Saturday, March 28, 2009
Thursday, March 26, 2009
CIT 174 – Blog 8 – Week 9
The "One Laptop Per Child" or OLPC idea began in 2004.
OLPC home page: http://laptop.org/en/
The ugly, slow computer, which looked like a pop-top VW Vanagon camper, was supposed to sell for $100. Many of the larger companies rejected the feasibility of the idea. But three and a half years later the vision produced the XO, a real laptop co-developed and manufactured by the world's largest notebook maker, Quanta. Whether or not this program is successful depends on your opinion of success. The computer currently sells for a $199 donation. There are approximately three quarters of a million laptops in the hands of deserving children. The president of the company hopes to double that sometime this year. It is said that imitation is the most sincere form of flattery, if that is the case; the company has been successful in stimulating a world wide interest in "low cost" laptops.
Source:
http://www.gizmodo.com.au/2008/08/secret_origin_of_the_olpc_genius_hubris_and_the_birth_of_the_netbook-2.html
Source:
http://www.cnn.com/2009/TECH/03/05/one.laptop.per.child/index.html?eref=rss_topstories
For a few years, from PC Magazine to Fox News, the OLPC and its competitors have been making news headlines. More than 25 low-cost notebooks based on Intel's upcoming Atom processor are in the works, including models from multinational PC vendors, according to the chip maker's top executive in Asia. There are lists of low cost laptops, there are reviews of low cost laptop companies, and there are companies vying for the global market. I think the vision has strayed from the non-profit ideas of Nicholas Negroponte, OLPC's founder. The OLPC project was designed to bring educational computing to children in the developing world. Although OLPC operated a Give One Get One scheme for two weeks at the end of 2007, the XO is not currently available for the general public to buy.
Source:
http://www.cio.com/article/194200/Atom_Based_Notebooks_to_Cost_Between_US_and_
Interesting Technical Details:
The picture above is how they depict the network the computer is on.
The XO is based on the AMD Geode LX700 processor, an embedded x86 device running at 433MHz, with 1GB of flash memory and 256MB of RAM. This supports a heavily customized version of Red Hat Fedora Core 6 Linux and a custom icon-based front end called Sugar, written in Python. A suite of educational applications including graphics, music making, word processing, simple programming concepts, chat and audio/video sharing is included; all of this is open source and defiantly kid-friendly.
The screen is the stand-out technology in the XO. An ingenious mix of reflective and transmissive LCD design, it is both high resolution and high density -- 1200 by 900 pixels at 200 dots per inch (dpi) in greyscale (reflective) mode, 800 by 600 pixels at 134dpi in colour (transmissive) mode. The latter activates when you turn the backlight on and mix primary colours behind the main LCD matrix.
Source:
http://www.zdnet.com.au/reviews/hardware/laptops/soa/OLPC-XO/0,2000065761,339286725,00.htm?omnRef=1337
To add insult to injury the co-designer of the original OLPC, who left the company, now has plans for its chief competitor. Her goal is for the Pixel Qi to be as technologically and aesthetically compelling as an iPod Touch. The $75 laptops now under development by what Jepsen calls a "spinout" of the One Laptop Per Child (OLPC) project won't be "Dells on a diet," and they will definitely run Linux. But the Pixel Qi is looking at Microsoft Windows and other operating systems, too.
Source:
http://www.betanews.com/article/Former-OLPC-CTO-75-laptop-will-run-Linux-and-maybe-Windows/1200087717
Last year ASUS marketed the Eee PC as a cost-effective but well built sub-notebook (or now known as a "netbook"). The original Eee PC 700 series had shipped with Intel Celeron hardware, a solid-state drive, and a Xandros-based Linux distribution. The newer models now use Intel Diamondville-based Atom CPUs. The cost of these is around $500, much more than the OLPC computers.
Source:
http://www.phoronix.com/scan.php?page=article&item=asus_eee_901&num=2
Pictures from:
http://www.foxnews.com/story/0,2933,309204,00.html
Wednesday, March 25, 2009
Instant Chat
Information about Pidgin:
http://pidgin.im/about/
The new update released this month:
http://planet.pidgin.im/
I Love Yum !!!!
http://yum.baseurl.org/
My Linux teacher responded to this post with:
"Real women use rpm and tar and make and config.........yum is too easy!"
I know, professor, but I still love YUM !!
:-)
Thursday, March 12, 2009
CIT 174
Week 7
Chapter 7 Review Questions
1.) Name three types of remote connectivity supported by Linux and explain why one is preferred over the other two. The three programs listed are Telnet, r-utilities, and SSH. SSH is the preferred way to connect because the transferred data is encrypted.
