The Birth of Mac Multitasking

The “one app at a time” part was the first big problem with the desktop metaphor. In the real world, people who work at desks tend to work on more than one task at a time, but not so on the original Mac: when you opened a document to work on it, it covered the desktop completely. To see your desktop again, you had to stop working.

These early limits were understandable: the first Macs barely had enough storage and processing power to handle even one app at a time. But new technology improves very quickly, and soon the one-app-at-a-time constraint on the Mac was a design instead of a performance constraint. The Mac user interface and its underlying software were not designed to run multiple apps at a time, even when the hardware got powerful enough to do so.

Several early schemes attempted to work around that. One of the first attempts was Switcher, which could keep more than one app at a time running. However, each app took over the entire screen: when you switched apps, the app you had been using was replaced on the screen with the next app, which slid in to cover the first. After Switcher, though, came MultiFinder, which finally did keep the desktop visible behind the windows of the currently running apps. But MultiFinder, which continued being a standard part of the Mac’s operating system until Mac OS X came along, multi-tasked…well, badly is the best way to describe it. Users had to fiddle with allocating memory to each app manually (virtual memory was not a Mac thing) and if a single app crashed, they all did (memory protection was not a Mac thing).

How the Mac Look and Feel Became the Face of Unix

Mac OS X’s arrival in 2001 rebuilt the Mac user interface on top of Unix. Except, well, it wasn’t the Mac user interface, it was a Mac user interface. It looked similar to what was now called the “Classic” Mac interface, but it was far from identical (Figure 31).

Of the numerous differences, large and small, between Classic and Mac OS X that bedeviled Mac users at the time (and remain sore points for many Mac users even today), these two app-related ones are illustrative:

• The death of Desk Accessories: Now that Mac’s had virtual memory, the design constraints that led to Desk Accessories (being able to run in a really small memory space was a big one) were gone, because you could run a lot of apps at the same time in Mac OS X’s virtual memory space. Apple repurposed the Apple  menu—but at least, it still had a purpose; an early draft of OS X had no Apple  menu, but merely a small inert  logo in the center of the menu bar!

• Different window layering rules: In the Classic interface, when you clicked a window belonging to an app, all of the windows belonging to that app moved in front of the windows from other apps. In macOS, windows from different apps can interleave on the screen (confusingly for long time Mac users). For example, in Figure 31 (just above), several windows from other apps are sandwiched between the two windows belonging to the Pages app.

In Mac OS X, many of the small apps and widget-y things that had been prime candidates for being packaged as Desk Accessories became full apps while others became background processes (sometimes known by the delightful and evocative name daemons but usually referred to by the more boring developers as services). Ordinary users like you and me managed such services/daemons/background processes in several different ways, which I describe a little later in The App Pursuit.

From Exposé to Mission Control

Mac OS X brought a number of techniques to address the mystery of managing the many windows that could populate the screen of a multitasking Mac, even one tricked out with really large multiple screens. After all, the bigger the desktop, the more clutter it can contain. Finding the window you were working on just a second ago is an everyday Mac mystery.

The first of these window managing techniques was known as Exposé when it was introduced, but it has since developed into a family of related window management functions and currently is known as Mission Control. Unfortunately, the name Exposé stuck, so now you’re likely to hear people talk about Exposé when they mean Mission Control, and Mission Control when they mean the specific function of showing all open windows at once that was the job of the original Exposé feature.

In any case, Mission Control/Exposé/whatever is controlled through a System Preference named (what else?) Mission Control (Figure 32).

Mission Control has three main functions related to handling the window clutter on your screen:

• Reveal the Desktop: This function sends all the open windows cluttering your screen skittering off to the screen’s edges so that you can see the clutter of icons littering the Desktop underneath. You can invoke it with a keypress, a trackpad gesture, or by moving your mouse to a designated screen corner (set in System Preferences > Mission Control > Hot Corners).

• Reveal the current app’s windows: Formerly, and sometimes still, referred to as App Exposé, this function arranges all the windows of the frontmost app (the one whose name appears beside the  menu) so that they all can be seen at once. Again, you can trigger it with a keypress, a trackpad gesture, or by moving your pointer to a designated corner.

