Can you slim macOS down? – The Eclectic Light Company

Skip to content

The Eclectic Light Company

Macs & painting – 🦉 No AI content

Main navigation

Menu

Downloads
Freeware
M-series Macs
Mac Problems
Mac articles
Macs
Art

hoakley

January 21, 2026
Macs, Technology

Can you slim macOS down?

Open Activity Monitor when your Mac isn’t doing a great deal and you’ll see hundreds of processes listed there. Even in a virtual machine with a minimum of services there are at least 500, and in a vanilla setup with no apps open a real Mac can exceed 700. Clearly some of those like WindowServer are essential, but aren’t there plenty we could do without? That’s a question I’m asked repeatedly, which this article tries to answer.
One of the first problems when trying to identify which processes we could do without is knowing what each does, and how they’re interrelated. I doubt whether any individual in Apple knows them all, and trying to establish what some do would be a challenge. If we assume that we need to identify just 500 candidates, and each takes an average of one week to research, that would take over 10 person-years, by which time they would all have changed again. Studying 500 targets that are ever-changing simply isn’t practical.
When problems get difficult, it’s often best to cheat, so I’m going to go for the low-hanging fruit and consider a well-known group of processes, those making Time Machine backups. I’ve been following these since macOS Sierra, and frequently study them in the log. They’re also good candidates for removal, as many folk don’t back up using Time Machine but use one of its alternatives. So some already have good reason to want to be rid of backupd and its relatives. They’re also relatively discrete: although they depend on other processes to function, I don’t know of any other subsystems that require Time Machine, making it potentially disposable.
Set up a basic VM in maOS 26.2 and, even though Time Machine has never been enabled, you’ll see its processes listed in Activity Monitor.

Here are backupd and backupd-helper showing they still take a little % CPU even when Time Machine is completely disabled.

They also take a little memory, here a total of 5.1 MB. While that isn’t much, added up over 500 processes it becomes worth caring about.
Those two processes are controlled by LaunchDaemons stored in /System/Library/LaunchDaemons, in property lists named com.apple.backupd-helper.plist and com.apple.backupd.plist. Here’s our first problem, as those are located in the Signed System Volume (SSV), so we can’t change them in any way. The same applies to the other 417 LaunchDaemons and 460 LaunchAgents that account for most of the processes listed by Activity Monitor. In the days before the SSV it was possible to edit their property lists to prevent them from being launched, but that isn’t possible any more when running modern macOS.
If we can’t stop the backupd-auto process from being run, is there any other way we could block it? To answer that we need to understand how it’s scheduled and dispatched.
Until macOS Sierra, Time Machine backups were run from launchd as timed events, but since then their scheduling and dispatch has been performed jointly by Duet Activity Scheduler (DAS) and Centralised Task Scheduling (CTS), using lightweight inter-process communication (XPC). DAS manages a huge list of activities including com.apple.backupd-auto, and decides when to dispatch it to CTS to run. For example, it won’t do that for the first five minutes after a Mac starts up, to allow other processes to run first.
Once that time is up, DAS decides to run the backup:
38.738 DAS 0:com.apple.backupd-auto:2052A3, Decision: CP Score: 0.949374}
38.738 DAS '0:com.apple.backupd-auto:2052A3' CurrentScore: 0.949374, ThresholdScore: 0.068531 DecisionToRun:1
38.762 DAS REQUESTING START: 0:com.apple.backupd-auto:2052A3
CTS then proceeds with the dispatch via XPC:
38.762 CTS-XPC DAS told us to run com.apple.backupd-auto (0xb671bcc80)
38.844 CTS-XPC Initiating: com.apple.backupd-auto (0xb671bcc80)
38.846 CTS-XPC _xpc_activity_dispatch: beginning dispatch, activity name com.apple.backupd-auto, seqno 0
38.846 CTS-XPC _xpc_activity_begin_running: com.apple.backupd-auto (0x7a9014280) seqno: 0.
38.878 CTS-XPC Running (PID 537): com.apple.backupd-auto (0xb671bcc80)
38.879 DAS STARTING <_DASActivity: "0:com.apple.backupd-auto:2052A3", Utility, 60s, [1/19/26, 8:50:43 PM - 1/19/26, 9:10:43 PM], Started at 1/19/26, 9:10:38 PM, Group: com.apple.dasd.default, PID: 537>
This is in a VM with Time Machine disabled, though, so Time Machine reports:
38.879 Time Machine Skipping scheduled Time Machine backup: Automatic backups disabled
However, com.apple.backupd-auto has now completed, and that’s passed back through CTS-XPC:
38.879 CTS-XPC _xpc_activity_set_state: send new state to CTS: com.apple.backupd-auto (0x7a9014280), 5
38.880 CTS-XPC Completed: com.apple.backupd-auto (0xb671bcc80)
The next run is then scheduled in DAS following an interval of at least 30 minutes, and ideally in about an hour:
38.881 CTS-XPC Rescheduling: com.apple.backupd-auto (0xb671bcc80)
38.881 DAS SUBMITTING: 0:com.apple.backupd-auto:B293AE
38.882 DAS Submitted: 0:com.apple.backupd-auto:B293AE at priority 30 with interval 1800 (Mon Jan 19 21:25:38 2026 - Mon Jan 19 21:40:43 2026)
So, even with Time Machine disabled in a VM, DAS-CTS continues to schedule automatic runs of Time Machine at hourly intervals. And, because DAS-CTS is isolated from all user controls, there’s nothing we can do to prevent that scheduling and dispatch. Does that matter, though? This whole sequence was completed in 0.144 seconds, using lightweight inter-process communication with negligible use of resources, and only repeats hourly.
To the Unix purist, this might appear wasteful and unnecessary, but macOS isn’t, and never has been, Unix. It’s a closed-source proprietary operating system designed for use by millions of consumers and regular users. Rather than configuring it using config files or its thousands of property lists, its controls are largely exposed in System Settings, with a few settings hidden away and only accessible through the defaults command.

