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System Design (GCSE IT)
So this is the Life Cycle. We are moving away from the Analysis now into the Design and
this is really the big leap where all the analysis of the current system is being done.
All the techniques have been through on the cycle and the [0:00:19 – inaudible].
We get to a point where something can be put together in terms of what the new system is
going to look like. This is a Design Spec. If you got a team of people who are going
to build this particular system, this is the thing that is going to hold it together. In
other words, these are the plans for the new system.
A Design Specification looks at the content, looks at the order on how these things relate
to each other. We are looking at all the parts of a system and it is better to think of something
quite grand here, quite big. Then you can start to think of how the things relate.
Analysis is being done as to how the existing system works and some of that may be changed
and some of that may be kept. But we are looking down the system and we are looking at how
things happen and how things go together, what’s going to be included and what’s
not going to be included.
This is what a Design Spec involves. I have pieced it together like this where I have
separated the separate elements, again, into the idea of Input, Process and Output because
you must always stick with that as the core foundation of everything to do with Systems
Analysis and Design. Indeed, anything to do with IT and computer, just to recall what
that is I – Input, P- Process and O- Output. Things go in, things get changed and something
comes out the other side. Data goes in, processing happens, changes are made, calculations or
whatever, output comes out in the form of information.
A Design Spec involves those different things happening at the Input stage. We’ve got
to add some checking. We are going to look at what the types of inputs. We are going
to look at the hardware involved in the inputting stage.
As you guys process and eventually lump together that, arguably that shouldn’t be there at
all, but there is nowhere else to put it, so you stand in outside it. With regards to
processing and this isn’t really the focus here. The focus is really in the Input and
the Output. What methods of processing are required and really, what storage has got
to happen?
Then the output is how you are going to communicate the information that is needed at the end.
For Input, the considerations that have to be taken into account, as got to put it together
at Design Spec and a little bit of hardware involved as purchased and they’ll be using
existing. Maybe you have to go out and buy some more. The form that the date comes in,
does it come in paper form? Do you take it from a particular place? Maybe it’s numerical,
words, images, or whatever. What form or idea that come with it? Then, the uses involved.
Don’t forget this could be people who are most likely who are going to input this data
or does it come automatically. The use in this case may not be an actual particular
person, it may be another system that it has got to talk to but that’s getting complicated.
Just think it in your head in terms of the person inputting data. These are the real
core things that go together into the mix of what makes up Input.
As I have already said, Processing is really not the most important thing here. If we just
look at Processing briefly, it has been split into what processing needs that are in system,
that’s going to be created and what storage and indeed, how you are going to get that
storage out? In other words, the retrieval needs of the system that’s going to be designed.
This is really two elements; the make up process.
You’ll notice this diagram for Output is exactly the same as the diagram for Input.
The factors you faced in designing Input for the system in putting together a spec that’s
going to decide what’s goes into Input, the same considerations are very similar.
I’m probably going to come in and get Output as well, in terms of what you are going to
use to Output. Are you going to output on screen? Is it going to output on paper? Is
it going to out to a system? Is it going to output to a particular platform? To mobile
devices and you could go on and on and on. What form does the output come in again? Does
it have to come in text? Does it have to come in images? Does it have to come in numerical?
Does it have to feed into another system?
Then, who are the people that needs to use these data? Who are the users? Who is it outputting
to?
Lastly, it’s worth to look at the Output in terms of the balance. What’s given in
the syllabus course, the text there is a number of considerations to look at. It is well worth
to read and memorization of some of those because they are really important aspects.
But it is really a balance. I want to get this idea of balance in your head, which is
the balance between too much information and not enough information. When you give in output
that is really a key to designing it, that strikes a balance between those two things.
It is also not just the too much and the not enough, there is also the factors of which
bits are the most important and which bits are the most important to particular people
as well.
[End of audio – 05:47] System Design (GCSE IT)
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