Web Design Programs, Jsp, Tomcat, J2Ee, Hibernate Programming Blog

This list shows some symptoms of a missing, incorrect, or corrupt systemkernel all would occur after you either make your menu selection andpress Enter, or just let the boot loader do its thing automatically withoutchoosing anything: The system freezes. A few dots appear across the top of the monitor, and then the systemfreezes. A few messages appear on the screen, and the final message readskernel panic. The system reboots automatically. You know when the kernel is loading because you start to see crazy text like: Uncompressing Linux… Ok, booting the kernel. audit(1092566112,337:0): initializedRecovering from a kernel loading failure (aside from operating system notfound see previous section) is one of the more challenging issues in Linux. This task is unfortunately not for the faint of heart. On the other hand, thefailed kernel may be an updated one. If you have more than one Linux optionin your boot menu, look at the version numbers for each of the options andchoose the second newest. Doing so lets you boot into the last working kerneland have a working system. Then you can open up www.google.comandsearch on the error messages or wait until the next kernel update comes outand ignore the bad one for now. In the case where it s your original install that doesn t properly start, youunfortunately don t have a fallback kernel option. If this is your problem, Irecommend either contacting your distribution s support address (if you pur- chased a commercial product) or joining the installation or beginner s helpdiscussion list if you downloaded a free product. See Chapter 2 to find outwhere to locate help for each distribution discussed in this book. Step 4: Control is handed over to initOnce the kernel s finished loading, it passes off the system initializationprocess to a program named init. The initprogram is responsible for start- ing all services and programs. You can see these processes starting as theyscroll up the screen with [OK]or [FAILED]on the right side of the monitor. Ifyou see these lines, you know that your kernel has finished loading. 99Chapter 5: Booting and Stopping Linux09_
Note: In case you are looking for affordable and reliable webhost to host and run your j2ee application check Vision best web hosting services

Sometimes bad things can happen to your boot loader. One common symp- tom of boot loader problems is a message saying that the operating systemcould not be found. Another hint that the problem is your boot loader is if younever see your boot menu,which is a screen that comes up during the bootprocess that lets you choose what operating system and version to boot. The boot menu will look different from distribution to distribution. If you suspect a boot loader problem, see the section Entering RescueMode, later in this chapter. For another option, see the sidebar CustomBoot Disks. Step 3: The boot loader (GRUB or LILO) loads the system kernel into memoryEvery computer (and electronic device) requires an operating system to run. The technical term for this operating system, or at least the core of it, is thekernel.If the kernel is your maestro, orchestrating all the components of yourcomputer and delegating resources in a logical and cooperative manner, theboot loader is the red carpet on which the maestro arrives. Many Linux distributions today actually put up a GUI progress screen duringthe kernel loading and system initializationphase (after the kernel finishesloading, when it finishes up the boot process). If you want to see what hap- pens, you can typically click an icon or press a key. Just look for instructionson how to see details. 98Part I:Getting Your Feet Wet Custom boot disksYou can protect against boot loader failures afteryou get your installation working by making acustom boot floppy disk, which you can use toboot the system if the boot loader on your harddrive gets corrupted. Many distributions havespecial programs or tools available to makecustom boot disks for you, and some will offer tomake the disks during installation. The programsto make a disk manually are mkbootdisk forFedora Core and Mandrake, drakfloppy forMandrake as well, yast for SuSE, and build-boot- floppy for Xandros. However, a custom boot diskwon t help you if something goes wrong with thelater boot steps. It s only good for boot loaderproblems. After you manage to boot with thefloppy, open a terminal window (see Chapter 14), type su -to become the root (administrative) user, and then double-check which boot loaderyour distribution uses. For LILO, type lilo -vto try to repair your boot loader on your harddrive. For GRUB, look in the file /boot/grub/ menu.lstand look for a line in the beginningwith the text boot= for example, it may sayboot=/dev/hde. Then, type grub-installbootdrive, where bootdrive is the hard drivelisted in the boot line, such as grub-install/dev/hde. Now you can try rebooting withoutthe floppy in the floppy drive.
Note: In case you are looking for affordable webhost to host and run your servlet application check Vision mysql5 web hosting services

