Okcoin digital currency trading platform
1. Bithumb
bithumb is the largest digital currency exchange in South Korea and the top ten in the world in terms of trading volume. Its daily trading volume exceeds 13000 bitcoins, accounting for about 10% of global bitcoin trading volume. It promises to provide the lowest handling charge in the world. Bithumb accounts for 75.7% of South Korea's bitcoin market, 10% of the global bitcoin market, and 50% of South Korea's Ethereum market
Bitmex is established in the Republic of Seychelles as a leading leverage trading platform. It can operate cryptocurrency derivatives trading as high as 100 times leverage, and also provide high leverage for other digital currency procts. Bitmex offers more than a dozen futures and swap procts. Bitcoin is one of the most active trading varieties, which can be divided into three types: xbtz17 (bitcoin / USD futures), xbjz17 (bitcoin / yen futures) and xbtusd (bitcoin / USD perpetual swap)
to register a bitmex account, just fill in the email, password and country. The name can be left blank. Bitmex does not accept the recharge and withdrawal of legal currency, so it does not have to follow the bank's KYC / AML requirements to obtain the user's personal information
Okex
3, okex
okex mainly provides global users with spot and derivative trading services of digital assets such as bitcoin, lightcoin and ethereal currency, which is subordinate to okex Technology Company Limited. Since 2014, we have been committed to providing bitcoin, lightcoin, ethercoin and other digital asset currency and derivatives trading services to global users, adopting advanced technologies such as GSLB, distributed server cluster, distributed storage, high-speed memory trading engine with multi machine mutual backup, cold wallet, hot money package with private key offline, etc
As one of the most concerned companies in the international blockchain instry, Qian'an is jointly founded by Zhao CHANGPENG, former blockchain CTO, a well-known blockchain company, and He Yi, former vice president of science and technology, to provide users with more secure and convenient digital currency exchange services and aggregate global high-quality digital currencies, It is committed to building a world-class blockchain asset trading platform. Only 50 days after its launch, the company's users have covered more than 180 countries around the world. This is the first time that the company has disclosed its financing information
5. Hotcoin is one of the three major exchanges in China. Headquartered in Beijing, it also has many exchanges, including domestic stations, international stations, quantitative trading, etc. hotcoin is a domestic station. Since its establishment in 2013, the accumulated trading volume of hotcoin has exceeded $100 billion, once becoming the largest digital asset trading platform in the world, It occupies 50% of the global share of digital asset transactions, and has been invested by Zhenge fund and Sequoia Capital
fire coin group has invested in more than 10 upstream and downstream enterprises, and has completed the establishment of compliance service teams in Singapore, South Korea, Hong Kong, Thailand, Australia, Canada, Brazil, Britain and other countries and regions, providing secure and reliable digital asset trading and asset management services for millions of users in more than 130 countries
6, bibox
bibox is the world's first artificial intelligence digital asset trading platform, which innovatively realizes transaction security, platform stability and operation convenience; Financial derivatives services are well-known in the instry. The platform not only provides spot trading, but also provides financing, currency financing and contract trading business. Investors can carry out long short two-way operation. They can obtain the income from the rise in the price of digital assets by buying long and obtain the income from the fall in the price of digital assets by selling short, which is convenient for traders to invest and hedge
Hitbtc
7, hitbtc
hitbtc was established in 2013 and obtained 6 million euro venture capital. Headquartered in Europe, it is a bitcoin trading platform in the UK, supporting the current mainstream encrypted digital currency portfolio trading, including BCC / BTC, ETH / BTC, XmR / BTC, LTC / BTC, EOS / BTC, EOS / eth, etc. at present, there are 762 trading pairs. Hitbtc is operated by hit Solutions Limited in Hong Kong and has a dedicated support and communications office in Santiago, Chile
Digifinex
digifinex is a block chain Digital Asset Exchange registered in Seychelles, which mainly provides currency trading services of bitcoin, Ethereum, lightcoin and other digital assets for global users. According to non trumpet data, there are 103 platform trading pairs at present. Digifinex is founded by blockchain and digital asset enthusiasts, with core teams from Xunlei, Tencent and Internet. It is operated by digifnex limited, which is registered in Seychelles, and its current operation center is located in Singapore
