How much does BT download and Thunder download affect the computer?

Category: resources * * * Enjoy >> Software * * *

Problem description:

It is said that downloading is bad for the brain, but I don't quite understand it. Please give me some advice ~! How much does BT download and Thunder download affect the computer?

Analysis:

Let's talk about BT first

Frequent hard disk reading hurts the hard disk. Does BT really hurt the hard disk?

For the record, I only mentioned BT here, not ed, because their principles are the same, and I'm too lazy to fight one by one.

Quote someone first.

Why does frequent reading and writing damage the hard disk?

The life of a magnetic head is limited. Frequent reading and writing will accelerate the wear of the head arm and head motor. Frequent reading and writing to a certain area of the disk will increase the temperature of the area, affect the stability of the magnetic media in this area, and lead to reading and writing errors. High temperature will also make the head and disk surface closer because of thermal expansion (normally, the head and disk surface are only a few microns, which is closer? ), it will also affect the data reading sensitivity of thin film magnetic head, change the clock frequency of crystal oscillator, and cause the failure of hard disk circuit components.

Too many tasks can also lead to premature damage of ide hard disk. Because of the shortcomings of ide hard disk itself, too many task requests will increase the failure rate of seeking, which will lead to frequent reset of the head (reset means that the head returns to track 0 to seek again) and accelerate the wear of the head arm and head motor.

Let me talk about the working principle of modern hard disk first.

The current hard disk, whether ide or scsi, adopts Winchester technology and has the following characteristics: 1. Sealing of magnetic head, magnetic disk and moving mechanism. 2。 The surface of the fixed and high-speed rotating plating plate is flat and smooth. 3。 The radial movement of the magnetic head on the disk. 4。 The magnetic head is in contact with the disk when it starts and stops, but it is in flight and does not directly contact the disk when it works.

Disc: Hard disk disc is to attach magnetic powder to the surface of aluminum alloy (new materials are also useful for glass). These magnetic powders are divided into several concentric circles called orbits, and there are countless small magnets randomly arranged on each concentric circle orbit, representing the states of 0 and 1 respectively. When these small magnets are influenced by the magnetic force from the magnetic head, their arrangement direction will change accordingly. Using the magnetic force of the magnetic head to control the direction of some designated small magnets, so that each small magnet can be used to store information.

Disk body: The disk body of a hard disk is composed of multiple disks, which are stacked together and placed in a sealed box. Driven by the spindle motor, they rotate at high speed, 3600, 4500, 5400, 7200 or even more per minute.

Head: The head of a hard disk is used to read or modify the state of magnetic substances on the disk. Generally speaking, each magnetic surface will have a magnetic head, starting from the top and numbering from 0. The magnetic head is in contact with the disk when it stops working, but it is in flight when it works. The magnetic head starts and stops in the landing area of the disk in a contact manner, and the landing area does not store any data, so the magnetic head starts and stops in this area, and there is no problem of damaging any data. When reading data, the disk rotates at high speed. Due to the ingenious aerodynamic design of the head movement, the head is in a "flying state", with a height of 0.2-0.5 micron from the data area of the disk. Contact with the disk surface will not cause wear, and data can be read reliably.

Motor: The motors in the hard disk are all brushless motors. With the support of high-speed bearings, the mechanical wear is small and they can work continuously for a long time. The high-speed rotating disk has obvious gyro effect, so the hard disk in work should not be moved, otherwise it will increase the workload of the bearing. Hard disk head seek servo motor mostly adopts voice coil rotation or linear motion stepping motor, which accurately tracks the track of the disk under the adjustment of servo tracking, so there should be no impact and collision when the hard disk works, so be careful when moving.

Speaking of principles, is everyone clear?

First of all, there is no contact between the head and the data area, so there is no wear problem.

Secondly, as soon as the hard disk is turned on, the spindle motor can rotate at 4500 or 7200 revolutions per minute, which has nothing to do with whether you use BT or ed. As long as it is electrified, they are turning. Their wear has nothing to do with software.

Thirdly, the head moves back and forth from left to right under the control of the seek motor, with a small amplitude. It starts from the innermost layer (landing zone) of the disk, slowly moves to the outermost layer, and then slowly moves back, from track to track to find data. There won't be any big jumps (not frogs). So its wear can also be ignored.

So how did the heat come from?

