[Year 12 IT Apps] VITTA ITA exam 2 - my ideas of errata

[Mark Kelly]

Thanks for the input Bill.  I still tend to disagree about the cable 
modem really modulating/demodulating.  I believe all it does is split 
cable internet signals from cable TV signals.  To modulate, I believe, 
involves an analogue-digital translation.

Of course I could be wrong.

It's happened before... sometime in 1982, I believe. Might have been a 
Friday...

  :-)

Mark

Russell Edwards wrote:
> Hi Mark, I agree with most of what you have said, just a couple of minor 
> points
> 
> On 15/10/2007, at 1:36 PM, Mark Kelly wrote:
>> Question 1
>> Which of the following enables several LANS to connect over a WAN?
>> Suggested answer: D. Router.
>>
>> A router protects a LAN from the outside world, but its role is not 
>> principally to enable communications.  I suspect the best answer would 
>> be a modem.
> 
> The primary role of the router is indeed to enable communications 
> between two or more networks. It may include a firewall of some sort 
> (=protection from the outside world) but need not.   A modem is not 
> necessary as you may have a data link that doesn't require 
> modulation/demodulation-- though you'd be hard pressed to find one that 
> could offer distances that classify as "wide area"!
> 
>> Question 3
>> Which type of backup uses two sets of backup media and backs up the 
>> most recent changes on the second media?
>> Suggested answer: B. Differential.
>>
>> This can’t be right.,  The question is very odd.  Two sets of backup 
>> media? From http://www.backuptool.com/incremental%20backup.htm...
> 
> I suppose what they're getting at is that incremental backups might use 
> more than twos set of media. But in fact, the terms are about _what_ you 
> backup, _when_ -- not _where_ you put the data (i.e. media).
> 
>> A modem is, for most people today, a digital device for ADSL or cable 
>> internet that has no modulation or demodulation happening!  The 
>> question should have referred to analogue modems if it wanted this 
>> answer.
> 
> No, ADSL and cable are still analog modems. ADSL goes over copper line 
> just as dialup, simply using a much higher (analog) bandwidth than plain 
> dialup and avoiding the voice band. Cable modems (afaik) use an optic 
> fibre data link so again this is a modem, as a carrier wave (in this 
> case a light wave) is modulated to transport data.  Even wireless, 3G or 
> satellite internet will rely on a pair of modems (with an 
> electromagnetic wave as a carrier) as part of the link, even though the 
> term isn't usually used in reference to them.
> 
> cheers
> 
> Russell Edwards
> Whittlesea Secondary College
> 


-- 
Mark Kelly
Manager - Information Systems
McKinnon Secondary College
McKinnon Rd McKinnon 3204, Victoria, Australia
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kel AT mckinnonsc.vic.edu.au

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