• Reveal all the windows: This function was once known, and often still is known, as Exposé, though now its current “official” Apple name is Mission Control, the same as the System Preference pane that controls all the window-management-related functions, because that isn’t confusing at all! When invoked (again, via keypress, pointer location, or trackpad gesture), it arranges all the windows of all the open apps so that they can be seen at once (Figure 33).

A Victim of App-instance

In the beginning, when a Mac had only a floppy disk drive, each app came on its own floppy disk and keeping track of your apps was not a computer problem, it was a physical clutter problem. You could put labels on your disks and store them in disk boxes (I have several lovely roll-top disk containers), and if you couldn’t find an app, it wasn’t your Mac’s fault, but your inability to keep track of things—actual, physical things.

Today, even the most pared-down Mac you can buy from Apple has 8 GB of RAM and 128 GB of internal storage. Such a device is capable of storing quite a few apps. What’s more, any Mac you buy today comes with a plethora of apps already installed, many of which the casual user would be hard-pressed to find by browsing with the Finder. One reason for that (but certainly not the only reason) is that today’s Unix-based macOS is a thriving community of interacting apps, processes, and services. In fact a number of the apps that users can buy today comprise several apps designed to work together: what looks like a single app to the user is in fact a team of apps laboring in hidden harmony.

Luckily, most users never need to get so granular as to poke under the surface of a commercial app to find what hidden treasures comprise it. Nonetheless, when the Unix-based Mac OS X arrived around the turn of the century, Apple began to divide apps into various categories and developed rules about where apps could be stored: the days of just storing an app wherever you wanted on your Mac’s hard drive was no longer guaranteed to work.

Permission Required

The Unixy foundation of the Mac’s new Mac OS X necessitated some of these rearrangements and restrictions. Unix (and, thus, Mac OS X) was designed to handle multiple users, and so Mac OS X brought the whole idea of user permissions into the Mac universe, to the confusion of many ever since (Figure 34).

Permissions allowed Sarah J. User’s files and folders to be only available to her and Barton Q. Otheruser’s folders and files to be only available to him. To enforce this, OS X gave both Barton and Sarah separate Home directories on the same Mac’s hard disk, and each Home contained the files and folders for their respective users—but neither user could traipse into the other’s Home without permission.

Great…until Sarah wanted to install a new app on the Mac. If she installed it in her Home directory, Barton couldn’t run it because he only had permission to access files (including apps) in his Home. Ditto for Sarah when Barton installed apps. For both Sarah and Barton to have access to the app, they would either each have to install a copy of the app somewhere in their respective Home directories (thus wasting storage space), or install the app in some special location to which both of them had access.

OS X, therefore, provided just such a special location for apps that any user can access, and that arrangement persists in today’s macOS. Here’s a broad overview of where you can expect to find your apps:

• Apps for all users: These go in the Applications folder, found at the top level of the boot volume (that’s the disk or SSD your Mac boots from). Apps in this folder and in its sub-folders (such as the standard Utilities folder) can be opened by any user on the Mac. However, only users with Administrator privileges can remove apps from the Applications folder and its sub-folders.

• Apps for individual users: These go, by convention, in the ~/Applications folder; that is, at the top level of a user’s Home directory, though single-user apps can, in fact, be installed almost anywhere in the Home directory.

• System apps: Starting in macOS Catalina, these can be found in the /System/Applications folder. The system apps are apps that come with macOS and that provide much of its functionality, such as Mail, FaceTime, and System Preferences (yes, it’s an app). Most users, regardless of whether they have Administrator privileges, can’t add apps to or remove apps from this folder. But, as a convenience to users, and to muddy the waters further, macOS displays these System apps in the top level Applications folder. This, though, is a macOS illusion: they’re really stored in /System/Applications (Figure 35). But since they all appear in the top level Applications folder, few users ever need to know or care where they really reside.

Apple has tried to hide the complexity of this arrangement in several ways. For example, when a user (whether Administrator or not) gets an App from the Mac App Store, the Store automatically installs the app in the Applications folder; the user need not worry about where to put the app.

