Partitions, Volumes, and Drives

Sometimes in IT there's some confusing terms out there that seem like they could be interchangeable. Partitions, volumes and drives are really closely related, but they are different aspects when it comes to storage.

When it comes to drives, there's kind of two different definitions of what a drive is. There's the physical aspect of what a drive is, and because we have this physical aspect of what a drive is, sometimes there's this logical drive that we will reference. So what we're going to do is address the physical drive and what a physical drive is, and then later on we'll address what a logical drive is.

Media and drives

What we have here on this side is our media. Three of these, this one, this one and this one, is what we call magnetic media. That is, those little bits, those little ones and zeros, are stored using little magnetic signals back and forth. It's a polarity thing, it's a north/south thing, and it stores these little signals on there. Versus this optical drive is little divots in foil that reflect a laser light on here, and so that's how that gets read.

So this is the media right here, but in order to be able to access what's on these, they each have a drive that they need to be placed in. Here on the right, this is an optical drive, and we call it a drive because it actually has a motor that drives, or spins, this disc right here. We'd put this disc inside of here to read it. Same thing, this is tape, and so it needs a cassette tape player. Same thing with this, except it's a different type of cassette. This is an audio cassette, so it needs an audio cassette player for it, versus this is a data cassette that this would go into, and you'd need a drive to drive that around. And then this is a floppy; you would need a floppy drive in order to be able to read this. So that's the difference between our media and our drive.

Then we have something like a hard disk drive. The hard disk drive combines the two. We have both the motor that spins this right here, and then we have this arm that goes back and forth to actually read the data. So what we have here is a hard disk drive that combines both the drive and the media. It's all in one.

Formatting and splitting a drive

When we have something like a hard disk drive, what we do is we go through the disk formatting process. What that does is it creates that allocation table, so we can start putting the references in the allocation table, as well as it creates all the structure that we are going to actually save the data into.

There are times when we may want to take our hard disk drive and then split it into multiple sections, and so we can split the drive so that way it presents itself as two different drives to the machine. One reason why we might want to split up a drive is to have a section that's devoted toward the operating system and one section devoted towards data. And the reason why we'd want to do this is the operating system can be very sensitive. That is, if the drive that the operating system is on fills up, it can be devastating. It can be really hard to get that computer up and running, so you could delete files and make it stable again, and so it can be really painful.

So we want to protect the operating system drive, and what we do is we split it off. The operating system takes up this drive, and maybe it takes up a good portion of the drive, but we make sure that we have plenty of extra space on this drive, so we have extra space for the operating system. And then the data could be just gathering here, and if there's any chance that that data fills up and fills up the whole drive, it's not going to crash the system, because you still have this extra space available for the operating system to run. And so that's one big example of splitting drives and why we'd want to.

Partitions and volumes

There's a couple of different ways we could split up this drive. One is with something called a partition. A partition is a section of the drive that can be used for booting up the device. So in this example right here, we've split it into a smaller section right here and a larger section.

A volume is what is then presented to the machine when you actually get onto the machine. What I mean by that is that when we get onto the machine, then we'll be able to access that drive through what is known as a volume. The volume becomes a volume when you format it, and then it's presented through the operating system. So what we'd do is we'd format the drive, and now notice that each partition has an allocation table to it, because it's been formatted now, and now it's visible in the operating system, and we call this a volume.

Some storage devices don't have partitions at all. A floppy is an example of this. There's no partition in a floppy, but you do have a volume. It gets presented to the operating system and you can see it, and it's a volume, it's been formatted, but there is no partition to it. So there are times when there's a volume without a partition.

A partition can also exist without a volume. That is, we can partition a drive but we have not formatted it, and so it doesn't show up on the operating system. At this point in time we would say that this is a partition without a volume.

One common setup for a lot of these devices, a lot of storage devices, is just to have one partition, there's no need for multiple partitions, and then within that we split it up into multiple volumes. This would be a great scenario where we had an operating system volume and then we also would have a data volume, and separate out the two.

Booting two operating systems

Here's an example where maybe we have a storage device that we want to use for booting up, but we want to boot up to two different operating systems, Windows and Linux. So what we're going to do is partition this drive into two different partitions. Maybe we format this first one as NTFS during the install process of Windows, and so now we have a Windows partition that's all set up and formatted, and it now becomes a volume that's accessible once Windows is installed and booted up and we're inside Windows.

And then what we are going to do with this one is we're going to instead format it with ext4. So this is not going to be a volume that's accessible in Windows. Instead, what we're going to do is install Linux on it, and during the boot up process we get to choose whether we want to boot to Windows or do we want to boot to Linux.

