VirtualBox settings for Linux Guest

First, set Paravisualization Interface as KVM.

Make sure you allocate enough CPU and RAM. If you’re running Desktop Environment, you should allocate at least 2G RAM. 4G RAM recommended.

If you meet any graphic problems, turn off 3D Acceleration. It will solve most graphic problems.

VirtualBox settings

VMware settings

If you find disk I/O is very slow, go to Storage setting page, click “Controller: SATA”, then check “Use Host I/O Cache”. You will find your Virtual Machine run fast beyond your imagination, even thought the disk is on HDD, not SSD. So you should enable this before installing Operating System, it will speed up your installation. (VirtualBox disable this by default)

Set sound hardware as AC 97, not Intel HD, to get best compatibility. Otherwise, you will meet some strange problems while playing sound, especially laggy or stuck.

Finally, don’t forget to install the VirtualBox Guest Additions, it will give you full power. Instructions here: https://www.virtualbox.org/manual/ch04.html#additions-linux

Last thing last, remember Snapshot will record the hardware settings too. After restoring snapshot, you should set your hardware settings again.

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If you run Pygame too slowly in VirtualBox or VMware, just change a setting to work fast

Try to turn off 3D Acceleration in VirtualBox or VMware.

VirtualBox settings

VMware settings

When you turn off 3D Acceleration, CPU will load much heavier instead of GPU so that you should increase your CPU power (increase your Virtual Machine CPU number, or upgrade your physical machine CPU). Though CPU will load heavier than before, that’s worthy because it only takes heavy load while running Pygame. While using other applications, CPU behaves as usual.

The system will pop this warning notification, just ignore it.

For VirtualBox users, maybe you find after switching VMSVGA to VBoxVGA or VBoxSVGA, it works more normally. That is because VBoxVGA and VBoxSVGA won’t enable 3D Acceleration. I recommend using VMSVGA by default.

So when you face the graphic problem, don’t waste your time like me, just turn off 3D Acceleration.

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If you meet other problems while using VirtualBox for Linux Guest, see this post: https://jaylinwu.wordpress.com/2022/01/03/virtualbox-settings-for-linux-guest/

“Processing triggers for man-db” takes too much CPU time or disk I/O

Recently I found a problem: while apt upgrade, it’s always being stuck at “Processing triggers for man-db”. In fact, the process is still running, just too slow.

I guess triggering man-db will take too much CPU time to finish so it looks like being stuck. I didn’t monitor the disk I/O status, I guess it needs a number of disk I/O actions. If you’re using HDD, that would be slow.

Maybe there’s a bug. As far as I know, man-db problem exists in every Debian-based Linux distribution, including Debian and Ubuntu. The earliest report I see is in 2012, and Debian 11, the latest stable Debian version, also has this problem.

Because triggering man-db is nearly the last step of the upgrade, it seems like organizing and concluding something. It doesn’t upgrade man-db package itself, so using apt-mark hold man-db command is useless.

Some tutorials say that removing the man-db package or deleting the cache folder of man-db, may cause other problems.

So my suggestion is that make sure your machine has a high enough CPU to calculate power and disk I/O amount.

RAM Overclock: Frequency, Voltage, Temperature, CAS

Higher Frequence requires higher Voltage, or you will find the PC cannot boot or the applications will close automatically, especially games.

But higher Voltage will cause higher Temperature. If the Temperature is too high, it will cause errors in RAM, and applications will crash, games will freeze. Sometimes the PC will shutdown.

In summer, the indoor Temperature is higher, we must watch out.

If you don’t install extras fans to ventilate the air from the rear to the front, you should not set Frequency and Voltage too high.

So you should make sure the balance between Frequency and Voltage. You can look for some guides about your RAM models online. But you must set and test by yourself.

While playing games, almost every parts of PC works at best and the Temperature is up to its highest. So don’t trust those posts which only works as normal conditions, unless you don’t play any 3A games. The best way to test RAM is playing games, especially 3A or MMO, like Dota2 and CSGO.

CAS is positive correlation to Frequence, so don’t set CAS too low. But the lower CAS, the lower latency. It’s up to you, but most DDR4 RAMs can only get 16 as CAS at best.

中华上古传说与周文明的暧昧

虽然从古至今中国人一直信奉黄帝、尧、舜等上古圣贤，但是根据历史资料考证得知，这些传说的明文记载最早只出现于春秋、战国时期，即周朝时期。尽管有人辩解说上古时期没有文字记载，但是有记载的文字也不至于晚到周朝时期，毕竟商代的甲骨文已经是经过考古证实的铁证。

0x800713AB error: replug your network cable

I know this sounds crazy, but trust me, it’s the right solution.

货拉拉跳车案宣判后，我的心情已经无法用语言来表达

货拉拉跳车事件今日宣判，司机周阳春被认定犯过失致人死亡罪，判处有期徒刑一年，缓刑一年。

虽然看起来司机不用坐牢，但是从此有了案底，其家人要被连坐，几代人无法通过政审。在中国，连送外卖都要经过无犯罪记录审查方可注册外卖员账号，等于该司机从此连外卖都送不得。司机在看守所又呆了半年，其损失当然也不用赔偿，因为他被判有罪。

可是问题的重点在于，司机到底犯了什么罪？

宗法制度的本质究竟是什么？浅谈嘉靖“大礼议”事件

作者撰写本文之时尚未阅读黄仁宇所著《万历十五年》，待到读毕，却又发现与黄仁宇的思想观点不谋而合。如果对本文感到兴趣，不妨前去拜读一下这部作品。此文因为围绕大礼议事件发散阐述，所以系统性不佳。关于宗法制的系统性论述，则待本人有余力时撰写。

如果给中国历史的本质找到一个命题，这个命题就是宗法制度。但是中国的宗法制度实际上是变幻莫测、讳莫如深的，直到今天依然如影随形，左右中国人。以嘉靖年间的“大礼议”事件作为切入点，可以略窥一二。

One command to find out which process prevents your PC from sleeping

When you click down the button of sleep, only screen is off but the PC is still running. After rebooting, sleep will work.

