Q: Fonts in RAM and font managers

I don't think you are entirely correct, hopefully someone will correct me if I am wrong but here is my assessment of the situation…

All installed or active fonts are not loaded into RAM at startup as it would be an unnecessary on memory constrained Macs. System fonts will be loaded into memory as they are commonly required.

I believe some font features do get cached, such as the previews for font selection panels that are used in some apps, these are often written to cache files stored on disk as far as I can tell.

Installing & activating thousands of fonts can cause some issues as apps may have to generate previews for those fonts - e.g. MS Word has it's own custom font picker that uses the actual font for the selection names. Some design apps may parse or search for fonts when opening certain documents with linked font styles. Other apps like TextEdit, Mail use system based pickers so they benefit from the system wide font caches.

The reason for FontBook is to help with the management of Fonts. OS X uses the 'Library system' to allow for multiple levels of abstraction, e.g. /System/Library is for OS level files (Apples own stuff), /Library is for third parties that need system wide support, ~/Library is for the users specific files. There is even support for resources to be stored in /Network/Library for use with a server on a large network.

Managing all of that gets complex without one central application. I believe the order of preference is from the user out toward the higher levels, so your own user Fonts folder is chosen over the system one if you have similarly named fonts. Part of the the idea is also that you can dump fonts into your own home library without affecting other users on the system.

Third parties also have font managers that attempt to 'do the right thing' based on what documents & applications you use. These are mostly for large design offices that use custom fonts or are required to typeset with specific font versions, variations and even if fonts are licences for specific clients etc. Dynamically loading & unloading fonts can cause many headaches depending on what software you use.

I don't think average users need to think about Fonts at all on OS X (beyond adding their favourites occasionally), you may be overthinking it unless you are into lots of design work.

If you are concerned by running out RAM, you probably need to install more, get a better Mac or run less apps. Just bear in mind OS X now tries to use all available RAM most of the time otherwise what its the point in having it fitted?

Drew has covered much of this very well. I'm just going to add some points, which may partly duplicate Drew's notes.

I'm running El Capitan 10.11.6, though I don't think this specificity is relevant.

Correct. It has no specific relevance. Font management in Apple's OS has been the same for as far back as I can remember.

I have the impression that the purpose of the ability to activate and deactivate individual fonts using font management software (Font Book or third party) is to eliminate it from the RAM (or at least in some other way offload it from the Mac's processing).

A representative for Adobe once described fonts as "plug-ins for the OS". That's a pretty good description. Each active font takes up space in RAM so applications can find and use them, and know what names they should display in your font lists. Inactive fonts take up no space in RAM. Fonts you deactivate are released from RAM so they no longer take up space. It's the same basic action as quitting an app. You're closing the item.

I also believe I read it mentioned somewhere that all fonts placed in the location User/Library/Fonts are always active in the RAM, and this is maybe why it's important not to just dump hundreds of fonts into that folder.

When you first add new fonts to Font Book, it automatically activates them in the assumption that since you just added them, you must want to use them. But they can all be deactivated any time afterward. All fonts that were previously active will be activated as the OS boots up on a startup or restart.

If using third-party font management software to disable a font placed in the User/Library/Fonts folder actually eliminates it from the RAM (as it presumably does for fonts outside system designated font folders)?

Yes, deactivated fonts are cleared from RAM. Manually moving a font out of the user account Fonts folder, or the root /Library/Fonts/ folder will do the same thing (as long as it's not from one Fonts folder to the other).

On the other hand, I suppose there is no harm in just avoiding the ~/Library/Fonts folder, and simply using a custom-defined location. I just liked the idea of using default practices as much as possible.

Yes, you can if you wish. My preference is to leave fonts where they are and activate them in place, which you can do with Suitcase, Font Book, and FontExplorerX Pro. They don't have to be in any particular Fonts folder as created by the OS.

I believe I've read you mention in the past that you recommend deleting Font Book…

Yes, that is my mantra. There's nothing special about Font Book. It's just another font manager. Removing it won't affect the OS one iota. You can always copy the Font Book app to another drive as a backup, then remove it. The rest of the components (such as framework files), will still all be on the drive. So all it would take to bring it back is to copy the app back into the Applications folder.

You can leave it, but you have to be a bit careful. You can reset Font Book by closing it, and then putting these two files in the trash. They are both in the Preferences folder of your user account.

com.apple.FontBook.plist

com.apple.FontRegistry.user.plist

With these files gone, Font Book is doing nothing on the system. There's no file for the OS to read that tells it what fonts Font Book thinks should be active or inactive. You preferred font manager will behave as you expect. Simply launching Font Book gums up the works as it will create the first file again, which keeps track of Font Book's preferences, and what fonts are active. Since it has just been created, all fonts in the System, root Library and user account Fonts folders will all be made active. Now your preferred manager is fighting with Font Book when you want to disable some of these same fonts. You say off with Suitcase. Font Book tries to hold that same font open since you haven't told it what to do. This will persist through restarts as long as the preference file remains. It's just easier to get Font Book completely off the system since you aren't using it as your manager anyway.

Axcylae wrote:

 

(EDIT: I'm not sure why, but I'm not able to mark Drew's original response as helpful. For the record, although I basically knew the information discussed, I consider it a helpful response to the question. Thanks guys.)

LOL, Apple must have it in for me, no problem glad it helped.

As the person who started the topic, you're allowed to mark two posts as Helpful, and one as Solved. Drew has a lot of good info there, and is worthy of a Solved, in my opinion.