The first is the rotation of spindle motor and servo motor, which is the main reason for the temperature of hard disk.

Secondly, the friction between the high-speed rotating disk and the air. This is also the main factor.

And hard disk reading and writing?

Unfortunately, its calorific value can be ignored! ! ! ! ! ! ! ! ! !

Hard disk reading operation is that the change of magnetic field on the disk affects the resistance value of the magnetic head. In this process, the disk will not generate heat, but the magnetic head will generate a little heat because of the change of current. What about the write operation? On the contrary, the current intensity passing through the magnetic head changes constantly, thus affecting the magnetic field on the disk. This process uses electromagnetic induction, so the magnetic head will generate a lot of heat. But the disk itself will not heat up, because the permanent magnets on the disk are cold and will not heat up because of the change of magnetic field.

But in general, the calorific value of magnetic head is dwarfed by the former two.

Heat can be conducted by radiation, so high heat will not harm the permanent magnets on the disk? In fact, the damage is very small. Under normal circumstances, the temperature of permanent magnet degaussing is much higher than that of hard disk. Of course, it's nobody's fault if your chassis doesn't heat well.

I have to say some people's mistakes here:

One. High temperature affects the resistance induction sensitivity of the magnetic head, so reading and writing errors will occur, which has nothing to do with the permanent magnet.

Two. The so-called thermal expansion will not shorten the distance between the disk and the magnetic head, because the flight of the magnetic head is an aerodynamic principle, and it always keeps a certain distance from the disk under normal circumstances. Of course, if you hit the hard disk hard, then this vibration. . . . .

Three. The so-called seek means that the hard disk moves from the initial position to the specified track. The so-called reset action does not happen often. Because the physical location of the track is stored in cmos, the hard disk does not need to move back to track 0 and start over. As soon as the magnetic head is started, the so-called reset action is completed, and the reset action will not happen again unless the computer is restarted.

Four. The disk structure of ide hard disk and scsi hard disk is similar. Only the interface bandwidth of scsi hard disk is larger than that of contemporary ide hard disk, and often scsi cards often have something similar to cpu to slow down the occupancy rate of main cpu. That's all, so Seagate will use its scsi hard disk technology on ide hard disks.

Five. Hard disk reading and writing are sectors based on cylinders. Cylindrical surface is a concentric track with the same radius of all magnetic surfaces in the whole disk. Dividing each track into several regions is called a sector. Hard disk write operation is to write a sector first, and then write the next sector of the same cylinder. The head will not move to other tracks until a cylinder is completely written. So the storage of files on the hard disk is not continuous (from the user's point of view, but from the bottom of the operating system, its storage is not continuous). Therefore, the search for BT or ed heads is generally not bigger than listening to songs while playing games. Of course, this situation is just a simple download or upload, but in fact, in this process, who can guarantee that they will not start other software that needs to read and write hard disks? Maybe many people like to play games or listen to songs while downloading. Not to mention that windows itself needs to read and write virtual memory files frequently. Therefore, with BT download or ed, the hard disk will be less tortured than usual.

Six. By the way, here is the download software flashget. Why is it not good to open too many threads? First of all, with more threads, the cpu utilization rate will be high, and the page-changing action will be frequent, so that the reading and writing of virtual memory will be frequent. As for why, as long as anyone who has studied system principles should know, I won't say it here. Similarly, what about BT and ED? Download a file from several people at the same time, and several people are downloading your file at the same time, similar to fg multithreading. So the hard disk light flashed. But now the hard disk has a cache, and the data is not written to the hard disk immediately, but stored in the cache first, and then written to the hard disk at one time after reaching a certain amount. No matter how it is set in fg, it is actually written into the cache first. However, this process also requires cpu intervention, so the setting time is too short and the cpu utilization rate is high, so the hard disk light is still flashing fiercely because the virtual file is reading and writing.

Seven. Hard disk reads and writes frequently, and the head arm moves frequently under the drive of seek servo motor, but this loss is not great for machinery. Unless your hard disk itself has a mechanical failure such as arm deformation (the most common failure of parallel imports). The real wear and tear lies in the magnetic head, and the changing current will cause its aging, but compared with its life. . . . . It should also be within a reasonable range. Unless the head hits the disk because of vibration.

