Ethereum logo
At present, there are many channels for domestic users to buy Ethereum. Here are some common channels:
< H2 > 1. Coincola is an over-the-counter trading platform for indivials to trade bitcoincoy Cola is affiliated to Hong Kong coincola limited, which is developed and operated by a professional international team, focusing on providing convenient and reliable blockchain services for global users. Coincola gathers global users and is committed to building a world-class blockchain asset platform
in coy cola, people from different countries can buy bitcoin with their own currency. The seller of the website publishes the advertisement of selling bitcoin, and explains the payment method and exchange rate. You can choose to trade directly online according to the content of the advertisement. Bitcoin is stored in Ke Ying Cola's Internet wallet. You can transfer bitcoin directly
2. How to buy eth
register the coincola account, and then click "buy" in the top menu of the home page to enter the advertisement list page
select the appropriate advertisement from the advertisement list and click "buy eth" to enter the transaction page
enter the amount of money to be purchased or the number of digital currency (please understand the message information of the other party, payment method, and transaction instructions of the platform before entering), click buy now, and the order confirmation pop up. After checking and confirming the information, click confirm purchase to enter the order page
in the chat box of the platform, you can inquire whether the other party is online according to the template statement, and make offline payment according to the collection information and collection method provided by the other party
after the completion of offline payment, click the mark that the payment has been completed at the first time (please complete this operation within 15 minutes at the beginning of placing an order, so as to avoid the payment cannot be recovered e to the cancellation of the order e to overtime), and then customize the input information in the chat box to confirm the payment and ask the seller to confirm the collection and release the digital currency
the progress bar in the top column shows that the goods have been received, indicating that the digital currency has arrived in the wallet. Make comments according to the seller's behavior, and click submit to complete the transaction
with the rapid increase in the number of trading platforms and competitive pressure, many trading platforms will have their own C2C trading. Here we take the relatively large ZB trading platform as an example to illustrate
What is C2C
C2C transaction is a customer to customer transaction, which is guaranteed by the transaction platform. There are many such platforms, such as: Fire coin, otcbtc, bitpai OTC, etc., which are guaranteed by the platform and traded between users. We can simply understand it as: our shopping situation on Taobao is the same as that. In case of dispute, the platform will arbitrate. As long as the transaction is carried out according to the normal process, the security of the transaction is guaranteed
2. ZB's C2C business
ZB platform has two choices: QC and usdt. The basic logic is the same. There are many usdt platforms. QC is the feature of ZB, EXX and other platforms. Here we focus on QC
< H2 > about QCQC is a token. At present, you may know more about usdt and bitcny. At present, there is a special area for QC transaction on ZB. Simply put, QC can buy all other digital currencies (BTC, ETH, EOS, etc.) on ZB. Therefore, after purchasing QC with RMB recharge, you can conct currency transaction on ZB station
The advantage of the < H2 > QC token is that the exchange ratio between the < H2 > < UL >and RMB is 1:1, which is easier to convert
purchasing other tokens with QC can be directly understood as purchasing RMB, and has an intuitive understanding of the currency price
it takes about half an hour to get to the account. It will take about two hours to get to the account in congestion
ZB platform is relatively reliable, and the reputation of ZB is still very good in the past
How to operate C2C of ZB < UL >log in to ZB trading platform and click "C2C trading" on the page
to get to the QC transaction page, you need to first bind your bank card. Then, in the buy QC interface, enter the quantity of QC you want to buy. At present, the ratio of QC to RMB is 1:1. Enter the purchase quantity and click "buy now"
after clicking "buy now", you will be prompted to complete the payment within 30 minutes. At the same time, payment information is generated. Please note that the payment must be made according to the prompt
business processing time 9:00-21:00. Non processing time orders will be processed at 9:00 the next day, and the payment will be completed within 24 hours after receiving the order
