1. Theoretical Foundations of Multimedia Chapter 3 CD-ROMs, DVDs, and Video Disks Media for external storage and transport of data Media for external storage and transport of data  Compact disk—read-only memory  Rewritable compact disk (CD-RW)  DVD  Video disk (laser disk); analogformat

2. Theoretical Foundations of Multimedia Chapter 3 CD-ROMs CD-ROMs Digital format Digital format Write once, read many times Write once, read many times A rewritable version (CD-RW) is available, and in common use today A rewritable version (CD-RW) is available, and in common use today Information is “written” by burning tiny holes in the disk surface with a laser Information is “written” by burning tiny holes in the disk surface with a laser The hole pattern is read by a laser and inter- preted as the bits comprising the data The hole pattern is read by a laser and inter- preted as the bits comprising the data Can store 600-700 megabytes of data; about 300,000 pages of double-spaced text, ormore than an hour of high fidelity sound Can store 600-700 megabytes of data; about 300,000 pages of double-spaced text, ormore than an hour of high fidelity sound

3. Theoretical Foundations of Multimedia Chapter 3 Creating Multimedia CD-ROMs Requires a hard disk large enough to store ~650 megabytes of data to be written to the CD Requires a hard disk large enough to store ~650 megabytes of data to be written to the CD Requires a CD-ROM recorder that writes the data to the blank CD using a laser Requires a CD-ROM recorder that writes the data to the blank CD using a laser The developer creates the multimedia material, stores it on the hard disk, and then tests it as completely as possible The developer creates the multimedia material, stores it on the hard disk, and then tests it as completely as possible When the material is in final form, it iswritten to the blank CD as if it were being copied from one disk to another When the material is in final form, it iswritten to the blank CD as if it were being copied from one disk to another

4. Theoretical Foundations of Multimedia Chapter 3 Video Disks or Laser Disks Much larger than a CD-ROM; ~12” in diameter Much larger than a CD-ROM; ~12” in diameter Hold ~54,000 video frames per side Hold ~54,000 video frames per side Hold ~30 minutes of video per side Hold ~30 minutes of video per side Read-only Read-only Analog format Analog format Requires a conversion board to be used with a computer Requires a conversion board to be used with a computer Excellent for large-scale, video-based multimedia projects Excellent for large-scale, video-based multimedia projects