[Year 12 SofDev] Resource flows in a DFD

Wed Apr 16 09:02:30 EST 2008

Again I agree.

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 Mark Kelly
Sent: Tuesday, 15 April 2008 11:33 AM
To: Year 12 Software Development Teachers' Mailing List
Subject: Re: [Year 12 SofDev] Resource flows in a DFD

Nor will I be including resource flows in DFDs, or even telling kids 
that non-data flows sometimes might appear.

Being bears of very little brain, they might be frightened by such 
complexities  :-)

Allan Barnes wrote:
> I agree, and I guess that is where theory merges with the realities of the
> real world. You have also alluded in other emails to the fact that there
are
> often no exact definition of some areas such as the SDLC for example, so I
> think some of these concepts need to be explained to students not as the
one
> and only explanation but as one possible solution.
> 
> I still believe that DFD's should not contain physical resources in them
> because then by definition it isn't a DFD, but that's just my opinion, but
I
> do understand the difficulties and frustrations when opening up books and
> finding a variety of explanations for the one concept.
> 
> 
> 
> 
>    
> 
> 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 Mark Kelly
> Sent: Tuesday, 15 April 2008 10:45 AM
> To: Year 12 Software Development Teachers' Mailing List
> Subject: Re: [Year 12 SofDev] Resource flows in a DFD
> 
> Hi Allan.  Yes, I realise DFDs have usually only shown data flows, as 
> their name implies.  My concern was my research has found that physical 
> resource flows (such as real books) have been included in context 
> diagrams and DFDs.  That's the sticking point.
> 
> Allan Barnes wrote:
>> 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
> 

-- 
Mark Kelly
Manager - Information Systems
McKinnon Secondary College
kel AT mckinnonsc.vic.edu.au
McKinnon Rd, McKinnon 3204, Victoria, Australia
Direct line / Voicemail: 8520 9085 Fax +613 9578 9253

Webmaster - http://www.mckinnonsc.vic.edu.au
IT Lecture notes: http://vceit.com
Moderator: IT Applications Mailing List

Only those who swim against the current know the current is there.
_______________________________________________
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/1uQ3FAvyMb/4qSu9yEwa7oo8goYTfZ9z9/0

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

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