Classic Mac OS was more modular, with optional installs that the user could pick and choose, as shown above in Mac OS 9.1. These days with the SSV, choice is more limited from the start, with the only real options being whether to install the cryptexes used in AI, and the x86 code translator Rosetta 2. The latter is transient, though, and likely to go away next year.
Like it or not, modern macOS isn’t designed or implemented to give the user much choice in which processes it runs, and architectural features including the SSV and DAS-CTS prevent you from paring its processes down to any significant degree.
Share this:
Share on X (Opens in new window)
X

Share on Facebook (Opens in new window)
Facebook

Share on Reddit (Opens in new window)
Reddit

Share on Pinterest (Opens in new window)
Pinterest

Share on Threads (Opens in new window)
Threads

Share on Mastodon (Opens in new window)
Mastodon

Share on Bluesky (Opens in new window)
Bluesky

Email a link to a friend (Opens in new window)
Email

Print (Opens in new window)
Print
Like Loading...

Related

Posted in Macs, Technology and tagged backupd, CTS, DAS, macOS, SSV, Time Machine. Bookmark the permalink.

25Comments
Add yours

1

Jean-Daniel
on January 21, 2026 at 7:52 am

Reply

“To the Unix purist, this might appear wasteful and unnecessary, but macOS isn’t, and never has been, Unix.”
To be pedantic, it is actually Unix ;-)
https://www.opengroup.org/openbrand/register/apple.htm
LikeLiked by 2 people

2

hoakley
on January 21, 2026 at 8:52 am

Reply

Thank you. Pedantry usually isn’t helpful, and in this case it’s misleading. Technical compliance with a base set of requirements doesn’t make macOS Unix at all.
It’s more accurate to describe macOS as Unix-based, just as it’s also NeXTSTEP-based, Mach-based, and ClassicMacOS-based. But it’s equally not NeXTSTEP, Mach, or Classic Mac OS.
Howard.
LikeLiked by 2 people

3

joethewalrus
on January 21, 2026 at 9:16 am

Reply

I appreciate this discussion, pedantic or no, unhelpful or no, Unix or no.
LikeLiked by 2 people

4

Boot
on January 21, 2026 at 11:08 am

Reply

It’s not just technical compliance, they’re one of the very few OSes still UNIX-certified: https://www.opengroup.org/openbrand/register/
LikeLiked by 1 person

