Some process called “dasd” is running on your Mac. Don’t worry: it’s part of macOS. But what is it?

This article is part of our ongoing series explaining various processes found in Activity Monitor, like kernel_task, hidd, mdsworker, installd, WindowServer, blued, launchd, backup, opendirectoryd, and many others. Don’t know what those services are? Better start reading!

RELATED: What Is This Process and Why Is It Running on My Mac?

Today’s process, dasd, is the Duet Activity Scheduler Daemon. That explains everything, so thanks for reading everyone!

Just kidding: obviously that’s cryptic, so let’s look a bit deeper. A Daemon is a background process. This particular daemon manages other background processes. To quote the man page for dasd:

dasd -- Daemon for background activity scheduling.

So the Duet Activity Scheduler helps manage background activities, but how? A post on Eclectic Light Company explains how macOS runs background apps. Here’s what is says:

Duet Activity Scheduler (DAS) maintains a scored list of background activities which usually consists of more than seventy items. Periodically, it rescores each item in its list, according to various criteria such as whether it is now due to be performed, i.e. clock time is now within the time period in which Centralized Task Scheduling (CTS) calculated it should next be run.

You can read the entire post for more details, but the summary is that dasd is maintaining a list of background processes that your Mac should run soon. This is stuff that most Mac users will never have to think about, but you Googled the process and now you know. Congrats! You’re really cool and we should hang out sometime. Not next week, I’m busy then, but someday maybe.

You shouldn’t notice dasd using up a lot of system resources—its job is pretty straight forward. If it does the problem is probably with a background task, so check to see what other processes are using up a lot of resources and look into them.

Photo credit: guteksk7/

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Justin Pot has been writing about technology for over a decade, with work appearing in Digital Trends, The Next Web, Lifehacker, MakeUseOf, and the Zapier Blog. He also runs the Hillsboro Signal, a volunteer-driven local news outlet he founded.
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