CyberGrind // Orange Book // Sections 03 + 04

File Systems & Partitioning

How operating systems organize, store, and access data on disk

// File System Features
🗜️
Compression
Re-encodes data to consume less space. Fifty consecutive zeros can be stored as "50×0" rather than fifty individual bits.
Transparent to the user in most implementations
🔐
Encryption
Converts file data so it cannot be read without the correct decryption key. Protects sensitive files from unauthorized access.
NTFS uses EFS; APFS has native full-volume encryption
🔑
Permissions
Controls which users can read, write, move, or delete each file. Managed via an Access Control List (ACL).
Critical for multi-user and server environments
📓
Journaling
Logs every file change before writing to disk. Allows the system to recover to a consistent state after a crash or power failure.
Used by NTFS, ext3/4, HFS+, APFS
📏
Size Limits
FAT32 caps individual files at 4 GB. NTFS supports up to 16 exabytes per file — enough for virtually any foreseeable use case.
Modern FS limits are effectively non-limiting
🌐
File Sharing
Allows users to share folders with others on the same network (P2P). Microsoft Workgroups are one implementation of this.
Cloud sharing preferred for persistent availability
// File Systems by Operating System
🪟
Windows
NTFS Current
Supports journaling, encryption (EFS), ACLs, and 16 EB max file size. Default for all modern Windows installs.
FAT32 Legacy
Max 4 GB file size. Still used for USB drives and SD cards due to broad cross-platform compatibility.
exFAT Current
FAT32 successor for removable media. Removes the 4 GB file size limit while keeping cross-platform support.
🍎
macOS
APFS Current
Default since macOS 10.13 (High Sierra). Optimized for SSDs with native encryption, snapshots, and cloneable files.
HFS+ Legacy
Hierarchical File System Plus. Used in older Macs. Still supported for compatibility with older Time Machine backups.
🐧
Linux
ext4 Current
Standard for most distros. Delayed allocation, reduced fragmentation, and larger volume/file support over ext3.
ext3 Legacy
Introduced journaling to the ext family. Still supported; largely replaced by ext4.
BtrFS Emerging
The future of Linux filesystems. Transparent compression, drive pooling, online defrag, and live snapshots.
// Feature Support Matrix
File System Journaling Encryption Permissions Compression Max File Size OS
NTFS ✓ ✓ ✓ ✓ 16 EB Windows
FAT32 ✗ ✗ ✗ ✗ 4 GB Universal
exFAT ✗ ✗ ✗ ✗ 16 EB Universal
APFS ✓ ✓ ✓ ~ 8 EB macOS / iOS
ext4 ✓ ~ ✓ ✗ 16 TB Linux
BtrFS ✓ ✓ ✓ ✓ 16 EB Linux

~ = partial or via external tools  |  ✓ = native support  |  ✗ = not supported

// Partition Styles: MBR vs GPT
MBR — Master Boot Record
Legacy scheme · stored in sector 0
MBR
Primary 1
Primary 2
Primary 3
P4
Boot sector
Primary partition
Extended
Max partitions4 primary
Max disk size2 TB
Boot modeBIOS / Legacy
RedundancyNone
Usage (2023)~43% of drives
GPT — GUID Partition Table
Modern scheme · UEFI required
Prot
HDR
Part 1
Part 2
Part 3
… 128
Bak
Protective MBR
Partition
Backup header
Max partitions128 (Windows)
Max disk sizeVirtually unlimited
Boot modeUEFI
RedundancyBackup header at end of disk
Usage (2023)~57% of drives
// Understanding File Paths
Hierarchical File System — Path Examples
C:\Users\Documents\photo.jpg
Windows path — drive letter → folders → file. Backslash (\) separates levels.
/home/logan/documents/photo.jpg
Linux / macOS path — root (/) is the top-level directory. Forward slash (/) separates levels.
Root Directory — top-level, contains all subdirectories
Subdirectory — folders that group related files
File + Extension — determines type and application association
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