Hard Questions! Help! (1 Viewer)

[Agent Z]

Hey everyone!! I was doing some study *for once in my life* and I was thinking about the following questions in IPT. Can someone please help me in answering them!! Thanx! If you are going to reply to a specific question just put that question number in the reply.

1. What is the broad difference between combination and non-linear storyboards?

2. The Heinemann text defines schema as the data definition of the database. It is an organized plan of the DB showing how and where data is found, descriptions of the data and the datas logical relationships. The question I ask is what does it mean and how does a schema describe how and where data is found?

3. Data modeling is the process of identifying entities, the relationships of those entities and the attributes of those entities in a relational database. Can someone give me an example of data modeling in real-life terms?

4. Can someone please further explain the concept of DKNF normalization?

5. A distributed database is a DB that is located on more than one site and acts as a single collection point of data but is geographically dispersed. So what I would like to know is an example of this an airline reservation system? If so can someone further explain the concept of a two-phase commit?

6. The Heinemann text defines SQL as a query that allows users to search and manipulate data in a relational database [sic]. How can a SQL manipulate data in a relational database? I thought there primary and only use was to search a relational database.

7. The Heinemann text defines Y-Modem as an extension to X-modem. Features include increased readability of errors, transfer of file names and increased file transfer [sic]. What is increased readability of errors and how does that work? Because it would still use one of the standard error checking methods i.e. parity, checksum or CRC. But if X-modem supported checksum and later versions CRC There would be no increased readability of errors. Or do I just have the entire concept of readability of errors wrong? If so, could someone please explain this!

8. X-modem transfers data in blocks of 128 bytes long. If a file is, for example, 170KB big, and we were using the X-modem protocol, it would transfer 128 bytes of data and then what would happen? A confirmation? The next block of data? Error Retransmission?

9. The Heinemann text defines Z-modem as having a Variable Block Size yet the excel defines it as having block size of 1024 bytes Which is correct? And if variable block size is correct, how does it determine the block size?

10. Do extranets require a password to access? What is the line we can draw between extranet of an organisation and the internet website for the organisation?

11. Can someone please clarify the concept of client-server architecture?

 

[del]

2. The Heinemann text defines schema as the data definition of the database. It is an organized plan of the DB showing how and where data is found, descriptions of the data and the datas logical relationships. The question I ask is what does it mean and how does a schema describe how and where data is found?

Shows where data is, as usually the schema shows attributes in a form in which you can tell what table it belongs to (have a look in Access or any DBMS).


6. The Heinemann text defines SQL as a query that allows users to search and manipulate data in a relational database [sic]. How can a SQL manipulate data in a relational database? I thought there primary and only use was to search a relational database.

Using SQL you can insert, update and delete data within a relational database. Eg. INSERT INTO someTable VALUES(some values) WHERE (some condition is true).


11. Can someone please clarify the concept of client-server architecture?

You can visualise this as the way the world wide web works. Your browser functions as a client. It sends 'requests' to a server, which 'responds' with the relevant info. Client/server basically operates on a request/response model.

 

[grendel]

1. Storyboards can either be linear, hierarchcal or hybrid(combination).

Linear story boards are useful for sequential multimedia presentations (eg. powerpoint slideshow, cel based animation)

Hierarchical storyboards are useful for websites where the homepage has several pages coming off it and those pages have pages coming off them and so on. Think "tree structure".

Hybrid storyboards combine linear and hierarchical elements. Thinking of a scenario is not easy but maybe a website that contains powerpoint could be described using this style of SB.

2. Ther are many different ways to draw a schema but all u need to know for the exam is that a schema or entity-relationship diagram (erd) contains all of the tables in a relational db, the fields contained within these tables and the links between these tables. So you need to identify the primary and foreign keys in each table.

3. Data modelling = schema + data dictionary.

Again there are heaps of data modelling methods but these are the main ones for databases. Try these links:

http://webopedia.com/TERM/s/schema.html

http://searchdatabase.techtarget.com/sDefinition/0,,sid13_gci212944,00.html

4. Normalisation is a process were redundant data is removed from a rdbms. I think there are 7+ normal forms but probably the first three are enough. Try this link:

http://www.webopedia.com/TERM/n/normalization.html

6. Hmmm.....well queries can not alter the data within tables but they can alter the data in reports and forms and these are also elements of a relational db. So queries can manipulate the data in this way...i guess.

