Centos knowledge extension

1. what is the difference between 32-bit and 64-bit? When will 32-bit and 64-bit operating systems be installed? How can I check whether the system is 32-bit or 64-bit? The so-called 32-bit and 64-bit indicate the data width of the General-PurposeRegisters (General-purpose register) CPU. A 64-bit cpu can perform integer operations in a greater range than a 32-bit cpu. it can support larger memory. The performance of a 64-bit processor cannot be simply considered due to changes in numbers.

1. what is the difference between 32-bit and 64-bit? When will 32-bit and 64-bit operating systems be installed? How can I check whether the system is 32-bit or 64-bit?
The so-called 32-bit and 64-bit indicate the data width of the General-Purpose Registers (General-Purpose register) of the CPU. A 64-bit cpu can perform integer operations in a greater range than a 32-bit cpu. it can support larger memory. We cannot simply think that 64-bit processor performance is twice the performance of 32-bit processor because of digital changes. In fact, in 32-bit applications, the performance of 32-bit processors is even stronger. even 64-bit processors have higher performance in 32-bit applications.

The operating system is also divided into 32-bit and 64-bit. Currently, most of the mainstream computer hardware is 64-bit cpu, so it supports the installation of 64-bit operating systems, of course, it is also possible to install a 32-bit operating system. to install a 32-bit or 64-bit system, it depends on how much memory our computer has. if it exceeds 4 GB, it will install 64-bit, otherwise, it will be better to install 32 bits.

Run the uname-a command to check whether the system is 32-bit or 64-bit. if X86_64 is displayed, it is 64-bit, i386 is displayed, and i586 or i686 is 32-bit.

2. what is the role of swap partitioning? How to determine the size of swap partition?
The swap partition is the virtual memory in windows. it is mainly used when the system memory is insufficient or is used up quickly, then the system will temporarily put the older data in the memory into the swap, so that you can free up some memory for other programs to use. Generally, when we install the system, we need to allocate part of the disk space to the swap. generally, we need to allocate two times of the memory size to the swap, however, if your server memory is large, for example, 32 GB or even 64 GB, it is unnecessary to allocate two times of the memory size to swap, because it is too wasteful. My suggestion is that when the memory is not greater than 8 GB, it will be divided into two times of memory. if the memory is greater than 8 GB, it will be divided into 16 GB.

3. how is a universal partition divided?
/Boot 100 M;
/20 GB;
/Usr/20G;
The swap memory is 2 times smaller than 8 GB memory, and 16 GB for 8 GB memory;
Divide the remaining space into/data/

4. after installing the system, try the vmwarevm clone function.
We often use virtual machines for various tests. it is a waste of time for beginners to reinstall the operating system because the system crashes and cannot be started due to misoperation. After the original operating system is installed on our virtual machine, clone it and prepare several copies for backup to facilitate subsequent experiments and avoid re-installing the operating system.

 

5. check the information to understand the concept of grub and briefly describe it.

Grub is a boot loader based on GUN. it is a multi-operating system manager used to guide different systems. Grub can manage either windows or linux.

6. How much do you know about the time zone? Which time zone is used in China?
According to the regulations of the 1884 International economic line Conference, the world is divided into 24 time zones by longitude, with each zone having 15 ° of longitude. The time zone with the primary meridian as the central meridian is the zero time zone. the time zone ranges from the zero time zone to the east and the West, and the East and West 12 are the half time zones. when using the 180 ° longitude line together.

In China, we generally use Beijing time, which is the so-called UTC + 8 zone. When installing CentOS, we can select Asia/Shanghai or Asia/Chongqing, but there is no Asia/Beijing