File management is a key function of the Operating System. The OS must effectively manage reading and writing data from different storage media, using different file systems and different disk access methods. The OS may also choose to cache data to improve performance of disks.
The I/O bus allows communications with hardware devices; each device on the bus has an address, and is instructed when to transmit and receive data. A device controller sits between the storage device and the bus, to provide a generic interface for the hardware to connect to. Software known as device drivers will allow the operating system to manage the actions which must take place to correctly communicate with different devices.
"But there are two drives in 'My Computer' but when I look inside the case, there's only one. How does that work?"
Some notes from aaaaages ago, not necessarily part of our syllabus.
There's are marked difference between physical disks and logical disks. The best way to get a feel for this is to look at the "Disk Management" snap-in of "Computer Management". Looking at the bottom half of the console, you'll see your physical disks running down the side, and within them are your logical disks. One physical disk may contain a number of logical disks, which are partitions of the physical disk.
Some notes from aaaaages ago, not necessarily part of our syllabus.
RAID stands for (Redundant Array of Independent Disks) (or originally, Inexpensive disks, unfortunately that's not the case any more!). Lets break that down into what it really means:
- "Array", so we're talking more than one disk drive here.
- "Independent", these are separate disks that we are linking together via our RAID controller. They could already be on the same bus or data channel - but they are independent devices.
- "Redundant". We're using more disks than we need in our array. Why is that? Well, by combining the resources of several hard drives, we can end up with a configuration that is faster, larger, more tolerant or more secure - depending on our needs.
Some notes from aaaaages ago, not necessarily part of our syllabus.
Wikipedia defines a Hard Drive as: "A hard disk (or "hard disc" or "hard drive" or "hard disk drive") is a computer storage device that stores data on rotating magnetic surfaces." Now, I'm less interested in the ins and outs of how the hard drive works and more in the types of hard drives, and their practical applications.