[Year 12 IPM] Exam Post Mortem now online

[Mike Brookes]

Hi Mark et Al
Thank you Mark for providing the starting point for the carping, 
bickering and protesting.
First an agree whole heartedly (always start on a positive note :-))

Q6b) I agree that an IPO chart is about Input (data), Processing (might 
be called tasks but steps would be better) and Output (details of what 
information is produced) and that the I and O in IPO diagrams refer to 
items not tasks.

Carping:
Q3) The method used to store data on a DVD RW is not pits in an 
Aluminium substrate - that's the method used to store data on mass 
produced Cds and DVDs that are read only.

DVD RW disks use a polycrystalline layer (usually an alloy of Silver, 
Indium, Antimony and Tellurium). In the normal ordered crystalline state 
the layer is shiny and reflects a low powered laser.

When the alloy is hit with a short high power laser burst the alloy 
melts (500 -700 degrees) then cools down quickly so that it forms an 
irregular mass of tiny crystals rather than the ordered crystalline 
form. This irregular form has a low reflectivity and scatters the low 
powered laser used to read the disk.

To erase the data the laser is used at medium power to heat the alloy to 
above the re-crystallisation temperature but below the melting point 
(around 200 degrees) for a sufficient time to allow the alloy to 
crystallise back into its shiny form.

Once upon a time in a galaxy far, far away IPM was a subsection of 
Information TECHNOLOGY - 'tis great to see a question which actually 
requires the students to know a bit about technology instead of being a 
glorified business management course. :-P

PS difficult to see how the question could be interpreted as how would 
the end user store data on these devices as you would use the same 
answer for all three - eg. drag the file icon to the icon representing 
the device/directory.


Bickering:
Q9 - Disagree that its only a systems question - Validation is a major 
part of an IPM solution so it is fitting that the validation should be 
tested and that appropriate data be selected to do the testing.

Protesting
Q5 Eneey Meeny Miney Mo section
Not a dogs breakfast - offered it to dog and said mutt ran off howling. 
RSPCA investigating :-)

Mike Brookes
Chief cook and bottlewasher
Copperfield College

Mark Kelly wrote:
> My annual whinge is now online at
> 
> http://www.mckinnonsc.vic.edu.au/la/it/ipmnotes/exam/2005exam/index.htm
> 
> Feel free to carp, bicker and protest.
>