Storage drive physical dimensions

[Jurrunio]

3.5" HDD are called like that because the spinning disk inside is 3.5" in diameter. The same applies to 2.5" HDD and is easy to understand. That raises two questions:

 

1. Do 2.5" SSDs get that name for being the same/similar size to a 2.5" HDD?

 

2. Why are 2.5" SSD/HDD also called as 7mm SSD/HDD? I mean, how do they measure 7mm? My Samsung 840 Pro is often advertised as '2.5" 7mm SSD', but it's 6mm thick. My Transcend SSD370 is even thinner at 5mm (flimsy, but it works)

[tikker]

2 minutes ago, Jurrunio said:

3.5" HDD are called like that because the spinning disk inside is 3.5" in diameter. The same applies to 2.5" HDD and is easy to understand. That raises two questions:

 

1. Do 2.5" SSDs get that name for being the same/similar size to a 2.5" SSD?

 

2. Why are 2.5" SSD/HDD also called as 7mm SSD/HDD? I mean, how do they measure 7mm? My Samsung 840 Pro is often advertised as '2.5" 7mm SSD', but it's 5mm thick...

1. Conventions tend to stick, so yes most likely.

2. Thickness. The official spec sheet lists the 840 Pro as 6.8mm thick, hence a 7mm SSD. This is specified as I believe some laptops do not have space for the slightly thicker models.

[NelizMastr]

21 minutes ago, Jurrunio said:

3.5" HDD are called like that because the spinning disk inside is 3.5" in diameter. The same applies to 2.5" HDD and is easy to understand. That raises two questions:

 

1. Do 2.5" SSDs get that name for being the same/similar size to a 2.5" SSD?

 

2. Why are 2.5" SSD/HDD also called as 7mm SSD/HDD? I mean, how do they measure 7mm? My Samsung 840 Pro is often advertised as '2.5" 7mm SSD', but it's 6mm thick. My Transcend SSD370 is even thinner at 5mm (flimsy, but it works)

1. Yes. The outside dimensions are more or less the same. SSDs are typically slightly slimmer, though. 

2. 2,5" harddisks can be 7 or 9mm thick, depending on the amount of platters. 7mm drives are considered slimline drives.