CompTIA Linux+ XK0-005 – Unit 06 – System Configuration Part 1

1. System Configuration

Now in this unit we’re going to talk about system configurations, mostly dealing with hard drives, but really we can talk about devices. So when we think about expanding onto our Linux operating system, we’re on the actual hardware platform adding new drives. We’re going to focus on making sure that they are formatted with the file system. We want partition the way we like. We’ll talk about how to create partitions and volumes and then we’re going to move from there and get into some of the extra features. Now we’ll review mounting again, we’ll even talk about how to make sure that when you reboot that these partitions and volumes are automatically mounted for you so you don’t have to do that every single time.

But the extra features we’re going to get into are things like quota management. We’re going to talk about swap space and configuring it. And then we’re going to look at some of the things that we get into, some of the disaster recovery business continuity by using rate arrays to be able to help recover from a hard drive failure in a very rapid manner. From there we’re going to talk about other types of devices, which could be USB devices, CDROMs PCI devices, but basically things you plug into the computer, into the hardware and you want to use them. They have to be recognized and so they’re called devices. So we’ll talk about devices in general and a couple of the special ones.

2. Topic A: Disk Management

So we’re going to begin on our first topic with disk management. And if you’re not familiar with hard drive technology and terminology, we’re going to give you kind of a quick review about the components of a hard drive and then talk about the types of tools that we would use to partition them and format them.

3. Disk Drives

All right, so when we talk about disk drives, we generally have a kind of a name that we use in describing them. Some of the older drives are known as Ata and IDE drives. Now, each of those acronyms talk about the type of connection or cable and controller that we use to communicate with those drives, the IDE being an older version of these, of these connections, which generally also determine the speed of transfer. Now, typically an Ata Idi drive has a single cable that has two connections on it. So I can put two hard drives into one Ata IDE controller. We generally call those drives the slave drive and the master drive. And it really just tells us where in the, on the cable that those drives are located.

It does not mean that the master drive is any more preferred than the slave, but really just becomes a drive number drive zero, drive one. Now, having said that, it is important when we’re mounting these drives that we recognize which one it is. Now, in the old days, you used to have to change the jumpers on these drives so that you not only knew where on the cable you put them, but you had to tell the drive which one it was. Now, we also have boards that often have more than one Ata IDE controller card, which means you can have another cable and hook up another set of drives as well, so you could have some secondary master, secondary slaves. Now, the world of scuzzy was very popular for a very long time. It still is fairly popular.

The Scuzzy was a technology that improved bandwidth and used what we called a bus mastering technology. So we could hook up to seven to 15 devices in what we kind of call a daisy chain fashion. In other words, I could hook up a Scuzzy printer, have connected to the printer, a Scuzzy based scanner, and they all would communicate through the same serial connection. In other words, the scanner connected to the printer or the printer connected to the computer. And each of those spots that we would create were given what we called stops or bus stops. They were given a unique number identifying which device was there 0123, all the way up to potentially 15. Now, having said that, you could potentially add on multiple hard drives by chaining them together.

They could be internally connected, they could be externally. The beauty about Scuzzy was it was just a type of adapter, a type of communications highway that we created. It was a bus based technology, but it did give us better throughput. Often it improved with time and we started adding extra adjectives to the term Scuzzy. We started having fast scuzzy and wide scuzzy and super wide and super fast. And it was just kind of going crazy with these names, but it just was a way of talking about the throughput and the speed. The reason people liked scuzzy was because I could have multiple drives on a single connection, a single bus and the throughput, meaning the amount of transfer, the speed of the transfer rate was significantly faster than Ata and idi. IDE drives.

4. Drive Components Part

Now, one of the things you didn’t hear us talk about are some of the newer types of drives that have a different type of connector called a Sadie or an SATA. But that is another improvement on the same type of ideas. So regardless of the type of drives you may be using your systems, the goal and the point is that we have a numbering system of where that drive is located and we know how to reference it. And that’s what’s that whole discussion was about.