10. Some parts of an extranet may require a password. The difference between an organisations website and extranet is that everyone can access the website whereas only designated people can access the extranet. eg. A company may grant access to customers to their LAN to browse for stock availability or prices. Basically an extranet is an extension of an organisations LAN utilising leased lines (telephone cables) and employing a variety of security methods such as user authentication (passwords, digital certificates), firewalls, VPN's and encryption.

11. The server can be a file server or mail server in a LAN or Web server on the internet.

The clients are any workstations that connect to the server.

The server can simply share files with the workstations or can actually provide the workstation with processing power. This is the case where the workstation is a Thin Client (or dumb terminal) where basically it consists of a monitor, keyboard, mouse, network card and a slow or no CPU.

Client Server networks need to be contrasted with Peer to Peer networks. Try this link:

http://www.webopedia.com/TERM/c/client_server_architecture.html

 

[del]

6. Hmmm.....well queries can not alter the data within tables but they can alter the data in reports and forms and these are also elements of a relational db. So queries can manipulate the data in this way...i guess.

actually you can change the data. by using the relevant sql statements. have a look at the INSERT, DELETE and UPDATE statements
http://www.w3schools.com/sql/default.asp

 

[Agent Z]

2. The Heinemann text defines schema as the data definition of the database. It is an organized plan of the DB showing how and where data is found, descriptions of the data and the datas logical relationships. The question I ask is what does it mean and how does a schema describe how and where data is found?

Shows where data is, as usually the schema shows attributes in a form in which you can tell what table it belongs to (have a look in Access or any DBMS).

ok i see what you mean del about where the data is found, but what about how the data is found? In a schema it does not show how it is collected. Or does how it is collected mean from the different fields it is related to?

Hybrid storyboards combine linear and hierarchical elements. Thinking of a scenario is not easy but maybe a website that contains powerpoint could be described using this style of SB.

Yes grendel you described a hybrid or combination storyboard, but what I want to know that in contrast with each other what is the differences and/or similarities between a hybrid and non-linear? Essentially arn't they the same thing? They both have no structure and allow users to move between layouts in any direction.

10. Some parts of an extranet may require a password. The difference between an organisations website and extranet is that everyone can access the website whereas only designated people can access the extranet. eg. A company may grant access to customers to their LAN to browse for stock availability or prices. Basically an extranet is an extension of an organisations LAN utilising leased lines (telephone cables) and employing a variety of security methods such as user authentication (passwords, digital certificates), firewalls, VPN's and encryption.

Yeah, grendel you say that some parts of an extranet may have a password. But wouldn't that mean that the parts of the extranet that dont have a password are available to anyone? If so this would just make it an extention of the companies internet website, as there is no special authenitication or verification procedures that must be met before access is granted. And if an extranet was a "LAN utilising leased lines (telephone cables)" how would customers be able to access it. It would mean that customers would need a physical connection to the line, which would not only be expensive but inefficient for the company.

____________________________

also i have one last question: The sylabus states we need to know the current cabling standards. Ok, so firstly WHAT is a cabling standard and what cabling standard are they up to now?

 

[Agent Z]

also i have one last question: The sylabus states we need to know the current cabling standards. Ok, so firstly WHAT is a cabling standard and what cabling standard are they up to now?

OK, the current cabling standard is cat5e.....buuuut what would the purpose of a cabling standard?

 

[del]

the closest thing I can think to showing how probably more relates to a relational database which has relationships between the various tables.

in that respect, because there are relations between the tables and with the use of primary and foreign keys, you could work out how to find a specific piece of info/data - i.e. using which key to inner join tables etc in order to retreive a specific value.

 

[del]

Originally posted by Agent Z
OK, the current cabling standard is cat5e.....buuuut what would the purpose of a cabling standard?

By that syllabus point, there talking about knowing about twisted pair, fibre optics, and coaxial cabling. You'd need to know the main characteristics of each.

 

[...]

Originally posted by Agent Z
OK, the current cabling standard is cat5e.....buuuut what would the purpose of a cabling standard?

woah?!?!?!
is this got to do with coaxial cabling? fibre-optic??

what topic is this under?

