Category:Memory Crystal

''You may be looking for the actual Floor 500 in Satellite 5

Floor 500 is the top-level category for the Tardis Data Core. Like its namesake from TV: The Long Game, our Floor 500 is a central hub for information. All pages are ultimately linked to this one. The category is divided into four major kinds of information: stuff within the fictional Doctor Who universe, fictional stuff that's not in the Doctor Who universe, behind-the-scenes production information, and stuff that helps the wiki itself run.

'''No individual article pages should link to this one. Category:Floor 500 should remain composed of only four subcategories.'''

Four on the floor
Category:Time-Space Visualiser is by far the largest of the subcategories. It contains the vast majority of articles present on this wiki. All categories and pages within it contain information written from an in-universe perspective. That is, they are written on topics that have to do with the narrative "reality" of Doctor Who and its spin-offs. Such articles are easy to spot, because they're written in the past tense and tend to treat their subjects as "real" things that once existed. Note that this category includes information about Doctor Who, Torchwood, The Sarah Jane Adventures, K9 and Company and K9 — and almost all licensed spin-off material arising therefrom.

Still, there are some works of fiction that are not within the Doctor Who universe for one reason or another. Articles about such fiction can be found in Category:Non-DWU material. A word of caution: please make sure you read T:CAN and T:VS before adding any of these categories to articles. There are actually very few works of fiction which can be classed, according to our rules, as truly "non-DWU".

Next comes Category:Real world. This category contains information about the production of Doctor Who universe stories. Its articles and subcategories are all written from the "real world perspective", usually in the present tense. It, too, includes production information from the above shows, along with information about the producers of both licensed and unlicensed material in other media. Note that even the producers of non-canonical material can be tagged with a real world category.

Finally, there's Category:The Hub, which is an administrative category for things that help the wiki function. Most of the things that get put in this category do so automatically, because a little piece of code makes it happen. Unless you really start editing the structure of this wiki, though, chances are you'll never peek inside this folder.

Keep 'em separate
No article should be tagged as being in more than one of these four main categories. An article can — theoretically — belong to an unlimited number of subcategories, but all these subcategories must be a part of only one of the four main categories. For instance, a thing cannot be both non-canonical and a part of the Doctor Who universe. Nor can it be both in the real world and in-universe.

This last assertion may be harder to grasp. If you have a category like category:People from the real world — which tags real-life people like Charles Dickens who have appeared in Doctor Who — you may believe that such a category belongs both within Category:Real world and Category:Time-Space Visualiser. In fact, though, the article Charles Dickens is written from an in-universe perspective. That is, it's about Dickens' relevance to the history of that universe, not our own. Thus, the category only belongs in Category:Time-Space Visualiser. Such cases, though, are rare. Most of the time, it's perfectly obvious which main category should house an article.

Exceptions
Despite the general desire to keep things only in one of the four categories, there are a couple of very specific exceptions, both having to do with Category:Merchandise:
 * It is possible for an article or category to be in both Category:Real world and Category:The Hub, because they're both real world categories. So far, the only category to cross over in this way is Category:Galleries, because galleries are created by a specific feature of wiki markup code, and because all the galleries in the category were displaying Doctor Who merchandise, organized under Category:Merchandise.
 * Because of a specific enumeration of Tardis:valid sources, Category:Doctor Who role-playing games is both a part of Category:Merchandise and Category:Non-DWU material.

Nomenclature
As a general rule, we've tried to make the distinction between real world and in-universe categories easy. Take, for instance, broadcasters. There are broadcasters in the Whoniverse, like AMNN. And there are broadcasters in the real world, like BBC America. Clearly, they shouldn't be in the same category, but somehow the word "broadcaster" will probably appear in the two separate categories that these articles require. Generally, it works like this:
 * Unmodified nouns name subcategories within Category:Time-Space Visualiser, and if it's in Category:Real world, it's prefaced with the words "Real world". Thus Category:Broadcasters is about broadcasters within the Doctor Who universe, whereas Category:Real world broadcasters is for broadcasters that actually exist. The odd exception is for noting real life things that appear within the fictional world of Doctor Who — and thus become a part of the Whoniverse — which we'll discuss next.

"Real world . . ." vs. " . . . from the real world"
Things which exist in the real world, but are part of the Doctor Who universe, are within the super-category Category:Time-Space Visualiser. They follow the syntax:  Category: from the real world . Thus: Category:Astronomy from the real world, Category:Science from the real world, Category:People from the real world.

However, things which exist in the real world, but not in the Doctor Who universe are a part of Category:Real world. They follow the syntax:  Category:Real world . Thus: Category:Real world directors, Category:Real world magazine publishers, and Category:Real world people.

Example
The need for this strict syntax perhaps becomes most obvious when speaking of people. Take the cases of Leonard Nimoy and Charles Dickens. Nimoy was once mooted as the director of a Doctor Who film, but he has never appeared as a character in Doctor Who. Thus he belongs to Category:Real world people. Dickens, by contrast, has never been a writer for Doctor Who, but he was a character in The Unquiet Dead. Thus he belongs to Category:People from the real world.