5

hoakley
on January 21, 2026 at 11:58 am

Thank you. So are you claiming that administrating macOS is just the same as any of the other Unixes that are listed there as being compliant and certified? I think someone fluent in managing HP-UX or AIX would be like a fish out of water when confronted with macOS Tahoe.
Howard.
LikeLike

6

Nicholas Hirras
on January 21, 2026 at 6:07 pm

Reply

I’d say too, many UNIX OS are also closed source. (Solaris / SunOS, HPUX, AIX, Xenix?) Some have GUI apps for configuration, some use console programs, some are configured through plain files.
How is MacOS not “just another closed source UNIX” with “another set of proprietary tools for configuring it?”
LikeLiked by 1 person

7

hoakley
on January 21, 2026 at 6:10 pm

Can you please define what exactly you mean by “UNIX”, without referring to standards compliance?
Howard.
LikeLike

8

Juan Pablo Rosenberg
on January 22, 2026 at 12:44 am

Reply

macOS is undeniably and fully UNIX, as it has the certification.
Now, what “UNIX” actually means is that you can grab the code for a program that only uses to use only standard libraries and interfaces, compile it, and it will run. It has nothing to do with the use case of the OS, the way it’s used, the way it’s configured, etc.
From the Open Group, who owns the UNIX trademark and get to decide what it means: “UNIX certification is a trusted and open system industry standard, ensuring that products conform to the most exacting criteria for [application] portability, compatibility, and global interoperability.” – https://www.opengroup.org/openbrand/register/ (from the “Learn More” button).
Even then, calling macOS UNIX is a huge stretch, as it requires a huge number of system modifications for full compliance (https://www.osnews.com/story/141633/apples-macos-unix-certification-is-a-lie/).
On the other hand, macOS is by far the most popular UNIX OS, so maybe macOS is the standard “UNIX” by now…
LikeLiked by 1 person

9

hoakley
on January 22, 2026 at 9:36 am

Thank you. It’s only appropriate that you seem to have changed your mind at least twice in what you write!
Howard.
LikeLike

10

Parasew
on January 21, 2026 at 8:06 am

Reply

I am a long-time macOS user and cannot believe how bloated and cluttered the operating system has become over time. Tahoe is the worst release of macOS yet: it is extremely inconsistent and the visual clutter is very demanding. I have documented the (agressive) removal of options and clutter on Github in what I call Tahoe Disenshittify. Take a look and let me know what you think
LikeLiked by 1 person

11

hoakley
on January 21, 2026 at 8:55 am

Reply

Thank you. I note you write there:
“This script is intentionally destructive. It disables MANY macOS features, background daemons, analytics, indexing, and continuity services. Expect: iCloud/Desktop & Documents sync broken, Spotlight search degraded, App Store/iCloud/Push/Continuity features partially or fully disabled.”
As I rely on several of those and want to keep them, it’s clearly not useful for me.
Seriously, I think if you have reached that stage, you should use a different OS.
Howard.
LikeLiked by 1 person

12

Maurizio
on January 21, 2026 at 8:52 am

Reply

On Apple Silicon framework and dylid cache are still provided on universal format to accomplish Rosetta 2 traslation ?
In that case we cannot hope for a true slimdown untill late 2027 at least , may be later if they have to support game toolkit translation
LikeLiked by 1 person

13

hoakley
on January 21, 2026 at 8:58 am

Reply

One of the requirements of Rosetta 2 is that it has access to the x86 dyld caches etc. So long as Rosetta 2 is supported, those will need to be supplied in their cryptex, together with Arm versions. What happens when the full Rosetta is withdrawn next year I don’t know, though.
Howard.
LikeLiked by 1 person

14

joethewalrus
on January 21, 2026 at 9:29 am

Reply

I have been quietly hoping for a less busy macOS for a while, in part for this reason:
I keep an M1 Mac Mini running as a server and appreciate its excellent power management. I’d like to add a second server as a virtual machine, but that would duplicate all the background processes, most of which would be not needed or used in the virtual machine, and even worse they would most certainly be running on P cores.*
Thank you for your time and thought on this, Howard, and for publishing the outcome today. And I appreciate Parasew’s contribution too, although it’s probably not the solution I’m looking for at this time.
*Off main topic, but a Pause/Suspend function in Viable, if supported by Apple’s framework, would be a welcome addition in a future update.
LikeLiked by 1 person

