Read this whole guide offline with no ads, for a very low price!
Click Here!
Use coupon code "SAVE50" to get it half price!

Custom Search







Table Of Contents  CertiGuide to A+ (Core Hardware)
 9  Chapter 0001:  Power Supplies - System Board

Previous Topic/Section
XVIII  Memory Mapping
Previous Page
Pages in Current Topic/Section
1
Next Page
Pop Quiz 0001.10
Next Topic/Section

XIX  Logical Names

The BIOS assigns Logical Names to the devices using an IRQ and memory address. Now IRQ 3 and I/O address 2F8-2FFh becomes Com 2.

This does not mean that you cannot change the standardized IRQ and I/O address. Be strongly cautioned however against doing this, "just because you can". And whenever you are building or working on a new system, be strongly advised to create a map of the system before you start making any changes.

Remember some programs will not ask the Operating System for details such as IRQ and I/O. Some programs require this information in their own setup. And there are a few older programs, such as games, that require the popular default settings for the ISA Sound Blaster. That is:

IRQ 5, I/O 220h, DMA 1

Table 9 shows the classical assignments of IRQs and I/O addresses in the PC.


Table 9: Typical PC IRQ I/O Address Device Assignments

IRQ

Used By

I/O Address

0

System Clock

40h

1

Keyboard

60h

2

Cascade

 

3

Com 2/4

2F8h / 2E8h

4

Com 1/3

3F8h / 3E8h

5

LPT2 / Sound

278h / 220h

6

Floppy

3F0h

7

LPT1

378h

8

Real Time Clock

70h

9

Open

 

10

Open / NIC

 

11

Open / VGA

A000h

12

PS/2 Mouse

 

13

Math Coprocessor

 

14

Primary IDE

170h

15

Secondary IDE

1F0h


IRQ TIP

Write the chart until you can do so from memory. Before you begin your test, re-create the chart.



Previous Topic/Section
XVIII  Memory Mapping
Previous Page
Pages in Current Topic/Section
1
Next Page
Pop Quiz 0001.10
Next Topic/Section

If you find CertiGuide.com useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider buying an inexpensive PDF equivalent of the CertiGuide to A+ (Core Hardware) from StudyExam4Less.com. (Use coupon code "SAVE50" to save a full 50% off the already low price!) Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

CertiGuide to A+ (Core Hardware) (http://www.CertiGuide.com/aplush/) on CertiGuide.com
Version 1.0 - Version Date: December 6, 2004

Adapted with permission from a work created by Tcat Houser.
CertiGuide.com Version Copyright 2004 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.