The Finder also makes it easy for users to find their way to the Applications folder: by default the sidebar in every Finder window includes that folder in its sidebar and gives it both a menu entry and a command-key shortcut in the Finder’s Go menu (Figure 36).

The Dock Disappearance

But Mac OS X brought a new tool for accessing apps to the Mac, and it persists in macOS today along with several other app accessing methods. That tool is the Dock, and it has been both a source of joy and consternation for Mac users old and new from its introduction.

I’m not going to delve into all the complexities of using the Dock; Apple’s online help provides a good summary. I do want to focus on one very important Dock property, one that trips up users all the time:

Nothing on the Dock is real.

The Dock displays shortcuts to your apps and documents. It is neither inclusive nor determinative: it only shows you the stuff that you put there or that Apple puts there, and when you remove an icon from the Dock, it doesn’t affect the item’s presence on your Mac—that item remains where it always was.

This last is an important point and is instructive for those who believe the interfaces they have designed are obvious and self-explanatory because (based upon the numerous calls and messages, some quite frantic, I’ve received over the years) lots of people believe that when an icon disappears from the Dock, the app or document it represents has vanished from their Macs, even though:

• When users drag an app or document from a Finder window to the Dock, the dragged item never leaves the Finder window, clearly implying that the icon that ends up in the Dock merely represents the actual app or document.

• When the item that a Dock icon represents actually is missing from the Mac, the icon remains in the Dock but has a question mark overlaying its icon to let you know the item is missing (Figure 37).

A large part of this confusion arises from the Dock’s success as an app launcher: the Dock, because it is always visible, is usually the first place users look for the apps they want to use; in fact many users seldom open the Applications folder or remember that it even exists. From their point of view, an app’s Dock icon is the app. That Dock items are so lively (they happily bounce when you click them) and so visually vivid (Dock icons generally show the best, most detailed version of an app’s icons) and so informative (unlike the actual app’s icon in a Finder window, an app’s Dock icon clearly indicates whether or not it is running, as in Figure 38) all help reinforce the mistaken belief that the Dock is where a Mac’s apps live.

What makes this belief so stressful for many users is that it is remarkably easy to make a Dock icon vanish: just drag it away and it’s gone. A mistaken wrist flick with the mouse or trackpad held down is all it takes (and trust me: this happens far more often than you might think). Nor does the Dock ask you to confirm the removal; why should it—you’re only removing an easily replaceable shortcut!

Between the illusion that the Dock is where your applications live and the ease with which you can change and rearrange your Dock’s contents, this very useful addition to the Mac experience nonetheless manages to provide unexpected thrills and chills.

The App Sequestration

As I’ve mentioned elsewhere, the success of the iPhone and iPad brought a number of new users into the Mac fold. And to help those new users become acclimated to the Mac, in 2011 Apple introduced a new app-launching feature that bore remarkable similarities to the iOS home screens from which iPad and iPhone users launch their apps: Launchpad (Figure 39).

Like an iOS/iPadOS home screen, Launchpad arranges your apps’ icons in grids on a sequence of screens that you can swipe between. It furthers the resemblance by:

• Giving you the capability of collecting sets of apps into “folders,” tile-shaped icons that bear no visually resemblance to the Mac Finder’s folders, when you drag one app icon onto another.

• Adding automatically any app you have purchased from the Mac App Store into Launchpad along with any other apps your Mac has in the /Applications folder and its subfolders. This includes those apps that appear in the /Applications folder but that are actually located in /System/Applications (see Permission Required). Launchpad also displays apps you may have in the ~/Applications folder if you have that folder in your Home directory.

• Jiggling the app icons when you hold down on one and displaying their deletion buttons (Figure 40) so you can delete apps you no longer want on your Mac. To protect users new to the Mac as well as users with twitchy fingers, these deletion buttons only appear for apps you obtain from the Mac App Store (which you can easily download again): apps you obtain through other means, and that may not be conveniently restored if deleted in error, are safe from erroneous clicks.