15

hoakley
on January 21, 2026 at 11:46 am

Reply

Thank you. The Suspend feature is down as one of my jobs in Viable et al. I did try to get it to work when it was still in beta, but failed at that time.
Howard.
LikeLike

16

Michele Galvagno
on January 21, 2026 at 10:59 am

Reply

In short, buy as much unified memory as you can afford and live a happy and long life!
LikeLiked by 1 person

17

Ali
on January 21, 2026 at 10:59 am

Reply

In this context, perhaps you should do a write-up on App Tamer ( https://stclairsoft.com/AppTamer/ ). It can “de-prioritise” processes that is useless (to me), like promotedcontentd, TVcacheExtension, MusicCacheExtension, AvatarPickerMemoji etc. by either earmarking those processes to run in low priority mode and / or reducing the CPU time to it. It can also be used to reduce the CPU time for useful processes, like Spotlight Engine and Spotlight Indexer, that sometimes suddenly try to hog your CPU, and I have noticed no practical impact on my user experience by allocating those 10% CPU time. Interestingly, it also allows you to stop system processes from running, which I though was not possible without disabling SIP. Before using App Tamer, my old Mac Mini’s (Intel) CPU always used to be around 80 to 85 degrees C (average use). After killing or throttling many system processes, using App Tamer, It now runs between 65 to 75 degrees C (average use). (Of course, like you said elsewhere, I have come to the conclusion that a bloated macOS is no longer the right OS for me, and I can no longer play whack-a-mole with it and am exploring replacing it with an xBSD OS soon).
LikeLiked by 2 people

18

hoakley
on January 21, 2026 at 11:53 am

Reply

Thank you, but I’m very well aware of App Tamer, and have often recommended it in articles here. If you’d like to look back to this one, for example, you’ll see its role described, and a link to it.
However, most of these processes are already running in the background, on E cores in Apple silicon Macs. App Tamer then has nothing to achieve with them. That’s true, for example, with those processes involved in Spotlight indexing. Furthermore, trying to limit their use of the E cores only prolongs the time they take to complete, and serves no useful purpose. macOS automatically controls core frequency as required by environmental factors including temperature. It’s far better at doing that than you ever will be.
Howard.
LikeLike

19

frpsr
on January 21, 2026 at 1:17 pm

Reply

I recall reading about The tale of a Thousand and One Nights recently . Withholding the surprise would be among the tales most potent directives . Those are amongst the power of ending a tale being a reductive power sublimating one power for another .
There is , in America , in my limited view of things a framed saying which goes a little like this -ArchitectsArchitects are those who know a great deal of what practicality will define as nothing .
I imagine there are a diminishing number of vice versa frames defining contractors -ContractorsContractors are those who know a great deal of what practicality will define as nothing .In my imagination there is a practical manner to deal with these insurmountable issues , in a less confining matter fact contest .
In psychology the use of daydreaming can afford one the space travel within issues . Oliver Sachs was recently described as using conflation as a means of penetrating the confusion of repeating a useless investigation . Practicality comes with its own perimeters . FRPSR .
LikeLiked by 1 person

20

hoakley
on January 21, 2026 at 3:29 pm

Reply

Thank you.
Howard.
LikeLike

21

Yoo Forker
on January 21, 2026 at 4:32 pm

Reply

As a recent asker of this question in a comment on a recent post, I greatly appreciate this detailed post. Thanks, Howard!
Parasew’s script reminds me of the free O&O Shutup tool available to do a similar thing for Windows (a similarly old, complex, monolithic, proprietary OS not really intended to be very modular and yet there are a legion of tools that users try to get back some control). Wrapping the script in a GUI with control of what gets disabled might be useful.
I appreciate that the list of processes and daemons is daunting. But at the same time, I think there is a lot of structure in the process tree and many inter-related processes. The kernel itself is open source and DTrace is available on macOS, so my thought is a DTrace script applied during bootup might yield a lot of information about the structure of the process tree and a grouping of the daemons into “species” that are related to particular features. This could greatly simplify analysis. A profile would also be good to identify things like daemons that don’t do a lot of useful work (perhaps disk writes and network traffic) or cumulative energy usage. The primary reason this bee got in my bonnet was that my new M1 Air’s battery would run down while suspended, way more than I was expecting from efficient Apple Silicon and an idle suspended system. It took a bunch of digging (and powermetrics logging to look at wakeups and sonon) to set both user-visible settings as well as less obvious things only accessible via the defaults command-line tool. That is why I think that while macOS might be non-modular and less modifiable at first glance, there is still fat available to be trimmed without breaking the system. Joe’s point about being able to run macOS efficiently as a VM also stands. We may not be able to be as compact as Alpine Linux, but it should be possible to shed a few daemons.
Thanks again, Howard.
LikeLike

