[Year 12 SofDev] Resource flows in a DFD

[Allan Barnes]

My understanding from Uni days is that DFD's are diagrams of logical systems
and represent flow of information. I don't quite follow what you mean when
you say a resource flow, Mark, but the DFD can in my opinion show things
such as book orders, for example, as this is a flow of information, however,
it would not show that it is Michael who has ordered the books, or that he
has ordered it over the phone, etc.

The physical design provides information about how the processing takes
place. It may show who sends or receives the information, who manipulates
the data, where it is manipulated, what happens to it, what structure it
takes, whether the transaction occurs on the computer, the Internet, by
telephone, by cash register or by a paper-based method. The physical design
will also include details about the specifications of the hardware and
software that is to be used in the information system. It uses diagrams such
as hierarchy charts, structure charts and system flow charts to represent
the information.



 

Kind regards
 
Allan Barnes, CEO
Australian Institute of Education and Training
P.O. Box 171
Brunswick West 3055
Ph: (03) 9387 2051
FAX: (03) 9387 3470
Mobile: 0409 428 221
 
-----Original Message-----
From: sofdev-bounces at edulists.com.au [mailto:sofdev-bounces at edulists.com.au]
On Behalf Of Kevin Feely
Sent: Monday, 14 April 2008 4:49 PM
To: Year 12 Software Development Teachers' Mailing List
Subject: Re: [Year 12 SofDev] Resource flows in a DFD

Hi mark,
In all of the exercises i have done with context diagrams (level 0) and 
DFD's (mainly level 1 and only discussion about level 2) i have always 
said only data (information) should be represented. That the DFD is not 
concerned with the actual goods ordered or purchased for example, but 
the information these transactions generate.
I suppose this is because we are modeling information systems using the 
DFD tool.
I suppose it is possible to model physical systems with the DFD as well 
( obviously from your link!) but  iam not sure they should be intertwined.
That is if a student represents a physical transaction on my information 
DFD i would regard that as an error.
regards
Kev

Mark Kelly wrote:
> I can't remember seeing a resource flow in an SD DFD, but apparently 
> they exist (e.g. 
> http://www.getahead-direct.com/gwba03-context-diagram.htm)
>
> Are they deliberately avoided in SD or are they not industry-standard?
>
> Cheers
> Mark
>

Important - This email and any attachments may be confidential. If received
in error, please contact us and delete all copies. Before opening or using
attachments check them for viruses and defects. Regardless of any loss,
damage or consequence, whether caused by the negligence of the sender or
not, resulting directly or indirectly from the use of any attached files our
liability is limited to resupplying any affected attachments. Any
representations or opinions expressed are those of the individual sender,
and not necessarily those of the Department of Education and Early Childhood
Development.
_______________________________________________
http://www.edulists.com.au
IT Software Development Mailing List kindly supported by
http://www.vcaa.vic.edu.au - Victorian Curriculum and Assessment Authority
and
http://www.vitta.org.au/vce/studies/infotech/softwaredevel3-4.html  - VITTA
Victorian Information Technology Teachers Association Inc
-- 
Message  protected by MailGuard: e-mail anti-virus, anti-spam and content
filtering.
http://www.mailguard.com.au/mg

Click here to report this message as spam:
https://login.mailguard.com.au/report/1uPJKYuEL6/ST7F0g43bxcQIVwsIXXTZ/0.001

No virus found in this incoming message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.22.13/1376 - Release Date: 13/04/2008
1:45 PM
 

No virus found in this outgoing message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.22.13/1377 - Release Date: 14/04/2008
9:26 AM