So what is YOUR Backup Plan?

    

This is a program presented by Bob Warwick at the Oct. 18, 2010 LPCUG meeting.  We need to know how a hard drive stores data in order to understand what is happening when we back it up.  We want to move slowly enough so that no one ends up completely lost...partially lost is okay!

A.  What am I backing up?  Basically a lot of "1"s and "0"s.

a.  How a hard drive works

In your computer's hard drive, there aren't really any iron nails. There's just a large shiny, circular "plate" of magnetic material called a platter, divided into billions of tiny areas. Each one of those areas can be independently magnetized (to store a 1) or demagnetized (to store a 0). Magnetism is used in computer storage because it goes on storing information even when the power is switched off. If you magnetize a nail, it stays magnetized until you demagnetize it. In much the same way, the computerized information (or data) stored in your PC hard drive or iPod stays there even when you switch the power off.

What are the parts in a hard drive?

A hard drive has only a few basic parts. There are one or more shiny silver platters where information is stored magnetically, there's an arm mechanism that moves a tiny magnet called a read-write head back and forth over the platters to record or store information, and there's an electronic circuit to control everything and act as a link between the hard drive and the rest of your computer.

After a hard-drive crash last year, I was left with an old drive that no longer worked. I took a peek inside, and here's what I found...

The parts/components inside a hard drive

  1. Actuator (compact electric motor that moves the read-write arm).
  2. Read-write arm swings read-write head back and forth across platter.
  3. Central spindle allows platter to rotate at high speed.
  4. Magnetic platter stores information in binary form.
  5. Plug connections link hard drive to circuit board in personal computer.
  6. Read-write head is a tiny magnet on the end of the read-write arm.
  7. Circuit board on underside controls the flow of data to and from the platter.
  8. Flexible connector carries data from circuit board to read-write head and platter.
  9. Small spindle allows read-write arm to swing across platter.

iPod PCMCIA hard drive and laptop hard drive (outside view). iPod PCMCIA hard drive and laptop hard drive (inside view).
Photo: Little and large: Here's the 30GB laptop hard-drive (shown in the other photos on this page) next to a 20GB PCMCIA hard drive from an iPod. The two drives look strikingly similar and work exactly the same way (both are made by Toshiba), but the iPod drive is even more of a miracle of miniaturization!

The platters are the most important parts of a hard drive. As the name suggests, they are disks made from a hard material such as glass or aluminum, which is coated with a thin layer of metal that can be magnetized or demagnetized. A small hard drive typically has only one platter, but each side of it has a magnetic coating. Bigger drives have a series of platters stacked on a central spindle, with a small gap in between them. The platters rotate at up to 10,000 revolutions per minute (rpm) so the read-write heads can access any part of them.

There are two read-write heads for each platter, one to read the top surface and one to read the bottom, so a hard drive that has five platters (say) would need ten separate read-write heads. The read-write heads are mounted on an electrically controlled arm that moves from the center of the drive to the outer edge and back again. To reduce wear and tear, they don't actually touch the platter: there's a layer of fluid or air between the head and the platter surface.

b. Why is the first or main hard drive in your computer called "C: drive"?

The answer is simple.  Back when almost all desk top computers had floppy drives the first two were called "A: drive" and "B: drive".  Many PCs had two of them so that you could easily copy the contents of one floppy disk to another one, without having to take one floppy out and replace it with the one that was to receive the copy.  Therefore, the next drive on the system was the hard drive or "C drive".

C.  What are "sectors", "tracks", "clusters" and "partitions"?

Sectors and tracks are magnetic roads and road markers, that are laid down on the platter when you format a hard drive.  Newer hard drives already have these permanently installed on the platter.  Clusters are the smallest group of sectors that windows can write to and later find.  Partitions may be added to the platter (with special software or during initial set up) to make it look like there are two or more hard drives (logical drives).

Drives can either be physical or logical.  There is no difference in how the operating system handles drives.  You can have two or more logical drives on one physical drive, or you can have two or three physical drives mounted in the computer.  If we put two logical drives, i.e. C: and D:, on one physical drive, we must "partition" the physical drive so that what happens on C: doesn't affect D: in any way whatsoever.  It is like a duplex house, where you share the same building but unless you have really noisy neighbors, everything else is separate--door, heating system, electric meters, Etc.

II.  How does the operating system make sense out of this stuff?

The purpose of the operating system, whether it be MSDOS, Windows, Windows95. Windows98, XP, Vista, Windows7, or all of the different flavors of LINUX, is to translate what is going on with all those 1's and 0's so that humans can make their computers do something useful. 

