Why aren't there hard drives bigger than 3.5"

[octopus41092]

I was just wondering, why don't they make hard drives bigger than 3.5". I would be fine with something bigger if it could hold more and was cheaper. Anyone know the reason?

 

[imported_Scoop]

They used to be the size of DVD-drives. It's called .. technological advancement or something. Can you imagine the noise and heat those monsters would put out spinning 7200RPM. Though I'm not sure if the actual platters were shrinked or just the exterior and stuff. But the trend is that they are getting smaller. Solid State Drives are coming and hopefully replace these noisy bastards we have now soon.

 

[degibson]

There are four reasons that I can think of off the top of my head.

1) Everybody makes 3.5" drives, and consumer-grade cases expect 3.5" to be the size. Its the chicken and the egg problem.

2) 3.5" is large enough so that the platters are reasonably sized, but small enough such that they don't have to be really really thick to keep from flying apart at 7200/10000 rpm. Older drives were bigger, but span a lot slower.

3) 3.5" conveniently matches various HD cooling technologies, probably a corollary of 1)

4) Random access latency is linear in the distance the head has to traverse -- in theory, smaller drives are faster. In practice, head settle time is just as bad as seek, but for really large drives that wouldn't be the case.

Track density variation might be a fifth, but it could be overcome in various ways.

 

[coupland]

Originally posted by: octopus41092
I was just wondering, why don't they make hard drives bigger than 3.5".

Because drive bays are only 3.5". Ask me why DVD discs aren't smaller...

 

[Rubycon]

Search for Quantum Bigfoot and you will find your answer.

 

[Modelworks]

Originally posted by: Rubycon
Search for Quantum Bigfoot and you will find your answer.

I remember the bigfoot drives.
Had a couple the failed repeatedly.

 

[Modelworks]

Originally posted by: octopus41092
I was just wondering, why don't they make hard drives bigger than 3.5". I would be fine with something bigger if it could hold more and was cheaper. Anyone know the reason?

As mentioned its the chicken and egg thing.

Why are dvd the same size as cd ? because the dvd players needed to be able to play cd, and the manufacturers that make dvd were already set up for the size.

look at this post, its all discussed there:
http://forums.anandtech.com/me...=2167512&enterthread=y

 

[Gillbot]

Ahh, I still have a Bigfoot somewhere I use to keep my door propped open. Not to mention a few full size Micropolis SCSI drives!

 

[Ratman6161]

To date myself, I once worked with a system in the military that used 16" removable platters. Trust me, bigger is not always better.

 

[Ratman6161]

Originally posted by: Ratman6161
To date myself, I once worked with a system in the military that used 16" removable platters. Trust me, bigger is not always better.

To date myself even more, I also worked with a system that used a gold plated magnetic drum memory unit that was about 2 fee long and about a foot in diameter and stored less data than a modern day floppy drive.