3.5" HDD's...aren't

[80251]

This might be a Captain Obvious moment but 3.5" HDD's don't measure out to be 3.5" in any dimension -- the closest is the width, which is a little over 4" (4.010in).

The obvious question is, why are they called 3.5" hard drives when they aren't?

 

[Blaeza]

Because INSIDE, they are. The magnetic platter, that is.

 

[80251]

2.5" format SSD's don't measure 2.5" in any dimension either so I guess they're using an internal dimension too? At least they're only off by 1/4".

 

[svenge]

Better not tell him about 2x4 lumber...

 

[Blaeza]

2.5" format SSD's don't measure 2.5" in any dimension either so I guess they're using an internal dimension too? At least they're only off by 1/4".

Ask google. Internal measurement.

 

[SL2]

Because INSIDE, they are. The magnetic platter, that is.

Exactly.

There are 3.5" hard disks in a 3.5" HDD.

 

[Blaeza]

Sometimes, I do have more brain than people on here that I consider to be intelligent. And I just just witnessed a car drive up my road, that is one way. Is there a coffee shortage?

 

[80251]

So if everyone here is such a genius why does the 2.5" SSD format NOT measure out to be 2.5"? Come on, don't be shy.

LOL, the format name has nothing to do with platter size, it has to do with the fact HDD's had to live (at first) in FDD bays, which, surprise, surprise, came in 8", 5.25" and 3.5" widths (from wikipedia):

8"
8-inch 9.5 in × 4.624 in × 14.25 in (241.3 mm × 117.5 mm × 362 mm). In 1979, Shugart Associates' SA1000 was the first form factor compatible HDD, having the same dimensions and a compatible interface to the 8" FDD.

5.25"
5.25-inch 5.75 in × 3.25 in × 8 in (146.1 mm × 82.55 mm × 203 mm). This smaller form factor, first used in an HDD by Seagate in 1980, was the same size as full-height 5+1⁄4-inch-diameter (130 mm) FDD, 3.25-inches high. This is twice as high as "half height"; i.e., 1.63 in (41.4 mm). Most desktop models of drives for optical 120 mm disks (DVD, CD) use the half height 5¼" dimension, but it fell out of fashion for HDDs.

3.5"
The format was standardized as EIA-741 and co-published as SFF-8501 for disk drives, with other SFF-85xx series standards covering related 5.25 inch devices (optical drives, etc.)[20] The Quantum Bigfoot HDD was the last to use it in the late 1990s, with "low-profile" (≈25 mm) and "ultra-low-profile" (≈20 mm) high versions. 3.5-inch 4 in × 1 in × 5.75 in (101.6 mm × 25.4 mm × 146 mm) = 376.77344 cm³. This smaller form factor is similar to that used in an HDD by Rodime in 1983, which was the same size as the "half height" 3½" FDD, i.e., 1.63 inches high. Today, the 1-inch high ("slimline" or "low-profile") version of this form factor is the most popular form used in most desktops. The format was standardized in terms of dimensions and positions of mounting holes as EIA/ECA-740, co-published as SFF-8301.[21] At least Seagate made 19.99-mm-high drives too.[3]

 

[natr0n]

Its like saying 5 1/2 inches is closer to 6.

Dont think about it.

 

[protain]

So if everyone here is such a genius why does the 2.5" SSD format NOT measure out to be 2.5"? Come on, don't be shy.

because the form factor was designed for drives that contained 2.5" spinning disks... it became a standard size so they kept the same external dimensions when moving to SSDs

 

[ExcuseMeWtf]

Its like saying 5 1/2 inches is closer to 6.

Dont think about it.

It's what my girlfriend tells me all the time.

 

[Blaeza]

So if everyone here is such a genius why does the 2.5" SSD format NOT measure out to be 2.5"? Come on, don't be shy.

LOL, the format name has nothing to do with platter size, it has to do with the fact HDD's had to live (at first) in FDD bays, which, surprise, surprise, came in 8", 5.25" and 3.5" widths (from wikipedia):

8"
8-inch 9.5 in × 4.624 in × 14.25 in (241.3 mm × 117.5 mm × 362 mm). In 1979, Shugart Associates' SA1000 was the first form factor compatible HDD, having the same dimensions and a compatible interface to the 8" FDD.

5.25"
5.25-inch 5.75 in × 3.25 in × 8 in (146.1 mm × 82.55 mm × 203 mm). This smaller form factor, first used in an HDD by Seagate in 1980, was the same size as full-height 5+1⁄4-inch-diameter (130 mm) FDD, 3.25-inches high. This is twice as high as "half height"; i.e., 1.63 in (41.4 mm). Most desktop models of drives for optical 120 mm disks (DVD, CD) use the half height 5¼" dimension, but it fell out of fashion for HDDs.

3.5"
The format was standardized as EIA-741 and co-published as SFF-8501 for disk drives, with other SFF-85xx series standards covering related 5.25 inch devices (optical drives, etc.)[20] The Quantum Bigfoot HDD was the last to use it in the late 1990s, with "low-profile" (≈25 mm) and "ultra-low-profile" (≈20 mm) high versions. 3.5-inch 4 in × 1 in × 5.75 in (101.6 mm × 25.4 mm × 146 mm) = 376.77344 cm³. This smaller form factor is similar to that used in an HDD by Rodime in 1983, which was the same size as the "half height" 3½" FDD, i.e., 1.63 inches high. Today, the 1-inch high ("slimline" or "low-profile") version of this form factor is the most popular form used in most desktops. The format was standardized in terms of dimensions and positions of mounting holes as EIA/ECA-740, co-published as SFF-8301.[21] At least Seagate made 19.99-mm-high drives too.[3]

You looked up something. Amazeballs.

This might be a Captain Obvious moment but 3.5" HDD's don't measure out to be 3.5" in any dimension -- the closest is the width, which is a little over 4" (4.010in).

The obvious question is, why are they called 3.5" hard drives when they aren't?

So, from this where you ask a obvious question, you then go into a full on Wikipedia article, who is the clever one? You, because you found "Google". Well done sir, congratulations.

 

[Toothless]

Take all your drives out and apart. Measure the platters.

Bet ya won't.

 

[95Viper]

Thread closed.

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