Data In, Data Out
by Bill O’Kane, Alternative Business Systems
Disk Drives are another part of the computer you will hear about. There are many types of drives but they are broken down into fixed and removable.
The fixed drive is usually the hard drive on your computer. It is referred to as fixed because you do not have physical access to the actual disk platters inside. The hard drive stores all the system, data, and application files on your computer.
Unlike RAM, disk storage is not dependent on being constantly refreshed and is stored magnetically, meaning it will stay on the disk until the user erases it. The most common removable media drives are floppy and CD drives. Removable drives allow you to change the disk media containing the data you want to access and depending on the type are writable (the data can be changed) or read-only (the data cannot be changed) such as some CDs.
Special forms of CDs are available such as CD-R and CD-RW that can be written and rewritten to with special devices. Floppy drives have been around since the early days of personal computing and have shrunk in sizes from 8 inches to 5.25 inches to today’s modern 3.5-inch diskettes. Although today’s floppies are quite rigid the name derives from the original diskettes that were quite flexible.
Disk storage today is measured in Megabytes and Gigabytes. Computers today regularly come with hard drives containing 20 – 80 Gigabytes of storage space. The average CD can store 700 Megabytes and floppy diskettes 1.44 Megabytes.
The most recent storage contender is the writable DVD, capable of storing Gigabytes of data, however there is no agreed upon standard yet and manufacturers are producing machines with their own standards, similar to the Beta/VHS wars with video tape.
Having too much storage is usually not a bad thing, but with all this Kilo/Mega/Giga talk, sometimes the new user has trouble relating. Think of it this way, it is possible to store all the information in an encyclopaedia on one, maybe two CDs that is 1.4 Gigabytes. How much more can you store on 10 or 100 Gigabyte hard drives?
There are other storage mediums available such as ZIP, JAZ, and tape. These all have their pros and cons, but in most cases the machine you buy will have the drives mentioned earlier. Do your homework on these drives before purchasing them. They tend to be expensive to use and although media such as tape is the preferred backup in large organisations I personally feel the expense far outweighs the need for home users. CDs are an excellent choice for home use as the software is easy to use and the cost per CD is low.
Large capacity and the ability to store your data is all well and good, but a measure of safety is required. All electronics can fail; any data you cannot live without should be safely stored as multiple copies.
Hard disks have a life of about ten years, although I still use disks that are older than that and work quite well. CDs are supposed to keep data securely for one hundred years, we’ll just have to wait and see, but CDs are quite fragile and a broken or scratched CD, makes a cool cheese cutter or a coaster but no longer contains easily retrievable data.
Recovering data from a damaged disk is a long and expensive process, so if you have important files burn them to CD, make a few copies, and do not store the copies all in the same place. A bit obsessive maybe, but if a catastrophic disk failure happens you will prepared.
This brings us to the humble floppy. Floppies are great for moving small files from one computer to another, as most computers still have floppy drives. Floppies are not however a safe storage medium. No matter how expensive a floppy disk you buy they are notorious for failing.
Personally, I use a floppy disk about five times and then good or not I copy the files to another disk and toss the old one in the wastebasket. I am sure there are readers that still have old disks that are quite usable, there are exceptions to every rule, but I personally will not risk valuable files that way.
This article by no means touches on all the hardware and electronics of the computer, I will save that for later, but it gives you a basic overview of the machine and it’s most common hardware. In later articles we will go into other hardware peripherals, with more specific functions, in more detail.
As you can see, this mysterious box is no different from your TV, DVD player, microwave, etc. It is merely a collection of electronic circuits that combine to provide an appliance that can do many amazing things. Today’s modern computers do a very good job of hiding the working from the user and just as you do not need to understand TV technology to enjoy your favourite show, understanding the working of your computer is not required to make use of it. Hopefully, by reading this article you will at least be familiar with some terms you may hear sellers or technicians using.
If you have any questions or comments, please feel free to contact me. I will be happy to help you with your questions.
Next time we will tackle software, the real ghost in the machine!
Contact Bill O’Kane at: Alternative Business Systems
680 Water Street
Miramichi, New Brunswick
E1N 4B8 Canada