In our first article in this series, which can be found here, I covered what a link really is. And, as promised, we can now talk about the details of these links and how they can affect you.
So let’s have some fun with this and let’s use an analogy to really show what file links are all about and how amazing they are.
A couple definitions:
A file that contains one or more links pointing to an external file is called a “parent file”. A file that is being pointed to by a link is called a “child file”.
A “link” is a set of instructions that tell the computer where to look for a child file and what to do when it finds that file. This is what a link, in essence, actually is. It’s a set of instructions that are placed inside the guts of one file (a parent file) and that direct the computer to go find another file (a child file) and then do something with that file.
As a side note, the terms “parent file” and “child file” were invented circa 2001 by David Greenbaum who later founded LinkTek Corporation. But the concept of what I’m talking about is fundamental for all situations where one file has a link to another file. The new terms were coined for the sole purpose of making the communication and education easier.
A Cool Analogy
Here comes the analogy that will make this so clear and easy that you will never forget it: Let’s say that you are in your office and you need something picked up, each and every day, from another location and brought to you.
So you send for a company courier named “Bob” who walks into your office. You tell Bob that you need the following done at Noon every single day. Then you hand Bob a piece of paper that says:
Drive to the house named “Castle” at address 1810 Lake Drive, Tampa, Florida USA. Get there by going west on Maple Street and then turn left on Lake Drive. It’s the sixth house on the right.
When you arrive, pick up the package labeled “Vital Material”. Bring that package back here, then open it and take out the slice of pecan pie and put it on my desk.
Your office is the parent file.
The house named “Castle” is the child file.
The address and the directions to the house compose the file path.
The package with the pecan pie is the target data residing inside the child file.
The courier Bob is the computer CPU that will execute your instructions.
The full set of instructions (which is everything on the piece of paper) is the link.
That’s what a link really is. It’s a set of instructions residing in one file that tells the computer where to look for another file and what to do when it finds the other file.
If Bob (the computer CPU) drives to the house (the child file), successfully retrieves the package (the target data), brings it back to your office (the parent file) and places the pecan pie on your desk, then the instructions (link) worked correctly, as did Bob. And all is well. This is a rough analogy for what a working file link is and what it does.
But unfortunately not all file links work like that all the time. Sometimes the instructions (link) have something wrong in them, such as wrong directions (file path) to the house (child file), in which case Bob would return to your office (parent file) and present you with either nothing or some sort of bad banana (error message). This is called a “broken link”. Or, in another scenario, perhaps the instructions (link) were completely correct, when they were written; but the house has been demolished or the people in the house have moved (taking the pecan pie with them). That would also cause Bob to fail in his mission and you to miss your delicious pie. In this case, the link itself was not messed up. What went wrong here is that someone moved the target! That is also referred to as a “broken link”, and will be the subject of our next issue.
Do you have questions regarding this article? Let us know in the comments below or e-mail us at: LinkMail@LinkTek.com