Tài liệu Planning the Installation ppt

2 Planning the Installation CERTIFICATION OBJECTIVES 2.01 Basic Hardware Knowledge 2.02 Hardware Compatibility 2.03 Disk Partitions ✓ Two-Minute Drill Q&A Self Test CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 Blind Folio 2:53 D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen O ne of the strong points of Red Hat Linux is its easy installation. There are several different methods of installation, and each is automated to a considerable degree. In many cases, it’s now possible to just pop the first Red Hat installation CD in the drive and install Linux from there. However, as you become a Linux expert, people are going to rely on you to install Linux in a variety of situations. You need to plan what you’re going to do. You need to know the basic hardware available for a personal computer, as well as what hardware is compatible with Red Hat Linux. You’ll also want to plan the organization of different Linux directories on individual hard drive partitions. Remember, one-third of the RHCE exam is based on your ability to install Linux. The exam is based on computers utilizing the Intel-based architecture, which allows for an extensive variety of hardware. Most hardware works well with Linux. In many cases, you can make other hardware work with Linux, even if it was originally built for another operating system such as Microsoft Windows. CERTIFICATION OBJECTIVE 2.01 Basic Hardware Knowledge While customized Red Hat Linux distributions are available for such diverse platforms as SPARC, Itanium, and S/390, the focus of the RHCE exam is on computers built to the Intel-based architecture. The architecture of a personal computer defines the components that it uses as well as the way that they are connected. In other words, the Intel-based architecture describes much more than just the CPU. It includes a number of specific standards for building and connecting other critical hardware components such as the hard drive, the network card, the keyboard, the graphics adapter, and more. All software, including Red Hat Linux, is written for a specific computer architecture. Even when a manufacturer creates a device for the Intel platform, it may not work with Linux. Therefore, it’s important to know some basic architecture of an Intel-based computer. This will be the last section that addresses the basic RHCE exam prerequisites like those covered in Chapter 1. 54 Chapter 2: Planning the Installation CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen Basic Hardware Knowledge 55 CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 Intel Communications Channels Three basic channels are used to communicate in an Intel architecture PC: interrupt request (IRQ) ports, input/output (I/O) addresses, and direct memory address (DMA) channels. An IRQ allows a component such as a keyboard or printer to request service from the CPU. An I/O address is a memory storage location for communication between the CPU and different parts of a computer. A DMA channel is used when a device such as a sound card has an independent processor and can bypass the CPU. IRQ Settings An IRQ is a signal that is sent by a peripheral device (such as a network card, graphics adapter, mouse, modem, or serial port) to the CPU to request processing time. Each device you attach to a computer may need its own IRQ port. Normally, each device needs a dedicated IRQ (except for USB and some PCI devices). The Intel architecture is currently limited to 16 IRQs (0–15), which is often not enough for a PC with multiple network adapters and hard drives, as well as a sound card, printer, game card, and more. If you have built your own PC(s), you probably know that there are a number of “bare-bones” PCs available in many computer stores. Even on these bare- bones PCs, basic components such as a keyboard, timer, BIOS clock, and CPU occupy a number of IRQs, leaving perhaps IRQs 5, 7, 9, 10, 11, and 12 free. Then you may add a sound card on IRQ 5 and a printer on IRQ 7. And then each video card, serial mouse, modem (although traditionally, a serial mouse and modem use IRQs 3 and 4) and network card that you install needs its own IRQ—which leaves a total of 1 free. (Maybe!) If you run out of IRQs, you may still be able to install another PCI device. Several PCI devices can share a single IRQ through the PCI bus, which manages the way each PCI device shares your IRQs. However, this requires BIOS support for PCI sharing, which you can enable through your computer’s CMOS settings. Most PCs manufactured after 1994 contain PCI buses. USB devices can help you conserve IRQs in the same way. The Universal Serial Bus (USB) host controller also regulates attached USB devices, including how they share IRQs. Most PCs manufactured after 2000 contain USB ports. If you’re having a problem with your USB ports, before you check anything in Linux, check your BIOS. Many BIOS menus include an option to turn USB connections on and off. D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen 56 Chapter 2: Planning the Installation CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 Planning