Backblaze may cause VMware fail to start

I’ve been using VMware Workstation 16 for a long time. Recently, I realize that sometimes my vmware virtual machines cannot start/resume.

The error message is:

Power on failure messages: The operation was cancelled by the user
Cannot open the disk 'X:\VMS\xxxxx\xxxxx-cl1.vmdk' or one of the snapshot disks it depends on.
Module 'Disk' power on failed.
Failed to start the virtual machine.

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Upgrade Mysql 5.7 to 8 “The following signatures were invalid” solution

If you are running Mysql 5.7 and would like to upgrade it to Mysql 8, here is a guide that actually WORKS for Ubuntu 18.04

sudo dpkg -i mysql-apt-config_0.8.10-1_all.deb

Choose mysql server and select mysql 8.0

sudo apt-get update
sudo apt-get install mysql-server

Continue reading “Upgrade Mysql 5.7 to 8 “The following signatures were invalid” solution”

Invisible reCAPTCHA Update

为了改善用户体验,我站已替换之前的reCAPTCHA v2(验证码v2)为Invisible reCAPTCHA(隐形验证码)。
For improving the general user experience of this site, we have replaced the reCAPTCHA v2 with Invisible reCAPTCHA.

Regex filter visible characters with character class


"[^a-zA-Z0-9 -/:-@\[-`{-~]"


Recently a task was put on my desk which I needed to write a regex to filter out all non-readable characters from . In other words, only alphabetic, numeric and symbolic characters are allowed in that field. Well, I did not find anyone wrote this kinda of regex on the internet and came up my own one:

"[^a-zA-Z0-9 -/:-@\[-`{-~]"

All characters meets the above regex will be replaced with an empty string. Though it can be more simple, for compatibility, I just isolated the symbolic part from other two parts (alphabetic and numeric). The symbolic part is not continues and has several chunks coz those chunks are not continuous on the ASCII table. Please feel free to use it and leave your comment below.

Recaptcha 2 is now on site

There was a spamming problem on my blog a few months ago. Though I have Akismet to block them, I quickly get bored seeing my spamming box is filled with trashes. It is necessary to include some kinda of verification stuff for the comment module.

Unfortunately, due to my laziness I left an unfinished verification system for months. :(

Well, the comment function here is no longer disabled. I just implemented Recaptcha 2. K, now please get busy commenting! XD





Windows Server 2012 on ESXi 4.1


My I.T infrastructure at home has 4 ESXi 4.1 servers which host a number of VMs that are used for home and work purposes.  However, my organically grown infrastructure has now reached the point where it needs re-organising.  As part of that I’m installing new A/D controllers and decided to use Server 2012.

And then found that ESXi 4.1 doesn’t support it.  Try it and you’ll get the Server 2012 sad face appearing.  I don’t have time just now to update to ESX5.X on my servers, so I hunted around the Internet to see if there was a workaround.

I found these set of instructions ( really don’t do this for a production environment )

    • Create a  new VM over the vSphere Client.
    • As “Guest Operating System” use Microsoft Windows Server 2008 R2 (64-bit)
    • After VM has been created but before first power on, download the following  bios file and upload it to your ESXi datastore into the folder of the VM
    • Now open the .vmx file of the new VM and add the follwing lines
bios440.filename = "bios.440.rom"
mce.enable = TRUE
cpuid.hypervisor.v0 = FALSE
vmGenCounter.enable = FALSE
    • Power on VM and Server 2012 will install and run


之前一段时间里我的附属服务器,也就是这个博客所在服务器,的数据库总是会定期挂掉。通常会显示Error establishing database connection.






[C++]Doubly Linked List with Iterator

During the study week I tried to implement an integer list using Visual C++. My goal is to be as similar to as the list and iterator in the standard library. My goal is to simulate the implementation of the standard library list and iterator.

There are many people having issues with insertion and deletion of the iterator. In order to delete the boundaries of the list, the iterator need to have the access of the front and back of the list. According to the standard iterator, it does not have such a function:

A sample source main is:

#include "DoublyLinkedList.h"
using namespace std;
int main(){
	DoublyLinkedList dll;
	while (!dll.isEmpty()){
		cout << "[DLL]Element:" << dll.getBack() << endl;
	int a[] = {55,66,77,88,99};
	DoublyLinkedList dll2(a, a + 5);
	for (DoublyLinkedList::iterator it = dll2.begin(); it != dll2.end(); ++it){
		cout << "[DLL2]Element:" << *it << endl;
	return 0;



Source Code(Please feel free to fork & contribute):