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With the wide support for system processors, a variety of bus architectures are supported, including:
Laptops pose a special problem due to the specific nature of their hardware design. As a result, it can sometimes be a challenge to get Linux to operate correctly on them. This primarily has to do with the customized nature of hardware services such as sound and video, modems and power management, or the use of PCMCIA cards; we discuss these issues later in this chapter.
Before moving on to the other topics, we should point out the proc file system structure can provide you with information about your system. For example, /proc/interrupts identifies the currently used interrupt request lines on your system, as shown in Figure 2.1.
Figure 2.1 The /proc/interrupts file shows what IRQ resources are presently in use.
From Figure 2.1, you can see the interrupts used on this machine and what they are currently assigned to. Note that this particular system does not have a parallel port (as neither interrupt 5 nor 7-typical for parallel ports-is in use on the system). Knowing the interrupts in use will be important later on when we're adding other hardware, such as serial ports.
The BIOS and its settings are different for each computer system in use today. A system that uses PCI bus architectures has different BIOS configurations than does a system with an EISA bus. These differences make configuring the BIOS a special challenge and require that you have the appropriate documentation for your BIOS revision and system board.
Figure 2.2 illustrates a sample BIOS from a PCI-based Pentium system (the exact version of which is unimportant for our discussion). This system has two hard disks: one configured as the primary IDE master and one as the secondary IDE master. The first disk has specific information entered regarding the disk geometry, and the second is set to autodiscover the disk geometry. The system diskette drives and video type also are defined at this level in the BIOS.
Figure 2.2 The BIOS holds drive-configuration details.
Changing the date and time in the BIOS affects the hardware clock and subsequently alters the time reported by the operating system.
Once the time zone is selected, you must set the correct date and time. Both of these steps will be reviewed.
Running the timeconfig program as root produces the display shown in Figure 2.3. You'll select the time zone from here. The time zones defined here cover the entire globe, and an option identifies if the hardware clock is set to GMT. If you set your hardware clock to GMT, be sure to check this box. Otherwise, leave it empty.
Figure 2.3 Configuring the time zone is a necessary step when setting the correct time.
After selecting the time zone, timeconfig exits to the prompt. At this point, we can set the correct system time using the date command. The date command is typically used to retrieve the system date, as in:
[root@localhost bin]# date Sun Nov 12 16:10:08 EST 2000
Multitudes of settings can be passed to the date command to adjust the actual output results, but these options aren't applicable to this discussion. To set the time, the superuser ("root") must provide the new date and time on the command line. This date and time is then applied to the system. Here is an example:
[root@localhost bin]# date Sun Nov 12 16:12:19 EST 2000 [root@localhost bin]# date 111110112000.22 Sat Nov 11 10:11:22 EST 2000 [root@localhost bin]#
In the preceding example, we see the current date and time how we change it. The arguments to the date command are:
MMDDhhmmCCYY.ss The parameters are:
The values for century, year, and seconds are optional, because the system applies the current century and year and resets the number of seconds to zero when setting the time. In the following example, we set the date and time using only the required arguments:
[root@localhost bin]# date 12252349 Mon Dec 25 23:49:00 EST 2000 [root@localhost bin]#The time zone and clock now are set. However, most systems suffer from clock drift, which affects the accuracy of the clock. The use of an NTP (Network Time Protocol) server is highly recommended to keep the system clock synchronized. From a security perspective, if all the systems in your network are synchronized to the same time source, it's easier to track any intrusions through the systems.
The CPU processes all the data that is received from the serial port. Consequently, the CPU must know where the data is to be received and what signal or interrupt is used to tell the CPU that data needs to be processed. These are called I/O ports and IRQs. Thus, every serial port device must store in its nonvolatile memory both its I/O address and its IRQ (interrupt request) number.
Don't confuse I/O addresses with memory addresses, because they aren't the same. The memory address normally used by main memory is ignored, and the I/O address is used to transmit and receive data with the serial device. Multiport serial cards are available in two formats: intelligent and dumb. A nonintelligent serial port card relies totally upon the CPU to perform all the I/O processing, just as a single-port serial card does. This reliance on the CPU greatly affects the performance of the system as the level of data on the serial ports increases. Intelligent serial cards alleviate this problem by putting a processor on the serial port card to perform the I/O processing and then sending a block of data to the CPU for processing.
The nonintelligent cards come in two varieties. One uses the AST Fourport approach, using a block of memory addresses and a single IRQ. The second format uses four IRQ lines for serial data processing. It's advisable to know the type of processing and amount of data to be handled through the serial port when making the decision to buy a multiport serial card.
