A HDD, or Hard Disk Drive is the thing in yours and every computer that enables them to store and recall information, such as games, pictures, videos, and even your OS.
Data is stored in different "bytes". The most commonly heard of is usually megabyte, of MB. People usually call them "megs" for short.
There are a whole list of other scales of storage, and I'll list them here in order.
One bit (the smallest form of data)
One byte is 8 bits
One kilobyte is 1024 bytes
One megabyte is 1024 kilobytes
One gigabyte is 1024 megabytes
(You can probably see where this is going, I'll continue anyways)
One terabyte is 1024 gigabytes
One petabyte is 1024 terabytes
One exabyte is 1024 petabytes
One zettabyte is 1024 exabytes
One yottabyte 1024 zettabytes
For scale, the average 650x800 jpg image file is around 60KB (kilobytes)
The average downloadable game (Borderlands 2, Tomb Raider 2013, Bioshock Infinite) is around 8GB (gigabytes)
An installation of Windows 7 Ultimate is 19.5GB
After terabytes, we don't really hear or talk about petabytes of anything after that, since to make a 1PB HDD now in 2013 would be pretty expensive. A 1 exabyte HDD would be insane.
A HDD is made up of a bunch of tiny spinning discs with a tiny reader controlled by a magnet. The tiny discs have to rotate to be read, so the faster they spin, the faster your game loads.
The speed they rotate is measured in RPM, or Rotations Per Minute. Most standard HDDs come in these speeds:
- 5200 RPM
- 5400 RPM
- 5700 RPM
- 5900 RPM
- 7200 RPM
- 10000 RPM
- 15000 RPM (At this point, just go buy a SSD)
SDD, Solid State Drives
Preferred by gamers and programmers for their extremely fast load times, SSDs, or Solid State Drives are different from HDDs, because they don't use discs or a reader, they are solid-state, and use semiconducter chips instead of a magnetic reader. Semiconducter chips already exist in your computer, your RAM, Random Access Memory use these chips, except they wipe them frequently to make space to load up other things. SSDs store the information loaded into them like a HDD, minus the two-minute wait time to move your game files, or photo album.
If you drop your laptop, or bump your desktop computer really hard while the HDD is functioning (basically if your computer is turned on), the magnetic reader could collide with the spinning disks inside and damage them, almost always resulting in corrupted and lost data. SSDs can't have this problem, since nothing in them moves.
Obviously, SSDs are more expensive, and are not really designed for mass storage. A Corsair Nova Series 2 30GB SSD costs around $65.99 for some comparison.
SSDs are mostly used as boot drives, the drive that your OS runs from so when you start up your computer, the bootup time is minimal, and all your programs you have set to run on startup (ew.) start up near-instant.
