Tuesday, June 12, 2012

The capacity of CD

The capacity of CD
The amount of data stored in the disc is the capacity of CD. It is usually measured in MB. A standard CD-R disc is used to record data, its capacity is 650MB. But now they have large capacity, for example, 700MB.

The capacity of CD can also be represented by time. In the standard speed, the standard capacity is defined as 74 minutes.

High-capacity CD can play 80-minutes (equivalent to 700MB). There are also two kinds of rare large-capacity CDs for 90 minutes and 99 minutes.

CD-R is used to indicate the capacity in two ways, such as the disk shall be marked "74 minutes, 650MB". Actually, the time is accurate, but with the "MB" of representation, it is right when the disc is used as a data disc, but as other types of discs used, its capacity will be more than 650MB.

Here we would like to set audio CD, data CD, and video CD as examples, their capacity of sectors are 2352, 2048, 2236 byte and their capacity would be:
Audio CD: 74×60×75×2352÷1024÷1024=746.93(MB)
Data CD: 74×60×75×2048÷1024÷1024=650.39(MB)
Video CD: 74×60×75×2336÷1024÷1024=741.85(MB)

Note: The disc capacity in the formula is measured by 74 minutes, every minute 60 seconds, 75 sectors per read, audio, CD-ROM for each sector 2352 Bytes, 1KB = 1024B, 1MB = 1024KB.

More details:http://www.powerdatarecovery.com/cd-dvd-resources/the-capacity-of-cd.html

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