USB hard drives.
Everyone has them yet almost nobody knows what they are and how they do what they do.
First I'll have a take at what a USB is, and then we'll move on to the rest of the material.
USB is a kind of connector with the sole purpose of transferring data between devices.
It stands for Universal Serial Bus and that exactly is what it is, an universal bus to transfer data between computers and devices through a protocol using a 1 bit wide serial cable.
Compaq, Intel, Sony, Microsoft, Digital Equipment Corporation, IBM and Northern Telecom sat down and agreed the early standard and they were the first to use and promote it.
Even the first version made 1.
5 mbit/sec transfer possible which was stunning at the time, literally humiliating 115kbit / sec RS232 serial port.
The second version, 1.
1, had a massive 12 megabits of second, that is about 1.
2 mbytes a second and that is still some speed to transfer data at even today.
Putting some documents on a USB key is no inconvenience even if it defaults to USB 1.
1 for some reason.
Third version to come was 2.
0.
With transfer rate at 480 Mbits a second or 60 megabytes it was the king of inter device connection for years and rightly so.
USB connectors were standardized, every manufacturer used them and they were cheap to produce.
Everything that needs to communicate with a computer or other devices either has a port or one that can be turned into USB with a special cable.
According to Wikipedia, some 2.
5-3 billion usb devices are sold every single year, with around 7-10 billion devices using it in total.
A USB hard drive is a hard disk drive that is connecting to a computer through this connector and is always an external device, and for this reason resides in its own external case.
This external USB case translates between USB and PATA or SATA, depending on which one the HDD in the case uses.
USB hard disks that are using 2.
5" HDD are usually powered through USB, but since USB is only capable of giving 1A at 5V, which means 5 watts of power, other, mainly 3.
5", devices need an external power supply.
These devices are using AC-DC adapters, a simple power supply to convert Alternating Current from the plug to Direct Current, what the hard disks need.
USB Drives are plug and play, which means most recent operation systems have no issues connecting to them without additional drivers, and that is good because you can carry your external drive and be sure that it will most probably work on any computer you connect it to.
External hard drives on the market range from 160 gigabytes to 1.
5 terabytes usually, and to give you a basic idea of how much data 1.
5 terabytes is, imagine a pile of 330 DVDs.