sporadic expenses below the settlement starting point (1000 yuan). 8. Other expenses determined by the people's Bank of China to be paid in cash.)
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