the IRQ Layout: Standard IRQs Now you should see that IRQs are a precious commodity on a PC. IRQ conflicts are common when you’re connecting a lot of devices. If your printer doesn’t work after you’ve connected a second network card, it can help to know the standard IRQ for printers. You can then assign a different IRQ to that network card. If you don’t have any free IRQs to assign to that network card, you may be able to sacrifice a component that uses a standard IRQ. For example, if you always connect to a server remotely, that server PC may not need a keyboard. If you can boot a computer with a CD-ROM, you may not need a floppy drive. Some IRQs are essential to the operation of a PC and just can’t be changed. These are reserved by the motherboard to control devices such as the hard disk controller and the real-time clock. Do not use these interrupts for other devices, or there will be conflicts! Other IRQs are normally assigned to common devices such as a floppy disk and a printer. In Linux, you can check /proc/interrupts to see which interrupts are being used, and which are free for new devices. The reserved and typical IRQ assignments are shown in Table 2-1. You can find a list of assigned IRQ channels in your /proc/interrupts file. Input/Output Addresses Every computer device requires an input/output (I/O) address. It’s a place where data can wait in line for service from your CPU. I/O addresses are listed in hexadecimal notation (base 16), where the numbers are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, and f. Some typical I/O addresses include those for the basic serial ports, known in the Microsoft world as COM1, COM2, COM3, and COM4. These ports normally use the following I/O addresses: 03f8, 02f8, 03e8, and 02e8. You can find a list of assigned I/O addresses in your /proc/ioports file. Direct Memory Addresses A direct memory address (DMA) is normally used to transfer information directly between devices, bypassing the CPU. Many components don’t need a CPU. For example, many sound cards include their own processor. This allows your PC to set up a DMA channel between a hard drive and a sound card to process and play any music files that you may have stored. D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen While DMA channels bypass the CPU, devices that use DMA are still configured with IRQ ports. There are eight standard DMA channels (0–7); DMA 4 is reserved and cannot be used by any device. You can find a list of assigned DMA addresses in your /proc/dma file. RAM Requirements You probably have no idea how much memory you absolutely need. The maximum amount of memory your system will use is the sum of all of the memory requirements of every program that you will ever run at once. That’s hard to compute. Therefore, you should buy as much memory as you can afford. Extra RAM is usually cost effective when compared to the time you would spend trying to tune an underpowered system. Linux will comfortably run at the command line for a single user on 32MB of RAM; 64MB is better, while 128MB of RAM and above are magical! Basic Hardware Knowledge 57 CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 IRQ Typical Assignments 0 System timer 1 Keyboard 2 Cascade for controller 2 3 Serial ports 2, 4 4 Serial ports 1, 3 5 Parallel port 2 or sound card 6 Floppy disk controller 7 Parallel port 1 8 Real-time clock 9 Redirected to IRQ2 10 Not assigned (commonly used for a network card) 11 Not assigned 12 PS/2 mouse, if installed 13 Math coprocessor 14 IDE hard disk controller 1 15 IDE hard disk controller 2 TABLE 2-1 Standard IRQ Assignments D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen 58 Chapter 2: Planning the Installation CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 If you’re setting up Linux as a server, RAM requirements increase with the number of users who may need to log in simultaneously. The same may be true if you’re running a large number of programs or have memory-intensive data such as that required by a database. If possible, install enough RAM to handle some growth in the number of users. Don’t hold back because of the cost of RAM. While it’s tempting to wait until the price of RAM goes down, the loss of productivity when you install additional RAM can easily exceed any money you might save. The enterprise version of Linux kernel 2.2 can address up to 4GB of RAM with older Pentium II and equivalent systems. With kernel 2.4, Linux can address up to 64GB of RAM. The total amount of addressable space for any one program to use is the sum of available RAM and swap space. In general, Linux utilities are usually small, except for something like a database service, which can load huge tables into memory and might possibly use all the available memory while doing so. The same goes for video productions and high-end graphics applications that create cartoons and mapping systems to name a few. Hard Drive Options (IDE, EIDE, and SCSI) Before your computer can load Linux, the BIOS has to recognize the active primary partition on the hard drive. This partition should include the Linux boot files. The BIOS can then set up and