Eight. Mechanical circuits are most seriously affected by high temperature, especially the circuit board outside the hard disk, and the integrated block on it will accelerate aging at high temperature. Therefore, a certain glass hard disk of ibm, although it has bad tracks, disappeared as soon as it was used with some software. If it is more serious, it will be normal to change the circuit board. That's the reason.

I'm really tired after typing so many words.

In short, the hard disk will affect its service life because of poor environment and improper maintenance, but it is definitely not the fault of the software.

Flashget, BT, ED, although reading and writing hard disks is more frequent, the damage to hard disks is not greater than that of playing games and listening to songs. More specifically, their so-called wear and tear on hard disks can actually be ignored. Don't worry about them just because they see the flash memory on the hard disk. Otherwise, servers that provide web services and ftp services can read and write hard disks better than servers that download software.

The hard disk has a parameter called continuous trouble-free time. Refers to the longest time from the start of hard disk operation to failure, in hours, abbreviated as mtbf in English. Generally, the mtbf of a hard disk is at least 30,000 or 40,000 hours. The specific situation can be seen in the parameter description of the hard disk manufacturer. This continuous trouble-free time, you can divide it yourself and see how many years it is. Then everyone thinks for themselves, how long is the longest time for their hard disks to work continuously at ordinary times.

At present, the machine I use has been turned on continuously 1 year, and it has never stopped except for cleaning the dust for more than ten minutes in the middle. In addition, three servers use scsi hard disks, which have not stopped for two consecutive years. The calorific value of hard disk is by no means comparable to that of ordinary ide hard disk (10000 rpm hard disk).

Finally, add a few points:

One. It is best not to buy parallel imports or repaired hard disks. Parallel imports are very unsafe during transportation. Although seemingly harmless, it may cause damage to the machinery due to various factors during transportation. Let alone return it. To tell the truth, those who complain that the hard disk is easy to damage, you should first see for yourself whether your hard disk is these goods.

Two. The working environment of the hard disk needs to be neat, and special attention should be paid not to use the hard disk in an environment with frequent power outages and a lot of dust. The chassis should be cleaned once every month or two.

Three. Hard disk machinery is most afraid of vibration and high temperature. Therefore, the environment should be better, especially the chassis should be firm to avoid an earthquake. Don't stagger the computer desks.

Four. Always tidy up the hard disk. Here is a misunderstanding of most people. Most people think that hard disk fragmentation will increase hard disk wear, but this is not the case. The increase of hard disk fragmentation itself will only make the hard disk read and write more time than when the fragmentation is less, and the loss of hard disk can be ignored (here I only say the fact that unix is the most used operating system for servers on the network at present, but there is no disk defragmentation software under unix. Even Microsoft's nt4 is not itself). However, due to the frequent movement of the head, the reading and writing time is increased, so the page changing action of the cpu is frequent, which leads to the frequent reading and writing of virtual files (in fact, the accurate statement here is page changing files), thus increasing the load of hard disk head seeking. This is the disadvantage of hard disk fragmentation.

Five. Try to avoid sudden power failure, cold start and other things that increase cpu load (such as listening to songs while playing games or playing large 3d games while downloading) when reading and writing hard disks, which are more harmful to hard disks than most people think.

zhidao.baidu/question/426 147

Except thunder.

Thunder 5.1.3.168 (February 2006.11)

* Fixed the crash of Thunder under special circumstances.

* Fixed the problem that some Rtsp links could not be downloaded.

* Fixed the problem that the resource detector could not access some sites.

Thunder 5.1.2.166 (2006.1.23)

===========================

* Added Thunder message system.

* Enhanced the DNS domain name resolution function of Thunder.

* Fixed the problem that some users automatically dropped the line after logging in.

* Optimized the resource publishing function.

* Early registered users can also use the function of retrieving passwords by asking questions.

Thunder 5.1.1.157 (2006.1.1)

===========================

* Fixed the problem of disabling IE download.

* Fixed the problem that files downloaded through Rtsp protocol could not be played normally.

* Fixed the problem that Thunder crashed when downloading small files.

* Fixed several text errors.

Thunder 5.1.0.153 (2006.1.6)

===========================

:: Increase services for releasing resources from mined areas.

* support Rtsp protocol

* support Mozilla Firefox browser

* Added intelligent site management rules.

* Added test link.

* flash and streaming media file download functions have been added.

