MUMPS Programming/Things
As you can see, it gets a bit confusing talking about things inside a computer, so we have to come up with words that describe what is going on in as simple a way as possible. Some things in a computer don't change very much, and other things in a computer are constantly changing. The problem is that usually, we don't want to be constantly telling a computer what to do. There are some games where we do tell the computer stuff to do all the time, but even then, we pretend we are driving a car using the computer screen like a car window, or pretend we are fighting or looking for something. Most of the time though, we want to use the computer as a way to record things, or retrieve things we previously recorded.
When computer people talk, they usually call the things that don't change much using the word Data. Since we don't really want to be constantly describing the things that change all the time, we create things that don't change inside the computer, and use the word Programs to group together all the things that describe the things that change all the time.
It's a lot easier to talk about things that don't change constantly, so for a while, so for a while, computer people didn't actually name the things that change all the time. So there are several different names for them, depending on who was needing to talk about them. Sometimes these things are called Processes or Tasks or Jobs or Transactions or Events. Some people with a lot of imagination pretended that the insides of computers are full of living things so they called them Actors or Daemons or Agents.
Some of the things that are constantly changing will show a person sitting at the computer that they are doing things, by changing something on the screen. An easy example of this would be a clock. Many times, a computer will show the current time and day in the corner of the screen. Since time is constantly changing, the letters and pictures of the clock have to constantly change too. The only way that the screen can change is if one of the computer's processes is making it change.
Depending on whether people can directly change them, a task might be called a foreground task or a background task. The idea is that if something is happening inside the computer that is not visible on the screen, or that a person can't control by using the keyboard or the mouse, then we talk about the task as if it is hiding in the background. If there is something happening that we can act on directly, it happens in the front of other things, and so we say it is in the foreground.
When you are working with MUMPS and VistA, you will find that we use some of these words to mean very specific things. For example, when the computer is doing something that only MUMPS tells it do, it is called a Job. When the computer is doing something that VistA told it to do, it is called a Task. There is even a part of VistA which lets a person manage all of these tasks, called TaskMan. (TaskMan is short for Task Manager) Usually Tasks happen in the background, but Jobs can happen both in the foreground and in the background.
