What topic is giving or have given you problems in A+ Core?

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I'm having problems learning Com ports, DMA, IRQs.

What are you struggling or have struggled with in A+ Core?

 

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You forgot the "DOS memeory in a windows world" section, caused a little confusion, but i will let you discover that for yourself

I tried to remember com ports by:

there are only 4 I/O address that are used by com ports (one for each port obviously) according to the address map, these are either a 2x8h or 3x8h

COMM 1 & 3 (both odd numbers) start with an odd I/O address and
COMM 2 & 4 (both even numbers) start with an even I/O address

useing this train of thought, if you are asked the I/O address of a particular port, you can rule out 2 of the address from the start

Lets say we have been asked what the I/O address for COMM 2 and COMM 4

because they are both even we know that it is either 2E8h or 2F8h, but which I/O is for which COMM port?

I remember this by thinking of the alphabet and numbers, 'E' comes before 'F' (We all know this already :roll: )and (COMM) 2 comes before (COMM) 4 however as with so many other things in hte IT industry if we think the other way round, we would swap only the letters OR the numbers round (not both) which would mean that, if we swaped the letters that:.....

(COMM) 2 Comes Before (COMM) 4 and
I/O add F Comes Before I/O add E

( Look, 2 is above F and 4 is above E, put them together and you have the address, COMM 2's I/O Address is 2F8h and COMM 4's I/O address is 2E8h)

I know it seems a little long winded but it worked for me, this should work no matter which I/O, or which COMM you are asked about


Hope this help, did it from memory and it's early so i hope you can understand the wording (I hope its right too, dont have my bible here to check it)

Someone do me a favour..........If the above is wrong delete this post

Thanks

 

I'd have to agree with Derek. The whole DOS Memory issue was a real pain for me. When doing my final studies before the exams, I really concentrated on what I considered my weakest area. I'm not sure they include that on the current test which would be a blessing.

Of course, it is kind of handy to know if working on legacy systems.

 

Hi..

I'm back. A question. Is the A+ for Dummies worth getting? I've just started it and got an interview on Friday and if that will help I'll get it?

Thanks.

Denise.

 

Hi Neice, glad to see you back

I personnally have never used the A+ for Dummies book but i have heard off a few people that the 'Dummies' range of books are quiet good

 

The I/O and IRQ section really did it for me. I couldn't remember them at all. To be honest iit's something that I'llnever use in my life as hardware is mostly plug and play these days.

 

Holy cow! This thing lets you vote more than once! I'd forgotten I'd voted before and took another whirl. I thought I would have gotten a message saying "Don't cheat...you can't vote twice" or something to that effect. Instead, it accepted my vote just now. I scrolled down to leave a message and saw I'd already done so. At least I picked the same issue.

 

It only shows you have voted once Trip :hhhmmm