Why? Because some process is running and preventing your PC from sleeping. After rebooting the PC, the process will be terminated so that you can sleep the PC.

We can use just one command to find out the process.

Open your CMD or Powershell, and input this command:

powercfg /requests

The result:

Well, we can find that a process named NeatDM.exe is preventing sleeping. It’s a download software. After closing it, I can sleep my PC at once.

Remember, this is for the situation where you sleep your PC but it wakes up at once.

However, sometimes you would face the situation where the PC slept successfully, but it wakes up later for a while. For this situation, you need to use this command to check which device woke your PC up last time:

powercfg /lastwake

However, sometimes things get wired. You just see the woke device is Fixed Power Button, but you didn’t press the button! OK, for this strange thing, I find it caused by Wake on LAN. Some devices in your LAN woke your PC up but Windows recorded it as Fixed Power Button.

Finally, maybe you need to check your Power Plan settings. Disabling Wake Timer is very useful. Many programmes, including Microsoft, will use some methods to wake your PC up. If you want to control the PC by yourself, just disable Wake Timer.

记一次给打气筒换气带的经历

打气筒的气带坏了。所谓气带，就是打气筒的那根橡胶软管。网上买了气带后，回来安装遇到不小的麻烦。

之前的气带损坏的表现是橡胶软管经常从根部断裂，从而导致漏气，只能剪掉坏掉的部分，然后插上底座的气嘴重新使用。但是没过多久就再次断裂，然后剪掉坏掉的部分装上去继续用。如此循环。

这个方法是我父亲之前使用的办法，所以我没多想，拿到新气带和旧的底座比对一下，就觉得应该把气带尾端的黑色塑料给拔掉，这样管子就能插在底座上。没想到黑色塑料卡得很紧，用老虎钳都拔不下来。

重新比对底座，发现底座上插着一块塑料，其结构为下部是圆柱体，上部是圆锥体，整个结构连成一体，上下有通气管道贯穿。之前插管子就是插在那个圆锥体上，也就是气嘴。

我仔细观察了一下新气带的结构，发现卡在橡胶软管里的结构正是圆锥体。因而，实际上气带的真正结构就是一根橡胶软管里卡着一个圆锥体，该圆锥体下部又有一个连体的圆柱体。这种设计使得出气口卡在软管里，不容易松脱。

更精妙的是，该结构上方还套着一个圆锥形的螺栓，用于和底座锁定。因为气嘴的圆锥结构撑大了管壁的直径，所以当圆锥体螺栓卡紧管子根部时，用手拔管子是无法拔出的，除非整个气带管子根部断裂，否则无需担心打气筒的气带因为意外被拔出。

经过这番推理可知，目前卡在旧底座上的结构正是从旧气带上脱落的结构，所以解决问题的思路不是拔掉新气带的塑料气嘴，而是拔掉底座上残留的塑料气嘴。但没曾想，我用螺丝起子刚一撬动底座的残余气嘴，气嘴的圆锥体部分当场断裂，还剩一个圆柱体部分卡在底座里。

我翻倒底座一看，底座是全封闭的铁块，根本没办法从下面往上面捅，使气嘴排出。我用螺丝起子撬，也毫无松动迹象。最好的办法是用像钩子一样的工具，从通气孔中插入，然后往外拔出。可是我又没有那样的工具。

一开始，我发现塑料的质地很软，可以被螺丝起子轻松刮碎，于是我就开始刮，刮了一阵嫌累。忽然想起电烙铁。电烙铁可以很好地融化塑料，而且底座是铁质的，不怕电烙铁灼烧。于是戴好口罩，防止吸入塑料燃烧后产生的毒气，拿着电烙铁烧一会儿，再刮一会儿，很快就刮掉大部分塑料。

快见底时，因为我不知道底座究竟是什么结构，怕下面还有一个凸出的气嘴，便不敢继续灼烧。让残余塑料上留着一个孔洞，然后拴上新气带。因为底座螺纹口还残余不少塑料，所以用手是很难上紧螺栓的，必须用老虎钳。新气带的螺丝栓没办法栓到底，因为残余的气嘴占据了一定的体积，不过整体上密封性还不错，用起来没什么问题。

事后我又专门查找了底座的结构，发现整个底座大概率就是一个光秃秃的圆柱体凹槽，完全由生铁铸造。如果是这样的话，那就和我之前设想的底座结构完全不同。我之前想象的结构是底部有个凸起的针状气嘴，质地也是铁质，然后软管端的气嘴是套在那上面的。但是现在看来，真正的结构是一个密封的圆柱体容器里直接插着一个圆柱体气嘴，没有任何连接点（想象一下奶茶上插着吸管）。如果是这样，那么完全可以放心地把底座残余的塑料全部清除干净，然后装上新气带即可。

通过这一次手工事件，一方面了解了反向推理能力的重要性，一方面也深刻认识到还有太多不了解的知识，哪怕只是这小小的打气筒也蕴含着十分精妙的工业设计。