Tag:Physics

  • Linux disk LVM root directory expansion

    Time:2022-4-12

    Basic concepts of LVM Physical volume (PV): the medium on which a volume group can be established. It can be a hard disk partition, the hard disk itself or a loopback file. The physical volume includes a special header, and the rest is cut into physical extents Volume group volume group (VG): collects a group […]

  • Install Kali into USB flash disk

    Time:2022-4-9

    Install Kali to USB flash drive objective Kali is installed into the USB flash disk, and part of the capacity of the USB flash disk can be stored and used tool Disk partitioning tool diskgenius VMware USB drive Kali image fileLink Processing USB flash disk (format – > partition) Format the USB flash disk and […]

  • User mode memory mapping and kernel mode kernel mapping

    Time:2022-4-1

    User mode memory mapping Principle of MMAP In the virtual address space section, we know that each process has a list VM_ area_ Struct, which points to different memory blocks in the virtual address space. The name of this variable is MMAP. In fact, memory mapping is not justMapping between physical memory and virtual memoryIt […]

  • How does Lua code run

    Time:2022-3-17

    Last“How does C code run?”In, we learned how C language, a high-level language, works. Although C language is also a high-level language, it is a very “ancient” language after all (almost 50 years old). In comparison, the abstraction level of C language is not high. From the expression ability of C language, we can still […]

  • Linux server swap virtual memory

    Time:2022-3-15

    1、 Memory mechanism of Linux We know that reading and writing data directly from physical memory is much faster than reading and writing data from hard disk. Therefore, we hope that all data reading and writing are completed in memory, and the memory is limited, which leads to the concept of physical memory and virtual […]

  • CPU, number of cores, number of threads literacy

    Time:2022-2-17

    The author is a java developer. Usually, when the project goes online, we will choose the server configuration, such as 8-core 16g, and so on. Here, we will make a basic understanding of the configuration of the server. Start with the CPU 1.CPU CPU refers to the number of visible chips, that is, the number […]

  • Storage and logic of data structure

    Time:2022-2-6

    data structure A collection of data elements that have one or more defined relationships with each other Logical structure It is a description of the relationship between data. It has nothing to do with storage structure and location. The same logical structure can have multiple physical storage structures It can be divided into two categories: […]

  • Analysis of screen adaptation of fluent (I)

    Time:2022-2-2

    Relevant supplements: Generally speaking, we don’t use units in the application of fluent. Unlike the traditional development, we use Px, rpx, Pt, VW, etc., but in the actual development process, we need to adapt to different screens on the mobile terminal. Here, three concepts are introduced:Logical resolution、Physical resolutionAndPixel ratio。 Figure 1: iPhone parameters Physical resolution: […]

  • Screen size, pixels, resolution, and devicepixelratio

    Time:2022-1-26

    Introduction At the beginning of writing the page, check the content in the pagepxI’m still curious. The resolution on the computer seems to correspond to the width value of page rendering, but it’s not like this in the mobile phone. I remember looking for relevant information at that time, as if I knew what was […]

  • Breaking the limitations of traditional physical machines, ucloud bare metal physical cloud, which supports RSSD cloud disk and can be delivered in minutes, is coming!

    Time:2022-1-24

    In recent years, virtual machine has gradually become the first choice for enterprises to deploy business because of its flexibility, ease of use and low cost. However, some enterprises with high requirements for business performance will still choose to use exclusive physical machines. Although the traditional physical machine has the natural characteristics of high performance […]

  • ECS practice case – instructions for creating and expanding logical volumes

    Time:2022-1-22

    Summary:Cross hard disk use can be realized. On the layer above the traditional hard disk, cross EVs can be realized in ECs. In some scenarios, users need to create logical volumes or expand the existing logical volumes, or the above operations fail due to misoperation. [background description]: Cross hard disk use can be realized. On […]

  • Start optimized binary rearrangement

    Time:2022-1-19

    1、 Virtual memory and physical memory If the process can directly access the physical memory, it is undoubtedly very unsafe. In order to solve the memory security, the current computer and operating system have established a layer of virtual memory on the basis of physical memory.Virtual memory and physical memoryI won’t repeat it here. We […]