Since some time, I don’t know exactly where, after some updates of my WordPress running on a small server with FreeBSD 7.2. I’ve started getting a lot of Apache crashes. Often the wordpress scripts stopped working completely and I got only empty pages when trying to process the wordpress blog in a browser.
After a bunch of reading online, I’ve figured out that the cause might be PHP APC stands for Alternative PHP Cache .
I was not sure if the PHP running on the server had an APC configured at all so I used a phpinfo(); script to figure out if I had it loaded. I saw the APC among the loaded to show off in the list of loaded php modules, so this further led me to the idea the APC could be really causing the unexpected troubles.
Thus first I decided to disable the APC on a Virtualhost level for the domain where the crashing wordpress was hosted, to do I placed in the VirtualHost section in the Apache configuration /usr/local/etc/apache2/httpd.conf the following config directive:
php_flag apc.cache_by_default Off
These get me rid of the multiple errors:
PHP Warning: require_once() [function.require-once]: Unable to allocate memory for pool. in /usr/local/www/data-dist/blog/wp-content/plugins/tweet-old-post/top-admin.php on line 6
which constantly were re-occuring in php_error.log:
Further after evaluating all the websites hosted on the server and making sure none of which was really depending on APC , I’ve disabled the APC completely for PHP. To do so I issued:
echo 'apc.enabled = 0' >> /usr/local/etc/php.ini
Similarly on GNU/Linux to disable globally APC from PHP only the correct location to php.ini should be provided on Debian this is /etc/php5/apache2/php.ini .
On FreeBSD ntpd , ntpdc , ntpdate , ntpq doesn't need to be installed via a specific package like on GNU/Linux as they're part of the FreeBSD world (binary standardly shipped with FreeBSD basis system).
No need for any modifications if you don't want to apply some specific restrictions on whom can access the ntpd server. If you update regularly the FreeBSD system with freebsd-update or directly by rebuilding the FreeBSD kernel / world adding restrictions might be not necessery..
If you check /usr/src/etc/ntp.conf you will notice freebsd project people are running their own ntp servers , by default ntpd will use this servers to fetch timing information. The exact server hosts which as of time of writting are used can be seen in ntp.conf and are:
server 0.freebsd.pool.ntp.org iburst maxpoll 9
server 1.freebsd.pool.ntp.org iburst maxpoll 9
server 2.freebsd.pool.ntp.org iburst maxpoll 9
2. Add ntpd daemon to load on system boot via /etc/rc.conf
By default ntpd is disabled on FreeBSD, you can see if it is disabled or enabled by invoking:
Now as the 3 rc.conf vars are set to "YES", the ntpd can be started. Without having this variables in /etc/rc.conf , "/etc/rc.d/ntpd start" will refuse to start ntpd.
3. Start the ntpd service
freebsd# /etc/rc.d/ntpd start
...
One interesting note to make is ntpd can also operate without specifying any config file (/etc/ntp.conf), the only requirement for the server to start is to have a properly set ntpdate server, like lets say (ntpdate_flags="europe.pool.ntp.org")
4. Permit only certain host or localhost to "talk" to the ntpd server
If you want to imply some ntp server restrictions, the configuration directives are same like on Linux:
To allow only a a host inside a local network with IP 192.168.0.2 as well as localhost, to be able to fetch time information via ntpd server put inside /etc/ntp.conf:
If you want to prohibit ntpd to serve as a Network Time Server, to any other host except localhost, add in /etc/ntp.conf :
restrict default ignore
Allowing and denying certain hosts can be also done on pf (packet filter) or ipfw firewall level, and in my view is easier (and less confusing), than adding restrictions through ntp.conf. Besides that using directly the server firewall to apply restrictions is more secure. If for instance a remote exploit vulnerability is discovered affecting your ntpd server. this will not affect you externally as access to the UDP port 123 will be disabled on a firewall level. Something good to mention is NTP servers communicate between each other using the UDP source/destination (port 123). Hence if the NTPD server has to be publicly accessible and there is a firewall already implemented, access to source/dest port 123 should be included in the configured firewall …
5. Check if the ntp server is running properly / ntp server query operations
To query the now running ntpd server as well as set various configuration options "on the fly" (e.g. without need for ntp.conf edits and init script restart), a tool called ntpdc exists. ntpdc tool could be used to connect to localhost running ntpd as well as to connect and manage remotely a ntpd server. The most basic use of ntpdc is to check (server peers).: freebsd# ntpdc localhost
ntpdc> peers
remote local st poll reach delay offset disp
===================================================
ntpdc has also a non-interactive interface, handy if there is a need for requests to a ntpd to be scripted. To check ntpd server peers non-interactively:
ntpdc is an advanced query tool for ntpd , servers. Another tool exists called ntpq which syntax is almost identical to ntpdc . The main difference between the two is ntpq is a monitoring tool mostly used just for monitoring purposes, where ntpdc can also change plenty of things in the server configuration.