 

[JRasnier]

Communications

 

[Agent Z]

By that syllabus point, there talking about knowing about twisted pair, fibre optics, and coaxial cabling. You'd need to know the main characteristics of each.

Del you sure? In the "Students Learn About" in the sylabus (p.41) it says:

• Network Hardware, including:
• Current Cable Standards
• Servers, including
  - file servers
  - Print Servers
  - Mail/Web Servers
• transmission media, including
  - wire transmission: twisted pair, coaxial cable and fiber optic
  - wireless transmission: microwave, satellite, wireless network etc.

so basically what i'm getting at it mentions "current cabling standards" and then below that it mentions the transmission media...soooo if it was only the characteristics, why isn't it a sub-bullet under "transmission media", not "network hardware"??

 

[JRasnier]

maybe there just asking which standards they are under like IEEE blah blah blah (numbers) and thats it, not how the standard is governed..

 

[Agent Z]

ugh damnit i forgot to close my list...no bullets

you could work out how to find a specific piece of info/data - i.e. using which key to inner join tables etc in order to retreive a specific value.

del, whats "inner join"?? I always see it when looking at access SQL. and isnt "inner join" specific to access only, meaning you shouldnt use it in an answer??

woah?!?!?!
is this got to do with coaxial cabling? fibre-optic??

what topic is this under?

... as far as I can see its not actually in any textbook, just in the sylabus, so that probably would mean it wont come up anywhere, buut i think if you knew it you could integrate it in an answer that is talking about transmission mediums...makes you sound smarter
the cat5e standard, it seems, is only used for twisted pair

and can anyone else answer any of the other questions I asked at teh start of the thread!! I'm getting more lost by the day..

 

[...]

q7 about Y-Modem, is not required in the syllabus

 

[del]

There are different types of joins available depending on the DBMS being used - MySQL has JOIN, CROSS JOIN, INNER JOIN and STRAIGHT JOIN for example.

Joins often are used to retrieve data from several tables. It's a bit out of the scope of IPT i reckon (unless your maybe looking to do databases or something in future).

If they talk about related tables in ipt, you only really need show that you understand the concept of relationships... e.g. tableX is linked to tableY through the use of the primary key A in tableX and the foreign key B in tableY

 

[Agent Z]

maybe there just asking which standards they are under like IEEE blah blah blah (numbers) and thats it, not how the standard is governed..

Yes, i see where your coming from....buuut how would you know what standards they are under?? As cat5e isn't under a particular standard, IT IS a standard. But i really don't think that much depth is required. And also cat5e isn't the most recent standard. Theres now "cat6.

I found out about all the cabling standards though, adn who ever's interested heres what i now know:
Category 5
A multipair (usually 4) high performance cable that consists of twisted pair conductors, used mainly for data transmission. The twisting of the pairs reduces unwanted interference. Basic CAT5 cable was designed for characteristics of up to 100 MHz. CAT5 cable is typically used for Ethernet networks running at 10 or 100 Mbps.

Enhanced Category 5
Same as CAT5, except that it is made to somewhat more stringent standards. CAT5e standard is now officially part of the 568A standard. CAT5e is recommended for all new installations, and was designed for transmission speeds of up to 1 gigabit per second (Gigabit Ethernet).

Category 6
The general difference between CAT5e and CAT6 is in the transmission performance and extension of the available bandwidth from 100 MHz rated for CAT5e to 200 MHz rated for CAT6. Has higher reliability for current applications and higher data rates for future applications.


but then I guess the standard that you want to use would primarily depend on its application, no? And argh! Im sooooo confused!! The heinamann text says "Transmission speeds of 60KB/sec" but would it not depend on what standard you are using?

Well that's just great, ive lost myself *sigh* once again...

 

[...]

wheres Huy!!!

 

[Agent Z]

q7 about Y-Modem, is not required in the syllabus

your right...buut if im correct (probably not) it doesnt say anything about X-modem and Z-modem either!! But EVERY textbook ive seen so far deals with X and Z. Can someone point out what page X and Z modem are on!

 

[Agent Z]

wheres Huy!!!

i know! where the hell are the smart people when you need 'em?

 

[Lazarus]

Tried the HSC Advice Line? 13 11 12.