ZB network is a global digital currency exchange. Currently, there are 168 platform trading pairs, which support OTC and spot trading. At present, it has obtained the exchange license of Thailand and Du, and has set up operation centers in Switzerland, Canada, the United States, Bangkok, Du and other places. ZB focuses on providing global customers with safe, convenient and compliant blockchain asset trading services
10, coin win international station
coin win is a global digital asset trading platform set up by Chinese state-owned enterprises in Hong Kong. It adopts bank level security technologies such as cold storage, SSL and multiple encryption to ensure the security and stability of virtual currency transactions. It mainly provides transaction services of digital assets such as ether currency and HSR for global users, and is subordinate to citicash Hong Kong Investment Limited. Currently, there are 51 platform trading pairs, which support OTC and spot trading
moreover, the above contracts are based on the index, so the cost of bursting positions is high. It's not like okex is a dog farm, forced to explode.
According to several okex and okcoin users, their accounts were stolen, with losses ranging from tens of thousands to millions. According to preliminary statistics, nearly 10 users have reported losing about 600 bitcoins, worth about 20 million yuan
On September 1, some users said that they had 468 okcoin accounts, only 125 of them were left, 343 less. The user said that there is no need for any password or verification to transfer the okcoin contract account to the spot account. The developed currency to currency transaction has no depth at all and is easy to be used by the number stealing personnel. Okcoin does not provide corresponding protectionon September 16, another user transferred 30 BCC tokens stored in okex to okcoin, and on September 23, the account was invaded again, buying and selling between bitcoin, Leyte, Ethereum and RMB for many times, exhausting 30 BCCs and 27 bitcoins, trading nearly 1000 pieces in two hours, and the abnormal IP addresses were Russia and the Netherlands
"if the virtual currency property is changed into legal currency for cash withdrawal, the account is required to have real name authentication, so it is necessary to withdraw the profit in one stroke by knocking or exploding the position." Liu Chaoqun thinks that several problems of okex platform include: there is basically no trading volume of currency trading at ordinary times, and the trading volume suddenly increases a hundred times, so the platform does not do any risk control on this; There is no email or SMS verification for remote login; After the remote login reminder, immediately contact the platform, and the platform does not respond at the first time; The withdrawal speed of profit account is obviously abnormal, much higher than the normal speed
how is this achieved
our ancestors watched the stars shine, but it took ten thousand years to figure out the laws of celestial bodies
our predecessors sat and watched the tide level, but it took thousands of generations to sail to the other side of the ocean
however, we are still ignorant of the earth under our feet
it is almost the whole logic of the history of human science from observation and record to law prediction
but every time we try our best to write down the data, it is just a trickle of knowledge
when we begin to calculate, we are looking forward to the moment when Archimedes jumps out of the bathtub and Newton raises the apple
Dr. Wang Weitao is the author of this calculation. He is from the Seismological Bureau of China. What he wants to know is every detail of the earth under our feet< Every earthquake we experience reminds us of the urgency of forecasting and warning this kind of disaster. However, we are still far away from this goal
in order to better understand the physical phenomenon of earthquake, we need extremely detailed crustal structure image, and in order to draw this underground map, we need detailed data calculation. So far, the deepest well drilled by human beings is the Kela ultra deep well drilled by the former Soviet Union, which is about 12.2km. However, the focal depth of earthquakes is often more than ten to dozens of kilometers underground. The current science and technology can not directly observe the focal depth
therefore, we need to rely on thousands of seismic stations distributed throughout the country to detect seismic waves. The propagation characteristics of seismic waves underground are affected by geological structure, which is also the principle that seismic waves can be used to draw underground images. These seismic stations can sense the "big seismic waves" of earthquakes, and also capture the daily "earth noise", such as the vibration of ocean tides hitting the mainland< According to the principle of underground imaging by seismic waves, Wang Weitao told reporters that geophysicists like him are almost half programmers. Because from seismic wave to underground imaging, we have to go through large-scale program calculation beyond the imagination of ordinary people. His calculation model is like this: each earthquake will be transmitted to each seismic station from near to far, so theoretically, each seismic station will make its own record of the same earthquake, and these data are both different and related
