Developed by Sony
(I believe) in the late sixties/early seventies the U-matic format was the forerunner
to all home video
It is named after the U-shaped route the tape takes inside the deck.
Different formats of U-Matic exist: Lo-Band, Hi-Band and SP, each with its own fans. Lo-Band is popular amongst advertising agencies and small TV outfits, due to its durability and suitability for presentations. It's also good enough quality to do on-line editing.
Hi-Band is used in many TV stations around the world as a companion to Betacam, and was the first casette based format used for broadcasting.
Superior Performance (SP), is very rare - only a handful of African broadcasters still use it. It's superior because of the chrome tape meaning less noise and better picture quality.
Further reading: the U-Matic PALsite at http://umatic.palsite.com/, Sony Broadcast and Professional Services at http://bpgprod.sel.sony.com/subcategory.bpg?cat=Videotape+and+Disk+Recorders&subcat=U-Matic