this means that the merchant you paid will transfer QC coin to your account within 24 hours. According to my experience, you can get to the account in 2 hours ring the day
< H2 > the following points should be paid attention to:1) make sure to use the newly bound bank card for transfer and payment
2) note information (that 6 digit) must fill in
3) do not use Alipay, WeChat and other transfers. p>
4) do not fill in the opposite account incorrectly
< UL >about 1-2 hours, you can check whether your QC has arrived in the financial center
after the account is received, you can trade in the "QC" zone of the "spot trading". You can choose the transaction you want to buy and buy the order
what is Ethereum
Ethereum is often compared with bitcoin, but the situation is different. Bitcoin is a kind of cryptocurrency and distributed payment network, which allows bitcoin to be transferred between users
related: what is bitcoin? How does it work
Ethereum has a bigger goal. As Ethereum says, "Ethereum is a distributed platform running smart contracts.". These smart contracts run on "Ethereum virtual machine", a distributed computing network composed of all devices running Ethernet nodes
"distributed platform" means that anyone can set up and run an Ethereum node just as anyone can run a bitcoin node. Anyone who wants to run "smart contracts" on nodes must pay the operators of these nodes in ether, which is a cryptocurrency related to Ethereum. Therefore, the person running the Ethernet node provides computing power and gets paid in the Ethernet, which is similar to the way that the person running the bitcoin node provides hash power and pays in bitcoin
in other words, although bitcoin is only a blockchain and payment network, Ethereum is a distributed computing network, and its blockchain can be used for many other things. Details are provided in the Ethereum white paper
what is ether
Ethernet is a digital token (or cryptocurrency) related to Ethereum blockchain. In other words, Ethereum is the token and Ethereum is the platform. But now people often use these terms alternately. For example, coinbase allows you to buy Ethereum, which stands for Ethereum
this is technically "altcoin", which actually means a non bitcoin cryptocurrency. Like bitcoin, ether is supported by distributed blockchain - in this case, Ethereum blockchain
developers who want to create applications or Ethereum smart contracts on Ethereum blockchain need Ethernet token to pay for nodes to host it, while users of Ethereum based applications may need Ethernet to pay for services in these applications. People can also sell services outside the Ethereum network and accept Ethernet payments, or they can sell Ethernet tokens in cash - just like bitcoin
mahjong is the earliest application of blockchain in China:
the idea that a wants to play mahjong is equivalent to creating a block:
a calls to inform B, C and D, which means "decentralization & quot; Point to point transmission of
ABCD has formed a consensus that the touch action is "mining", and four people are "miners"
mahjong is a hash value. The Hu card is to hit the correct hash value and get the corresponding chip reward, which is called bitcoin
each of the four recorded the first round of the game. In the whole blockchain, this is only one node. If 20 mahjong games were played that day, that is, 20 nodes (blocks), and 20 blocks were connected together to form a complete ledger, that is blockchain< According to historical records, China is the world's earliest application group in blockchain, so you can be proud to say that China is more than 1000 years ahead of the world in blockchain application
it's powerful. Our country is [strong] [strong] [strong]
3 --- three slots
0 --- zero sub slot
1 --- one port
/ --- separator
一般购买的服务器都有4个网卡，这个时候在安装好服务器后，配置IP的时候就郁闷了
如是一个浪潮8560M2服务器安装Redhat后的网卡显示：
[root@DBSERVER51 ~]# ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:E0:ED:2D:0F:58
inet addr:192.168.4.10 Bcast:192.168.4.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:40428 errors:0 dropped:0 overruns:0 frame:0
TX packets:392 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3413500 (3.2 MiB) TX bytes:44521 (43.4 KiB)
Memory:faee0000-faf00000
eth1 Link encap:Ethernet HWaddr 00:E0:ED:2D:0F:59
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Memory:fae60000-fae80000
eth2 Link encap:Ethernet HWaddr 00:25:90:5A:15:B6
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Memory:fafe0000-fb000000
eth3 Link encap:Ethernet HWaddr 00:25:90:5A:15:B7
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Memory:faf60000-faf80000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:10 errors:0 dropped:0 overruns:0 frame:0
TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:660 (660.0 b) TX bytes:660 (660.0 b)
从一个机房搬下来时，忘记标记了这个时候还是想修改eth0作为通信口但是一个一个插拔比较麻烦，于是就想能不能有个好办法，毕竟Linux不像Windows那样直观，打开网络连接就可以看到这个时候就要用到ethtool这样一个命令，命令详解如下：
命令描述：
ethtool 是用于查询及设置网卡参数的命令
ethX是以太网卡的名称，Linux系统将检测到的第一块以太网卡命名为eth0, 第二块为eth1,…….