22

hoakley
on January 21, 2026 at 4:43 pm

Reply

Thank you. I wish whoever takes that project on, every success, even more so at working out how those processes can be disabled completely while keeping the SSV intact.
My understanding of Joe’s point about not being able to run macOS efficiently in a VM has little to do with this. It’s because VMs run on P cores first, and don’t have access to E cores unless they’ve overrun the P cores first. Thus its background processes, that would normally run quietly on E cores and not take up P cores, could easily overwhelm the VM.
I’m not sure how valid that point is on a dedicated server, though, as the P cores are primarily for running user interactive apps at full performance, not something you’re likely to do on a server.
It’s also possible that Apple will release some Macs with a more server-oriented ratio of P to E cores.
Howard.
LikeLike

23

nikitadanilov
on January 22, 2026 at 2:57 am

Reply

UNIX, in its generality, is defined not by its widely varying user or administrator interfaces, but by the abstractions provided by its system calls. Given this definition, MacOS is definitely a UNIX system, it’s a fairly standard BSD implementation on top of MACH (there are a few other very similar hybrid UNIX systems). In fact, ‘osfmk’ in XNU sources (https://github.com/apple/darwin-xnu/tree/main/osfmk) goes all the way back to the project to implement _Linux_ on top of MACH.
LikeLiked by 1 person

24

Paul R
on January 22, 2026 at 4:43 am

Reply

What is Unix is a can of worms. I’ve seen discussions among people who involved in the development of different flavors of Unix who don’t agree.
I’d suggest there are several categories of Unix definition.
First is the oldest, and currently least relevant. It’s the copyright definition: does this OS contain original AT&T Unix code? It was an important definition in the ’80s and ’90s, but not anymore. MacOS does not.
Second is the genealogy definition, which is looser: does this OS have a direct lineage that can be traced back to Research Unix? MacOS does. Linux (for example) does not.
Third is the compatibility definition: even if unofficially, does this OS run POSIX software?
Fourth is the trademark definition: is this OS allowed by the trademark owners to use the Unix name? This means meeting the third definition, and paying for the privilege. MacOS is certified Unix.
Fifth is the one that I think matters most: the “trade secrets” definition. This means: is the OS based on the ideas, structure, and philosophy first established by Research Unix? This is both a legal definition (it was used by the courts when AT&T sued Berkeley; AT&T lost when the court ruled that the secrets were unenforceable because they’d been freely given away). It’s also a practical definition. Does this thing work like Unix?
Howard is arguing that Unix-based is not the same thing as Unix, but I think every Unix is just Unix-based now. By the trade secrets definition, Linux is also clearly Unix.
MacOS just has a whole lot of non-Unix stuff on top of Unix. But what’s underneath is a historical and legal and functional Unix variant.
LikeLiked by 2 people

25

hoakley
on January 22, 2026 at 9:37 am

Reply

Thank you, Paul.
Howard.
LikeLike

Leave a comment Cancel reply

Δ

Quick LinksFree Software Menu
System Updates
M-series Macs
Mac Troubleshooting Summary
Mac problem-solving
Painting topics
Painting
Long Reads
Search

Search for:

