Top 10 Lists: Week 03

  1. The Concept of Files
    File is an important method of data storage on mass-storage devices. Files may contain binary files that readable by computer or alphanumeric text that readable by computer. Each file has a unique name and directory so all of them won’t mix up.

  2. File Access Method
    There are three main methods of accessing data: Sequential Access (the most common way to access a file, one information will be read after the other one), Direct Access (files is seen by system as a block of number that will be called without any particular order) , and Index Sequential Method (index contains sources of information or files, and the file will be opened by the help of a pointer).

  3. Disk Structure
    Modern disks contain a one-dimensional array of logical blocks, each contains 512 bytes of data. This array mapped from the outer part of the disk to the inner part of the disk.

  4. Allocation Methods
    Allocation methods provides a way for utilizing a disk and accessing a data there. The methods are: Contiguous Allocation; Extent, Linked Allocation, Clustering, FAT, Indexed Allocation, Linked Indexed Allocation, Multilevel Indexed Allocation, Inode.

  5. File Allocation Table (FAT)
    As named, FAT contains a structure of locations of where a data/file is stored, with the form is a table. There is some major version available: FAT12, FAT16, and FAT32, named after the number of element bits.

  6. Disk Partitioning
    Disk Partitioning is a method to divide storage disk into several part, each can be used differently. When a partition created, it will generate information about it’s location and size in a partition table.

  7. Filesystem Hierarchy Standard (FHS)
    FHS is implemented for Linux since 1993, it tries to enable both software and users to predict the location of files and directory by specifying guiding principles for each area of the filesystem and specifying the minimum files and directory required.

  8. Free Space Management
    This system helps users by keeping track of unused storage space for future usage. Its usage become crucial when a file is deleted, that it has to update the information. The free space lists are implemented from being a bitmap, linked list and grouped.

  9. Filesystem in Userspace (FUSE)
    FUSE is an interface for userspace programs to export a filesystem to the Linux kernel. The FUSE project consists of two components: the fuse kernel module (maintained in the regular kernel repositories) and the libfuse userspace library (maintained in this repository). libfuse provides the reference implementation for communicating with the FUSE kernel module.

  10. [Virtual File System (VFS)] (http://openstorage.gunadarma.ac.id/linux/docs/v06/Kuliah/SistemOperasi/BUKU/SistemOperasi-4.X-2/ch16s05.html)
    VFS is using the object-oriented concept to implements file system. Inside a VFS is a file represents every file exists, known as common file model.