5.12: Recording Media Types

Recording Media Types

• Magnetic Tape (analog legacy)
• Optical Discs (CD, DVD, Blu-Ray)
• Hard Drives and SSDs (standard today)
• Flash memory (SD cards in portable recorders)
• Cloud storage (collaboration and backup)

Optical Disc Storage Capacities

• CD-R (Compact Disc Recordable) – typically holds 700 MB – 800 MB of data, or about 72–80 minutes of stereo audio.
• DVD (Digital Versatile Disc) – holds 4.7 GB on a single-layer disc (about 7 times the capacity of a CD) and 8.5 GB on a dual-layer disc.
• Blu-Ray Disc – holds 25 GB on a single layer and 50 GB on a dual-layer disc, with newer versions exceeding 100 GB.

CD History and 72-Minute Limit

The Compact Disc (CD) was introduced in 1982 by Philips and Sony as a digital replacement for vinyl records and cassette tapes. The CD’s 44.1 kHz sample rate and 16-bit resolution were chosen to ensure full-range, high-quality stereo audio.

The disc was designed to hold 72 minutes of stereo audio because Sony executive Norio Ohga insisted that a single CD should be able to contain the full performance of Beethoven’s Ninth Symphony, one of the longest pieces in the standard classical repertoire. To achieve this, the disc diameter was set at 12 cm, giving it enough capacity to store 650–700 MB of digital audio data.