was running properly before you began your Linux installation, your com- puter should be getting through the POST just fine POST problems don ttend to be caused by installing a new operating system; they re far more fun- damental to the computer itself. For all but the last of these errors, it s time to question your nephew Mortimer, who was last seen lurking around your computer with a screwdriver. (Or takeyour computer into a computer repair shop!) If you see an error message indi- cating a hardware failure, you might have a shot of fixing the problem in theBIOS. As the POST does its thing and finishes up, it briefly displays (usually atthe bottom of the screen) instructions on how to enter setup. Typically, theseinstructions mention pressing the DEL key or a function key such as F1. Whenyou press this key, if all goes well, you usually see a blue screen with black andwhite text. From here, if you re familiar with your hardware, you can try tofigure out and fix the problem. However, many people would rather have a rootcanal with no anesthesia than mess with this stuff, so you may want to grab thenearest teenager or computer repair shop to take a look. The good news is that if you can get to the BIOS at all, the problem may beeasier to fix than one where the computer fails before you reach the BIOS. Step 2: The BIOS passes the baton to the boot loaderAfter the BIOS gives the okey-dokey with a successful POST, the BIOS locatesthe first hard drive in your system and reads the first sectorof that disk, whichis often referred to as the MBR (Master Boot Record). On that first chunk ofdisk is a small program called a boot loader.The boot loader doesn t knowmuch about anything, except how to start loading your operating system. Two boot loader programs understand how to load a Linux operating system: LILO (LInux LOader) and GRUB (GRand Unified Boot loader). LILO has been atried-and-true boot loader for as long as Linux has been a gleam in a geek seyeball. GRUB is a newer and much more sophisticated boot loader programthan LILO. Many distributions allow you to choose your boot loader. Typically, most people just stick with the defaults, which are as follows for the five dis- tributions discussed in this book: DistributionDefault Boot LoaderFedora CoreGRUBLinspireLILO, with its own special routines on top of it. MandrakeLILOSuSEGRUBXandrosLILO, with its own special routines on top97Chapter 5: Booting and Stopping Linux09_
Note: If you are looking for reliable webhost to maintain and run your java application check Vision java hosting services

Giving Linux the BootLet s face it: As enjoyable as the experience of staring at a dormant computeris, the real fun starts when you turn on the computer. As with any electronicdevice, opening the electron floodgate is the first step to fun. A computer, however, has much more stuff to do than your toaster oven. Rather than actas a simple heating element, your computer has to check all those gizmosthat you (or the manufacturer) plugged into your computer s motherboard. After the initial power-up, the computer performs some simple hardwaretests (called the POST, or Power-Up Self Test) to determine whether thosevarious components are working properly. Checking all your hardware is just the beginning. Between the time you turnthe computer on and the moment the glowing phosphor on your monitorprompts you for a login name, the computer is building itself an empire. Ifyou listen and watch carefully, your computer and monitor show signs of theboot process through bleeps, buzzes, whirring motors, clicks, messages onthe monitor, and blinking lights. Although you have heard the clich Rome wasn t built in a day, the bootprocess goes fairly quickly. This is pretty amazing, considering that the archi- tecture of an operating system makes Rome s look like a stack of cardboardboxes and that each time you power up your computer, it must build itswhole operating system in memory. (Remember that an operating systemisthe core software that makes your computer work.) This process can bebroken into four main steps, which I discuss in the following sections. Step 1: Power-On Self-Test (POST) leads to BIOSThe POST process really has nothing to do with the operating system. Yourcomputer performs this step whether you re running Linux or another oper- ating system such as Windows XP. Some symptoms of a failed POST include An unusual series of long and short beeps. Nothing displayed on the monitor. No apparent activity other than the whirring fan on the power supply. A puff of smoke or the pungent smell of burning electrical componentsfrom your computer case. An error message, displayed on the monitor, indicating a hardware failure. If you encounter any of these problems, you have hardware troubles thatneed to be resolved before you can proceed. Chances are, if your computer96Part I:Getting Your Feet Wet
Note: In case you are looking for affordable webhost to host and run your web application check Vision http web server services

