Cd Rom
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CD-ROM is an optical disc used to store digital data originally developed for storing digital audio. It has a flat, round shape coated with a reflective material. Data is stored on CD-ROMs in the form of pits and lands, which are read by a laser focusing on the disc's spinning surface. CD-ROMs can store up to 650-700 MB of data and are read at varying speeds up to 52x, while writing is slower up to 32x. They use file systems like ISO 9660 to organize data on tracks and sectors. CD-ROMs provide large data storage in a compact, portable format but have slow writing speeds and data cannot be rewritten.
Cd Rom
- 2. CD-ROM BySadaf KhanJavaria KhalidSumayyahIfra
- 3. IndexStorage devices.Categories of storage devices.CD-ROM.Structure of CD-ROM.Reading of CD-ROM.Pits & Lands.Reading Speed.Writing of CD-ROM.File System.Tracks & Sectors.Writing Methods.03
- 4. Storage Capacity.Advantage of CD-ROMDisadvantages of CD-ROMSummary.References.Question & Answer Session04
- 5. The storage devices store data –even when the computer is turned off.It is used to keep important data and files which are of regular use on permanent basis.Storage Devices05
- 6. Categories of Storage DevicesThe two main categories are magnetic storage and optical storage.Optical StorageMagnetic Storage06
- 7. CD-ROMCD-ROM stands for compact disc read-only memory. It is an optical disc used to store digital data, originally developed for storing digital audio.
- 8. CD StructureA CD is flat, round, portable metal disc, which is coated with a thin metalor plastic or other material that is highly reflective. It is usually 0.75 inches in diameter and less than one-twentieth of an inch thick.08
- 9. Reading Data On CD-Rom
- 10. Reading data from CD-ROMA CD-ROM drive reads digital data from a spinning disc by focusing a laser on the disc’s surface.Some areas of the disc reflect the laser light into a sensor, and other areas scatter the light.10
- 11. Pits and landsThe CD-ROM holds digital data.Data is stored in the form of lands and pits.Lands are flat areas on the metal surface.Pitsare depressions or hollows. 11Reading logic ‘1’Reading logic ‘0’
- 12. Reading SpeedReading speed is measured in kB/sReading speed determines the transfer of data in one second.1× or 1-speed which gives a data transfer rate of 150 kB/s in the most common data format.Maximum speed available today is 52x.12
- 13. Writing Data On CD-Rom
- 14. Writing Data On CD-ROMA laser is used to heat a chemical dye in the disc to create marks that will be read as data.As marks (pits) are created through burns, this process is also referred as burning.Burning a CD is comparatively slower than reading it.Maximum burning speed is 32x.14
- 15. File SystemThe format of the CD (file system) describes how the data is stored on the CD.The earliest file system was High Sierra Standard.The ISO 9660format is now the most common format.15
- 16. Tracks and SectorsFor burning, the first process is to format a blank CD.CD-ROM drive creates a set of concentric rings, called tracks on each side of CD.Tracks are divided into short segments called sectors.Sectors are where data is stored physically.16Tracks
- 17. Writing MethodsThere are many methods to write a CD.Monosession: Creates a single session on the disc.Multisession: This method lets a CD to be written several times, by creating a 14MB-long table of contents (TOC) de 14Mo for each session. 17
- 18. Storage Capacity Of CD-Rom
- 19. Storage Capacity of CD-ROMStorage capacity is the maximum limit of data storage on a CD.A standard compact disc can store 650 MB of data or about 70 minutes of audio.A new generation of compact disc, however, can hold 700 MB of data or 80 minutes of audio. 19
- 20. Advantages of CD-ROMLarge storage spaceCompactand lightCan be manufactured on a large scale20
- 21. Disadvantage Of CD-ROMSlow Writing speedNot easily re-writableCost Concerns21
- 22. SummaryCompact Disk is a type of optical storage.It holds data through physical marks.Its is played in a CD-Player, and is read at different speeds.Files system is required to write data on CD by different methods.CDs are compact storage devices that can be moved from on place to another easily.There is always a doubt in their durability.22
- 24. Thank You