What is a hard disk?
Before I can answer the question in the title, I must take a temporary diversion to explain exactly which bit of the computer I am talking about. Many people think that the name ‘hard disk’ or ‘hard drive’ refers to the computer itself, but in actual fact that box contains a number of parts, a motherboard, processor, memory, graphics card, and yes, the hard disk. The hard disk is the bit that stores all of your data, documents, photos, etc. It also stores a copy of Microsoft Windows, which tells the computer what to do and how to do it. (Some people don’t have Windows, but that’s a different article.) The hard disk is not the same as memory. Memory, or RAM, is a set of microchips used to keep track of your data while it is actually being worked on, but once finished with, all that data is stored on the hard disk.
The picture above is an example of what a hard disk actually looks like. It’s a small box about 10 x 15 x 2 cm and it contains several disks spinning at about 7,500 revolutions per minute, and it has some heads that move back and forth over the disks and read and write information. The reading and writing is done magnetically in roughly the same way that a cassette tape works. Click here if you want to see what the inside looks like. (Click the back arrow at the top left of your browser to return here afterwards.)
Do you trust your hard disk?
Now that we know what a hard disk is, we must address the question that I asked in the title. Do you trust your hard disk?
The answer to that question should be a very emphatic ‘NO!’
By far the most common computer fault that we fix here at Refresh Technology is hard disk failure. Every hard disk will fail eventually. Some will fail before the computer has even left the factory. Most will last many years, maybe even ten or fifteen. But a huge number of them will fail after just a few years in use.
Some disk failure will be sudden and catastrophic. One day your computer will be working, and the next day you will turn your computer on and could be faced with nothing more than a black screen with the words “insert system disk” staring you in the face.
Other disk failure can be much slower, and much more subtle. Disks are divided in to small segments called sectors. When there is a problem reading a sector, the disk will try a few more times. It will quite often manage to read the data after a few tries, and will carry on without you being any the wiser. If this happens a lot, the data will be moved to a different sector and the faulty one marked as bad and avoided in future. Over time, as the disk slowly wears out, more and more sectors will be marked as bad and your computer will get slower and slower as it gets held up repeatedly trying to read from the dying sectors. It is at this point that the repair technician is often called in, and has to tell the unfortunate customer that the reason their computer is unusably slow is that the hard disk is actually about to fail.
A replacement hard disk is not as expensive as you might think and can usually be had for about £40. The charge for labour to recover your data and to reinstall Windows is the more expensive part. In the event of complete and sudden disk failure, data recovery is only possible in a laboratory and can cost from a few hundred pounds up to several thousand! With gradual disk failure, it is often possible to recover your data but the process is slow and tortuous. It can take a whole day to copy your data to the new hard disk, and there is a high chance that some of it will be unreadable. Fortunately the computer can be left to its own devices during this copying process and so this does not rack up a large bill for labour.
What can you do about it?
Now that we know that a hard disk cannot be trusted, what should we do about it? The answer is simple.
Backup
You must make a backup copy of your data. And not just make a copy, but you must update that copy every time your data changes enough that you don’t want to lose it.
There are many ways of backing up your data. Traditionally, computer data was backed up on to tape. You might be surprised to know that it still is, in businesses everywhere. Tapes can be difficult to use and expensive to buy though, and so for the individual user or the small business they can be overkill.
The simplest way is to use a USB memory stick. Plug in the memory stick, find the files that you want to back up, and drag them across. It’s simple and effective and allows you to take a copy of your data away with you to guard against fire and theft.
If you have too much data for a memory stick, how about a USB hard disk? Exactly the same principle except that you can store much more data on one device. Some external hard disks come with software that automates the backups for you and can be set to copy your data either once a day or every time that you change it. (So does Windows, but it’s not very good!) A step up from this would be a network disk, or NAS.
Backup over the internet is a good alternative to the methods above. Services such as Mozy and Carbonite cost a small amount each month and they work by installing a piece of software on your computer which will automatically copy your files to their servers. Again, it can be done once per day or every time you change a file. The benefit is that you automatically have a copy of the data in a different location, and it can all happen behind the scenes so that you don’t have to remember to do it. The downside is that it can take days to send all of your information to the servers, and should you need to get at your backup copy, it can take days to get it back too.
Finally, a very useful variant of online backup is a service called Dropbox. Dropbox creates a folder on your computer called “My Dropbox.” Every file that you save in that folder will be immediately copied to the Dropbox servers. Two things make it different from the tools previously talked about though. Firstly, Dropbox will store 2GB of your data for free. Secondly, if you install Dropbox software on a second computer, any file that you save in your dropbox folder on the first computer can be automatically downloaded on the second! Here at Refresh Technology we use Dropbox to synchronise our data across our office computers and our home offices. When one of us update a file in the office, another of us can read that file from home. If you decide to sign up to Dropbox, you might consider using this affiliate link which will give the author a little extra space as a reward for referring you.
I hope that all of this information will be useful to you. If you are worried that your hard disk might be on the way out, you could take advantage of our PC Health Check service. We also offer a Fixed Fee repair for home users should your disk actually need replacing.
If you only take one message from this article, it should be Make a copy of your files! Do that, and you will save us the unpleasant task of informing you that all of your photos, music and documents have been lost forever.
This article first appeared at the Refresh Technology blog.