使用概要：
ethtool ethx //查询ethx网口基本设置，其中 x 是对应网卡的编号，如eth0、eth1等等
ethtool –h //显示ethtool的命令帮助(help)
ethtool –i ethX //查询ethX网口的相关信息
ethtool –d ethX //查询ethX网口注册性信息
ethtool –r ethX //重置ethX网口到自适应模式
ethtool –S ethX //查询ethX网口收发包统计
ethtool –s ethX [speed 10|100|1000] [plex half|full] [autoneg on|off] //设置网口速率10/100/1000M、设置网口半/全双工、设置网口是否自协商
ethtool [ -a | -c | -g | -i | -d | -k | -r | -S |] ethX
ethtool [-A] ethX [autoneg on|off] [rx on|off] [tx on|off]
ethtool [-C] ethX [adaptive-rx on|off] [adaptive-tx on|off] [rx-usecs N] [rx-frames N] [rx-usecs-irq N] [rx-frames-irq N] [tx-usecs N] [tx-frames N] [tx-usecs-irq N] [tx-frames-irq N] [stats-block-usecs N][pkt-rate-low N][rx-usecs-low N] [rx-frames-low N] [tx-usecs-low N] [tx-frames-lowN] [pkt-rate-high N] [rx-usecs-high N] [rx-frames-high N] [tx-usecs-high N] [tx-frames-high N] [sample-interval N]
ethtool [-G] ethX [rx N] [rx-mini N] [rx-jumbo N] [tx N]
ethtool [-e] ethX [raw on|off] [offset N] [length N]
ethtool [-E] ethX [magic N] [offset N] [value N]
ethtool [-K] ethX [rx on|off] [tx on|off] [sg on|off] [tso on|off]
ethtool [-p] ethX [N]
ethtool [-t] ethX [offline|online]
ethtool [-s] ethX [speed 10|100|1000] [plex half|full] [autoneg on|off] [port tp|aui|bnc|mii] [phyad N] [xcvr internal|external]
[wol p|u|m|b|a|g|s|d...] [sopass xx:yy:zz:aa:bb:cc] [msglvl N]
标志
-a 查看网卡中 接收模块RX、发送模块TX和Autonegotiate模块的状态：启动on 或 停用off
-A 修改网卡中 接收模块RX、发送模块TX和Autonegotiate模块的状态：启动on 或 停用off
-c display the Coalesce information of the specified ethernet card
-C Change the Coalesce setting of the specified ethernet card
-g Display the rx/tx ring parameter information of the specified ethernet card
-G change the rx/tx ring setting of the specified ethernet card
-i 显示网卡驱动的信息，如驱动的名称、版本等
-d 显示register mp信息, 部分网卡驱动不支持该选项
-e 显示EEPROM mp信息，部分网卡驱动不支持该选项
-E 修改网卡EEPROM byte
-k 显示网卡Offload参数的状态：on 或 off，包括rx-checksumming、tx-checksumming等
-K 修改网卡Offload参数的状态
-p 用于区别不同ethX对应网卡的物理位置，常用的方法是使网卡port上的led不断的闪N指示了网卡闪的持续时间，以秒为单位
-r 如果auto-negotiation模块的状态为on，则restarts auto-negotiation
-S 显示NIC- and driver-specific 的统计参数，如网卡接收/发送的字节数、接收/发送的广播包个数等
-t 让网卡执行自我检测，有两种模式：offline or online
-s 修改网卡的部分配置，包括网卡速度、单工/全双工模式、mac地址等
Modify / etc / udev / rules.d/70-persistent-net.rules
comment or delete the line eth0, which records the MAC address when the system was cloned, but the MAC of the newly started system has been changed, and the name = & quot; eth1" Change it to "eth0", the MAC address marked by attr. This is the MAC assigned by the virtual machine for the virtual network card. Replace the MAC in / etc / sysconfig / network scripts / ifcfg-eth0 with the above MAC
and then restart it
another way is to use eth1 instead of eth0, Copy / etc / sysconfig / network scripts / ifcfg-eth0 into / etc / sysconfig / network scripts / ifcfg-eth1
3. Modify the network card configuration of the machine
VI / etc / sysconfig / network scripts / ifcfg-eth0
you can use the graphical interface to install and configure the network
# install setuptool
Yum install setuptool
# you can find that the setup is incomplete, and then install another firewall for system service management
Yum install ntsysv
# and then install a firewall, as well as the supporting firewall settings in setup Network settings
Yum install iptables
? Install firewall settings in setup
Yum install system config securitylevel Tui
? Install network settings in setup
Yum install system config network Tui
don't forget to use service network restart
4 Modify the host name
VI / etc / sysconfig / network
attach the ifcfg-eth0 file that is easy to use in the virtual machine:
device = & quot; eth0"< br />NM_ CONTROLLED=" yes"< br />ONBOOT=" yes"< br />IPADDR=192.168.9.202
NETMASK=255.255.255.0
BOOTPROTO=yes
TYPE=" Ethernet"< br />UUID=" 4874beeb-8c63-4b56-96f2-d78de825ceb2"< br />PREFIX=24
DEFROUTE=yes
IPV4_ FAILURE_ FATAL=yes
IPV6INIT=no
NAME=" System eth0"< br />HWADDR=00:0C:29:80:64:30
LAST_ CONNECT=1355405012
GATEWAY=192.168.9.2
DNS1=8.8.8.8
USERCTL=no
explanation of environment variables
bootdelay