For people who want to learn more on ntpd the man page is a great reading , containing chapters describing thoroughfully exactly how NTPD time servers operate, etc.
Every now and then I have to work on servers running CentOS or Fedora Linux. Very typical problem that I observe on many servers which I have to inherit is the previous administrator did not know about the existence of NTP (Network Time Protocol) or forgot to install the ntpd server. As a consequence the many installed server services did not have a correct clock and at some specific cases this caused issues for web applications running on the server or any CMS installed etc.
The NTP Daemon is existing in GNU / linux since the early days of Linux and it served quite well so far. The NTP protocol has been used since the early days of the internet and for centuries is a standard protocol for BSD UNIX.
ntp is available in I believe all Linux distributions directly as a precompiled binary and can be installed on Fedora, CentOS with:
[root@centos ~]# yum install ntp
ntpd synchronizes the server clock with one of the /etc/ntp.conf defined RedHat NTP list
server 0.rhel.pool.ntp.org
server 1.rhel.pool.ntp.org
server 2.rhel.pool.ntp.org
To Synchronize manually the server system clock the ntp CentOS rpm package contains a tool called ntpdate : Hence its a good practice to use ntpdate to synchronize the local server time with a internet server, the way I prefer to do this is via a government owned ntp server time.nist.gov, e.g.
[root@centos ~]# ntpdate time.nist.gov
8 Feb 14:21:03 ntpdate[9855]: adjust time server 192.43.244.18 offset -0.003770 sec
Alternatively if you prefer to use one of the redhat servers use:
[root@centos ~]# ntpdate 0.rhel.pool.ntp.org
8 Feb 14:20:41 ntpdate[9841]: adjust time server 72.26.198.240 offset 0.005671 sec
Now as the system time is set to a correct time via the ntp server, the ntp server is to be launched:
[root@centos ~]# /etc/init.d/ntpd start
...
To permanently enable the ntpd service to start up in boot time issue also:
[root@centos ~]# chkconfig ntpd on
Using chkconfig and /etc/init.d/ntpd cmds, makes the ntp server to run permanently via the ntpd daemon:
If you prefer to synchronize periodically the system clock instead of running permanently a network server listening (for increased security), you should omit the above chkconfig ntpd on and /etc/init.d/ntpd start commands and instead set in root crontab the time to get synchronize lets say every 30 minutes, like so:
The time synchronization via crontab can be also done using the ntpdate cmd. For example if you want to synchronize the server system clock with a network server every 5 minutes:
ntp package is equipped with ntpq – Standard NTP Query Program. To get very basic stats for the running ntpd daemon use:
[root@centos ~]# ntpq -p
remote refid st t when poll reach delay offset jitter
======================================================
B1-66ER.matrix. 192.43.244.18 2 u 47 64 17 149.280 41.455 11.297
*ponderosa.piney 209.51.161.238 2 u 27 64 37 126.933 32.149 8.382
www2.bitvector. 132.163.4.103 2 u 1 64 37 202.433 12.994 13.999
LOCAL(0) .LOCL. 10 l 24 64 37 0.000 0.000 0.001
The remote field shows the servers to which currently the ntpd service is connected. This IPs are the servers which ntp uses to synchronize the local system server clock. when field shows when last the system was synchronized by the remote time server and the rest is statistical info about connection quality etc.
