ACSP File System and Storage 4 — Questions and Answers
Question 1: A user reports that their external SSD is not appearing in Finder but shows up in Disk Utility. What is the most likely cause?
- The drive has no partition scheme recognized by macOS
- The volume is not mounted (Correct answer)
- The drive is formatted as ExFAT
- The drive lacks a valid GUID Partition Table
Correct answer: The volume is not mounted
When a drive appears in Disk Utility but not Finder, it typically means the volume exists but is unmounted and needs to be mounted manually.
Question 2: Which macOS command-line tool can be used to display detailed information about disk partitions and their GUIDs?
- diskutil list (Correct answer)
- fdisk -l
- gpt show
- lsblk
Correct answer: diskutil list
The `diskutil list` command displays all disks and partitions including their types, sizes, and identifiers on macOS.
Question 3: What happens to a file's data when it is moved to the Trash on an APFS volume and then the Trash is emptied?
- The data blocks are immediately overwritten with zeros
- The file's space is marked as free but data may persist until overwritten (Correct answer)
- APFS encrypts the blocks to prevent recovery
- The file is moved to a hidden recovery partition
Correct answer: The file's space is marked as free but data may persist until overwritten
Emptying the Trash marks the file's storage blocks as available but does not immediately overwrite the data, so forensic tools may recover it.
Question 4: A technician needs to enable journaling on an HFS+ volume via Terminal. Which command accomplishes this?
- diskutil enableJournal /dev/disk2s1 (Correct answer)
- fsck_hfs -j /dev/disk2s1
- hdiutil journal enable /dev/disk2s1
- diskutil repairVolume /dev/disk2s1
Correct answer: diskutil enableJournal /dev/disk2s1
The `diskutil enableJournal` command enables HFS+ journaling on the specified volume, improving crash recovery.
Question 5: Which APFS feature automatically reclaims space from deleted files and snapshots without requiring user intervention?
- Trim support (Correct answer)
- Space sharing
- Defragmentation
- Clonefile pruning
Correct answer: Trim support
APFS supports TRIM, which signals the SSD controller to erase blocks from deleted files promptly, maintaining performance and reclaiming space.
Question 6: A Mac with Apple silicon displays 'Your disk appears to be damaged' during startup. What is the first recommended step?
- Boot to macOS Recovery and run First Aid in Disk Utility (Correct answer)
- Reinstall macOS immediately
- Initialize the disk from DFU mode
- Replace the SSD
Correct answer: Boot to macOS Recovery and run First Aid in Disk Utility
Booting to macOS Recovery and running First Aid in Disk Utility is the first non-destructive step to diagnose and repair file system errors.
Question 7: What is the purpose of the 'Preboot' volume in an APFS container on Apple silicon Macs?
- It stores Time Machine snapshots
- It contains boot data and system policy for each installed macOS volume (Correct answer)
- It holds kernel extensions for third-party software
- It acts as a swap partition for virtual memory
Correct answer: It contains boot data and system policy for each installed macOS volume
The Preboot volume stores per-OS boot files, cryptographic measurements, and system security policy needed to start each macOS installation.
ACSP File System and Storage 4
A user reports that their external SSD is not appearing in Finder but shows up in Disk Utility.
What is the most likely cause?