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Form Factor Comparison
For ease of comparison, the summary table below lists all of the standard internal hard disk form factors with their dimensions, typical platter sizes found in hard disks that use the form factor, and common applications:
Form Factor |
Profile |
Platter Size (in) |
Width (in) |
Depth (in) |
Height (in) |
Application |
5.25" |
Full-Height |
5.12 |
5.75 |
8.0 |
3.25 |
All drives in early 1980s; Large capacity drives with many platters as late as the mid-1990s |
Half-Height |
5.12 |
5.75 |
8.0 |
1.63 |
Early 1980s through early 1990s |
|
Low-Profile |
5.12 |
5.75 |
8.0 |
1.0 |
Quantum Bigfoot, mid-to-late 1990s |
|
Ultra-Low-Profile |
5.12 |
5.75 |
8.0 |
0.75 - 0.80 |
Quantum Bigfoot, mid-to-late 1990s |
|
3.5" |
Half-Height |
2.5, 3.0, 3.74 |
4.0 |
5.75 |
1.63 |
High-end, high-capacity drives |
Low-Profile |
2.5, 3.0, 3.74 |
4.0 |
5.75 |
1.0 |
Industry standard, most common form factor for PC hard disks |
|
2.5" |
19 mm Height |
2.5 |
2.75 |
3.94 |
0.75 |
Highest-capacity 2.5" drives, used in full-featured laptop systems |
17 mm Height |
2.5 |
2.75 |
3.94 |
0.67 |
Mid-range capacity drives used in some laptop systems |
|
12.5 mm Height |
2.5 |
2.75 |
3.94 |
0.49 |
Low-capacity drives used in small laptops (subnotebooks) |
|
9.5 mm Height |
2.5 |
2.75 |
3.94 |
0.37 |
Lowest-capacity drives used in very small laptops (mini-subnotebooks) |
|
PC Card |
Type I |
1.8 |
2.13 |
3.37 |
0.13 |
Not used for hard disks (yet?) |
Type II |
1.8 |
2.13 |
3.37 |
0.20 |
Smaller-capacity expansion hard disks for laptops and consumer electronics |
|
Type III |
1.8 |
2.13 |
3.37 |
0.41 |
Higher-capacity expansion hard disks for laptops |
|
Compact |
Type I |
1.0 |
1.69 |
1.42 |
0.13 |
Smaller-capacity flash cards for digital cameras, hand-held computers and consumer electronics; not used for hard disks (yet) |
Type II |
1.0 |
1.69 |
1.42 |
0.20 |
Larger-capacity flash cards and hard disks for digital cameras, hand-held computers and consumer electronics |
Next: External Hard Disks
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