how to Remember IRQ, I/O etc

borris9borris9 Member Posts: 11 ■□□□□□□□□□
in A+
Hello everybody,

i've just finished my A+ OS and HW training and am ready to go and sit my exams. But i still have a problem trying to remember IRQ's, I/O addresses, BIOS beep error code's in my head.
Does any one have a way of easily remembering these, so if a question is asked what is IRQ 11 for example, you could have a way or code or somthing to remember the order.
PLEASE LET ME KNOW IF YOU DO

Tanks icon_cry.gificon_confused.gif
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Comments

  • ghaoufghaouf Inactive Imported Users Posts: 317
    i do not know any way to know them except to memorize them
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  • kesjwkesjw Member Posts: 16 ■□□□□□□□□□
    sorry i agree with "ghaouf" the only way to remember is to memerize until u get it icon_wink.gif Why not just try saying each one at least 3 times until you finally get it. :) (thats what i did)
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  • BobbyZ_UKBobbyZ_UK Member Posts: 14 ■□□□□□□□□□
    The best way I find is to come up with some crazy mnemonics

    You know that IRQs go from 0 to 15 so construct a sentence (the crazier the better) taking the first letter of the device and matching it to the number

    EG

    0 S (system timer)
    1 K (keyboard)
    2 C (cascade from 9)

    I know someone called Sue who keeps cats.....so I use Sue Keeps Cats...and so on

    It sounds really weird but works (for me anyway) :D

    Give it a try
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  • lazyartlazyart Member Posts: 483
    I have the IRQs commited to memory (which is kinda silly because the list is nearly obsolete). Probably the best way to do it is to start with 2 or 3, memorize them, then add a couple after a few days.

    For the I/O addresses, do this:
    323232
    then 
    ffee77
    then fill the last line with 8s:
    323232
ffee77
888888

    reading vertically downward, you have in order:

    com1,com2,com3,com4,lpt1,lpt2

    BIOS beep codes (borrowed elsewhere from this forum)..the number in the list corresponds to the number of beeps:

    "SMacK For Coming Home Naked"
    (or, I prefer)
    "Slap My Knees For Coming Home Naked"

    System board, Memory, Keyboard, Floppy, CMOS, Hard Drive, Network.

    Original post: http://www.techexams.net/forums/viewtopic.php?p=122

    I'm sitting Thursday (6/26) for Core. Salivating in the meantime. :)

    Good luck!
    I'm not a complete idiot... some parts are missing.
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  • bellboybellboy Member Posts: 1,017
    i started by learning them like the multiplication tables, then i wrote them down. actually with irq, i recalled them better by writing them from 0 to 7 and 15 back to 8.

    working with windows 95 helps know them when you use legacy hardware because of the configuration you have to do. it made me glad that i retained my old p133 and got some adapters from ebay to mess with ;)
    A+ Moderator
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  • WyldstarWyldstar Member Posts: 32 ■■□□□□□□□□
    I think the best way to memorize them is just to write them on paper over and over again until you're so sick of doing it you can't possibly forget them icon_lol.gif .

    - WS
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  • w^rl0rdw^rl0rd Member Posts: 329
    Flash cards! Also, remember that the COM and LPT ports' IRQs are numbered backwards. For example:

    COM1 - IRQ 4
    COM2 - IRQ 3

    LPT1 - IRQ 7
    LPT2 - IRQ 5

    Also, you know that IRQs 2 & 9 are cascaded and IRQs 10-12 are reserved.

    As for I/O adresses, there is a pattern for those too. Just make some flash cards with these column headings and you will see:

    IRQ Default Function I/O Address
    0 System Timer 40h
    1 Keyboard 60h
    2 Cascade -
    3 Default COM2 (external modem), COM4 2F8h, 2E8h
    4 Default COM1, COM3 3F8h, 3E8h
    5 LPT2 / Sound card * 278h
    6 Floppy drive 3F0h
    7 LPT1 378h
    8 Real time-clock 70h
    9 Cascade / USB -
    10 Open for use -
    11 Open for use -
    12 PS/2 mouse * -
    13 Math coprocessor F0h
    14 Primary hard drive controller 1F0h
    15 Secondary hard drive controller 170h

    * Optional
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  • trick000trick000 Member Posts: 89 ■■□□□□□□□□
    I think it's helpful if you know how to read hexadecimal.
    For example the I/O address for:

    IRQ 4
    COM1 - 3F8
    COM3 - 3E8

    IRQ 3
    COM2 - 2F8
    COM4 - 2E8

    I just rank them with com1 being the highest or the first or has priority or however you wanna look at it. Since com 1 is ranked number 1, it is assigned the highest hex value in the group and so on and so forth. This also works for the LPT I/Os and the HD controller I/Os.

    LPT1 - 378
    LPT2 - 278

    Primary HD - 1F0
    Secondary HD - 170

    That's how I remembered. As for the IRQs I just memorized them and remembered what shinobi was talking about (numbered backwards).

    Also, what really helps is if you see them all the time on practice exams.
    My Red GTI
    How to do IT
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  • WebmasterWebmaster Admin Posts: 10,292 Admin
    trick000 wrote:
    Also, what really helps is if you see them all the time on practice exams.

    Great idea ;)

    I will create a separate quiz with only IRQs/DMAs/IO addresses, which you can use to drill yourself. :D
    LinkedIn - FaceBook
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  • lazyartlazyart Member Posts: 483
    trick000 wrote:
    I think it's helpful if you know how to read hexadecimal.
    For example the I/O address for:

    COM1 - 3F8
    COM2 - 3E8
    COM3 - 2F8
    COM4 - 2E8

    I just rank them with com1 being the highest or the first or has priority or however you wanna look at it. Since com 1 is ranked number 1, it is assigned the highest hex value in the group and so on and so forth.

    COM2 and COM3 are incorrect (swap them).
    I'm not a complete idiot... some parts are missing.
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  • trick000trick000 Member Posts: 89 ■■□□□□□□□□
    lazyart wrote:
    COM2 and COM3 are incorrect (swap them).

    woops... sorry bout that. edited.
    My Red GTI
    How to do IT
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  • hammer headhammer head Member Posts: 8 ■□□□□□□□□□
    I have all the IRQ's and the addresses for COM 1,2,3,4, and LPT1,2 remembered. Do any of the real questions ask for any of the other devices? I hope I can get by with with this!
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  • hammer headhammer head Member Posts: 8 ■□□□□□□□□□
    I meant I know all 15 IRQ's plus what is in the other post.
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  • borris9borris9 Member Posts: 11 ■□□□□□□□□□
    Tank You all for ur reply.
    Its all great advise and i will see which one works best with me.
    icon_lol.gificon_lol.gif :P icon_lol.gif:D
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  • WebmasterWebmaster Admin Posts: 10,292 Admin
    And if all the above doesn't help you can try the DMA IRQ I/O quiz I promised here. :D

    (be sure to print out the printer-friendly version at the end of the exam)
    LinkedIn - FaceBook
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