defines the number of seconds to wait for automatic startup
baudrate
defines the baud rate of serial console
netmask
defines the mask of Ethernet interface
ethaddr
defines the MAC address of Ethernet interface
bootfile
defines the default download file
bootargs
define the command line parameters passed to the Linux kernel
bootcmd
define several commands to be executed ring automatic startup
ServerIP
define the IP address of TFTP server
IPADDR
define the local IP address
stdin
define the standard input device, generally the serial port
stdout
define the standard output device, Generally, the serial port
stderr
defines the standard error information output device. Generally, the serial port
refers to u-boot, and its environment variables are set as follows:
uboot & gt; printenv
bootdelay=3
baudrate=115200
ethaddr=00:12:34:56:78:9a
ipaddr=192.168.0.9 ①
serverip=192.168.0.1 ②
netmask=255.255.255.0
rootpath=/home/zht/rfsys ③
stdin=serial
stdout=serial
stderr=serial
bootcmd=tftp 21000000 uImage; Bootm 21000000 ④
bootargs = root = / dev / NFS RW nfsroot = 192.168.0.1 / home / zht / rfsys nfsaddrs = 192.168.0.48:192.168.0.1:192.168.0.1:255.255.0 console = ttys0115200 MEM = 32m ⑤
① set IP address of target board
② set IP address of server
③ set path of root file system on server, Note that the path must be set to the NFS directory on the server
④ bootcmd is the command executed after u-boot is started, and the commands are separated by semicolons
TFTP 21000000 uimage means that the kernel image is downloaded to ram through TFTP, and the address is 0x21000000
bootm 21000000 starts the Linux operating system
⑤ defines the command line parameters that u-boot transmits to the Linux kernel. The command line specifies the network file system as the root file system
where root = / dev / NFS is not a real device, but a flag telling the kernel to get the root file system through the network
parameter nfsroot tells the kernel which machine, directory and network file system options to use as the root file system. The format of the parameter is as follows:
nfsroot = [:] [,]
if the nfsroot parameter is not given on the instruction line, the default value of '/ tftpboot /% s' will be used. Other options are as follows:
-- specify the IP address of the network file system server. If this field is not given, the value determined by the nfsaddrs variable (see below) is used. One of the purposes of this parameter is to allow different machines to be used as reverse address resolution protocol (RARP) and network file system servers. Usually you can leave it alone
-- the name of the directory to be hung as the root on the server. If there is a token in the string, it will be replaced by the ASCII representation of the client's Internet address
-- standard network file system options. All options are separated by commas. If this option field is not given, the following default values are used:
port = as given by server portmap daemon
rsize = 1024
wsize = 1024
Timeo = 7
retrans = 3
acregmin = 3
acregmax = 60
AC Dirmin = 30
acdirmax = 60
flags = hard, nointr, noposix, CTO, AC
parameter nfsaddrs sets various network interface addresses required for network communication. If this parameter is not given, the kernel will try to use the reverse address resolution protocol and / or BOOTP to find these parameters. The format is as follows:
nfsaddrs =:
-- the Internet address of the client. If not, this address will be determined by the reverse address resolution protocol or boot protocol. Which protocol to use depends on the options and parameters opened when configuring the core. If this parameter is set, the reverse address resolution protocol or boot protocol will not be used
-- the Internet address of the network file system server. If the reverse address resolution protocol is used to determine the client address and this parameter is set, only the response from the specified server will be accepted. To use different machines as reverse address resolution and network file system server, specify your reverse address resolution protocol server here (keep blank) and specify your network file system server in nfsroot parameter (see above). If this item is blank, use the address of the server that answers the reverse address resolution protocol or boot protocol