If the ntp server is to be run in daemon mode (ntpd to be running in the background). Its a good idea to allow ntp connections from the local network and filter incoming connections to port num 123 in /etc/sysconfig/iptables :
-A INPUT -s 192.168.1.0/24 -m state --state NEW -p udp --dport 123 -j ACCEPT
-A INPUT -s 127.0.0.1 -m state --state NEW -p udp --dport 123 -j ACCEPT
-A INPUT -s 0.0.0.0 -m state --state NEW -p udp --dport 123 -j DROP
Restrictions on which IPs can be connected to the ntp server can also be implied on a ntpd level through /etc/ntp.conf. For example if you would like to add the local network IPs range 192.168.0.1/24 to access ntpd, in ntpd.conf should be added policy:
# Hosts on local network are less restricted.
restrict 192.168.0.1 mask 255.255.255.0 nomodify notrap
To deny all access to any machine to the ntpd server add in /etc/ntp.conf:
restrict default ignore
After making any changes to ntp.conf , a server restart is required to load the new config settings, e.g.:
[root@centos ~]# /sbin/service ntpd restart
In most cases I think it is better to imply restrictions on a iptables (firewall) level instead of bothering change the default ntp.conf
Once ntpd is running as daemon, the server listens for UDP connections on udp port 123, to see it use:
r freedomYesterday silently with zero publicity, Bulgarian representatives ratified the ACTA (Trade agreement for fighting counterfeit.) The name sounds really good, but it has not much to do with what ACTA is about, when applied to digital medias and data sharing. The ACTA legislation has been ratified in Tokyo last week, where 22 of the European Union membership countries signed in favour of these "malicious" treaty.
The basic idea of ACTA looks tempting as it gives more freedoms to copyright holders, however if you look closely you will understand actually this copyright infringement clauses are not so in favour of us the users but mostly in favour of multinational corporations. For all those who have not heard about ACTA and SOPA in short this is anti freedom of speech treaty, which if put in action could lead to serious filtering of the internet. The ACTA 's controversial treaty has already raised an outcry from dozens of computer literated individuals who daily use the internet. Unfortunately, ACTA is less known among non-tech guys … and hence most people on the internet have no about its existence.
If ACTA is ratified and set to be valid as a legislation to Bulgaria, this could lead to total Internet censorship in BG (more or less like it is in china now). ACTA legislation will make sharing files via torrents and other P2P community file sharing networks a criminal activity. Another effect of ACTA is that practically free software which reads a proprietary formats like DVD becomes illegal in Europe (like it is currently in America) and I will become guilty for just reading the non-free format.. As a result of ACTA our ISP (Internet Service Providers) will be forced to log and keep all traffic flowing through their (Routering servers). Filters on a local ISP level that will be censoring free speech could also become totally lawful… Already there are plenty of ANTI-ACTA and ANTI-SOPA propaganda website which are trying to bring some more awareness to the public for the issue… Once an individual is suspected, to fraudulent activity or anything that breaks what is in ACTA is he is presumed to be guilty of crome … Just watch the two videos below and you will see how terrible the consequence could be if this legislation is integrated with todays Bulgarian government laws. If you're hearing for ACTA for a first time and you live in a country which has still not rafitied ACTA as a local country legislation, make sure you spread the word and let all your friends about the bad impact of this anti-human legislation. We have to really stand up and protest to retain our digital freedom !
The Internet can be censored if Protect IP ACT (PIPA) and Stop Online Piracy Act (SOPA) are put in action !
Kraptor is another Raptor Shadow of Death free software, open source clone arcade game for GNU/Linux, DOS and Windows (98, XP etc.).
The game is not under active development anymore since 2004. Kraptor features a powerful engine for creating quickly 2D shooter games, so the game should be a good learning curve for people interested into creation of arcade game shooter games.
The game just like Rafkill is built upon DUMB sound engine. The game intro is quite entertaining 😉 The intro plays one by one the text:
Near Future:
Blobalization
Imperalizm
Corporations
Megalomaniacs
Money and Power. Slaves of the New Millenium!
After years of oppression, the slaved people of the world have raised against their masters. You, has a mercenary pilot, has been
contacted by the popular rebellion to fight against the forces of oppression.
In the morning, you jump into your cockpit and start up the engines. It's time to get airborne and start the attack. Get ready to
scramble the scum hired by the masters. Murder for freedom is the only way, you're on a mission, don't defraud us...
Like Rafkill, Kraptor is one man masterpiece created by a free software Argentinean geek known under the Kronoman artistic pseudonim. The game is really incredible for a one man work … a true masterpiece. The game is licensed under MIT License.