Although Launchpad lacks a few niceties (for example, there’s no way to Get Info on a Launchpad icon), it provides a clean, easy way for users to get at their apps without rummaging through Finder folders. It might well prove to be the app-launching feature of choice for many Mac users except for this central mystery: why has Apple hidden it so remarkably well?

By default, the only visual indication that your Mac even has a feature called Launchpad is a muted gray Dock icon that provides no clue as to its function (Figure 41). There is no Launchpad item in the Finder’s Go menu, it isn’t listed as one of the “Apps included on your Mac” in Mac Help, and it isn’t even available in Launchpad itself unlike most of the /System/Applications apps that Launchpad includes in macOS Catalina—good luck restoring it again if you mistakenly drag it off your Dock! (Thankfully, it does appear in the Applications folder.)

Nonetheless, you can make Launchpad conveniently accessible. It is one of the items you can trigger with a Hot Corner (see The Edge Case), you can trigger it with a trackpad gesture (a rather contorted thumb-and-three-finger pinch, enabled via System Preferences > Trackpad > More Gestures), and it is assigned by default to the F4 key.

For ease of use, Launchpad earns a deservedly high mark; for discoverability, it is a sad, mysteriously inexplicable failure.

The Quest for Screen Space

Macs have always had screen space issues. The 9-inch diagonal screen on the original Mac was just wide enough to display a 6½-inch line of type (with a small margin on each side) in MacWrite, the first Mac word processor. It could have displayed more, except that the Mac was designed to give users a what-you-see-is-what-you-get (WYSIWYG) view of their documents, and scaling the display to show more content ran counter to the WYSIWYG intent. That the pixels on the original Mac screen were exactly 1/72-inch (equal to one point, the measurement unit used in typography) was not a coincidence: a 12-pixel tall character in MacWrite was exactly as tall as a 12-point typeset character. Verisimilitude came at a price.

Thankfully, that strict WYSIWYGishness eased over the years, and as Mac displays became larger and capable of finer resolution, and as the Macs themselves more powerful, users could not only scale documents to show more or less of their contents at will, but the Mac display itself. The 1 pixel=1 typographer’s point equivalency no longer held true: today’s Retina displays typically offer resolutions well over 200 pixels per inch, and the macOS software can scale whatever an app needs to display on the screen quickly and smoothly regardless of the resolution the user picks (which you can do via System Preferences > Displays > Display).

Nonetheless, screen space remains limited: there’s only so much you can cram into the bounds of even a 27-inch iMac display set at its highest usable resolution. And if you happen to have a MacBook Air (which has about ¼ of the screen real estate as a 27-inch iMac), it can feel like you spend half of your multitasking time in window management.

One solution is to add a second display, but that is both expensive and awkward, especially for laptop users on the go. Another solution is to add virtual displays: extra desktops you can dedicate to different main tasks. And that’s the solution that Mission Control’s Spaces provides.

Going into Spaces

Spaces, which has been available on the Mac since OS X 10.6 Leopard (2006), remains a mystery to many Mac users because it isn’t all that easy to discover and because how you get to it has changed in the Mac interface over the years. You currently get to it by using Mission Control, which (as mentioned in The Task Trouble) you can trigger in several ways:

• Keypress: Control-↑ by default, but you can change it in System Preferences > Mission Control (and take a look at System Preferences > Keyboard > Shortcuts > Mission Control for additional keypress possibilities).

• Trackpad gesture: Either a three- or four-finger swipe up, which you can configure in System Preferences > Trackpad > More Gestures.

• Dock icon: In recent versions of macOS, the Mission Control icon is in the Dock by default (Figure 42), although it can be removed.

  

• Hot Corner: You can set one of the screens corners (via System Preferences > Mission Control > Hot Corners) to trigger Mission Control when you move your pointer to that corner.

When you do trigger Mission Control, not only does its Exposé function reveal all the currently open windows on the desktop but it also replaces the menu bar with a Spaces bar, showing you the currently available spaces (Figure 43). Move your pointer to the Spaces bar, and the bar expands to show you thumbnails of what’s currently in whatever spaces are available—which, in the case of users who have never tried using Spaces, will usually consist of one thumbnail.

