Time zone resolution and how to adjust the time zone in Linux

Time zone resolution and how to adjust the time zone in Linux preface today we found that the system time of Centos6.0-64bit in Vmware is several hours different from that of the host machine. after adjusting the system time, restart and restore the system. So I figured out why. What is the time zone... time zone resolution and how to adjust the time zone in Linux preface today we found that the Centos 6.0-64bit system Time in Vmware differs from the host time for several hours, after adjusting the system time, restart and restore the system. So I figured out why. What is the time zone? although this basic knowledge has been mentioned in the geography class of junior high school, traveling abroad is always time-difference, and I have never traveled in China, let alone going abroad, at that time, I did not really pay too much attention to its role. Now that I have used it in my work, I will try it out. Several keywords: Universal Time is the earliest time standard. In 1884, 1 s was set internationally to 1/8. 64 × 104 of the average daily length for the year. The time system formed by this standard is called the world, that is, UT1. In 1972, the International Atomic Time mark was used internationally. Since then, the time passed by the Greenwich mean Observatory's primary Meridian has been called the universal time, namely UT2, or Greenwich Mean Time (GMT ), it is the universal time after the periodic difference of the Earth's rotation speed is corrected. Atomic time in 1967, people developed a high-precision atomic clock by using the characteristics of the extremely regular atomic oscillation cycle, and set the time experienced by 9192631770 weeks of atomic energy transition radiation to 1 s. Now, the time used is the International Atomic Time defined in October 1971. it is a uniform atomic time that is obtained after being compared by more than 200 atomic clocks in the world and then processed by the time of the International weighing and balance Bureau, TAI for short. World coordination is a time standard based on the rotation of the Earth. Since the Earth's rotation speed is uneven, not every day is accurate 86400 atomic s, resulting in a 1 s error between the rotation time and the world. To correct this error, the International Institute of Earth rotation adjusted the Greenwich Mean Time by s based on the actual condition of the Earth's rotation, and released the standard time to the World jointly with the time of the International Bureau of Weights and Measures, this is the so-called world coordination Time (UTC: Coordinatde Universal Time ). The format of UTC is as follows: Year (y), month (m), Day (d), Hour (h), Minute (min), and second (s. GMT is short for Greenwich Mean Time. it can be translated into Greenwich Mean Time (GMT) or Greenwich Mean Time (GMT ". Greenwich is located on the banks of the times in the southeast direction of London. In general, it is used to regulate the time of various regions around the world. all countries use a fixed time as the reference point to calculate the local time. To this end, in Washington, D. C., held the international economic conference on 1884, confirming that Greenwich mean is the place where the east and west longitude is 0. People divide human beings on Earth into 24 equal portions, each of which is a time zone. each time zone spans 15 degrees of longitude, that is, the time is exactly one hour, and the time zone in the Greenwich mean is the time zone, assume that the GMT time is the early morning of January 1, January 10 (that is, zero o'clock), and a time zone is West, minus one hour. then, the local time is on January 1, January 9, and an hour is added to the Eastern time zone, then the local time is a.m. on April 9, January 10, and so on. China is on the east longitude 120 degrees. this calculation can be done in this way. (The East longitude 120 °-The East longitude 0 °) the obtained degree is divided by 15, that is, 8, so China is located in the GMT + 8 zone. at this time, China is eight o'clock on January 1, January 10. UTC is the abbreviation of Coordinated Universal Time. it can be translated into "Coordinated Universal Time" or "Coordinated world Time ". At present, it refers to the GMT time. Why does it mean the GMT time? Because the meridian (Meridian is the meridian, and the meridian is the zero-degree meridian) actually passes through Mecca on the west side of Saudi Arabia, rather than Greenwich mean. At that time, the Royal Society temporarily determined that Greenwich mean the passage point of the primary meridian? In addition, in the prosperous period, the world will make mistakes and use them now. Maybe it is impossible to change the time of Mecca to the standard time someday. Therefore, we generally use UTC instead of GMT. PDT is short for Pacific Daylight Time. it is translated into Chinese as "Pacific summer Time", 7 hours later than UTC Time. Google once mentioned in its AdSense that "Our engineers will maintain the website from AM to am on the 09-6-13 ." PST starts in the U.S. summer on the first Sunday of 1st every year, and ends on the last Sunday of every year. The daylight saving Time is one hour earlier than the normal Time, which corresponds to PST and Pacific Standard Time. It is PST after the daylight saving time. PST is the standard time in the Pacific Ocean (West 8). It has a time difference of-16 hours from Beijing Time (UTC + 8), that is, Beijing time minus 16 is the PST time. PDT is one hour earlier than PST, which means that the time difference between PDT and Beijing is-15 hours. In fact, apart from PDT and PST, there is still a lot of time in North America: short name Chinese description NST Newfoundland Standard Time New Finland Standard Time NDT Newfoundland Daylight Time new Finland summer Time AST Atlantic Standard Time ADT Atlantic Daylight Time Atlantic summer Time EST Eastern Standard Time EDT eastern Daylight Time Eastern Daylight Saving Time CST Central Standard Time CDT Central Daylight Time Central Daylight saving Time MST Mountain Standard Time MDT Mountain Daylight Ti Me mountain summer Time PST Pacific Standard Time PDT Pacific Daylight Time Pacific summer Time AKST Alaska Standard Time AKDT Alaska Daylight Time Alaska summer Time HAST Hawaii-Aleutian Standard Time Hawaii- aliyushen standard Time HADT Hawaii-Aleutian Daylight Time Hawaii-alyushenxia Time Linux Time zone adjustment view current Time zone [root @ bogon ~] # Date-RTue, 09 Apr 2013 20:04:40 + 0800 copy the corresponding time zone file, replace the system time zone file, or create a link file format: cp/usr/share/zoneinfo/$ Main time zone/$ time zone/etc/localtime Method 1: cp/usr/share/zoneinfo/Asia/Shanghai/etc/localtime Method 2: ln-sf/usr/share/zoneinfo/Asia/Shanghai/etc/localtimePs: The second method is used to adjust the time in centos.