Even though Kraptor is older game than Rafkill, the design is more resembling the original Raptor game. The game music is high quality stereo. Besides that music and fx sound effects are quite awesome. After each level you have a Raptor like weapons "blackmarket", where you can buy new weapons, recharge ship energy, upgrade ship etc. The blackmarket implementation part of the game is probably the worst moment in the game along with the game menus (in my view). Talking about graphics Kraptor supports really high number of resolutions ranging from 320×240 to 1280×1024! 640×480 is the standard resolution in which the game is running.
Something I really like in the game is the number of multiple weapons your ship uses during play. Even if played in Easy mode it is taught.
There are game Saves after each level, so thanksfully you don't have to start again from zero once death. At the end of each level there is a huge bad BOSS you have to destroy ;).
Installing Kraptor on Debian / Ubuntu and deb derivatives is with:
debian:~# apt-get install kraptor
On most rpm based Linux distributions, you can install the game by converting the deb package to rpm with alien or by building from source from Kraptor's sourceforge page
Its interesting the game name e.g. Kraptor is also a death / grind metal band name, (Maybe Kronoman is metalhead big fan of Kraptor and that's how he came up with the playful name. For all the old school game addicts there is the joystick support. I've tested it with my Genius analogous joystick and it works fine.
The game is lacking .desktop gnome definition and after once installed it only appears through Debian (section) GNOME menus and not in Applications -> Games :
Applications -> Debian -> Games -&act; Action -&t; Kraptor
Just like Rafkill on Debian the game exacutable binary is located in /usr/games/kraptor . Also like with the Rafkill case when launched the game has troubles with choppy sound and music caused by the stupid buggy! pulseaudio
Analogously like with Rafkill's case, the work around to the problematic music en sound is to use a little bash shell script like:
All the old school raptor addicts will be interested to hear Kazzmir (Jon Rafkind) a free software devotee developer has created a small game resembling many aspects of the original Raptor arcade game. The game is called Rafkill and is aimed to be a sort of Raptor like fork/clone. Originally the game was also named Raptor like the DOS game, however in year 2006 it was changed to current Rafkill in order to avoid legal issues with Apogee's Raptor.
The game is not anymore in active development, the latest Rafkill release is from January 2007, anyhow even for the 2012 it is pretty entertaining. The sound and music are on a good level for a Linux / BSD shoot'em'up free software game . The graphics are not of a top quality and are too childish, but this is normal, since the game is just one man masterpiece.
Rafkill is developed in C/C++ programming language, the game music engine it uses is called DUMB (Dynamic Universal Bibliotheque). By the way DUMB library is used for music engine in many Linux arcade games. DUMB allows the Linux game developer to develop his game and play a music files within different game levels in "tracked" formats like mod, s3m, xm etc.
The game is available in compiled form for almost all existent GNU/Linux distributions, as well as one can easily port it as it is open source.
To install Rafkill on Debian, Ubuntu, Xubuntu and Linux Mint en other Debian based distros
root@debian:~# apt-get install rafkill
Installing on Fedora and other rpm based is with yum
debian:~# apt-get install rafkill
...
Once rafkill is installed, in order to start it on Debian the only way is using the rafkill (/usr/bin/rafkill) command. It appears the deb package maintainer did not wrote a gnome launcher file like for example /usr/share/applications/rafkill.desktop Just to explain for all the GNOME noobs, the .desktop files are a description file GNOME reads in order to understand where exactly to place certain application in the (Gnome Applications, Places, System …) menu panel.
Even though it miss the .desktop, it is launchable via Applications menu under the Debian section e.g. to open it from the GNOME menus you will have to navigate to:
Applications -> Debian -> Games -> Action -> Rafkill
This "shortcut" to launch the game is quite long and hard to remember thus it is handy to directly launch it via xterm:
hipo@debian:~$ rafkill
or by pressing ALT+F2 and typing rafkill :
Starting the game I got some really ugly choppy music / sound issues. My guess was the fizzling sounds were caused by some bug with the sound portions streamed through pulseaudiosound system. To test if my presume is correct, stopped pulseaudio and launched rafkill once again:
This way the game was counting on ALSA to process sound en the sound was playing perfectly fine.