initialize that hard drive, and then load Linux boot files from that active primary partition. After Linux has loaded, the settings for the disk subsystems can be modified or dealt with utilities such as fdisk or Disk Druid. IDE and EIDE IDE stands for Integrated Drive Electronics. It is built on the IBM PC ISA 16-bit bus standard, and was itself adopted as the Advanced Technology Attachment (ATA) standard in 1990. Unfortunately, the first ATA standard hard drives could access only 504MB of disk space at fairly slow speeds. The Enhanced IDE (EIDE) standard was created in 1994 for larger hard drives and faster access speeds. Support was also added for additional hard disks, direct memory access (DMA), and ATA Packet Interface (ATAPI) devices, such as CD-ROMs and tape drives. The standard Intel architecture PC is configured to manage up to four IDE drives. If you need more, the typical procedure is to use SCSI devices. D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen Hardware Compatibility 59 CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 SCSI The Small Computer System Interface (SCSI), developed by Apple Computer, allows your computer to interface to disk drives, CD-ROMs, tape drives, printers, and scanners. SCSI is faster and more flexible than EIDE, with support for 7, 15, or even 31 devices, depending on the SCSI bus width. Data transfer speeds for SCSI range from 5 to 160 or 320 megabytes per second. SCSI controllers are not common on most modern-day desktop PCs, as SCSI drives are usually more expensive. The major PC vendors, however, will almost always provide SCSI drives and controllers for their high-end server products, as the larger number of hard drives and faster bus speeds make them a better choice. If you want to use SCSI and IDE drives on the same computer, check your BIOS. Some PC BIOS can be configured to boot an operating system from a SCSI hard drive. Others may defer to the BIOS associated with a SCSI adapter. If that is not possible, you may need to install the Linux boot files on an IDE hard drive partition. Alternatively, you can boot Linux on a SCSI disk from a 1.44MB floppy drive. CERTIFICATION OBJECTIVE 2.02 Hardware Compatibility Now it’s time to explore in detail the hardware that Red Hat Linux can handle. Unfortunately for Linux, hardware manufacturers are still targeting the Microsoft Windows market. While some manufacturers now include their own Linux hardware drivers, most Linux hardware support come from third parties. Fortunately, there is a vast community of Linux users, many of whom produce drivers for Linux and distribute them freely on the Internet. If a certain piece of hardware is popular, you can be certain that Linux support for that piece of hardware will pop up somewhere on the Internet and will be incorporated into various Linux distributions, including Red Hat Linux. Be careful when purchasing a new computer to use with Linux. Though Linux has come a long way the last few years, and you should have little problem installing it on most modern PCs, you shouldn’t assume Linux will run on any PC, especially if the PC in question is a laptop or some new, state-of-the-art machine. The latest and greatest existing technology may not be supported under Linux (not yet, anyway). D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen 60 Chapter 2: Planning the Installation CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 The hardware may also be targeted for specific operating systems and configurations. Laptops are often designed with proprietary configurations that work with Linux only after some reverse engineering. Other kinds of hardware, such as “winmodems” and “winprinters,” are designed to use Microsoft Windows driver libraries. Integrated hardware (e.g., video chips that share system RAM) and parallel port devices can also be problematic. While there may be ways to make these types of hardware work, the process of actually making them work may cause more frustration than they’re worth. Last year’s model is an ideal choice; it is less expensive and more likely to be supported. When it comes to laptops, your chances are best with brand names. Linux runs very well on lower-end computers. This is one of Linux’s strong points over other operating systems, such as Microsoft’s Windows XP. Linux runs fine on 32MB of RAM, although more is always better, especially if you want to run any graphical applications. While it is important to know how to select and configure hardware components to get to a smoothly running Linux computer, the RHCE exam is not a hardware exam. Linux Hardware Documentation You are not left without help or resources when choosing the right hardware for Linux. You have many places to turn to for help, including mailing lists and newsgroups. Perhaps the best places to look are the Linux Documentation Project (LDP) or the Red Hat Hardware Compatibility List. The LDP is a global effort to produce reliable documentation for all aspects of the Linux operating system, including hardware compatibility. You can find the Linux Hardware HOWTO at the LDP Web site, www.tldp.org. Linux Hardware HOWTO