5. Drive Components Part

Moving into the components of a drive. If you were to take these things apart, you generally would see some common parts. First is a bunch of platters. Now, it could be a single platter, it could be multiple platters, it depends on the drive itself. But a platter is nothing more than a disk that is connected to a center spindle or a center cylinder that allows you to spin this thing around. And that’s, that’s what a drive does. It continues to spin. And we have what’s called a read write head connected to an arm that moves back and forth. So as these things spin, they spin underneath this head and the head moves back and forth to different locations.

So that basically, if I tell you I’m looking for a file that’s on a certain track and is in a certain sector on that track, the head would move to that track and wait for that sector to spin underneath that head so it could read the data. Now, some of your drives are dependent on the speed in which it can spin the RPMs. The faster it spins, we consider to be a faster drive, because it has usually a faster seek time. It can grab and find the data much faster because it’s not waiting as long. Also, the things we see about these drive components is often if you open up one of these brand new Terabyte drives and you open up one of the old ones from five years ago, that maybe we were lucky, it did 100GB, and you look at them, you say, hey, they look the same.

Well, what also has changed, of course, is the size of that head, the shrink size, so that it can actually read finer amounts of detail on these drives. And even some of the technology of the drives has changed now. So it’s not necessarily a flat platter, as it has been with a magnetic coating, but they had a while that they were advertising flipping the bits up on its side, kind of like having grooves to get more data in the same space and it just continues to improve. Now, of course, the new thing you hear about is solid state technology and moving away from, of these hard drives.

6. Drive components Part

Anyway. So I gave you kind of the basics of the idea of what the hard drive does. And the reason we’re moving away from them, many people argue, is that in a computer, in a server, this is the only thing that moves right. It’s got the read, write head moving back and forth and a spindle spinning the platters around. Because it’s a physically moving piece, it is actually the slowest part art or slowest component of all of our systems. One of the benefits of a solid state drive is that there are no moving parts. And so we’re hoping to see better seek speeds, better speeds in general for performance, even though we don’t have quite the same storage capability.

But there’s another whole argument that you can see. A person like me, who likes to be a politician sometimes can take both sides of the argument. It’s again about business design. So anyway, whatever you’re using for storage, we are going to have to designate it by its volume and partitions. And that’s kind of the goal. So now you have kind of a picture of what the drive is consisting of and we’re still going to logically separate this thing down into these things called partitions and volumes.

7. Drive Geometry

Now, if you take a look at a typical hard drive, the platter technology, it is technically broken down into tracks. And I talked about these tracks. Now a track is just a ring around this platter that is broken up into sectors. And as I store my files, I have to actually reference what track and sector the file is located on. Now some people will tell you you that if I look at the track on a top platter, if you have multiple platters, that same track exists on every platter that you have. And so they call that a cylinder. But the whole purpose of knowing these names is just to know this, that when you create a volume or a partition, you’re going to have a file system that’s put on there. The file system is nothing more than a table. I like to call it a table of contents that lists information about the file that inload information. I talked about the metadata, including the actual physical location on the hard drive the file is stored at that’s back to the tracks and the sectors or the cylinder track and sector.

Now that address is what the read write head is trying to move to, waiting for that to spin underneath so it can read the information that you asked it to retrieve. Having said all of that, that gives you kind of an idea of what’s going on when you format, when you format a drive, you’re creating a table of contents that says, I’m going to be able to keep track of the addresses on the actual drive, of where files are stored. Hopefully I haven’t confused you with all those terms. So why do we care about knowing about tracks, sectors and cylinders? We need to know know that so you have an idea behind what’s really happening when you save a file, when you save it as being written in a physical location on the hard drive, its address, that location is copied in a separate table. That is this thing we call the file system.

8. Partitioning

Now, having said that, you might choose to take your hard drive and partition it into smaller units of storage, often for organizational or administrative purposes. What I want you to know is that partitioning a drive, a single hard drive does not increase your capacity. It does not increase your speed or your throughput because it’s the same physical drive. If you decided, well, well, hey, if I have three partitions on the same drive, I’m going to get some good performance because this partition won’t interfere with the other one. Well, guess what? That drive is still a single drive. It has one read, write head that’s moving back and forth. In this case, it’s just broken down into logical sections or organizational units called partitions.