using these data, we can calculate some "virtual earthquakes". By comparing and calculating the cross-correlation data between every two seismic stations, we can obtain the valuable data needed to study the overall underground structure in China
virtual earthquake can simulate the same data as real earthquake, so it can be used for underground imaging in areas where there was no earthquake. Each seismic wave data has e, N, Z (east-west, north-south, vertical) components. More than 2000 permanent and temporary seismic stations in China have 6000 components, and the annual data volume is about 30tb, And our total amount of data has reached the Pb level
since we need to compare each component data of each seismic station at each time point, the amount of calculation increases exponentially. Wang Weitao's wisdom and experience are reflected in the programs and algorithms he designed. But Dr. Wang Weitao, who spent a lot of effort to complete the algorithm, found that he had just stepped on the first step of the Long March, and there was still a huge difficulty ahead of him
the connection (gray) between every two seismic stations in the figure is the data to be calculated, and the total amount of calculation is extremely large. If a single computer is used to calculate these data, it will take about seven years. According to a person's career of 20 years, I can only complete three calculations before retirement. In this case, large-scale distributed cloud computing seems to be the only choice< However, the mechanism of cloud computing is not as light as it sounds. The reporter also interviewed the children's shoes of Alibaba cloud, a partner of the China Earthquake Administration. In their eyes, cloud computing, like scientific research, integrates the best wisdom of human beings
required storage space, amount of computation and estimated time required for stand-alone computing
distributed storage: games about farms
cloud storage is like a big farm, each server is like a worker, and your data is sheep. Said Cheng Zong, senior expert of Alibaba cloud storage. Looks like he's a rancher“ Distributed storage "can be regarded as the basic condition of distributed computing. That is to say, your sheep should be put into alicloud's "farm" first, and its workers will help you care for, feed, shear and spin
for Dr. Wang Weitao's data, just storing it in the cloud requires countless "black technologies"
in the future computing, the computing system will access the storage system on a large scale. But these visits must hit the server equally, and there must be no hot spots. But this is not enough, because the server hardware failure in a large-scale cluster will become a normal event, so we must do a good job in real-time resource scheling and fault tolerance
for example, make sure that when one hard disk is removed, the rest of the hard disks should be quickly recovered with backup data
Chengzong cited the above two examples. These two examples can be translated into the analogy of a farm, which is roughly as follows: the workload of the farm workers should be evenly distributed, and the situation of "collecting wool from a sheep" should never happen. In addition, every day, some farm workers fall ill and ask for leave, so their work should be reasonably distributed to many people in the shortest time, so that other workers will not be overloaded
the whole alicloud distributed file system is named Pangu. In Chengzong's mind, Pangu also has many intelligent "black technologies"
he gives an example: we all see the same disks, but Pangu sees different disks. It will score the health of each disk according to the accumulation of historical access data, such as the speed and efficiency of writing
for the disks with poor health, some work assignments should be reced accordingly. These underlying technologies can prepare for Dr. Wang Weitao's next real calculation< According to Cheng Zong, data bandwidth has become an important parameter in distributed computing. From Dr. Wang Weitao's point of view, if you store data on your own server and only use Alibaba cloud's computing power to output results, it can't be achieved. The principle is very simple. All servers of distributed computing send data reading requests to a storage unit, and the bandwidth will be blocked instantly. No matter how powerful the computing power is, it will not be able to play
as for the specific data, the bandwidth of 100 MB optical fiber is generally 100 MB / s, while the bandwidth of hard disk can reach several GB / s at most, and the access bandwidth of Alibaba cloud storage intranet (within the cloud computing system) can reach TB / s level