The Linux Hardware HOWTO is a document listing most of the hardware components supported by Linux. It’s updated irregularly with added hardware support, so it is a relatively up-to-date source of information. As of this writing, various LDP HOWTOs are supplied on the documentation CD-ROM in text format and in various languages, in the /HOWTOS directory. The official up-to-date list can be found at the LDP Web site. D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen Hardware Compatibility 61 CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 The Red Hat Hardware List The Red Hat Hardware List specifies name brand hardware that has been tested with Red Hat Linux. If you purchase an official Red Hat Installation, Red Hat will provide limited installation support for any certified or compatible hardware. Some hardware that has been tested by Red Hat has specifically been found not to work with Red Hat Linux and is therefore not supported. Red Hat hasn’t tested all PC hardware; as a courtesy, they also include a list of hardware that others have tested with Red Hat Linux, as “Community Knowledge” hardware. These four categories of hardware are described in Table 2-2. Like the LDP, the Red Hat Hardware List draws upon the efforts of volunteers. If you want to check if any of the “latest” hardware (such as USB) will run on your Linux system, it’s probably best to consult the Red Hat support site first, then maybe LDP’s Linux Hardware HOWTO. However, if you want the option of being able to contact Red Hat for support, you should stay within the “supported” list of the Red Hat Hardware List. Check the documentation for your hardware. Find a component such as a modem or a network card. Cross-check this component against the Red Hat and LDP hardware compatibility lists (HCLs). Find the Red Hat lists by starting at http://www.redhat.com. Find their HCL in their support area. Find the LDP Hardware HOWTO by starting at http://www.tldp.org. Find this list in the LDP section on HOWTOs. Compare the results. While in most cases the results are identical, it’s good to know how to search through both sources just in case. As part of this process, find a component listed on one or both of these HCLs as incompatible with Linux. Do a search on your favorite search engine or the newsgroups based on the name and model of the product. Don’t forget to include “linux” in your list of search terms. You might be pleasantly surprised. As of this writing, a searchable newsgroup database is available at groups.google.com. Status Description Certified Approved by Red Hat, Inc., through the Red Hat Hardware Certification Program. Compatible Reviewed by Red Hat, Inc., and known to be supported. Not Supported Reviewed by Red Hat, Inc., and known not to work with Red Hat Linux. Community Knowledge Untested by Red Hat, Inc.; others have reported some degree of compatibility with Red Hat Linux. TABLE 2-2 Red Hat Hardware Compatibility Categories D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:04 AM Color profile: Generic CMYK printer profile Composite Default screen 62 Chapter 2: Planning the Installation CertPrs8 / RHCE Red Hat Certified Engineer Linux Study Guide / Jang / 222485-1 / Chapter 2 CPU and SMP Support Red Hat Linux for Intel supports computers with Intel and compatible processors. It is “Itanium-ready,” which means that it will be able to support this 64-bit Intel CPU when it is finally released. Linux is commonly used as a server operating system. Many server applications can take advantage of the flexibility provided by multiple CPUs. This is known as symmetric multiprocessing (SMP) support. With the release of the 2.4 kernel back in 2001, Linux now supports computers with up to eight CPUs. Since the release of Linux kernel 2.4, there have been problems with SMP support. Older versions of this kernel don’t support SMP with non-Intel processors. As of this writing, current versions may have problems keeping threads limited to one CPU. If you’re running Linux on a SMP computer, keep up to date with the latest kernel developments at www.kernel.org. Plug and Play Plug and play (PnP) refers to the capability of an operating system to automatically allocate IRQ, I/O, and DMA ports or addresses to specific devices such as hard drives, sound cards, or modems. Linux’s capability to work with plug and play devices is somewhat limited. For example, if you have the right network modules installed with the kernel, Linux may be able to automatically detect and install the drivers for a new network card in a PCMCIA slot. However, if you connect a printer to a standard printer port, you’ll probably have to use the techniques discussed in Chapter 8 to install the appropriate print driver. A plug and play system has three parts: the BIOS, the device, and the operating system. Unless all three work perfectly, problems can arise with plug and play. The BIOS has to allow the operating system to find the devices on your computer. Plug and play devices have to accept port and channel assignments from the operating system. And a plug and play operating system is constantly searching each connection for new hardware. Computer users should not have to tell the computer a plug and play device is there. The operating system should be able to recognize the device and set it up automatically. Plug and play has been available for Macintosh computers for quite some time, and it has been incorporated with varying degrees of success into Microsoft’s Windows operating systems. Linux is a little behind on this technology, though it is able to configure most ISA and PCI PnP devices. Red Hat developed the kudzu utility to look for and configure any hardware changes when you boot Linux. D:\omh\CertPrs8\485-1\ch02.vp Wednesday, September 18, 2002 10:13:05 AM Color profile: Generic CMYK printer profile Composite Default screen [...]