If you truly want to have a speed performance, have a second hard drive. One can have a partition, the other one can have a different partition, and you can read from both of them at the same time. Then you truly are getting a benefit of the different hardware. Okay, so why then would you create different partitions on a single drive? Well, at first there are always going to be two partitions, a root partition and a swap partition. The idea here is that I’m organizing it, maybe for administrative or business needs. The swap partition’s job is to act with the virtual memory so that we have what appears to be an increase in actual memory for applications. I talked about that in a different unit. But in a nutshell, an application may be promised it has two gigs of memory.

Well, maybe that’s all the more memory you have on that system. So what happens when another application starts and it’s promised two gigs of memory? Well, the problem now is that you don’t actually have four gigs of memory. But what we do is we utilize part of your hard drive to virtually appear to be memory so that every application gets what it needs. And we also hope that those applications don’t actually need all two gigs of memory. It just has that addressable spots. Anyway, that partition that we use to move data from memory to the hard drive. From the hard drive. To memory as it’s needed because it’s pretending to be memory. That’s the swap partition.

The root partition is all of the files we use to boot up the operating system. All the stuff you’re storing your home directories all. Those files that make Linux what it is and consists of all the user data that’s stored on the root partition now, you could put those on different hard drives if you like to you would get a better performance but we do separate them so that we don’t have any overlapping. I don’t want my swap partition or my swap file to be so variable that it might overtake root files or not give me enough hard drive space. For my users by putting them in separate partitions. I’m guaranteeing that my root partition has so much space that I’m guaranteeing that there’s so much space on my swap partition, whether I use it all or not.

But I’m keeping them separate. Now, you might also want to look at device files. A device file is the way we represent a partition. So when we talk about devices and device files, we realize that we really are going back to the file system hierarchy that says there are no real objects, there are no C drives, there’s no D drives. That a partition, a volume. Although an organizational unit of storage is represented by a file, we called it a device file. Now, when you open up or access that device file, whether you navigate it through it to the shell or you click it open with a Gui, when you access that file, you then are accessing what it represents, which is all the files stored on that partition.

Now, remember, there are different types of partitions or formattings that we can use for these partitions. The common ones you see are the extended file systems, version two, three and four. They provide different features, different capabilities, can address different size of drives. We also have partition types, like we said, the swap type of partition. But these are some of the questions we’re going to come across and answer as we get into how do I create the partition? What should I be looking for as far as a file system?

9. fdisk

Now, one of the tools you can use to create and format your partitions is an old program called Fdisc. And yes, believe it or not, there was an old Dos utility in Windows by the same name. Now, Fdisc’s job was to tell you about the geometrics of the drive and ask you to say, well, how much of the drive do you want to make a certain partition? What do you want to call it? All those types of things. Its job was to logically partition the drive so that it could be read as different partitions. Obviously, some of the initial sectors of a drive would help describe the method in which the drive is actually partitioned. So in many ways, what you are creating is a logical area and you have to tell a drive as well. So when it’s red and it starts up, this is how you’re partitioned.

10. fdisk – Drive and Partition List

Now when you run Fdisc, one of the things it should do is read the drive’s information to let you know how it is currently partitioned. It should show you the starting location, the ending location, which tells you how many blocks or roughly how much storage was available on that particular partition and any name that it might have. Now this is crucial because you might be trying to load Linux onto a machine that already has Windows running. So it’s nice to see what are the existing partitions so that as you make a new one, you, number one, know if you even have room on the disk to make a partition, and two, that you’re not going, to blow up some other operating systems existing partition, which could also then cause this cascading effect of blowing up user files and doing something good.

At getting your name recognized by those people whose lives you just destroyed.So be careful with the fdisc. You look at the information, make the decisions and then as I said, you can go in from there and follow basically a menu set of options to create new partitions if that’s what you want to do. Now remember, creating a partition with Fdisc does not then format it with fdisc. You would still have to separately choose to make the file system on that drive. So it’s kind of a two step process where there are some tools that you can run all in one that will make the partition and then format it for you as well. Fdisc, like I said, is one of the older ones.

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