What is secondary memory and types ?
Secondary memory is called 'secondary memory'. Secondary 'Memory' is also called 'Auxiliary Memory'. Secondary memory includes magnetic disk, optical disk and solid state disk. Magnetic Disks Magnetic disks include hard disk drives and floppy disk drives. Hard disk drive . Hard disk drive is also called 'magnetic drive'. Six hard disk drives have circular tracks. A circular track is made up of small sectors. Information is stored between them in magnetic form. A hard disk drive has a coating of Aryan Oxide. Usually the speed of hard disk drive: 5400 to 7200 RPM RPM: Rotation per Minute 0 Personal computer hard disk capacity is 10 GB to 500 GB. External hard disks of different sizes and capacities such as 350 GB, 500 GB and 1 TB are also available outside the computer.
The hard disk drive is connected to the motherboard in two ways. 1) SATA: Serial Advanced Technology Attachment 2) IDE: Integrated Drive Electronics A floppy disk drive stores information in a magnetic strip. 0 Floppy disks have a common storage capacity of 1.2 MB and 1.44 MB. The floppy disk opens in the A / B drive in the computer. Optical Discs Optical discs include CD, DVD and Blu-Ray. CD CD: Compact Disc CD has a general storage capacity of 650 MB. CD has a maximum storage capacity of 700 MB. A flat, circular, and easily portable type of storage medium, usually 4.75 inches in diameter. Data is written on the surface of the disk in the form of Pits and Lands. The first CD was produced by Sony Company.
CD-ROM: Compact Disc Read Only Memory CD-ROM stores data only once, which cannot be erased. CD-ROM is also called 'WORM'. WORM: Write Once Read Many a CD-R: Compact Disc Recordable CD-R can record data only once. CD-RW: Compact Disc Rewritable > Data in CD-RW can be deleted and re-stored. The process of writing data in aCD is called 'burn process'. Nero software is used to write data. DVD: Digital Versatile Disc / Digital Video Disc. DVD is also called 'Super Density Disc'. 7 The first DVD was produced by the Sony company. DVD has a normal storage capacity of 4.7 GB (more than 4 GB). DVD includes DVD-ROM, DVD-R, DVD-RW. BLU-RAY Discs .BLU-RAY discs have a storage capacity of 25 GB to 128 GB. Single Layer: 25 GB. Two Layer: 50 GB BEND .Three Layer: 100 GB Four Layer: 128 GB GRID RE 7 BLU-RAY disc includes BD-ROM, BD-R, BD-RW. BD-RW is used for HDTV recording.
HDTV : High Definition Television RES Solid State Disk. Solid State Disk includes pen drive and memory card. Other names of pen drive are thumb drive and flash drive. Pendrive has a USB interface. USB : Universal Serial Bus. File System The systematic arrangement of data in a computer is called 'File System'. USB flash disks and memory cards used with mobile phones are usually formatted with the FAT file system. USB: Universal Serial Bus. FAT: File Allocation Table USB flash disks can be reformatted to NTFS for better performance and security benefits. NTFS: New Technology File System 7 CDs generally use the ISO 9660 file system. ISO: International Organization for Standardization DVDs use the UDF file system. UDF : Universal Disk Format.
What is difference between file and directory ?
File system mainly consists of two types of objects. 1) File: The primary unit of data storage on a computer is a file. The file is identified by its name. Due to the large number of files on disk, directories are used to manage them. 2) Directory: It is also known as folder. A directory contains many files and many other directories and the other directories in that directory are known as 'sub directories'. Every file system has a root directory. which is the beginning of the file system. Each directory in the system contains many objects (files and directories) and each object within that directory is given a unique name.
An initially blank file system structure is created on the disk through a process called formatting. To Know: 1. Sequential access: Sequential access means getting information according to order. 0 Sequentially stores data in a long string serially or sequentially. There are two ways of getting data in order: FIFO and LIFO. FIFO (Firs In First Out) This is like a row. In which the information entered earlier comes first and the last number also remains the last. LIFO (Last In First Out) can be compared to a stack of paper, the paper placed last in the stack comes out first. Accordingly the information entered last comes out first. Know: 2 Search Floppy Disk CD DVDA.
Image Representation in Computer :
Memory An image (picture) stored in a computer is called a 'digital image'. Because, the storage of the image in the computer memory happens after the transformation into a series of 0's and 1's. One way to represent an image is through Vector Image Representation. Vector images are a great way to represent fonts, logos, pictures, etc. Another way to store images in computer memory is to divide the image into a specified number of rows and columns. Each cell formed by the intersection of this row and column is called a 'pixel' (Pixel-Picture Element). this Each pixel has a value. Which shows the brightness of the color of a specific point.
Generally, a set of pixels is stored as a raster image (Raster Image) or a raster map (Raster map) using a two dimensional array (Two Dimensional Array) in the computer memory. Common Raster Image Formats .bmp : Bitmap .jpeg : Joint Photographic Experts Group .png : Portable Network Group e.gif : Graphics Interchange Format. .tiff : Tagged Image File Format LL HEL Digital Video Digital video is a type of digital recording method. is Which uses digital signal instead of analog signal. Digital video is a series of rapidly displayed digital images. Each image is called a 'cam'. More than 45 kams are usually passed in one second to produce a continuous effect of the event. Popular formats for odpa videos are fla (Flash Video Format), .avi (Audio Video Interface), .wmv (Windows Media Video) and .mp4 (Moving Picture Expert Group).
How is the name of the first connected network in the history of computers?
Two or more computers connected in such a way that information can be exchanged between them is called 'Network'.
World's first network: ARPANet (by America) - ARPANet: Advanced Research Projects Agency Network ARPANet.
History : In the late 1960s, DARP (Defense Advanced Research Projects Agency) began to formulate a plan for broadcasting in computer networks. Funding for this project (ARPANET) was provided by the US military. The purpose of ARPANET was to create a secure and safe communication system between US military computers.
E-mail was first used on this network. 2 In the mid-1980s, the US National Science Foundation (NSF) developed NSFNET. The invention of different protocols made the functioning of the Internet easier. Other examples of LAN networks include BITNET (Because Its Time Network) and CSNET (Computer Science Network). A gateway facility was developed to connect BITNET to other networks. It made possible the use of e-mail, especially for e-mail mailing lists. ARPANET was dismantled in 1990. The network started in India in 1986. First Network in India .ERNat : Education And Research Network Network Types Ma Hat Fi PAN PAN : Personal Area NetworkArea : Used for personal use.
LAN: Local Area Network. Area: School, Office, Building. Range: 100 m Maximum Range: 1 Km. Medium for LAN is cable and wireless. Cable: Coaxial Cable, Twisted Pair Cable LAN based on wireless technology is called 'WLAN'. WLAN: Wireless Local Area Network Example. Wi-Fi: Wireless Fidelity. Wi-Fi follows the IEEE 802.11 standard.
IEEE : Institute of Electrical and Electronics Engineers. Range of Wi-Fi : 250 m CAN → CAN : Campus Area Network → CAN : Cluster Area Network. CAN : Controller Area Network A network which combines more than one LAN in the same campus. It is called CAN. Range : 1 Km client . MAN : Metropolitan Area Network. Area : City. Range : 50 Km. WAN : Wide Area Network. Area : Whole World Local Area Network → Example : Internet, GSWAN : Internet : Interconnected Network. GSWAN : Gujarat State Wide Area Network.