... monitor the Linux kernel Web site for updates 9 You installed a printer onto a Linux workstation After changing the IRQ and the I/O address, you find that the sound card no longer works What is the most likely problem? A The sound card was probably a plug and play device, so the printer now conflicts with either the newly assigned IRQ port or the I/O address B There is an IRQ conflict between the printer... Linux from a SCSI disk, the BIOS assigns the number 0x80 to /dev/sda (the SCSI disk) and 0x81 to /dev/hda (the first EIDE drive) Linux, however, assigns 0x80 to /dev/hda, 0x81 to /dev/hdb (the second EIDE disk), and 0x82 to the SCSI disk There is a disagreement between the BIOS and the boot loader Your boot loader (GRUB or LILO) will not find the boot sector on /dev/sda and, therefore, will not be able... letters followed by a number The first letter identifies the type of drive (h is for IDE/EIDE, s is for SCSI) The second letter is d for disk, and the third letter represents the relative position of that disk, starting with “a.” In other words, the first IDE drive is hda, followed by hdb, hdc, and hdd The number that follows is based on the relative position of the partition There are primary, extended,... cases, the first logical partition on the first IDE drive is hda5 You can create logical partitions with names between hda5 and hda16 on the first IDE drive, or sda5 and sda15 on a SCSI drive In this configuration, if you then created another primary partition from some free space, the IDE drive would renumber the partitions in your BIOS The numbers wouldn’t match the Linux names such as hda2 The boot... should know the manufacturer, model number, and capacity of the drive In addition, if it’s a SCSI drive, make sure you know its SCSI ID number ■ Hard drive controller Know the manufacturer and model number of the drive controller If this data is hard to find, at least try to find the chipset of the controller If it’s an IDE controller, the documentation is associated with the computer motherboard If... mouse ■ Graphics card If you will be running the Linux graphical user interface (GUI), also known as X or X11, you will need the manufacturer, the model number, the chipset, and the amount of video memory If it’s a fairly common graphics card and you can’t find the chipset or memory, you should be able to select a generic or older version of the card from the X installation database D:\omh\CertPrs8\485-1\ch02.vp... printer and the sound card C The sound card and printer are using the same device file in the /dev directory You need to create a new link to use both devices D None of the above 10 How would you know if your serial mouse is properly attached to a serial port? A Run the ls -l /dev/mouse command You should see a file link to the appropriate serial port B Check the physical connection If the connection... on your computer, the Linux plug and play subsystem may have already linked the device for that port with the device for your modem Run the ls -l /dev/modem command If it shows something like the following output, you know that Linux has already linked your modem driver with the second serial port: lrwxrwxrwx 1 root root 10 Apr 4 11:28 /dev/modem -> /dev/ttyS1 Otherwise, you can use the ln command to... should now have enough information to find the hardware that fits your needs Alternatively, you now know about the resources that help you determine what other hardware you need that also works with Linux Planning your Linux installation makes it easier to handle a wide variety of hardware You can imagine how frustrating it would be to begin the installation and then discover something wrong; for example,... usable The extended partition is used to contain up to 12 logical partitions ❑ You can create a total of 15 partitions for SCSI, with all 15 usable ❑ Linux has a simple naming standard for disk partitions: three letters followed by a number The first letter reflects the type of drive (h for IDE, s for SCSI) The second letter is d for drive The third letter represents the relative position of the disk The . essential to the operation of a PC and just can’t be changed. These are reserved by the motherboard to control devices such as the hard disk controller and the. Linux, the BIOS has to recognize the active primary partition on the hard drive. This partition should include the Linux boot files. The BIOS can then set