Internal storage
It's not the locker room type of storage we're talking about here. Instead it's something much more important and often underrated: the place where information is stored.
When it comes to computer storage, judging from many questions friends and readers send me, there's quite a bit of confusion among general users as to what it actually is. And it's not your fault; digital storage can be as messy as my desk. This is the reason for this series, where I sort out the basics and more, in layman's terms.
1. Understanding the units
No matter how boring this is, you can't grasp digital storage without know its measurement unit, which is byte.
Byte (symbol: B): Byte is generally the smallest unit in digital storage. You can think of 1 byte as one character in a document. For example, we actually need to use 4 bytes to store just the word "byte." In real life, we use larger units, including kilobyte, megabyte, gigabyte, and terabyte.
Note: Technically, there's another smaller unit called bit (symbol: b), which is a single binary unit that represents the state 0 or 1, which encodes digital information. A byte is a sequence of bits, and generally 1 byte equals 8 bits. Bit is more commonly used to show the data being transferred, especially over a long distance, such as the speed of the Internet, which is measured in bits per second. Byte is more commonly used to show the amount of storage or in situations you can move a large amount of data. When it comes to storage space, it's better to use byte; much like it's more practical to count the number of cows than counting the number of feet and then divide by four.
Kilobyte (KB or kB): By general definition, one kilobyte is 1,024 bytes. In many cases, for the sake of simplicity, 1 kilobyte is understood as 1,000 bytes.
Megabyte (MB): By general definition, 1 megabyte is 1,024,000 bytes. Similarly, it can also be understood as 1,000,000 bytes.
Gigabyte (GB): By general definition, 1 gigabyte is 1,000,000,000 bytes.
Terabyte (TB): By general definition, 1 terabyte is 1,000,000,000,000 bytes, or 1,000GB.
2. Storage vs. memory
These are two terms that are often mistakenly used for each another, though they are two very different things.
Storage, in a nutshell, is where the information (such as Word documents, photos, movie clips, programs, and so on) is stored. In a computer, the whole operating system itself, such as Windows 7 or Mac OS, is also stored on the internal storage device. Storage is nonvolatile, meaning that the information is still there when the host device (a computer, for example) is turned off and is readily accessible when the device is turned back on. It's like a book or a paper notebook that's always there, ready for you to read or write on.
Memory (aka system memory, random access memory, or RAM), on the other hand, is where information is being processed and manipulated. Data in the system memory is volatile, meaning that when the computer is turned off, it's gone; the memory becomes blank, as if nothing has been there before. It's somewhat like the short-term memory part of your brain, where images or ideas are being formed and processed when you read a book -- those that disappear the moment you stop reading.
Despite their differences, there's a strong relationship between system memory and storage. The Word document that you're working on, for example, is in the computer's memory. When you save it, a copy of it now resides on the computer's storage. When you close Microsoft Word completely, the document now only resides on the hard drive (storage) and is no longer in the memory, until you open it again.
All this means is that you generally don't actually experience storage. Everything that's presented to you on a computer's screen or via the speakers actually takes place in the system memory. Before it gets there, however, it needs to be loaded from the computer's storage device into the system memory. So the larger and faster system memory the computer is equipped with, the more quickly the information becomes ready and the more you can do with a computer at one time (multitasking). You generally need far less memory than storage. Most new computers come with somewhere between 2GB to 8GB of memory, and you don't need more than that. This is a good thing, too; gigabyte to gigabyte, memory is much more expensive than storage.
Of course, memory is just one of many factors in a computer's performance. Another factor is the storage itself, which is either a hard drive (aka hard disk) or a solid-state drive (SSD).
Hard drive vs. solid-state drive
The hard drive has been the most common storage device for decades, dominating since the early 1960s. Solid-state drives, however, are relatively new and have been getting more and more popular in the last three years. In most case, they can be used interchangeably, and both have pros and cons.
Hard drive (or HDD)
While the hard drive has evolved a lot since its inception, the basics remain the same: it's a box that contains a few magnetic disks (known as platters) attached to a spindle, very similar to a spindle of blank CDs or DVDs. Each of the platters has a reading/writing head hovering on top. As the spindle spins, the head moves in and out to write or read data to and from any part of the platter, on a tiny information-recording unit called the "data track." This type of access to information is called "random access," as opposed to the inefficient "sequential access" found in the old and obsolete types of storage, such as tape.
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