Other metadata is used to store high-level information about the subdivisions of the disk, such as logical volumes and partitions. This includes the data structures required to support a hierarchical directory structure structures to determine which blocks of space on the disk are used and which are available structures that allow for maintaining the names of the files and directories information about the files such as their size and times they were created, modified or last accessed and the location or locations of the data belonging to the file on the disk. Once the namespace has been defined, a metadata structure is necessary to provide the logical foundation for that namespace. It also defines the logical structure of the data on a disk, such as the use of directories for organizing files instead of just lumping them all together in a single, huge conglomeration of files. This defines how a file can be named, specifically the length of a filename and the subset of characters that can be used for filenames out of the total set of characters available. However, there are many other important functions that flow from that requirement.Īll filesystems need to provide a namespace-that is, a naming and organizational methodology. Obviously, a filesystem is designed to provide space for non-volatile storage of data that is its ultimate function. A partition or logical volume formatted with a specific type of filesystem that can be mounted on a specified mount point on a Linux filesystem.ĭisk storage is a necessity that brings with it some interesting and inescapable details.Each of these filesystem types uses its own metadata structures to define how the data is stored and accessed. Linux supports almost 100 types of filesystems, including some very old ones as well as some of the newest. A specific type of data storage format, such as EXT3, EXT4, BTRFS, XFS, and so on. The entire Linux directory structure starting at the top (/) root directory.These meanings will be explored in greater detail in the following sections of this article. Note that while attempting to conform to standard "official" meanings, my intent is to define the term based on its various usages. I will attempt to define the various meanings of the word "filesystem" based on how I have observed it being used in different circumstances. The word itself can have multiple meanings, and you may have to discern the correct meaning from the context of a discussion or document. You may hear people talk about filesystems in a number of different and confusing ways. This was very expensive at about $1.00 per bit! Definitions A typical cost for RAM is around $0.0000000043743750 per byte today.įor a quick historical note to put present RAM costs in perspective, in the very early days of computing, one type of memory was based on dots on a CRT screen. a 2TB hard drive, shows that the RAM is about 71 times more expensive per unit than the hard drive. A quick calculation of the cost per byte, based on costs for 16GB of RAM vs. Both RAM and disk costs have been dropping rapidly, but RAM still leads the way in terms of cost per byte. The second reason that data needs to be stored on hard drives is that even standard RAM is still more expensive than disk space. There are non-volatile types of RAM that can maintain the data stored there after power is removed (such as flash RAM that is used in USB memory sticks and solid state drives), but flash RAM is much more expensive than standard, volatile RAM like DDR3 and other, similar types. First, RAM loses its contents when the computer is switched off. Free online course: RHEL Technical OverviewĮvery general-purpose computer needs to store data of various types on a hard disk drive (HDD) or some equivalent, such as a USB memory stick.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |