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Linux, PHP, SMS - USSD Examination

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Linux, PHP, SMS - USSD Examination

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Linux, PHP, SMS - USSD Examination

  1. 1. Linux, PHP, Network Operator Exam 1. Where may GRUB be installed? A. The MBR, a Linux partition’s boot sector, or a floppy disk B. The MBR, a Linux partition’s boot sector, or a Windows partition’s boot sector C. A Linux partition’s boot sector or a Windows partition’s boot sector D. The MBR, a floppy disk, or a swap partition 1. A. GRUB may reside in any of the locations listed in option A. If you install it in a FAT or NTFS partition (used by DOS or Windows), these partitions will be damaged, and if you install GRUB in a swap partition that is then used, GRUB will be wiped out. See Chapter 1 for more information. 2. Under which of the following circumstances will a chmod command not work? A. The user issuing the command doesn’t own the file but does own and have write permission to the directory in which the file resides. B. The root user issues the command on a file that resides in a read/write filesystem, although the file itself has no write permissions active. C. The owner of the file issues the command, but the file’s permissions don’t grant the owner write access to the file. D. The owner of the file issues the command, but the file resides in a directory to which the owner has read but not write access. A. Only the file’s owner and root may change permissions on a file via chmod. Whether the file is writeable by the owner is irrelevant, as is whether the directory in which the file resides is writeable. See Chapter 2 for more information. 3. What is the function of the su command? A. It gives the named user superuser privileges. B. It acquires the named user’s privileges, or the superuser’s if no username is specified. C. It acquires superuser privileges for the user who runs the command. D. It gives everybody currently logged in superuser privileges. B. Typing su username gives the person who runs the command the privileges associated with that username, assuming that the person who runs the command successfully enters the user’s password. When the username isn’t specified, root is assumed. The su command also runs a program as the specified user. Normally, this is a shell, but you can specify another program using a command-line argument. Although option C describes part of what su can do, option C is incomplete; option B is a more complete answer. The su command does not give superuser privileges to the named user, nor does it give everybody who’s logged in superuser privileges. 4. You want to set up a firewall on a Linux computer. Which of the following tools might you
  2. 2. use to accomplish this task? A. Apache B. iptables C. wall D. TCP Wrappers B. Option B, iptables, is a tool for configuring the 2.4.x and 2.6.x Linux kernel’s firewall features. (The ipfwadm and ipchains programs perform these tasks for the 2.0.x and 2.2.x kernels, respectively.) Apache is a Web server, and wall sends messages to all currently logged-on users. TCP Wrappers controls access to specific servers, but it isn’t a firewall per se. 5. How would you direct the output of the uptime command to a file called uptime-stats.txt? A. echo uptime uptime-stats.txt B. uptime > uptime-stats.txt C. uptime | uptime-stats.txt D. uptime < uptime-stats.txt B. The output redirection operator is >, so option B sends the output of uptime to uptime-stats.txt. The echo command displays information on the screen, so option A simply causes uptime uptime-stats.txt to appear. Option C uses a pipe. If uptimestats. txt were a program, it would process the output of uptime, but the result of this command will probably be a file not found or permission denied error. Option D uses an input redirection operator, so uptime receives the contents of uptime-stats.txt as its input. 6. A workstation ordinarily runs with a load average of 0.25. Suddenly, its load average is 1.25. Which of the following might you suspect, given this information? (Choose all that apply.) A. The workstation’s user may be running more programs or more CPU-intensive programs than usual. B. A process may have hung—locked itself in a loop consuming CPU time but doing no useful work. C. A process may have begun consuming an inordinate amount of memory. D. The CPU may be malfunctioning and require replacement. A, B. Sudden jumps in load average indicate that programs are making heavier demands on the CPU than is normal. This may be because of legitimate factors such as users running more programs or more demanding programs, or it could mean that a program has locked itself into an unproductive loop. Memory use isn’t reflected in the load average. A malfunctioning CPU is likely to manifest itself in systemcrashes, not a change in the load average. 7. Your company makes computer hardware, and you want to enable customers to download Linux, Windows, and MacOS drivers and documentation files for this hardware. Which of the following are the best choices to enable users to retrieve such files? (Choose two.)
  3. 3. A. SMTP B. FTP C. HTTP D. NFS B, C. The question requires a publicly-accessible file download systemusing a widely-used network protocol. Both the File Transfer Protocol (FTP) and the Hypertext Transfer Protocol (HTTP; the Web’s main protocol) fit the bill, although an FTP server will need to be configured for anonymous access. You might want to run option A’s Simple Mail Transfer Protocol (SMTP) to receive e-mail from customers, but it won’t help to achieve the stated goals. The Network File System (NFS) is a file-sharing protocol that could, in principle, be used to achieve the question’s goals; however, Windows-using clients are unlikely to be able to easily access an NFS server and most Web browsers don’t support NFS, making it a more awkward choice in this role even for Linux users. Thus, option D is a poor choice, and since the question asks for precisely two answers, B and C are both superior responses. 8. Which of the following statements are true of SSH? (Choose all that apply) A. Most default configurations allow root to log in directly. B. Encryption makes SSH safer than Telnet. C. The default port used is 53. D. By default, SSH uses UDP. A, B. Most default SSH configurations allow root to log in directly. Although SSH’s encryption makes this practice much safer than the equivalent when using Telnet, you can gain the added benefit of requiring two passwords by disabling direct root logins via SSH. The default port used by SSH is 22, and it is a TCP protocol. 9. Where may the Linux root (/) partition reside? A. On a primary or logical partition B. On a logical partition only C. On a primary partition only D. On a partition that falls below the 1,024th cylinder A. Linux isn’t fussy about primary versus logical partition types, even for the root partition. On old BIOSs or with old versions of LILO, the kernel must reside below the 1,024th cylinder, but this isn’t a requirement of the root partition. 10. Which of the following best describes a typical Linux distribution’s method of installation? A. The installation program is a small Linux systemthat boots from floppy, CD-ROM, or hard disk to install a larger systemon the hard disk. B. The installation program is a set of DOS scripts that copies files to the hard disk, followed by a conversion program that turns the target partition into a Linux partition.
  4. 4. C. The installation program boots only from a network boot server to enable installation from CD-ROMor network connections. D. The installation program runs under the Minix OS, which is small enough to fit on a floppy disk but can copy data to a Linux partition. A. Most Linux distributions use installation programs written in Linux, not in DOS or Minix. The systemusually boots from floppy or CD-ROM, although other boot media (such as hard disk or even network) are possible. 11. Which of the following is an advantage of a GUI installation over a text-based installation? A. GUI installers support more hardware than do their text-based counterparts. B. GUI installers can provide graphical representations of partition sizes, package browsers, and so on. C. GUI installers can work even on video cards that support only VGA graphics. D. GUI installers better test the system’s hardware during the installation. B. A bitmapped display, as used by a GUI installer, can be used to show graphical representations of the system’s state that can’t be done in a text-mode display. Text-based installers actually have an edge in hardware support because they can run on video cards that aren’t supported by X. 12. Where might the BIOS find a boot loader? A. RAM B. /dev/boot C. MBR D. /dev/kmem C. The master boot record (MBR) can contain a small boot loader. If more space is required, the boot loader must load a secondary boot loader. Although the boot loader is loaded into RAM, it’s not stored there permanently because RAM is volatile storage. Both /dev/boot and /dev/kmem are references to files on Linux filesystems; they’re meaningful only after the BIOS has found a boot loader and run it and lots of other boot processes have occurred. 13. Who may set default environment variables for an ordinary user? A. Either root or the user, with the user’s settings taking precedence B. Either root or the user, with root’s settings taking precedence C. root only D. The user only A. The root user may set environment variables in /etc/profile or other system-wide configuration files, and users may set their own environment variables in .bashrc or other user-level configuration files or by typing them in manually. Because the user’s settings come later, they override systemdefaults, if in conflict.
  5. 5. 14. What key does the Bash shell use to complete filenames based on the first few characters? A. End B. Tab C. Enter D. Insert B. When you press the Tab key when you are typing a command or filename, Bash checks to see whether the characters you’ve typed so far are enough to uniquely identify the command or filename. If they are, Bash completes the command or filename, saving you keystrokes. 15. What command would you type to change the ownership of somefile.txt from ralph to tony? A. chown ralph:tony somefile.txt B. chmod somefile.txt tony C. chown somefile.txt tony D. chown tony somefile.txt D. Typing chown ralph:tony somefile.txt sets the owner of the file to ralph and the group to tony. The chmod command is used to change file permissions, not ownership. Option C reverses the order of the filename and the owner. Answer D uses the correct command and options. 16. You want to move a file from your hard disk to a floppy disk. Which of the following is true? A. You’ll have to use the --preserve option to mv to keep ownership and permissions set correctly. B. The mv command will adjust filesystempointers without physically rewriting data if the floppy uses the same filesystemtype as the hard disk partition. C. You must use the same filesystemtype on both media to preserve ownership and permissions. D. The mv command will delete the file on the hard disk after copying it to the floppy. D. When moving from one partition or disk to another, mv must necessarily read and copy the file and then delete the original if that copy was successful. If both filesystems support ownership and permissions, they’ll be preserved; mv doesn’t need an explicit --preserve option to do this, and this preservation does not rely on having exactly the same filesystemtypes. Although mv doesn’t physically rewrite data when moving within a single low-level filesystem, this approach cannot work when you are copying to a separate low-level filesystem(such as from a hard disk to a floppy disk); if the data isn’t written to the new location, it won’t be accessible should the disk be inserted in another computer. 17. Which of the following commands is an improved version of more?