A. What are root directories, subdirectories, files, and folders and subfolders?

How does this stuff get so confusing?  Well, it is because in efforts to help people make sense out of where stuff was located on their computer, computer experts decided to use analogies that people were already familiar with in their life experience.  Unfortunately, they changed analogies in midstream, so we have a bunch of terms that mean the same thing and confuse everyone who didn't get started in this field at the beginning.

Basically, we are talking about how documents, pictures, programs, spread sheets, operating system, are stored on the hard drive so that it makes sense to humans.  The computer knows what it is doing, but it is kind of nice when we know what it is doing!

a.  Analogy #1  A tree that is upside down.

b.  Analogy #2  A filing cabinet.  (Thank you Microsoft!)

In this analogy, the file drawer is the disk drive.  If you have more than one drive in your computer, such as a CD-ROM drive or maybe your hard drive is partitioned into two logical (drive C: and D:) then you would have more than one drawer in your filing cabinet.  In the drawer, you may have files that are not in folders, but most files are in folders (subdirectories).  Often you have folders inside of folders!  While I am just going to do the bare basics, I found this little mini-tutorial below that will help understand the concept if you are new at this stuff.

Folders, Files, and Icons

All the information that's "in your computer" is actually stored on your computer's hard disk (often referred to as drive C:). In a sense, your hard disk is like a filing cabinet. And like a filing cabinet, the information on your hard disk is organized into files and folders. Figure 1 shows the simple analogy.

Figure 1: A disk is like a filing cabinet

Just as a folder in a filing cabinet is a "container" for storing paper documents, a computer folder is a container for storing computer documents. A computer document, in turn, is anything that you might want to look at on the screen, or print on paper. That includes typed text, spreadsheets, and pictures. In the computer world, music (songs) and video (movies) are also documents. And just like any documents, music and video files are stored in folders.

You wouldn't want to open up your real filing cabinet and dump all its contents onto your real desk. You'd end up with a big disorganized mess. Your computer's hard disk can hold tens of thousands of files and folders. You wouldn't want all that stuff open on your Windows desktop (screen) at the same time, for the same reason. It would just be too much clutter.

A folder or file that's currently visible on your screen is said to be open. One that's still "in the filing cabinet", so to speak, is said to be closed. On your computer screen, all folders and files are represented by icons -- those little emblems you see all over the place. It's pretty easy to tell a folder from a file just from the icon. As a rule, icons that represent folders have a manila file folder as part of their icon, as in the top of Figure 2. Icons that represent documents usually have a little dog-eared sheet of paper as part of their icon, as in the bottom of Figure 2.

Figure 2: Icons representing folders (top) and documents (bottom)

To open a folder or file, you typically double-click its icon. When you open a document, some program that's capable of displaying (or "playing") that document opens, and displays the document. For example, when you open a song (music) or a movie (video), Windows Media Player or some other program will open to play the document.

When you open a folder, a program named Windows Explorer opens and shows you the contents of that folder. I'll talk more about Windows Explorer in the next mini-tutorial, for those of you who are interested. For now, the main thing to focus on is understanding the different between folders and files. To recap:

 

A Note on Programs

A program is neither a document, nor a folder. A program is actually a "tool" that you use to create, view, or print documents. Icons for programs don't have either the manila file folder symbol, nor the dog-eared piece of paper. Rather, the icon for a program is just the program's logo. You can see this for yourself by clicking the Start button. As you can see down the left side of the sample Start menu in Figure 3, there are no manila folders or dog-eared sheets of paper in the programs' icons.

Figure 3: Icons down the left of the Start menu represent programs

No document can open "by itself". A document must open within some program. When you double-click a document's icon, the document opens in the default program for that document type. The logo atop the "dog-eared sheet of paper" portion of a document's icon matches the logo of the default program for that document type. Figure 4 shows an example.

Figure 4: Document icons sport the logo of the their default programs

But the main points to remember from this mini-tutorial is that folders are "containers" for storing documents. The icon for a folder will always look like a manila folder, as in the examples shown in Figure 5.

Figure 5: All of the above icons represent folders

Documents, on the other hand, are things like typed text, and pictures -- the types of things you might actually store in a filing cabinet if they were on paper rather than on a computer. To keep the "paper" analogy, icons that represent documents tend to sport a sheet of paper as part of their icon, as in the examples shown in Figure 6.

Figure 6: All of the above icons represent documents

B.  Let's take a look at my computer and identify some of these concepts as you would see them on your computer.  We need to do this in order to know just what we are going to backup.

III.  Now that we know how to navigate around our computer and find where stuff is stored, we can decide what we want to backup and how we want to do it.

