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User profile for user: Revianmac
Revianmac Author
User level: Level 4
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Am I correct about this security feature?

I was given a 2013 iMac last week by a friend. This iMac is in amazing condition and works fine. I did, however, notice that there are two volumes on the single HDD: Macintosh HD (11 GB) and Macintosh HD - Data (21 GB).. and one of them is "read only". Why two volumes? I have noticed that boot time is rather long for a desktop computer. Does the system make a copy of the "read only" volume at boot time and use it in a virtual machine.. then delete the VM on shutdown and start that whole process up again at boot time? That would explain the long boot time, and it would explain why macOS is so secure.


Anyway, I love this iMac.. I don't even care if it's 9 years old, it works fine.

iMac 21.5″, macOS 10.15

Posted on Oct 21, 2022 10:01 AM

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User profile for user: Tesserax
Tesserax
User level: Level 10
155,012 points

Posted on Oct 21, 2022 10:23 AM

Revianmac wrote:

I was given a 2013 iMac last week by a friend. This iMac is in amazing condition and works fine. I did, however, notice that there are two volumes on the single HDD: Macintosh HD (11 GB) and Macintosh HD - Data (21 GB).. and one of them is "read only". Why two volumes?

With the latest releases of macOS, the operating system is contained in an APFS volume group. By default, they are Macintosh HD (the read-only system volume) & the Macintosh HD - Data volume, which contains some system files, but mainly consists of user apps & data.


To best answer your other question, I suggest you give the following article a read. You may find it informative.


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User profile for user: Tesserax
Tesserax
User level: Level 10
155,012 points

Oct 21, 2022 10:23 AM in response to Revianmac

Revianmac wrote:

I was given a 2013 iMac last week by a friend. This iMac is in amazing condition and works fine. I did, however, notice that there are two volumes on the single HDD: Macintosh HD (11 GB) and Macintosh HD - Data (21 GB).. and one of them is "read only". Why two volumes?

With the latest releases of macOS, the operating system is contained in an APFS volume group. By default, they are Macintosh HD (the read-only system volume) & the Macintosh HD - Data volume, which contains some system files, but mainly consists of user apps & data.


To best answer your other question, I suggest you give the following article a read. You may find it informative.


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User profile for user: Tesserax
Tesserax
User level: Level 10
155,012 points

Oct 21, 2022 11:08 AM in response to Revianmac

You're very welcome! Yes, The Eclectic Light Company is a great source for information. They have numerous in-depth articles on a variety of Apple topics ... amongst other things, and come out monthly. Well worth reading, and highly recommended. I'm sure the author will be pleased that you liked the article I provided you. Enjoy!

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Am I correct about this security feature?

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