* Support batch downloading of pictures on web pages.

* Increased the intelligent analysis function of the webpage.

* Optimized the starting speed of Thunder.

* Enhanced password protection function.

Thunder 5.0.6.98 (2005.11.21)

===========================

* Fixed the problem that the 5.0.5.97 version could not be installed on some systems.

* Fixed the problem of slow interface refresh in some environments.

Thunder 5.0.5.97 (2005.11.17)

===========================

* Fix problems with proxy support.

Thunder 5.0.4.96 (2005.11.16)

===========================

* Support English

* Allow registered users to modify the e-mail address filled in when registering.

* The message system has been adjusted.

* When naming with comments, only the first line of text is taken.

* Thunder can directly use ie's agent.

* Fixed some problems that could never be completed.

* Fixed several problems that caused Thunder to crash.

* Fixed the problem that users using proxy servers could not register to log in to minefields.

* Fixed the problem that only 1 0 tasks could be created when the wildcard was1when creating tasks in batches.

* Fixed the problem that non-super users can't use Thunder under XP system.

* Fixed the problem that the toolbar registration button was inconsistent with the login status.

Thunder 5.0.3.86 (2005.10.11)

===========================

* Fixed the problem that windows media player related files would be replaced when installing Thunder.

Thunder 5.0.2.80(2005. 10.3)

===========================

* The problem that there is no "Gansu" in the revised area.

Thunder 5.0.1.79 (September 24, 2005)

===========================

* Increase the registration service.

* adjusted the download algorithm.

* Support traditional Chinese.

* Integrated a patch to modify the number of TCP connections in XP system.

* Increase the function of changing skin.

* Strengthened the antivirus function after downloading.

* Adjusted the display effect of completed task details.

* Added the function of opening the address bar of the new task panel and automatically filling the links in the clipboard.

* Add "Open Category Directory" in the right-click menu of the task management window.

* Fixed the problem of interface flicker in some cases.

* Correct the abnormal function of the task queue.

* Fixed the problem of abnormal monitoring of clipboard.

Thunder 5.0.0.72 beta (August 25, 2005)

===========================

* adjust the algorithm of disk reading and writing.

* Correct the errors caused by configuring antivirus software.

* Fixed renaming function.

* Fixed the function that auto-start could not be configured in the configuration panel.

Thunder 5. 0. 0. 7 1 beta (August 24, 2005)

===========================

* Adjust the scheduling algorithm to make the download faster and more stable.

* Provide a variety of display modes, you can choose different display modes according to your needs.

* Add floating information window to view task information more conveniently.

* Detailed function introduction to help users use Thunder better.

* Intelligent operation tips, automatically put forward relevant suggestions according to the user's usage.

* The error diagnosis function will automatically prompt the user why the task failed and provide relevant solutions.

* Intuitive resource display mode to help users better understand the working status of tasks.

* The batch download function has been strengthened, and wildcards in letter format are supported.

* Add toolbar configuration to allow users to select buttons to display.

* Add anti-virus function after downloading.

* Allow the import of unfinished download files.

* Add the function of importing/exporting download list files.

* Improve the automatic upgrade system, and prompt users to upgrade when there is a new version.

* Add the function of downloading only from the original address.

* Support multi-agent settings

* Increase the function of clearing the previously used storage directory.

* More detailed connection information is provided.

* Increase the function of automatically opening files after downloading.

* Added search function.

* Increase the download problem to 99%.

* Fixed some problems that the connection and ftp connection could not be downloaded.

* Fixed the problem that the original address does not support breakpoint continuation task, and the download will lose data after suspension.

* Fixed the problem of creating data files when the connection failed.

Thunder 4.7.3.53 (July 2, 2005)

===========================

* Increase the function of Thunder Music Assistant

* Add Thunder Entertainment.

* Improve the efficiency of resource query.

* binding the network translator.

* Fixed the problem of interface locking in some cases.

* Fixed the problem of getting the wrong extension when downloading.

Thunder 4.7.2.51(26 June 2005)

===========================

* Fixed the problem of failure to connect to Thunderbolt server.

* Fixed the problem that system resources occupied too high due to suspension in some cases.

* Fixed the problem that resources could not be queried due to the use of proxy server.

* Enhanced support for MMS protocol.

* Optimize the resource query function and allocate download resources more reasonably.

