Computer Equals Tapedrive

In older movies and TV shows, made before the invention of the personal computer, all computers had large nine-track reel-to-reel magnetic tape drives, which were always moving back and forth. They usually had banks of blinking lights as well. Most viewers were left with the impression that the tape drive was the computer.

This was primarily done because the computer itself is very visually uninteresting when in operation. When a Tape Drive is operating, there is obviously something going on.

No longer as common, since in Real Life, almost everybody has stopped using the old-fashioned 9-track mag tape reel because of size and cost, e.g. a 6250 bpi, 1600 foot tape could hold, at most, about 75 megabytes of data, and costs about US$12. By 2012, it was possible to walk into a stationery store and buy a microSD card the size of a man's thumbnail for close to $12, and it would hold at least 4 billion bytes, or about 50 times as much as the above tape reel. And that's not even the cheapest example. A top-the-line 2 terabyte hard-drive could often be purchased at or under US$200. That means data storage on modern hardware is thousands of times cheaper today, and that's before factoring in inflation.

In modern works, this trope shows up only in period pieces set before approximately 1975, or when dealing with technology built before then.

Superseded by Computer Equals Monitor, since modern LTO tape drives don't look anything like those tape drives of old and are so uncommon that not many people have seen one. Not to mention that the lack of activity indicators on one and the inability to see the tape reels spinning makes it a very boring subject to film.

Anime and Manga

 * In Kino's Journey one country obviously has very highly advanced technology, but the computers there apparently still use tape drives.

Comic Books

 * In the original X-Men comic in the '60s, Cerebro (!) had a tape drive.

Film

 * In The Italian Job (1969), all the traffic lights in Turin were controlled by computer. Our heroes caused a massive traffic jam by sneaking into the computer center and hanging a magtape that made the whole system go haywire. Presumably the control software read the tape automatically, as no other interaction was needed.
 * It shouldn't have worked anyway - when we see the tape being read, we see that it's actually twisted over the heads, and should therefore be unreadable
 * In the film Fail Safe a (for then) large mainframe computer is focused upon, with the tape drives running backwards. When tapes were used for main storage, not just backup, changing direction and rewriting part of a tape was common.

Live-Action TV

 * Star Trek: The Original Series had "memory tapes".
 * Doctor Who in the 1960s, of course, although some episodes set in the future eschew the tape drives for more blinking lights. An Egregious example in the First Doctor serial The War Machines: WOTAN, the Master Computer, is expectedly chock full of blinking lights and tape drives - but so are the titular war machines, which were built on the mastercomputer's specifications. But that's not the best bit. The war machines, which were largish mini tanks that roamed the streets of London, had the tape drives mounted on the outside.
 * From Thunderbirds, Thunderbird 5, the manned observation satellite from which poor, neglected John Tracy monitored the world's radio airwaves for distress calls, used reel-to-reel memory exclusively.
 * In fact, the entire premise of the programme would be completely undermined by digital technology.
 * In Lost, the computer room in the first hatch (Desmond's, the Swan, 2nd season) has 'em. Whether or not the inclusion is realistic, it's good for maintaining that Forbidding Doomsday Computer vibe. The overall effect of pairing this visual with the song "Make Your Own Kind of Music" is positively surreal (especially compared to the outdoors setting that formerly predominated).
 * It's established later in the series that the installation and computer were set up in the late 70s and then  isolated from the outside world, so the tape drives (and monochromatic text-prompt computer interface) are completely era-appropriate.
 * In the Gerry and Sylvia Anderson series UFO a montage of flashing lights, spinning tape drives, blocky letters on coloured monitors, swaying female buttocks, and rows of large luminous buttons accompany every Red Alert.
 * Averted in A for Andromeda (written by astronomer Fred Hoyle who used computers in his work). The protagonist has to destroy all the components of the Master Computer to be sure it won't be rebuilt.

Music

 * The music video for the song "Computer Games" by New Wave group Mi-Sex was filmed on location at what was then Control Data Corp's North Sydney processing centre. In 1979. It does overlap with Computer Equals Monitor though.

Video Games

 * The memory banks from the videogame Evil Genius are big mainframes with a nine-track tape drive, which makes sense since the game is a 1960's Diabolical Mastermind simulator.
 * Also somewhat justified in that those items are pure memory banks, and the actual computing is done with a separate item looking more like a large desk (think N.A.S.A. computers in Apollo 13)
 * Surprisingly, most videogames - even current ones - where you get to see large, room-sized server farms (or mainframes, or whatever) seem to have at least one instance of a spinning tape animated texture slapped on a large block of metal.
 * It's justified in Team Fortress 2 as well, since it takes place in the actual 1960s. Granted, this world has been shown to have more advanced science than its period (or our own, or the laws of physics), but nothing that would have been out of place in a sci-fi flick of the period, which still probably would have featured tape drives.
 * The computers in Fallout are often found with tape drives. In Fallout 2, these are described as being very modern real-to-reel devices. Justified, given the slightly twisted alternate history the games exist in.

Web Comics

 * In The Inexplicable Adventures of Bob, not only does the Yoyodyne-built computer in the Generictown University Science Department have a tape drive (to be fair, the Dean's personal computer is a TRS-80), but so does a random gizmo on the alien planet of Butane.

Machinima

 * Lampshaded in Freeman's Mind when Gordon enters an old but still in-use reactor test site. Despite being under attack from an Eldritch Abomination, it is the sight of a tapedrive that sends him to a raging rant.

Western Animation

 * Played with in Megas XLR in the episode "Viva Las Megas", which features R.E.C.R, a giant military robot built in the 60's. It has a tape reel and a "massive" 56 kilobyte processor.
 * In The Venture Brothers, The computer system that stores is apparently run on tape.
 * In another episode,  M.U.T.H.eR. is on a reel-to-reel mainframe. Lampshaded when M.U.T.H.eR.  ; while everyone is panicking, Pete White mentions that a computer that runs on such an ancient mainframe (and uses a dial-up modem) can't act very quickly.
 * In one of the numerous SpongeBob SquarePants TV specials, the Atlanteans have a giant machine which can shrink people down to the size of viruses, and everyone's data gets stored on a magnetic tape drive.