You always have at least one space: the desktop on which you are currently working. To add others, trigger Mission Control and then click the Add button that appears at the end of the Spaces bar. You can use System Preferences > Mission Control to control how your spaces arrange themselves on the Spaces bar.

You can assign apps to open always in a particular space: Control-click the app’s Dock icon and choose from the Assign To items on the contextual menu’s Options submenu.

Spaces makes it easy to create specific desktops set up for tasks you commonly undertake. For example, I personally have six spaces I regularly use on my iMac (squint closely at Figure 43 just previously to see them): one dedicated for Mail work, one for Safari web browsing, one dedicated to text editing with BBEdit, one with a plain blue background that I use when I want to take screenshots for a book or article, one for working with Photos, and one for Music. To switch between them, I use a four-finger swipe (left or right) or use Control-← and Control-→.

Full and Split Screens

Dealing with many windows and apps is one half of the space management issues that modern Mac users face. The other half is avoiding the distraction of all of those windows and apps when you’re trying to focus on the task at hand.

The original Mac, with its small screen and limited resources, didn’t have that problem because, as I mentioned way back at the beginning of The Task Trouble, Macs of that era could generally run only one app at a time, and the main windows of those apps usually filled the screen.

But even back then, Mac windows were resizable, and their title bars usually had a mysterious button known as the “zoom” button at their right ends. What made that button mysterious was that you never knew what clicking it would do. In some apps, like the Finder, the zoom button might enlarge the window just enough so you could see its complete contents (if possible); if those contents were paltry enough, the window might grow only by a little. In other apps, clicking it would cause the window to fill the screen completely, regardless of the window’s contents.

When Mac OS X arrived, the zoom button went away, and the first version of the familiar “traffic light” window buttons appeared in Mac window title bars, with the green button replacing the zoom button. However, its function remained as ambiguous as it had in the old classic Mac OS days.

No longer! Today, with multiple spaces a standard part of macOS, and with a range of Mac screen sizes ranging from the relatively cramped MacBook Air screen to the spacious iMac 27-inch Retina display, that green zoom button now has a predictable function: to create a new space and then completely fill the screen in that space with the zoomed window.

With full-screen apps, you can focus on the task at hand, relegating all the other tasks-at-hand to different desktop spaces, but making them easily accessible with either a keyboard combination or a mouse gesture or a trackpad gesture. Switcher redux!

Full-screen apps are a wonderful enhancement for modern Macs with lots of storage but limited screen real-estate…such as just about every laptop Mac that Apple sells. On the other hand, the feature can offer lesser value for many apps running on large-screen Macs—read a book full-screen in Apple’s Books app on a 27-inch Retina iMac and revel in the wasted white space!

It’s a draconian split: either have a bunch of apps’ windows competing on the screen for your attention, or relegate all but one app to other desktop spaces and let that one app have the whole screen. Surely, there must be some middle ground. And there is: the 2-way Split View, introduced in OS X 10.11 El Capitan (2015).

Using Split View, you can split the screen between two apps instead of restricting your screen to one. This can suit a number of situations, such as (to pull one completely out of thin air) the case of a writer who needs to do research in a web browser while working on his book about Apple interface mysteries. As with a full-screen app, a split view creates a new, temporary desktop space in the Spaces bar, so you can easily navigate from it to any other desktops you may have available (Figure 44).

Split View does not eliminate all the complexity that multitasking with multiple apps can engender, but it simplifies those tasks that require you to work with two apps at the same time—and my experience suggests that’s a good proportion of multitasking scenarios.

How you create a split view, though, has been something of a mystery, although less so now than in the past: starting with macOS 10.15 Catalina, when you hover your pointer over a window’s zoom button you see a menu offering full screen and split view choices (Figure 45). This finally makes discoverable your Mac’s previously well-hidden Split View feature. (Apple’s support article, Use two Mac apps side by side in Split View, describes how to create a split view in Catalina as well as in previous versions of the Mac operating system.)