Hexworth Prime
House of Forge
Storage Devices
CompTIA A+ Core 1 (220-1101) • Domain 3.0 Hardware
Key Concepts:
HDDs
SSDs
NVMe
SATA
Form Factors
HDD vs SSD Overview
HDD
Hard Disk Drive
Mechanical, spinning platters
VS
SSD
Solid State Drive
No moving parts, flash memory
Hard Disk Drives (HDDs)
HDDs use magnetic platters spinning at high speeds with read/write heads on actuator arms.
HDD Components
Platters
Magnetic disks storing data
Multiple platters = more capacity
Magnetic disks storing data
Multiple platters = more capacity
Read/Write Heads
Hover nanometers above platters
One head per platter side
Hover nanometers above platters
One head per platter side
Actuator Arm
Positions heads over data
Controlled by motor
Positions heads over data
Controlled by motor
HDD Speeds (RPM)
| Speed | Use Case | Performance |
|---|---|---|
| 5400 RPM | Laptops, external drives | Lower power, quieter, slower |
| 7200 RPM | Desktop standard | Good balance of speed/reliability |
| 10,000+ RPM | Enterprise/servers | Fastest HDD, highest cost |
Solid State Drives (SSDs)
SSDs use NAND flash memory with no moving parts, offering faster speeds and better durability.
NAND Flash Types
| Type | Bits/Cell | Endurance | Speed | Cost |
|---|---|---|---|---|
| SLC | 1 | Highest | Fastest | Most expensive |
| MLC | 2 | High | Fast | Expensive |
| TLC | 3 | Moderate | Good | Affordable |
| QLC | 4 | Lower | Slower | Cheapest |
A+ Exam Tip: SLC has highest endurance (enterprise), QLC offers best capacity per dollar (consumer). TLC is the most common consumer SSD type.
Storage Interfaces
| Interface | Max Speed | Connector | Use Case |
|---|---|---|---|
| SATA III | 6 Gbps (600 MB/s) | 7-pin data, 15-pin power | HDDs, 2.5" SSDs |
| NVMe (PCIe 3.0 x4) | 32 Gbps (3,500 MB/s) | M.2 or PCIe slot | High-performance SSDs |
| NVMe (PCIe 4.0 x4) | 64 Gbps (7,000 MB/s) | M.2 slot | Latest gen SSDs |
| NVMe (PCIe 5.0 x4) | 128 Gbps (14,000 MB/s) | M.2 slot | Cutting-edge SSDs |
Speed Comparison
HDD (7200 RPM): ~150 MB/s
SATA SSD: ~550 MB/s
NVMe PCIe 3.0: ~3,500 MB/s
NVMe PCIe 4.0: ~7,000 MB/s
Form Factors
Traditional Drives
| Size | Use |
|---|---|
| 3.5" | Desktop HDDs |
| 2.5" | Laptop HDDs, SATA SSDs |
M.2 Drives
| Size | Common Use |
|---|---|
| 2230 | Ultra-compact (Steam Deck) |
| 2242 | Compact devices |
| 2260 | Some laptops |
| 2280 | Most common (desktops/laptops) |
M.2 Naming: 2280 = 22mm wide × 80mm long. Always check motherboard compatibility!
M.2 Keys (Notches)
| Key Type | Interface | Common Use |
|---|---|---|
| B Key | SATA or PCIe x2 | SATA SSDs (older) |
| M Key | PCIe x4 (NVMe) | NVMe SSDs (fastest) |
| B+M Key | SATA or PCIe x2 | Compatible with both slots |
Compatibility: An M-key SSD won't fit a B-key slot. B+M drives are most versatile but may not use full NVMe speed.
Other Storage Types
Optical DrivesCD (700 MB), DVD (4.7-8.5 GB), Blu-ray (25-100 GB)
Becoming rare in modern systems
USB Flash DrivesPortable, various capacities
USB 2.0/3.0/3.1/Type-C
Tape DrivesHigh capacity, sequential access
Enterprise backup (LTO)
SD CardsSD, microSD, SDHC, SDXC
Cameras, phones, IoT devices
HDD vs SSD Comparison
| Feature | HDD | SSD |
|---|---|---|
| Speed | ~150 MB/s | 550-7,000+ MB/s |
| Durability | Sensitive to shock | Shock resistant |
| Noise | Audible spinning/clicking | Silent |
| Power Usage | Higher | Lower |
| Cost per GB | Lower ($0.02-0.03/GB) | Higher ($0.05-0.10/GB) |
| Max Capacity | Up to 20+ TB | Up to 8 TB (consumer) |
| Best For | Mass storage, archives | OS, applications, games |
Knowledge Check
Q1: What is the maximum speed of SATA III?
Q2: Which NAND flash type stores 4 bits per cell and offers the best value?
Q3: What does "2280" mean in M.2 drive specifications?
Q4: Which M.2 key type is required for the fastest NVMe SSDs?