2.) One advantage of Telnet is that (c) it can be used on many different platforms, including Linux and Windows.
3.) Name three utilities that are part of the r-utilities suite and explain what each does. The first is rsh that allows you to execute a program, rcp that allows you to copy files, and rwho that lists the users that are logged on to the remote computer.
4.) The rcp program is able to copy files between (d) any two computers that are configure to use the r-utilities programs.
5.) Name the three types of authentication that SSH can use to connect to a remote system. Which is preferred as the most secure? SSH can use r-utilities, user passwords, or public key encrypting, the later is the preferred method.
6.) Which utility is used to prepare a set of keys needed to use public key encryption within SSH? (b) ssh-keygen.
7.) Why might you need to use the -l option with the ssh command? If you have a user account on the server this option only prompts you for your password.
8.) If you use the ssh command without first creating and storing a key pair on the remote host (a) you are prompted for a password to aid authentication.
9.) If you have installed and configured r-utilities, then including a host and user name in your .rhosts file allows a person using the rcp command on another host to (a) copy files to or from your home directory without entering a password.
10.) SSH is commonly used in place of Telnet because (a) SSH provides a secure communications channel that is much more immune to security attacks.
11.) When using Telnet you might refer to VT100 because it is (c) the most commonly used terminal emulation standard.
12.) Telnet is considered dangerous because (b) It transmits data--including passwords--without encrypting them, so anyone on the network can see them by using special software.
13.) When using the wget command, you should include the http:// designation to download a Web page so that (a) the program knows which protocol to use when accessing the server.
14.) Suppose you want to mirror a Web site to your local computer in order to study the information it contains. You intend to update the mirror once each month to view changes in the Web pages on the site. You are concerned that the Web site administrator will block access if he realizes you are mirroring the entire site instead of using a regular browser to access it. In order to reduce the chance that the wget program creates suspicion, you can (c) use the --random-wait option with wget.
15.) The rsync program is best suited for (a) synchronizing collections of files such as software development files.
16.) On a publicly available anonymous FTP server, the first level subdirectory that you should go to when locating files to download is virtually always (d) /pub.
17.) A graphical FTP client can be more convenient than a text-mode FTP client such as ncftp because (b) the graphical program lets you see lists of files locally and remotely and drag and drop multiple files between systems.
18.) The ncftp package includes a utility that is similar in functionality to wget. This utility is called (a) ncftpget.
19.) If an IP address is not assigned explicitly when networking is configured, one must be obtained automatically from a server on the network using (a) DHCP.
20.) The process of resolving a domain name (b) determines the IP address associated with that domain name by contacting a DNS server.
21.) ping is used to test networking connections by (a) trying to contact systems that are progressively further from your host to see if any networking problems occur.
22.) traceroute is a useful troubleshooting tool because (c) it reports each router that a packet passes through to a remote computer, along with the time needed to reach that router.
23.) If you cannot ping a host on your local network using that system's IP address, you probably wouldn't bother checking (a) whether you could ping a host on the Internet.
24.) Which of the following is not included in the output of the traceroute command? (d) The size of the test packet sent by traceroute.
25.) A DHCP server can provide what information to a host on the network in response to a DHCP client request? (b) an IP address, a network mask, a gateway address, a DNS server address, and a host name, among other things.
Chapter 7 Review Questions
1.) Name three types of remote connectivity supported by Linux and explain why one is preferred over the other two. The three programs listed are Telnet, r-utilities, and SSH. SSH is the preferred way to connect because the transferred data is encrypted.
2.) One advantage of Telnet is that (c) it can be used on many different platforms, including Linux and Windows.
3.) Name three utilities that are part of the r-utilities suite and explain what each does. The first is rsh that allows you to execute a program, rcp that allows you to copy files, and rwho that lists the users that are logged on to the remote computer.
4.) The rcp program is able to copy files between (d) any two computers that are configure to use the r-utilities programs.
5.) Name the three types of authentication that SSH can use to connect to a remote system. Which is preferred as the most secure? SSH can use r-utilities, user passwords, or public key encrypting, the later is the preferred method.
6.) Which utility is used to prepare a set of keys needed to use public key encryption within SSH? (b) ssh-keygen.
7.) Why might you need to use the -l option with the ssh command? If you have a user account on the server this option only prompts you for your password.
8.) If you use the ssh command without first creating and storing a key pair on the remote host (a) you are prompted for a password to aid authentication.
9.) If you have installed and configured r-utilities, then including a host and user name in your .rhosts file allows a person using the rcp command on another host to (a) copy files to or from your home directory without entering a password.
10.) SSH is commonly used in place of Telnet because (a) SSH provides a secure communications channel that is much more immune to security attacks.
11.) When using Telnet you might refer to VT100 because it is (c) the most commonly used terminal emulation standard.
12.) Telnet is considered dangerous because (b) It transmits data--including passwords--without encrypting them, so anyone on the network can see them by using special software.
13.) When using the wget command, you should include the http:// designation to download a Web page so that (a) the program knows which protocol to use when accessing the server.
14.) Suppose you want to mirror a Web site to your local computer in order to study the information it contains. You intend to update the mirror once each month to view changes in the Web pages on the site. You are concerned that the Web site administrator will block access if he realizes you are mirroring the entire site instead of using a regular browser to access it. In order to reduce the chance that the wget program creates suspicion, you can (c) use the --random-wait option with wget.
15.) The rsync program is best suited for (a) synchronizing collections of files such as software development files.
16.) On a publicly available anonymous FTP server, the first level subdirectory that you should go to when locating files to download is virtually always (d) /pub.
17.) A graphical FTP client can be more convenient than a text-mode FTP client such as ncftp because (b) the graphical program lets you see lists of files locally and remotely and drag and drop multiple files between systems.
18.) The ncftp package includes a utility that is similar in functionality to wget. This utility is called (a) ncftpget.
19.) If an IP address is not assigned explicitly when networking is configured, one must be obtained automatically from a server on the network using (a) DHCP.
20.) The process of resolving a domain name (b) determines the IP address associated with that domain name by contacting a DNS server.
21.) ping is used to test networking connections by (a) trying to contact systems that are progressively further from your host to see if any networking problems occur.
22.) traceroute is a useful troubleshooting tool because (c) it reports each router that a packet passes through to a remote computer, along with the time needed to reach that router.
23.) If you cannot ping a host on your local network using that system's IP address, you probably wouldn't bother checking (a) whether you could ping a host on the Internet.
24.) Which of the following is not included in the output of the traceroute command? (d) The size of the test packet sent by traceroute.
25.) A DHCP server can provide what information to a host on the network in response to a DHCP client request? (b) an IP address, a network mask, a gateway address, a DNS server address, and a host name, among other things.
Tuesday, March 3, 2009
CIT 174
Week 6
Chapter 6 Review Questions
1. The command ps –A xo comm displays the following information (d) all processes running on the system, including those with no controlling terminal, with the command-line field displayed for each one.
2. The (a) TIME field in the ps command output defines how much cumulative CPU time a process has used since it was started.
3. The CMDLINE files of the ps command output displays (b) the command line used to start the process shown on each line.
4. Which of the following commands is invalid if run by a regular user? (a) renice -10 1035.
5. Which of these programs does not allow you to change the nice level of a running process? (b) free.
6. To update the process data displayed by the top command, you press which key? (b) spacebar.
7. Dynamically linked applications are preferred for their better memory usage unless (c) the necessary libraries to run the application are not installed on the Linux system.
8. Thrashing occurs when (a) an excessive amount of information is moved to and from the swap partition in a short time.
9. The command “vmstat 4” does which of the following? (c) displays continuous updates of the virtual memory status on a new line every four seconds.
10. How can you switch between multiple virtual consoles in text and graphical
environments? By using the Ctrl+Alt+F2 key combination.F2 to F6 are available for virtual consoles. While the graphical interface (X) runs on F7.
11. Describe at least four fields of information provided by the command “ps auxf”. The PID is the process ID, the command field tells what command began the process, the %CPU tells how much time and memory are being used by the process, and the state of the process.
12. By starting multiple jobs form one shell, you can (c) manage those jobs with the jobs, bg and fg commands.
13. Briefly explain the difference in time specification formats for the “at” and “crontab” commands. The “at” command allows you do execute a command in the future. The “crontab” command allows you to execute commands repeatedly in the future at regular intervals.
14. The background processes that manage commands submitted using at and cron are (c) atd and crond.
15. When using the at command interactively to enter commands scheduled for future execution, you indicate that you have finished entering commands by pressing (a) Clrt+d.
16. The batch command is used to schedule jobs so that (c) the system will not be overloaded with scheduled tasks.
17. A simple method for root to schedule recurring systems administrations tasks is to (b) add a script to a directory shuch as /etc/cron.daily or /etc/cron.weekly.
18. The output of a “cron” job is normally sent via email to the user who submitted the “cron” job or to the user defined by the MAILTO variable within the file containing the “cron” job.