Logical drives

Now, we mentioned about drives as being that motor that drives our media, but I also said that let's address the logical drive and what a logical drive is. You might have actually heard me refer to certain things; I'm trying not to use drive as a general term, but I probably have a few times throughout these lessons. And so that's actually thanks to Microsoft.

The reason is because this CD-ROM shows up, a lot of times it's the D drive, shows up as a drive on Microsoft, and then you put your media into it, your optical media into it, and then you're able to access the media through this drive. Well, this is a physical drive, but it shows up as a logical drive on the computer. And then same thing, because this is kind of the same thing, we're accessing data on it, and so this shows up as a drive on a Windows machine. And then if we split this into two partitions and there's two volumes now, and those volumes are on our computer, it shows up as two different drives on a Windows machine.

So that's where some of the confusion comes in when it comes to drives. Drives could mean that actual physical drive that actually spins the media, but it also could refer to this logical drive of these volumes that are on a computer.

So as an example, we have this hard disk drive, and maybe we've partitioned it into two different partitions. We've now formatted it, so now we have volumes that show up inside of the machine, that they're accessible, we can actually store data on it now, and they show up on a Windows machine as drives. So these are now drives on a Windows machine. What Windows does is it assigns it a letter, so we would have maybe this is the C drive right here, and then this is the data drive, or the D drive, or maybe it's the E drive or the F drive. And so now these are presented as letters on a Windows machine.

Disk Management

I jumped on the Windows machine to see what this actually looks like. I'm going to click on the start button and type in Disk Management. In fact, I don't even need to type in the whole thing, I can just hit enter, and it'll pop up with this Disk Management window. It already recognizes that there's some discs on here. I'm going to click cancel for that for now, so we can take a look at this window.

This Disk Management window shows you all of the volumes up here in list format, and then we see some visuals down here. So one of them is this disk zero. Disk zero is partitioned into three partitions here, and one of them is showing up as a volume here, the C drive. So this is the lettering here, the C drive, and it's 95 GB big. And then we see a couple of these partitions right here, which show up at 100 megabytes and 822 megabytes.

Let's take a look at the CD-ROM as well. So we've got a CD-ROM that's on here, and the CD-ROM is the D drive, it's got the D drive letter, and so that is another volume that's on here, or another drive that's on here.

So let's take a look at this disc. I've mounted this disc on here and it just shows up as being unavailable right now; it's unallocated. So the first thing I'm going to do is initialize this. It says it's not initialized, so I'm going to right-click on this and say initialize disk. It's going to ask me disk one or two. Well, we're just talking about disk one here, so let's just do disk one. It gives me a couple of options: MBR, which is master boot record, and GPT, which is good partition table. So this gives us a clue what we're creating right now is a partition. So what I'm going to do is click on okay.

Next, what we need to do is create our volumes on here. So I'm going to right-click and say new simple volume, and I'm going to create a volume that's a little bit smaller, so I'm just going to call this five gigabytes of information. So I got 5 gigabytes in there, or 5,000 megabytes is what it is. And then I'll hit next, and I choose a drive letter. So here's where I can choose a drive letter, and where Microsoft calls this a drive. And then I'll click next. I'll just use E, that's fine.

I'm going to choose the format, so this is the file system, and what format do I want the file system? I've got two choices, I can do FAT32 or NTFS. Well, since this is just going to be a local drive on this machine, NTFS is going to be my best bet. And then I'm going to give it some sort of name, so I'm just going to call this data. And then we have this perform a quick format. Since this is all a virtual drive, it actually wouldn't matter whether I check it or uncheck it, but let's just do a perform a quick format. So now it's formatting this data drive as that drive E, and it's going to be NTFS.

So I'm going to click next. It gives me a confirmation: is this everything that I want? Check it over and click finish. And now what I've got is this volume right here that's available to the machine.

And then this is unallocated, so let's go ahead and create something out of that as well. In this case I'm just going to use whatever's left over. Let's call it the Z drive, so it's a snooze. Let's click next. NTFS again, or why not, let's do FAT32, let's choose that out. And then we'll call this FAT32, and click next and finished, and then what it's going to do is create that volume there. So now I've got the E drive and the Z drive.

If I want to see these drives now, I can open up my Explorer window, my File Explorer. I'm going to click on This PC, and there's all the drives there on here, quite a few actually, but we have that E drive that's on here. So I can save a file into here. So maybe I say new, maybe we just create a folder in here, we'll call it test. So there's my folder in there. Then I can go into the, here's the FAT32 drive, so I can go into there and then add something in there. So there you go.