Chapter 5Booting and Stopping LinuxIn This Chapter Understanding what happens when you turn on your Linux machine Identifying and isolating boot problems Shutting down safelyI like work; it fascinates me. I can sit back and look at it for hours. Jerome K. JeromeIf you came here from Chapter 3 or 4, you likely just survived the first gaunt- let of the Linux world: installing the operating system. I hope that bootingfor the first time worked well. If it did and you decide that most of this chapterisn t for you, at least skip to the last section in this chapter, Don t Just TurnOff the Machine! Otherwise, if you re interested in learning about what yourmachine does as it boots (this chapter can get pretty geeky!), read on. Your Linux installation failing to boot properly is not necessarily an emer- gency. Much of this chapter is designed to help you deal with any problemsyou might run into. Before you curse Linux, remember that installing an oper- ating system is no small task and that, because many technical variables areassociated with such an installation, many computer manufacturers insist onperforming the task at the factory. Companies such as Hewlett Packard andWal-mart (believe it or not) have been offering Linux pre-installed, so if you retoo discouraged at this point or are reading ahead and are too nervous togive it a shot, you can either use Knoppix (see Chapter 4 for how to useKnoppix without having to install it) or purchase a pre-installed machinefrom a vendor or a local computer builder. To unravel the mystery of a Linux system that won t boot requires a bit ofunderstanding of how your computer starts up.
Note: In case you are looking for affordable webhost to host and run your web application check Vision cheap hosting services

94Part I:Getting Your Feet Wet
Note: If you are looking for high quality webhost to host and run your jsp application check Vision christian web host services

tools to one another with different configurations, documentation, GUI trap- pings, installation procedures, and other bells and whistles. Even then, somegeneral-purpose distributions serve some markets better than others. Forexample, TurboLinux is popular in Japan, Red Flag Linux is the official choice inChina, and Conectiva is popular in Spanish-speaking countries. More special- purpose distributions exist as well. LiveCDs fall under this category, but eventhey fall into subcategories, with some of them (like Knoppix) serving the general-purpose segment, while others are fine-tuned as multimedia centers, system-rescue environments, and other cool specialist toys. To dig through themany distributions available, check out DistroWatch (www.distrowatch.org) and let your mouse do the walking through over three-hundred distributions. Ifyou can t find enough to choose from here, go to this site s Related Links sec- tion, and you can find plenty more. If you don t want to download and burn all this stuff and don t know any help- ful Linux geeks, you may want to look up a local Linux Users Group (LUG). You can find a list of LUGs worldwide, listed by geographic region, on theGLUE (Groups of Linux Users Everywhere) Web site: www.ssc.com:8080/ glue/groups. These folks are always happy to help the technologically chal- lenged. These user groups also regularly sponsor events, called demo days orinstall-fests,where you can bring your computer and get all the help you need. These events are usually lots of fun for computer enthusiasts hot- andcold-running caffeine and enough know-how to do just about anything with acomputer. 93Chapter 4: Installing Other Linux Distributions08_
Note: If you are looking for cheap and reliable webhost to host and run your web application check Vision coldfusion web hosting services

Using LiveCDsAs I mention throughout this chapter (and book), LiveCDs(or bootable distri- butions) are versions of Linux that you can launch directly by rebooting a com- puter using a Live CD-ROM (or DVD-ROM). The beauty of these versions, from aLinux newbie s point of view, is that you can try something out without havingto actually install anything on your system. Old-timers love LiveCDs, too. If asystem is broken into, rebooting it with a LiveCD is a way of giving yourself a known good (undamaged) system to work from while repairing the damageon the computer itself. Also, many bootable distributions offer highly special- ized environments for particular tasks . . . but I m getting ahead of myself. You also need to keep in mind that LiveCDs tend to be slower than a tradi- tionally installed system. Everything has to run directly from the CD or DVD- ROM, after all. Make sure, too, that you re able save things if you need to. Doing so canrequire some planning, or at least a bit of thought see Chapter 21 for how toaccomplish this. When all else fails, I quickly configure the mail client and juste-mail attachments to myself. That s how I got those NTFS resizing images (seeChapter 2) from Knoppix over to my Fedora machine while writing this book! You also can usually access your real hard drive space from a bootable distri- bution, though whether it supports NTFS or not depends on the version. Knoppix does support NTFS, though it s best to use it as read-only. Another popular option with LiveCDs is to use portable storage like USB key- chains. That way, you can carry around your keychain and your bootable dis- tribution and have access to your preferred environment andyour data at thesame time. The important thing to know about USB storage is that Linux seesthese items as SCSI drives, so if you have to access them manually (seeChapter 11) you ll access them as SCSI partitions. For example, if you ve gotyour USB keychain plugged into the first SCSI slot, it would probably be/dev/sda1. Finally, not all LiveCDs work with all PCs. The cool thing is that if one doesn twork with yours, you just shrug and download another! Finding Even More LinuxMore than 200 different Linux distributions are available today, with newones being created every year while others fade from existence as the initialenthusiasm or funding behind them dwindles away. Many of these distribu- tions are general purpose, or at least similar purpose (full desktop, fullserver, and so on), and so provide similar base software and surrounding92Part I:Getting Your Feet Wet
Note: In case you are looking for affordable webhost to host and run your servlet application check Vision make web site services