19. Name, in order form left to right, the fields of the “crontab” time specifications, giving the range of valid numeric values for each one. Minute of the hour (0-59), Hour of the day (0-23), Day of the month (0-32), Month of the year (0-12), Day of the week (0-7).
20. Output from a command executed as part of a new “cron” job cannot be redirected to a file using standard redirection operators because the environment in which the “cron” job was created is likely to exist when the job is executed. False.
21. The /etc/cron.deny file can include a user name in order to deny that user access to the “crontab” command.
22. Name the two separate commands that can be used instead of at –l and at –d. The alternate commands for list are atq (or at –l)and for delete atrm (or at –d).
23. All processes in Linux, except the init process (PID1) are created (b) when another process forks.
24. A zombie process is one that (d) is no longer in existence, though the Linux kernel still maintains information as if it were.
25. Describe why you should try SIGTERM before using SIGKILL. SIGTERM is better because the process shuts down and saves the work in progress. Unlike SIGKILL which simply pulls the plug on the process.
Chapter 6 Review Questions
1. The command ps –A xo comm displays the following information (d) all processes running on the system, including those with no controlling terminal, with the command-line field displayed for each one.
2. The (a) TIME field in the ps command output defines how much cumulative CPU time a process has used since it was started.
3. The CMDLINE files of the ps command output displays (b) the command line used to start the process shown on each line.
4. Which of the following commands is invalid if run by a regular user? (a) renice -10 1035.
5. Which of these programs does not allow you to change the nice level of a running process? (b) free.
6. To update the process data displayed by the top command, you press which key? (b) spacebar.
7. Dynamically linked applications are preferred for their better memory usage unless (c) the necessary libraries to run the application are not installed on the Linux system.
8. Thrashing occurs when (a) an excessive amount of information is moved to and from the swap partition in a short time.
9. The command “vmstat 4” does which of the following? (c) displays continuous updates of the virtual memory status on a new line every four seconds.
10. How can you switch between multiple virtual consoles in text and graphical
environments? By using the Ctrl+Alt+F2 key combination.F2 to F6 are available for virtual consoles. While the graphical interface (X) runs on F7.
11. Describe at least four fields of information provided by the command “ps auxf”. The PID is the process ID, the command field tells what command began the process, the %CPU tells how much time and memory are being used by the process, and the state of the process.
12. By starting multiple jobs form one shell, you can (c) manage those jobs with the jobs, bg and fg commands.
13. Briefly explain the difference in time specification formats for the “at” and “crontab” commands. The “at” command allows you do execute a command in the future. The “crontab” command allows you to execute commands repeatedly in the future at regular intervals.
14. The background processes that manage commands submitted using at and cron are (c) atd and crond.
15. When using the at command interactively to enter commands scheduled for future execution, you indicate that you have finished entering commands by pressing (a) Clrt+d.
16. The batch command is used to schedule jobs so that (c) the system will not be overloaded with scheduled tasks.
17. A simple method for root to schedule recurring systems administrations tasks is to (b) add a script to a directory shuch as /etc/cron.daily or /etc/cron.weekly.
18. The output of a “cron” job is normally sent via email to the user who submitted the “cron” job or to the user defined by the MAILTO variable within the file containing the “cron” job.
19. Name, in order form left to right, the fields of the “crontab” time specifications, giving the range of valid numeric values for each one. Minute of the hour (0-59), Hour of the day (0-23), Day of the month (0-32), Month of the year (0-12), Day of the week (0-7).
20. Output from a command executed as part of a new “cron” job cannot be redirected to a file using standard redirection operators because the environment in which the “cron” job was created is likely to exist when the job is executed. False.
21. The /etc/cron.deny file can include a user name in order to deny that user access to the “crontab” command.
22. Name the two separate commands that can be used instead of at –l and at –d. The alternate commands for list are atq (or at –l)and for delete atrm (or at –d).
23. All processes in Linux, except the init process (PID1) are created (b) when another process forks.
24. A zombie process is one that (d) is no longer in existence, though the Linux kernel still maintains information as if it were.
25. Describe why you should try SIGTERM before using SIGKILL. SIGTERM is better because the process shuts down and saves the work in progress. Unlike SIGKILL which simply pulls the plug on the process.
Linux News
The freelance marketplace Odesk recently found that
Linux related jobs surged from 128 in 2006
to 2014 jobs listed in its service in 2009.
http://events.linuxfoundation.org/training
Linux related jobs surged from 128 in 2006
to 2014 jobs listed in its service in 2009.
http://events.linuxfoundation.org/training
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