What’s Special About Peek-a-Boo

originally published June 2004; last updated & converted to blog entry September 2011

An updated version of this article is available as a blog entry. The old version is maintained here as an archive, but updates and commentary will be easier over in the blog.

Peek-a-Boo is Clarkwood Software’s OS X application to watch processes. (See sidebar.)

There are several factors that we think make Peek-a-Boo special; this page explains some of the decisions behind Peek-a-Boo’s design philosophy and why Peek-a-Boo has been maintained, updated, and used for two decades.

What is a Process?

Basically a process is a program running on your Mac. When you start up your Mac and begin to work, there are dozens of processes running simultaneously behind the scenes to keep your Mac working.

Each application that you open is another process, and each process may spawn even more.

Use Peek-a-Boo to
Explore Processes

Peek-a-Boo is the most intuitive way to explore what’s happening in the universe of processes on your Mac.

Peek-a-Boo offers a wide choice of ways to help you explore the processes running on Mac OS X; you can choose between watching overall system behavior in a variety of windows, or zooming in to scrutinize individual process behavior.

Use Peek-a-Boo’s innovative OpenGL-powered Process Throb window for a hypnotic (yet useful) display of your OS X system’s processes. Or use the traditional Process List window to watch whatever process attributes you care about.

Many Pieces of Information Available

A primary design philosophy of Peek-a-Boo, since its 1.0 release in 1993, has been that it should be able to show as many items of process information as possible, and allow the user the freedom to pick which of those items are important to view. That’s why you’ll never see a version of Peek-a-Boo with a handful of process information items hardcoded to what we think are the most important pieces of process information.

There are three kinds of processes encountered on OS X, and Peek-a-Boo is the only utility able to display information about each kind.

  1. OS X Applications are processes which are OS X native and offer a user interface. Generally if a process has an icon, it’s an OS X Application.
  2. Darwin processes are generally lower-level processes, which do not offer an Aqua user interface. These can be seen from command-line tools like ps and top, as well as from Peek-a-Boo.
  3. Classic Applications are applications running in the Classic compatability environment. (These are becoming rarer, as more of the installed based of Macintosh computers are Intel-based; Intel-based Macs do not support the Classic compatibility environment.)

Virtually any piece of information can be seen in Peek-a-Boo’s process list. The View menu contains one submenu with many pieces of information that Peek-a-Boo knows how to extract (the Built-in Items submenu), and another submenu with all the pieces of information extractable by the ps (process status) Darwin/Unix utility.

Many Sources of Process Information

OS X offers several different ways to extract process information, and Peek-a-Boo uses all of them.

  • OS X’s Unix foundation supplies many pieces of information for each process (except individual Classic applications).
  • The ps command-line tool offers several dozen pieces of information for each process (except individual Classic applications).
  • The Carbon Process Manager offers information for each running application.
  • The Classic Process Manager supplies additional information for each running Classic application.

Peek-a-Boo is the only utility available which can extract information from all these sources and coelesce all the information into one easy-to-understand interface.

Focus on Processes

Peek-a-Boo’s design philosophy is heavily biased towards being able to analyze information on a process-by-process basis, as opposed to a system-wide basis. This focus can be seen in features such as the CPU Usage History windows and the Logging windows which also enable logging information to a file.

Highly Customizable

Peek-a-Boo has a history of being very highly customizable. The tyranny of being bound to eight pieces of process information is over! The View menu allows extraordinary customization of which process items you see (only a few if you want, or a plethora of arcane process data if you’d prefer), and the Preferences panes allow further view-specific customization such as how frequently each kind of window is updated, and even whether CPU Usage History windows’ graphs should be pegged to 100% or should shift dynamically depending on the process’ CPU usage.

Easy to Monitor Process Behavior

Peek-a-Boo makes it easy to monitor resource usage. Memory information takes the guesswork out of knowing when adding memory will improve performance; and Peek-a-Boo’s graphical CPU interface makes it clear when performance is CPU bound.

Peek-a-Boo makes it easy to notice processes that are using a surprising -- even absurd -- amount of memory or CPU time. The logging windows can be very helpful for detecting processes that may leak memory over time. These features can be particularly useful to developers and quality assurance departments as well as anyone who simply wants to know what’s going on with the applications they are running.

Easy to Manipulate Processes

Peek-a-Boo makes it easy to perform process-specific operations such as bringing an application to the front, hiding an application, or killing a process. Obviously some of these features must be used with care, but having many common “tools” at your fingertips makes Peek-a-Boo an even more useful process-watching utility.

Pssst: On The QT, You Need Peek-a-Boo

Peek-a-Boo has been described by one long-time user as “the utility I didn’t realize I needed, until I’d used it for awhile.”

Peek-a-Boo focuses on two things: clarity and flexibility. From the moment you first launch Peek-a-Boo, it will be clear what is happening with processes on your Mac. And you will find the flexibility to explore any process-related questions you face.


Peek under the hood of your Mac OS X system using Peek-a-Boo! Use this
powerful and beautiful tool to twirl into process-comprehension nirvana.

We’re confident that even at the peak of your frustration towards the Mac’s complexity, a quick peek under the hood will pique your curiosity and lead you upwards, onwards, and forwards, twirling into process-comprehension nirvana.

We challenge you to give Peek-a-Boo a try, to see if you would also describe Peek-a-Boo as the utility you didn’t realize you needed.