Monthly archives

January 2026 (49)
December 2025 (75)
November 2025 (74)
October 2025 (75)
September 2025 (78)
August 2025 (76)
July 2025 (77)
June 2025 (74)
May 2025 (76)
April 2025 (73)
March 2025 (78)
February 2025 (67)
January 2025 (75)
December 2024 (74)
November 2024 (73)
October 2024 (78)
September 2024 (77)
August 2024 (75)
July 2024 (77)
June 2024 (71)
May 2024 (79)
April 2024 (75)
March 2024 (81)
February 2024 (72)
January 2024 (78)
December 2023 (79)
November 2023 (74)
October 2023 (77)
September 2023 (77)
August 2023 (72)
July 2023 (79)
June 2023 (73)
May 2023 (79)
April 2023 (73)
March 2023 (76)
February 2023 (68)
January 2023 (74)
December 2022 (74)
November 2022 (72)
October 2022 (76)
September 2022 (72)
August 2022 (75)
July 2022 (76)
June 2022 (73)
May 2022 (76)
April 2022 (71)
March 2022 (77)
February 2022 (68)
January 2022 (77)
December 2021 (75)
November 2021 (72)
October 2021 (75)
September 2021 (76)
August 2021 (75)
July 2021 (75)
June 2021 (71)
May 2021 (80)
April 2021 (79)
March 2021 (77)
February 2021 (75)
January 2021 (75)
December 2020 (77)
November 2020 (84)
October 2020 (81)
September 2020 (79)
August 2020 (103)
July 2020 (81)
June 2020 (78)
May 2020 (78)
April 2020 (81)
March 2020 (86)
February 2020 (77)
January 2020 (86)
December 2019 (82)
November 2019 (74)
October 2019 (89)
September 2019 (80)
August 2019 (91)
July 2019 (95)
June 2019 (88)
May 2019 (91)
April 2019 (79)
March 2019 (78)
February 2019 (71)
January 2019 (69)
December 2018 (79)
November 2018 (71)
October 2018 (78)
September 2018 (76)
August 2018 (78)
July 2018 (76)
June 2018 (77)
May 2018 (71)
April 2018 (67)
March 2018 (73)
February 2018 (67)
January 2018 (83)
December 2017 (94)
November 2017 (73)
October 2017 (86)
September 2017 (92)
August 2017 (69)
July 2017 (81)
June 2017 (76)
May 2017 (90)
April 2017 (76)
March 2017 (79)
February 2017 (65)
January 2017 (76)
December 2016 (75)
November 2016 (68)
October 2016 (76)
September 2016 (78)
August 2016 (70)
July 2016 (74)
June 2016 (66)
May 2016 (71)
April 2016 (67)
March 2016 (71)
February 2016 (68)
January 2016 (90)
December 2015 (96)
November 2015 (103)
October 2015 (119)
September 2015 (115)
August 2015 (117)
July 2015 (117)
June 2015 (105)
May 2015 (111)
April 2015 (119)
March 2015 (69)
February 2015 (54)
January 2015 (39)

TagsAPFS
Apple
Apple silicon
backup
Big Sur
Blake
Bonnard
bug
Catalina
Consolation
Console
Corinth
Delacroix
Disk Utility
Doré
El Capitan
extended attributes
Finder
firmware
Gatekeeper
Gérôme
High Sierra
history of painting
iCloud
Impressionism
landscape
LockRattler
log
M1
Mac
Mac history
macOS
macOS 10.12
macOS 10.13
macOS 10.14
macOS 10.15
macOS 11
macOS 12
macOS 13
macOS 14
macOS 15
malware
Metamorphoses
Mojave
Monet
Monterey
Moreau
myth
narrative
OS X
Ovid
painting
performance
Pissarro
Poussin
privacy
Renoir
riddle
Rubens
Sargent
security
Sierra
SilentKnight
Sonoma
SSD
Swift
Time Machine
Tintoretto
Turner
update
upgrade
Ventura
xattr
Xcode
XProtectStatistics
21,256,560 hits

Blog at WordPress.com.

Footer navigationFree Software Menu
About & Contact
Macs
Painting
Downloads
Mac problem-solving
Extended attributes (xattrs)
Painting topics
SilentKnight, Skint, SystHist, silnite, LockRattler & Scrub
DelightEd & Podofyllin
xattred, SpotTest, Providable, Spotcord, Metamer & xattr tools
32-bitCheck & ArchiChect
XProCheck, T2M2, LogUI, Ulbow, blowhole and log utilities
Cirrus & Bailiff
Precize, Alifix, UTIutility, Sparsity, alisma, Taccy, Signet
Versatility & Revisionist
Text Utilities: Textovert, Disclipper, Nalaprop, Dystextia and others
PDF
Keychains & Permissions
Updates
Spundle, Cormorant, Stibium, DropSum, Dintch, Fintch and cintch
Long Reads
Mac Troubleshooting Summary
M-series Macs
Mints: a multifunction utility
VisualLookUpTest
Virtualisation on Apple silicon
System Updates
Saturday Mac Riddles
Last Week on My Mac
sysctl information

Secondary navigation

Search

Post navigation

Medium and Message: TondoThe Dutch Golden Age: Decline and legacy

Search for:

Begin typing your search above and press return to search. Press Esc to cancel.