batch computing: build a pyramid
next, Dr. Wang Weitao's data will enter the final calculation. I am familiar with the Linux system that I am used to. All the computing code is completed in this environment. How to make my code play a role in the cloud computing environment is a very important problem
calculation process of underground imaging data
in seismic science research, alicloud obviously has no way to put forward algorithm suggestions, so what they need to do is to provide a common interface, so that Wang Weitao can use his computer, interface and Linux system in his computer room to control the computing on the cloud
Lin Heshan, a computing expert at Alibaba, is proud of the compatibility and adaptation capabilities provided by Alibaba cloud. Dr. Wang has never used a distributed cluster or "supercomputing" before, so it will be a challenge for him to go directly to the cloud in terms of operation and control
the computing interface we provide allows stand-alone programs to execute efficiently in the cloud environment without modification. With a few simple commands, users can mobilize large-scale computing resources in the cloud for analysis without learning complex distributed computing knowledge. In fact, many people who transition from other places to cloud computing will have such problems, so not only Dr. Wang, but also many other users will use our general computing interface. He said. At this time, the obstacles to large-scale computing are basically cleared
however, Lin Heshan told reporters that the real core technology of cloud computing lies in the computing power scheling of batch computing
the acceleration process and mode of large-scale computing, after the scale of computing is expanded, the access to storage resources will be very frequent. At this time, the control of the concurrency of access should be very "careful"
Dr. Wang's application has many small I / O requests. If every I / O request directly accesses cloud storage, the resulting delay will affect the computing efficiency. In order to further optimize the computing performance, batch computing adopts the "distributed cache" strategy, which caches the data that may be used around the computing nodes in advance. In this way, the computing power is not limited by the cluster size. Lin Heshan said
even so, it is far from enough. It is an important moment to test the intelligence of the system to determine the "granularity" of data access. If one read is too much, it may cause bandwidth congestion. If one read is too little, it will cause frequent access. For different types of data, it is an arous task to make reasonable prediction and read automatically
for example, it's like building a pyramid. Tens of thousands of "slaves" have to work together. The engineer has to decide whether to transport multiple stones to the site at the expense of speed at one time or to transport one stone to the site at a time at the expense of quantity
similarly, in the face of the vast pyramid project, how many slaves should be assigned to mix mortar, carry stones, and build each block? Even engineers need to carefully consider how many slaves can be assigned to the system to complete the task automatically, and the difficulty can be imagined
of course, errors often occur in such a complicated calculation process
Lin Heshan gives an example: when rendering the animation "little door god", alicloud's fault tolerance mechanism plays a role At that time, 2000 servers participated in large-scale batch computing at the peak.) In general, video rendering is a continuous and long process. If there is only one problem in a frame rendering, it will cause large-scale access delay, logical congestion and "hot spots"
Lin Heshan said: "alicloud's approach is to run again in the shortest time after a calculation error, if
This is a Linux system IP address configuration command. The specific meaning is:
set the IP address of the system to 192.168.0.2; The subnet mask is 24, that is 255.255.255.0; The broadcast address is 192.168.0.255; The name of NIC device is eth0
all computers in the network must set a unique IP address to communicate normally. Because of this unique address, users can select the objects they need from thousands of computers efficiently and conveniently when they operate on networked computers
The IP address is just like our home address. If you want to write to a person, you need to know his or her address so that the postman can deliver the letter. A computer sending information is like a postman. It must know the only "home address" to avoid sending the letter to the wrong person. But our address is expressed in words, the address of the computer is expressed in binary numbers eth0 is the name set by the system for the network card. If there are al network cards or multiple network cards, there will be names like eth1 and eth2. The name can be set artificially. It is the unique name of the network card in the current computer system