[chare@localhost chare]$ ls -l /dev/ttyS* crw------ 1 root tty 4, 64 May 5 1998 /dev/ttyS0 crw------ 1 root tty 4, 65 May 5 1998 /dev/ttyS1 crw------ 1 root tty 4, 66 May 5 1998 /dev/ttyS2 crw------ 1 root tty 4, 67 May 5 1998 /dev/ttyS3 [chare@localhost chare]$
It's important to remember that just because the device file exists does not mean a physical device is associated with it. The serial port driver in the kernel maintains a list of the I/O addresses for ea_h serial port, and this table maps the physical device to its name. The setserial command is usad to list and alter the serial port configuration. The arguments for setserial are identified below....
|Chapter 1||LPI Certification Exams||1|
|Chapter 2||Hardware and Architecture||11|
|Chapter 3||Linux Installation||45|
|Chapter 4||The Linux Kernel||71|
|Chapter 5||Package Management||99|
|Chapter 6||Working with vi||121|
|Chapter 8||Shells in Linux||167|
|Chapter 9||Shell Scripting||187|
|Chapter 10||The X Environment||217|
|Chapter 12||Network Services||275|
|Chapter 14||Sample Test||313|
|Chapter 15||Answer Key||331|
Exam Cram books help you understand and appreciate the subjects and materials that you need to pass LPI certification exams. Exam Cram books are aimed strictly at test preparation and review. As such, they do not teach you everything you need to know about a topic (such as the ins and outs of building your own servers). Instead, we present and dissect the questions and problems that you're likely to encounter on a test. I've worked from LPI's own objectives, preparation guides, and tests. My aim is to consolidate as much information as possible about LPI certification exams.
Nevertheless, to completely prepare yourself for any LPI test, you should begin by taking the self-assessment that's included in this book. This tool will help you evaluate your knowledge base against the requirements for the actual exam under both ideal and real circumstances.
Based on what you learn from the assessment, you might decide to begin your studies with some classroom training, or you might pick up and read one of the many Linux guides that are available from third-party vendors. We strongly recommend that you also install and configure the software and tools that you'll be tested on, because nothing beats hands-on experience and familiarity when it comes to understanding the questions you're likely to encounter on a certification test. Book learning is essential, but hands-on experience is the best teacher of all.
Many of the higher-level exams are currently under development, and the best place to keep tabs on the program and its various certifications is on the LPI Web site. (The current URL for the LPI program is www.lpi.org.) Before undertaking any certification venture, you should make certain that you have the latest and most accurate information about the organization's certification programs.
Although VUE is flexible about scheduling, it is best to call at least ten days in advance. Exam seats are limited and might be booked solid around the time you realize you are ready for the test. To cancel or reschedule an exam, you should call at least two days before the scheduled test time to receive any sort of refund. When calling to schedule, please have the following information ready for the staff member who handles your call:
All exams are completely closed-book. In fact, you will be required to stow anything you brought with you under your desk. You will be furnished with a blank sheet of paper, a pencil, and any other tools you might need for your exam. We suggest that you immediately write down on that sheet of paper all the information you've memorized for the test.
When you complete an exam, you'll get an immediate printout of your results and know whether you passed or not. All exam components are scored on a percentage basis.
Together, the two series make a perfect pair. Check ExamCram.com for additional products from Coriolis.
You'll find that this book complements your studying and preparation for the exam, either on your own or with the aid of the previously mentioned study programs. In the section that follows, I'll explain how this book works and why this book is a part of the required and recommended materials list.
In addition to the Exam Alerts, we have provided occasional notes that will help build a better foundation for Linux knowledge. Although the information might not be on the exam, it is certainly related and will help you become a better test taker.
This is how tips are formatted. Keep your eyes open for these, and you'll become a Linux guru in no time.
Finally, the tear-out Cram Sheet attached next to the inside front cover of this Exam Cram book represents a condensed and compiled collection of facts and tips that We think you should memorize before taking the test. Because you can dump this information out of your head onto a piece of paper before answering any exam questions, you can master this information by brute force. You need to remember it only long enough to write it down when you walk into the test room. You might even want to look at it in the car or in the lobby of the testing center just before you walk in to take the test.
Given all the book's elements and its specialized focus, I've tried to create a tool that will help you prepare for-and pass-LPI's exam 102. Please share your feedback on the book with me, especially if you have ideas about how we can improve it for future test-takers.
Please send your questions or comments to The Coriolis Group at email@example.com or to the author at firstname.lastname@example.org. Please remember to include the title of the book in your message; otherwise, we'll be forced to guess which book you're writing about. Also, be sure to check out the Web page at www.examcram.com, where you'll find information updates, commentary, and clarifications on documents for each book. You can either read this material online or download it for use later on.
Thanks, and enjoy the book!