If you are unsure about the difference between memory and storage in computers, this article covers the differences between the two.
The term memory refers to the component within your computer that allows for short-term data access. You may recognise this component as DRAM, or dynamic random-access memory. Your computer performs many operations by accessing data stored in its short-term memory. Some examples of such operations include editing a document, loading applications and browsing the internet. The speed and performance of your system depend on the amount of memory that is installed on your computer.
If you have a desk and a filing cabinet, the desk represents the memory of your computer. Items you need to use immediately are kept on your desk for easy access. However, not much can be stored on a desk due to its size limitations.
Whereas memory refers to the location of short-term data, storage is the component within your computer that allows you to store and access data on a long-term basis. Usually, storage comes in the form of a solid-state drive or a hard drive. Storage houses your applications, operating system and files for an indefinite period. Computers need to write information and read it from the storage system, so the speed of the storage determines how fast your system can boot up, load and access what you’ve saved.
While the desk represents the computer's memory, the filing cabinet represents the storage of your computer. It holds items that need to be saved and stored but is not necessarily needed for immediate access. The size of the filing cabinet means that it can hold a large number of things.
An important distinction between memory and storage is that memory clears when the computer is turned off. On the other hand, storage remains intact no matter how many times you shut off your computer. Therefore, in the desk and filing cabinet analogy, any files that are left on your desk when you leave the office will be thrown away. Everything in your filing cabinet will remain.
In computing, a file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one large body of data with no way to tell where one piece of data stopped and the next began, or where any piece of data was located when it was time to retrieve it. By separating the data into pieces and giving each piece a name, the data is easily isolated and identified. Taking its name from the way a paper-based data management system is named, each group of data is called a "file". The structure and logic rules used to manage the groups of data and their names are called a "file system."
There are many kinds of file systems, each with unique structure and logic, properties of speed, flexibility, security, size and more. Some file systems have been designed to be used for specific applications. For example, the ISO 9660 file system is designed specifically for optical discs.
File systems can be used on many types of storage devices using various media. As of 2019, hard disk drives have been key storage devices and are projected to remain so for the foreseeable future. Other kinds of media that are used include SSDs, magnetic tapes, and optical discs. In some cases, such as with tmpfs, the computer's main memory (random-access memory, RAM) is used to create a temporary file system for short-term use.
Some file systems are used on local data storage devices; others provide file access via a network protocol (for example, NFS, SMB, or 9P clients). Some file systems are "virtual", meaning that the supplied "files" (called virtual files) are computed on request (such as procfs and sysfs) or are merely a mapping into a different file system used as a backing store. The file system manages access to both the content of files and the metadata about those files. It is responsible for arranging storage space; reliability, efficiency, and tuning with regard to the physical storage medium are important design considerations.
A file system stores and organizes data and can be thought of as a type of index for all the data contained in a storage device. These devices can include hard drives, optical drives and flash drives.
File systems specify conventions for naming files, including the maximum number of characters in a name, which characters can be used and, in some systems, how long the file name suffix can be. In many file systems, file names are not case-sensitive.
Along with the file itself, file systems contain information such as the size of the file, as well as its attributes, location and hierarchy in the directory in the metadata. Metadata can also identify free blocks of available storage on the drive and how much space is available.
A file system also includes a format to specify the path to a file through the structure of directories. A file is placed in a directory -- or a folder in Windows OS -- or subdirectory at the desired place in the tree structure. PC and mobile OSes have file systems in which files are placed somewhere in a hierarchical tree structure.
Before files and directories are created on the storage medium, partitions should be put into place. A partition is a region of the hard disk or other storage that the OS manages separately. One file system is contained in the primary partition, and some OSes allow for multiple partitions on one disk. In this situation, if one file system gets corrupted, the data in a different partition will be safe.
There are several types of file systems, all with different logical structures and properties, such as speed and size. The type of file system can differ by OS and the needs of that OS. The three most common PC operating systems are Microsoft Windows, Mac OS X and Linux. Mobile OSes include Apple iOS and Google Android.
Major file systems include the following:
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File allocation table (FAT) is supported by Microsoft Windows OS. FAT is considered simple and reliable, and it is modelled after legacy file systems. FAT was designed in 1977 for floppy disks but was later adapted for hard disks. While efficient and compatible with most current OSes, FAT cannot match the performance and scalability of more modern file systems.
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Global file system (GFS) is a file system for the Linux OS, and it is a shared disk file system. GFS offers direct access to shared block storage and can be used as a local file system.
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GFS2 is an updated version with features not included in the original GFS, such as an updated metadata system. Under the terms of the GNU General Public License, both the GFS and GFS2 file systems are available as free software.
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Hierarchical file system (HFS) was developed for use with Mac operating systems. HFS can also be referred to as Mac OS Standard, and it was succeeded by Mac OS Extended. Originally introduced in 1985 for floppy and hard disks, HFS replaced the original Macintosh file system. It can also be used on CD-ROMs.
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The NT file system -- also known as the New Technology File System (NTFS) -- is the default file system for Windows products from Windows NT 3.1 OS onward. Improvements from the previous FAT file system include better metadata support, performance and use of disk space. NTFS is also supported in the Linux OS through a free, open-source NTFS driver. Mac OSes have read-only support for NTFS.
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Universal Disk Format (UDF) is a vendor-neutral file system used on optical media and DVDs. UDF replaces the ISO 9660 file system and is the official file system for DVD video and audio as chosen by the DVD Forum.
Cloud computing is the ability to access information and applications over the Internet. Cloud computing allows users to access applications and data from any location, as long as they have an Internet connection.
Cloud computing is a type of Internet-based computing that provides shared computer processing resources and data to computers and other devices on demand.
It is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.
- [Infrastructure as a Service (IaaS)](Cloud Computing/Cloud_Computing.md#infrastructure-as-a-service-iaas)
- [Platform as a Service (PaaS)](Cloud Computing/Cloud_Computing.md#platform-as-a-service-paas)
- [Software as a Service (SaaS)](Cloud Computing/Cloud_Computing.md#software-as-a-service-saas)