Comment

Reblog

Subscribe

Subscribed

The Eclectic Light Company

Join 8,955 other subscribers

Sign me up

Already have a WordPress.com account? Log in now.

The Eclectic Light Company

Subscribe

Subscribed

Sign up
Log in

Copy shortlink

Report this content

View post in Reader

Manage subscriptions

Collapse this bar

Loading Comments...

Write a Comment...

Email (Required)

Name (Required)

Website

%d

Okay, here’s a detailed summary of the Eclectic Light Company article “Can you slim macOS down?”

The article, authored by Howard Blum, explores the possibility of reducing the resource footprint of macOS, specifically examining whether users can effectively diminish the operating system’s demands. Blum identifies a common question among macOS users: “Can you slim macOS down?” The core argument presented is that, while macOS is inherently complex and laden with processes, not all of these are essential or provide fundamental value. The article emphasizes that the system is not designed for modularity, a characteristic often found in Unix-based systems. Instead, it is a closed-source, proprietary OS primarily targeted toward a large user base, making user customization of the core operational processes challenging.

Blum begins by highlighting the sheer number of processes running in macOS, potentially numbering in the hundreds even in a minimal configuration. He recognizes the difficulty of identifying and removing unnecessary processes, particularly given their constant evolution and interdependencies. The author wisely concedes that a comprehensive analysis would require a sustained, multi-person effort—estimates suggesting over ten years—making a systematic removal impractical.

He then pivots to a more immediately achievable goal: isolating and examining Time Machine backups. Time Machine processes, while frequently used, are presented as a prime candidate for reduction. Many users don’t actually utilize Time Machine, therefore the associated processes remain active. Blum demonstrates that even with Time Machine disabled – as he did in a MaOS 26.2 VM – the backupd and backupd-helper processes continue to consume CPU and memory, highlighting the system's proactive operation. These processes are controlled by LaunchDaemons residing in the Signed System Volume (SSV), a restriction that prevents direct user modification.

The article details the architecture surrounding Time Machine, describing how it now relies on the Datasync Activity Scheduler (DAS) and Centralised Task Scheduling (CTS) to manage backup execution – a shift from the earlier launchd implementation. This change introduces a layered system, involving DAS, which is in charge of many tasks and CTS, acting as the dispatcher. Blum illustrates the timing constraints imposed by this system, explaining how DAS won't trigger a backup for the first 5 minutes after a Mac starts, preventing resource contention. He explains that the activity is first dispatched under priority 30 for a 1800-second interval, meaning that backupd-auto would run hourly.

The core of the article centers on examining the interaction between DAS and CTS, particularly the automated scheduling of backupd-auto. The process involves multiple steps – first, DAS uses a "CP Score" to determine the likelihood of running a backup, then sending the task to CTS for dispatch. The full cycle for the backupd-auto process takes 0.144 seconds, illustrating the streamlined nature of this interaction.

Despite this lightweight execution, the system persists in scheduling backups hourly, even with Time Machine disabled. This is due to the inherent setup of that scheduler, and a lack of user control over the scheduling. The author concedes that this activity is, perhaps, unnecessary, but makes the point that reducing the system’s complexity in an environment as complicated as macOS is nearly impossible.

The article then encourages the reader to consider App Tamer, a utility designed to prevent the execution of unnecessary system processes. It suggests that this approach—rather than trying to directly remove daemons—is a more realistic and achievable goal. He also points out that App Tamer’s use of E cores, coupled with the potential that the system does not use them optimally, creates an avenue whereby resource usage is reduced.

Ultimately, the article concludes that while users can minimize the impact of macOS, the system’s architecture makes significant reductions fundamentally challenging. The closed nature of the OS, combined with the automated scheduling and monitoring processes, prevents users from directly controlling the system’s runtime behavior.