MC_2013_12_Computer Component.ppt

* * * The Structure of CD-ROM CD-ROM Data Layout Logical data layout on a CD-ROM Sector Structure in CD-ROM CD-ROMs contain 333,000 sectors Single speed is 75 sectors per second . Each sector contains 2352 bytes: 12 bytes to mark the start of the block 4 bytes for a header 2048 bytes of user data 4 bytes for error detection 8 unused bytes 276 bytes for error correction CD-ROM Capacity Capacity is calculated as follows: 333,000 sectors * 2048 bytes per sector = 681,984,000 bytes 681,984,000 ≈ 660 Mbytes Data rate is: 2048 bytes * 75 sectors per second ≈ 150 Kbytes/sec (1x) 40x ≈ 6000 Kbytes/sec or 6 Mbytes/sec CD-ROM File System The ISO 9660 directory entry The Universal Disk Format (UDF) ISO/IEC 13346 (ECMA-167) a replacement of ISO 9660 widely used for (re)writable optical media DVD-Video media use UDF version 1.02 Philips DVD+VR format uses UDF 1.02 with an ISO 9660 bridge for DVD+R and DVD+RW. The DVD Forums DVD-VR format uses UDF 2.00 for DVD-R, DVD-RW and DVD-RAM. Blue-ray and the DVD Forums HD-DVD will use UDF 2.50 or UDF 2.60. CD Recorder Two most common types CD-Recordable (CD-R): once CD-Rewritable (CD-RW): repeatedly refers to how fast data transfers from a disc to the computer refers to how fast it can write to a CD-RW disc refers to how fast a CD-RW can record data on a CD-R disc CD-RW drives operate at several speeds. Example: Write 12X Rewrite 10X Read 32X CD-RW Speed DVD-ROM More capacity: 133 minutes of high resolution MPEG-2 video Smaller pit size, tighter track spacing, multiple layers Needs very precise reading mechanism Uses MPEG-2 video compression; requires MPEG-2 controller to decode compressed data Audio is stored in Dolby AC-3 compression DVD Formats Different formats… Single-sided, single-layer 4.7 GB – DVD5 Double-sided, single-layer 9.4 GB – DVD10 Single-sided, double-layer 8.5 GB –DVD9 Effectively two disks bonded toge