A.  What if I just want to save my email, my pictures, and maybe the documents that I have saved?  Do I need to run a full backup of my entire PC and download special software to do this task?

a.  No, most versions of windows have a backup program that will do this task easily.  If you don't happen to have it installed, you can add it from your windows installation disk or download it from Microsoft.  This link will work for XP and Vista--make sure you download the NtBackupRestore_x86.msi file, not the one for Windows 64, unless, of course you are running a 64 bit version of windows--unlikely.  Windows 7 has the backup program built into the operating system, but it works pretty much the same way.

The windows backup program does permit you to back up the whole machine, but you can't extract individual files and folders from this backup.  As you will see below, it is kind of useless to backup the whole computer with this program.   It works best to backup just the files and folders that you feel are valuable, should you not lose the whole operating system.

b.  Now that we know how stuff is stored on our hard drive, we are ready to take a look at how we can recover this information should disaster strike.

B.  Let's look at the Windows backup program that everyone already has on their computer--or can easily get it from Microsoft.

a.  Where is it?  Start Button>All Programs>Accessories>System Tools>Backup

b.  How do I use it?  Well, this is why we spent so much time explaining how your computer stores information.  To use any backup program, you have to tell it which folders or files to backup.  There is a pretty neat tutorial on how to use the Microsoft backup program.  The formal name for this backup program is NTBackup.  Both XP and Vista run the same way.  Windows 7 has a bit more complex, but if you understand the XP and Vista version, you should be able to figure out the Windows 7 version.  Lets  the look at the program now.  You can use the tutorial ,which has everything spelled out, as a reference for when you get home and try it out on your PC.

C: While the Windows Backup Program (NTBackup) does the job for saving some data and files, it is not to be trusted for a full machine recovery.  

The advanced features of NTBackup does allow you to save the system state, but you need a bootable floppy disk for recovery--what's a floppy disk--good grief!  Plus it is flaky...just what you need when you are dealing with a crashed system.  But it does do a good job of saving individual folders and files.  To mirror the whole partition or hard drive, we have a couple of free programs that will do the job.

a.  The main requirement that I have for a backup program is that it provides a function that makes a bootable CD so even if you have to reformat your hard drive, you can restore the system back to the point where you made the last backup.  You should be able to put in the CD start the system, run the backup file, and like magic, your machine runs normally again.  Both programs listed here have this capability.  The first program, like its name, EASEUS Todo Backup,  is very easy to use and does everything that you would want a mirror backup program to do, except automatically schedule the backups.  Read the CNET description and review, then download from the same link.

Just a note on booting up your machine from a CDRom.  Your machine is probably set up to first look at the boot track on the hard drive to boot the machine.  If this track has been damaged, you could spend the rest of the day waiting for the machine to boot.  Every computer has a way of changing the order of where the machine looks for the boot track.  You want to change the order so that it looks at your CDRom first, rather than the hard drive.  On this Compaq laptop, you tap on the esc key after you push the power button in order to bring up a screen that allows you to change the boot order.  Other machines you have to tap on another key (perhaps F10--nothing is standard) to go into the Setup screen and find the page that allows you to change the boot order.  Whatever you do, remember to change it back to the hard drive after you have recovered from your crash.  Otherwise, every time you boot the machine, it will waste time looking for the boot track on the CD drive, before looking at the hard drive.

b. Macrium-Reflect-Free is another very popular free backup program that has over a million users.  It is a bit more complex, but it does all of the basics and then some.  It also has an automatic scheduler in case you are prone to forgetting regular backups--until your hard drive crashes!  There are many choices to boot up your dead PC including a flash memory stick.  Again, it can only be used to mirror a partition or a whole disk drive i.e. all of the logical drives on the physical drive, or, to say it another way, all of the partitions on the physical drive.

D.  Final thoughts.

We see that we can duplicate most of the features of a full featured commercial backup program by using a combination of free software and using software that is available in Windows XP and Vista.  Windows 7 may have refined this process further, but I have not played with this operating system enough to be knowledgeable about how the backup program works.  There is also free backup software that does the same thing as the built in XP and Vista program.  If interested, you can find many free backup programs on CNET that you can try out.

If you are really serious about backup programs, or have data on your PC that you cannot afford to lose, then a commercial program is the way to go.  From my review, the best of them appears to be Acronis True Image which lists for about $50.  I've seen it on Ebay for $26 shipped.  You can down load a free trial version from their website or read the review and download the trial version from CNET.  The commercial software has the ability to do incremental backups--backup only the files that have changed since the last backup; schedule regular backups; can mirror the whole partition or physical drive; can pick out individual files that were accidentally erased or destroyed without having to do a full restore;  and many other neat tricks that probably are not necessary in the home environment.  It isn't a bad investment, since even though they come out with a new version every year, there really isn't that much difference.