Under Registration, it s up to you whether you want to register immedi- ately. You can always register later. You need to register in order to gettechnical support, so you ll probably want to register beforeyou run intotrouble. Registration also lets you download some of the programs avail- able in Xandros Networks (see the section Recognizing some Xandrosspecial features ) for free! When you reach the Finish screen, if you re on a network that s alreadyconnected to the Internet, click the Xandros Networks icon to updateyour system. This action makes sure that you ve got all the latest secu- rity and bug fixes. The updater is automatic. When your update is complete, you re left with the Xandros Networks screenin the foreground and the First Run Wizard in the background. Click the FirstRun Wizard icon on your lower panel to pull this dialog box to the front andthen click Finish to complete your first run process. You may get a messagethat your desktop has to be restarted. Click Yes, which logs you out of youraccount and restarts the GUI, bringing you back to a login prompt. About the various Xandros versionsXandros focuses on the desktop and has offerings for both home and busi- ness users. The free and commercial versions from Xandros include (at thetime of this writing): Xandros 2.5 Open Circulation Edition:A free version, slightly differentfrom the main commercial version, available through bittorrent, a P2Pfilesharing network popular with legitimate software distributors as away to get CD and DVD images quickly to their users. See www.xandros. com/products/home/desktopoc/dsk_oc_download_windows.htmlfor instructions. Xandros Desktop OS Version 2.5 Standard Edition: The primary homeuse version of the Xandros desktop. Xandros Desktop OS Version 2.5 Deluxe Edition:Includes additionalsoftware for interoperating with Windows and Windows software, includ- ing the ability to resize NTFS partitions. Xandros Desktop Version 2.5 Business Edition:Includes extra softwareon top of what you would get with the Deluxe Edition, which allowsXandros to better integrate as a desktop on a Windows network, alongwith Sun s StarOffice, the commercial product behind the OpenOffice. .000.orgsuite covered in Chapter 17. However, Xandros 3 may well beavailable by the time you purchase this book. If so, it s well worth check- ing out. 91Chapter 4: Installing Other Linux Distributions08_
Note: In case you are looking for affordable and reliable webhost to host and run your business application check Vision ftp web hosting services

24.Enter your full name in the Full Name text box. This name will, for example, as the full name field in your e-mail. 25.Enter your password in both password text boxes and click OK tocreate the account. 26.Click Next to proceed. The Installation Summary dialog box appears. 27.Inspect the summary. If everything is as it should be, click Finish. Otherwise, click Back as much as you need to in order to fix thingsand then work forward to this step once again. Up until this point, nothing has been changed on your computer. Whenyou click Finish, your installation actually begins. After it s done, theInstallation Complete dialog box appears. 28.If you want to create a boot floppy disk (recommended), then put afloppy disk in your floppy drive and click Create. Otherwise, go toStep 29.29.Click Exit once you re ready to reboot the computer into Xandros. 30.Eject the CD when prompted and press Enter to reboot. When the Xandros boot screen appears, you can either select theXandros option and press Enter, or wait until it starts up on its own. As with the other distributions covered in this book, Xandros has a numberof post-installation setup tasks for you to walk through. When you reach thelogin prompt, use your regular user account, which should automatically beselected. Type your password and click Login (or press Enter) to log into theaccount and start the First Run Wizard. Some notes for walking through thisprocess: Under Regional Settings, Locale is just for your language issues. It doesn thave anything to do with your time zone and whatnot. Also, unless youknow for a fact that you want a particular item in Character set, just stickwith what you re assigned. It s chosen based on your language, because acharacter set is literally the characters you have available to type. It s thesame with keyboard layout. You don t have to set up your printers right now, but if you want to, goahead in the Printers dialog box. I look closer at printers in Chapter 6. Under System Behavior, you re choosing a combination of look and feelelements (will it look like Microsoft Windows, MacOS, Linux referredto as KDE here rather than Linux, you find out more about KDE inChapter 6 , and so on?) along with how the system actually behaves. My coverage of Xandros in this book sticks to the default Xandros setting unless otherwise stated, but feel free to play with yours! 90Part I:Getting Your Feet Wet
Note: In case you are looking for affordable webhost to host and run your servlet application check Vision make web site services