-- the Internet address of the gateway, if the server is on a different subnet. If this item is blank, no gateway is used and the server is assumed to be on the local network unless the value is received by the boot protocol
-- the network mask of the local network interface. If it is blank, the netmask is derived from the Internet address of the client, unless a value is received by the boot protocol
-- the name of the client. If it is blank, the ASCII notation of the client's Internet address or the value received by the boot protocol is used
-- the name of the network device to be used. If it is blank, all devices will be used to issue reverse address resolution requests, and the start protocol request will be issued by the first device found. A network file system uses a device that receives a response from a reverse address resolution protocol or boot protocol. If you have only one device, you can ignore it
-- used as an automatic configuration method. If it is ` RARP & #39; Or ` BOOTP & 39; The indicated protocol is used. If this value is ` both & # 39; Or blank, if both protocols are opened when configuring the core` none' Indicates that automatic configuration is not used. In this case, you must specify all the necessary values in the preceding fields
this parameter can be used alone as a parameter of nfsaddrs (there is no ':' character in front of it). In this case, automatic configuration will be used. However, you cannot use ` none & # 39 in this case; As the value
note: This is just a saying on the Internet, but it doesn't start. Because my kernel doesn't have cs8900 NIC driver, it can start normally after burning, but it can't mount NFS. I wonder if I can set the address parameters passed by uboot to the kernel through command line parameter setting, so as to indirectly drive the NFS service. I've done this through vivi before, and it's feasible
it can be understood that the previous kernel kernel has already configured the drivers of each basic mole, so that it can be used
the capacity of a buffer is the number of elements it contains. The size of the buffer cannot be negative and cannot be changed
the buffer limit is the index of the first element that should not be read or written. The buffer limit cannot be negative and cannot be greater than its capacity
the location of the buffer is the index of the next element to read or write. The location of the buffer cannot be negative and cannot be greater than its limit
no insert or read can exceed the limit
tag, location, limit and capacity values follow the following invariants:
0 & lt= Mark & lt= Location & lt= Restrictions & lt= Capacity
a newly created buffer always has a 0 position and an undefined tag. The initial limit can be 0 or some other value, depending on the buffer type and how it was built. In general, the initial content of the buffer is undefined
clear() prepares the buffer for a series of new channel read or relative place operations: it sets the limit to capacity and the position to 0<
channel read refers to reading data into the buffer from the channel, and relative placement refers to inserting data into the buffer from the position
flip() prepares the buffer for a series of new channel write or relative acquisition operations: it sets the limit to the current position, and then sets the position to 0
setting the limit to the current location is to ensure the reliability of the data. The data written from the buffer to the channel is the data that already exists in the buffer
rewind() prepares the buffer for rereading the contained data: it keeps the limit unchanged and sets the position to 0
similar to clear(), but without changing the restriction
these three methods do not make any changes to the buffer data in the source code