Durable Knowledge

Although the article says it was created in 2004, it would appear that this author died in the 1980s. At the end of each "timeline," he makes it sound like the 1980s are the present day; "In the early 1980s Sony developed the 3.5 inch floppy and with improvements this has became the floppy standard used to the present day." Well, in any case, here is my timeline of what the article discussed.

Sound
1820: Hans Oersted discovers relationship between electricity and magnets. Andre-Marie Ampere (note the name) discovers that wires exert magnetic force on each other.
1873: James Maxwell establishes theory on electromagnetism (still used). 
1878: Oberlin Smith writes about magnetic recording in Electrical World magazine. 
1894: Valdemar Poulsen discovered principles of magnetic recording.
1900: Prototype of Telegraphone built, it was first successful magnetic sound recorder. 
1905: American Telegraphone Company sells Poulsen's machines 
1927: Vacuum tubes and AC biasing improve the quality and practicality of magnetic recording. Carlson and Carpenter patent AC biasing. 
1928: Fritz Pfleumer patents tape-recording (magnetic powder on paper/ film).
1930s: AEG improves commercial development of tape recorder. Germany's Magnetophone premiered at Berlin Radio Fair, shocked audiences. 
1937: Clarence Hickman of Bell Labs found new material to lessen amount of material used in recording. 
1948: Ampex and Magnecord steal AEG model during WWII. Multi-channel and multi-track recording soon revolutionized tape-recording. 
1965: 8-track introduced.
1970: cassette deck introduced. 

Video

1950: After WWII, video signal recording was a new goal. Bing Crosby helped fund first multitrack tapes for large bandwidth. VERA by the BBC was inspired by their works. 

1956: Ampex's Quadruplex 2 Inch; tape moved at 15 in/sec, same as audio recording. Soon released VRX-1000, equivalent of $650,000 today, was first practical video tape recorder. Could only be played back 30 times. 

1958: RCA and NBC broadcast first prime-time color show from videotape. 

1960s: Sony and Philips develop VTRs.

1970: Sony releases videocassette recorder (VCR).

1980: Philips releases VHS format cassettes. 

Computes

1951: Magnetic tape for storage in UNIVAC.

1955: Magnetic hard disks in IBM 350.

1967: IBM 370 used semi-conductor.

1971: magnetic disk enclosed in envelope (floppy disk).

1980s: Sony's 3.5 inch floppy released.