Thunder 4.7.2.50 (June 2005.17)

===========================

* Bundled search through Yi Bei and Autopass.

* Modified the problem of interface deadlock.

Thunder 4.7.1.48 (May 26, 2005)

===========================

* Fixed the problem that Thunder would automatically shut down under some special circumstances.

* Fixed the problem of resource display.

* Optimized download logic

* Improve the video entertainment function of Thunder.

Thunder 4.7.0.47 (May 2005 16)

===========================

* Added video entertainment function.

* Added MMS function.

* Solve the problem of slow download of the last 20% small files.

* Modified company information.

* Confirm that "Delete files at the same time" in the delete panel is selected by default in the recycle bin.

Thunder 4.6.1.44 (April 27, 2005)

===========================

* Fixed a problem that you would get different files when downloading.

* Fixed the problem that the storage directory could not be specified as a network address.

* Modified the length limit of the annotation content.

* Add. Mpg file is converted into monitoring file type.

Thunder 4.5.3.40 (April 7, 2005)

===========================

* Support FTP active mode download.

* Modified the required fields of installed machines.

* Fixed a bug in FTP resource detector.

* Fixed the problem that Thunder did not support some websites well.

* Fixed an abnormal problem when Thunder downloaded files that did not support breakpoint continuation.

Thunder 4.5.2.38(2005. 3. 17)

===========================

* Support agreement

* Support mmst protocol.

* You can query resources through agents.

* Added user tips and help after installation.

* Added description when deleting tasks.

* Added columns required for installation.

* During installation, you can create a new folder when selecting the installation directory.

* Click/double-click the system bar icon to display the main window of Thunder.

* The new panel adjusts the location of task classification and storage directory.

* Fixed the error of FTP resource detector support port.

* Fixed the display of Thunder connection information.

* Fixed the problem that the user will automatically add a directory after selecting the directory during installation.

* Fixed the problem that historical files would be damaged when they were closed abnormally.

* Fixed the problem that the download task status information was not refreshed.

* Fixed the problem of Thunderbolt interface locking when creating files.

* Fixed the problem that the deletion confirmation message box would pop up when the task was not selected and the "Delete" key was pressed.

* Fixed some problems with poor support of special ftp.

* Fixed a problem that could not be installed under some WIN98 systems.

Thunder 4.5.1.35 (February 28, 2005)

===========================

* add FTP resource detector

* When creating a new task, the focus is automatically positioned to "Download" and the connection information is displayed at the same time.

* Right-click menu of floating window/right-click menu of system bar icon to add options.

* Changed the storage directory browsing interface of the new task panel/default configuration panel.

* in the "download" and "downloaded" to add the right-click menu "delete all"

* Automatically correct file extension

* Standardize all menu items.

* Cancel the task management window minimization.

* the problem of wrong file name.

* Clicking on the new version of the advertisement will cause the system to be unresponsive.

* Slow pause in some cases.

* Download files that do not exist, and the task has not failed for a long time.

* Change 2003-2004 to 2003-2005 in the help information page.

* query resource return time is too long

* downloading file connection information is unfriendly.

* ftp detector shows that the file size is wrong.

* 99% cpu problem for a long time when the speed limit is suspended.

* Error in reloading Thunder when downloading files from Thunder.

* Strengthen and improve the error correction function.

* Connections that cannot get the file size can be downloaded.

* Once the original website is connected and the resources are retrieved successfully, the download can be started immediately.

* can automatically retrieve resources according to certain strategies.

* When the original url cannot be used to query resources, you can use the redirected url to retrieve resources.

* Download the bug fix that can't get the correct file name.

* Download error when the download file is larger than 2G.

* Fixed some bugs that could not be downloaded under special circumstances.

* Support for ftp busy chain is better

* After the download rate reached 99.9%, the problem that the remaining data could not be downloaded for a long time was improved.

* Fixed the bug that bho caused ie to die and 98 hours of incomplete uninstallation.

* Solve the problem that "Download with Thunder" disappears in ie right-click menu.

Thunder 4.3.1.28 (2005.1.19)

===========================

* If the reference page is too long, "browse the reference page" and Thunder will automatically exit immediately.

* Unable to save the directory changes made by the configuration panel.

* You cannot set the category directory to the c:\ root directory in the task management window.