  6. 6. A. grep B. tail C. cat D. less D. The less program, like more, displays a text file a page at a time. The less utility also includes the ability to page backward in the text file, search its contents, and more. 18. You’ve finished typing a document in Vi, and you want to save it. How would you do this? A. Press Esc to enter command mode, and then type :w to write the file. B. Select File Save from the menu. C. Press Ctrl+X and then Ctrl+S. D. Any of the above. A. Option A correctly describes how to save a file in Vi. (Some other key sequences have similar effects; for instance, you can save and exit from Vi by typing ZZ or :wq rather than :w.) Option B describes the method of saving files in many GUI text editors, but this method doesn’t work with Vi. Option C describes the method of saving files in Emacs, but this method doesn’t work with Vi. 19. Which mode in Vi would you use to type text? A. Ex mode B. Command mode C. Type mode D. Edit mode D. Edit mode is used for entering text. Ex mode is used for file operations (including loading, saving, and running external programs). Command mode is used for entering commands of various sorts. There is no “type mode” in Vi. PHP 1. What will the following script output? <?php $x = 3 - 5 % 3; echo $x; ?> A. 2 B. 1 C. Null D. True E. 3 Answer B is correct. Because of operator precedence, the modulus operation is
  7. 7. performed first, yielding a result of 2 (the remainder of the division of 5 by 2). Then, the result of this operation is subtracted from the integer 3. 2. Which data type will the $a variable have at the end of the following script? <?php $a = “1”; echo $x; ?> A. (int) 1 B. (string) “1” C. (bool) True D. (float) 1.0 E. (float) 1 Answer B is correct.When a numeric string is assigned to a variable, it remains a string, and it is not converted until needed because of an operation that requires so. 3. Is it possible to pass data from PHP to JavaScript? A. No, because PHP is server-side, and JavaScript is client-side. B. No, because PHP is a loosely typed language. C. Yes, because JavaScript executes before PHP. D. Yes, because PHP can generate valid JavaScript. Answer D is correct. JavaScript, like HTML, can be dynamically generated by PHP. Answers A and B are incorrect because the 4. Is it possible to pass data from JavaScript to PHP? A. Yes, but not without sending another HTTP request. B. Yes, because PHP executes before JavaScript. C. No, because JavaScript is server-side, and PHP is client-side. D. No, because JavaScript executes before PHP. Answer A is correct. Although your instincts might lead you to believe that you cannot pass data from JavaScript to PHP, such a thing can be achieved with another HTTP request. Answer B is incorrect because PHP executing before JavaScript is not what makes this possible.This is actually the characteristic that might lead you to believe (incorrectly) that the answer is no. Answers C and D are incorrect because the answer is yes, but also because the explanations given are false. 5. Which of the following form element names can be used to create an array in PHP? A. foo B. [foo] C. foo[] D. foo[bar]
  8. 8. Answer C is correct. PHP will create an enumerated array called foo that contains the values of all form elements named foo[] in the HTML form.Answers A, B, and D are incorrect because any subsequent form elements of the same name will overwrite the value in previous elements. 6. Which of the following functions can be used to sort an array by its keys in descending order? A. sort B. rsort C. ksort D. krsort E. reverse_sort D is correct.The sort() and rsort() functions operate on values, whereas ksort() sorts in ascending order and reverse_sort() is not a PHP function. SMS, MMS, Modems, Gateways 1. What does the abbreviation “SIM” stand for? (1 mark) 2. Name any 2 functions of the SIM card. (2 marks) 3. Name and briefly explain any two types of interactions between the SIM Application Toolkit and the Mobile Handset. (4 marks) 4. Give any 2 drawbacks of downloading applications onto the SIM. (2 marks) 5, What is the purpose of the microbrowser on the SIM? (2 marks) 6. What is a procactive command in the context of a SIM? (1 mark) 7. How many characters can a GSM SMS carry when using 8-bit characters? (1 mark) 9. Name the 4 layers of the SMS protocol stack. (4 marks) 10. Name any 2 drawbacks of using MMS over SMS. (2 marks) 11. In the SMPP standard, what is an outbind operation used for? (2 marks) 12. Give any 2 layers in the WAP protocol stack. (2 marks)

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