* Fixed the problem of large memory occupied by Thunder, and minimized the memory occupied by Thunder to only about 3M.

Thunder 4.3.0.27 (2005.1.14)

===========================

* Added support for MMS protocol.

* Added the function of downloading all links using Thunder.

* Minimize Thunder when the new task does not pop up the main interface of Thunder.

* Changed the style of the directory selection window that pops up when browsing the new panel point storage directory.

* Added the option of "Remember the last used category and directory"

* right-click menu to add "rename"

* The function of directly deleting tasks by holding down the "shift+ delete" key or clicking the "shift" key on the delete button has been added.

* The "Speed Limit" button has been added to the toolbar.

* Added CRBT download and * * * on-demand audio and video files.

* Bundle a search toolbar

* Fixed the problem of unstable speed display.

* Fixed the problem of "downloaded" and the corresponding directory unchanged in the configuration after modifying the subcategory attribute.

* Fixed the problem that the "File Move to" function could not be used under Win98 and WinMe.

* Fixed the problem that Thunder could not shut down or log off normally when it was running under WIN98.

Thunder 4.2.0.25 beta

===========================

* Increased information content.

* Fixed the problem of refreshing the page.

Thunder 4.1.2.24 (2004.12.12)

===========================

* When there is an error in the check, a message box will prompt whether to reset.

* Some changes have been made to the advertising controls, which can't solve the problem of frequent online refresh.

* Fixed the problem of rapid increase of i/o bytes.

* Fixed the problem that the second half of the file had to be downloaded again after the upgrade due to the problem of historical file conversion.

Thunder 4.1.1.23 (2004.1.24)

===========================

* Check for errors. Download repeatedly after pausing.

* After setting up the proxy server, save the previously selected one.

* Data download error occurred when downloading FTP link through proxy server.

* take the network card address sometimes take the address of the virtual network card, rather than the real network card address.

Thunder 4.1.0.22 (2004.11.5)

===========================

* Hash the full text of the file, and then check the correctness of the file.

* Make a link conversion tool, and Thunder can download the exclusive link of Thunder.

* All pictures are changed from Chinese names to Chinese names.

* Added a time list classified by completed and garbage bins, which is convenient for users to sort by time.

* Provide a configuration that can make the prompt sound and mute.

* speed limit function

* After the downloaded subcategories are deleted, do not create new related directories after Thunder restarts.

* Thunder will flash the interface when the computer is turned on.

* After the properties of the download directory have been changed many times, the task list will be garbled.

* Advertising-related errors

* There is a link that cannot be downloaded.

* The server is not allowed to filter resources.

* Copying the 1 suffix link monitored in Thunder, such as ok.mp3, will prompt' Illegal URL found'.

* Left mouse button, the new panel will pop up twice.

* The speed limit configuration in the setting cannot be greater than 999/k..

* Create a new task panel. If there is a space in front of the URL, it will prompt "URL is illegal, please re-enter".

* If there is a space before the storage directory, the file cannot be created.

* Create/move to the task category window. If the default directory format is correct and the input length is too long, Thunder will crash.

Thunder 4.0.3.21(2004.10.438+0)

===========================

* Fixed the bug that the file could not be found after downloading after entering "\" in the new task storage directory.

* Click on the properties of the download task, and the task properties will pop up instead of the file properties.

* Improved the starting speed of Thunder.

* Fixed the problem of incorrect real-time speed display.

* Fixed the problem that some connections could not be downloaded.

* Fixed the problem that some ftp connections could not be downloaded.

* Fixed the problem that some ftp connections could not pass through the proxy.

* Fixed the problem of lightning crash when clicking the right mouse button in the taskbar window.

* Fixed the problem of desktop shortcut or Thunder 3 icon after installing Thunder 4.

* Fixed the problem of mislabeling when downloading url.

* Fixed the problem that the directory created by Thunder sometimes could not be deleted.

* The website of the advertisement has been adjusted.

Thunder 4.0.2.20(2004. 10.5438+0)

===========================

* Solve the problem that bho can't be used.

* Solve the problem of toolbar icon error.

* Banner has been replaced.

Thunder 4.0.1.19 (September 30, 2004)

===========================

* The has been revised.

Thunder 4.0.1.18 (September 28, 2004)

* The has been revised.

Thunder is more popular.

zhidao.baidu/question/480969 1