I solved this problem through small wrapper shell script. The script did kill pulseaudio before launching rafkill and that way solve gchoppy sound issues, once the game execution is over the script starts pulseaudio again in order to prevent all other applications working with pulseaudio.
Finally, I've placed the executable script in /usr/bin/rafkill :
Interesting in Ubuntu Linux, rafkill music is okay and I suppose the bug is also solved in newer Linux distributions based on Ubuntu. Probably the Debian Squeeze pulseaudio (0.9.21-4) package version has a bug or smth..
After the change the game music will be playing fine and the game experience is cooler. The game is hard to play. Its really nice the game has game Saves, so once you die you don't have to start from level 1.
I've seen rafkill rolling around on freebsd.org ftps under the ubuntu packages pool, which means rafkill could probably be played easily on FreeBSD and other BSDs.
Acid3 Test is a group of browser compitability tests. Acid3 test is a good indicator on how Web ready is your browser.
Acidtest is part of the web standards project. Latest Firefox 9.0.1 passes the test on 100% (100/100). I've tried it with Epiphany and it scored only 67/100, still I'm using Epiphany on daily basis and I'm quite happy with it. The tests involved are testing browser for:
DOM
DOM2
Checks on HTML tables and forms browser rendering
SVG compitability testing
DOM1 and DOM2 compitability
Various ECMA Script Javascript compitability tests
Unicode (UTF-16 and UTF-8) browser compitability
XHML, SMIL, CSS, HTML compitability
Content-type image/png, text plain etc.
The Acid3 test is written itself in Javascript. It consists of 6 testing "stages" (buckets) upon which the browser tested is evaluated. Each of the test is represented visually by a rectangle. If the a test stage is passed you see a new rectangle appearing in the tested browser. In wikipedia, there is a thorough list with web browsers by type and engine and the level of support for the Acid3 test. The test is of great use if you're web developer.
I needed a G/Linux distribution that will work fine on an old PC with hardware configuration:
guest@xubuntu-desktop:~$ grep -i cpu /proc/cpuinfo; free -m; df -h
cpu family : 6
cpu MHz : 797.613cpuid level : 2
total used free shared buffers cachedMem: 497 470 26 0 35 259-/+ buffers/cache: 176 321Swap: 1454 10 1444File System Size Used Free % Mounted on
/dev/sda1 37G 4,3G 31G 13% /
I've read a lot on the internet and come to the conclusion I have basicly two popular Linux distros as option to install on archaic x86 hardware:
1. Puppy Linux 2. Xubuntu Linux
I first give Puppy Linux a try. It worked quite nice, but the interface was too old school and the desktop felt like a bit out-dated. Besides that many of the Puppy Linux shipped programs were not a mainstream programs available across most of the other Linux distributions.
Many of the programs shipped with Puppy are great, but more suitable for a computer geek than for a Windows accustomed GUI user.
My opinion on Puppy (from what I've seen) is that its great distro for old school hardcore Linux users. Anyways its not suitable for absolutely "uniniated" users who encounter Linux for a first time.
Secondly I installed Xubuntu. Most of the archaic hardware on the PC was detected during install time (a pleasently surprise). Xubunto works fast and Xfce menus opens "light fast" as on the old 800Mhz pc with 512 mem of ram. Generally the GUI worked quick and responsive. To conclude I liked Xubuntu a lot and I strongly recommend it to anyone who want to quickly roll on Linux on an old PC.
What impressed me most is the minimalistic look & feel and simplicity.
I'm sure Debian will be working great on old hardware as well, however configuring it will be hell a lot of work. Thus I think Xubuntu is a good choice for people who want save some time in obscure configurations and easily have a neat Linux ready for desktop use.
I always love so much to go back to the times, when games were games and people had still valued words like moral and respect. In that great days of old school computing, we used to play the awesome old schools Tyrian and the Nintendo 1941 game (hopefully some still remember).
For all who don't Tyrian is one of the best Spaceship Arcades of all times!, and especially for DOS operating system the best I've personally seen.
Recently I was checking the arcade games available for install on my Debian GNU / Linux and happily come across a game called KETM.
KETM acronym stands for the memorizable KILL EVERYTHING THAT MOVES and is free software distributed game under GPL. The original creation idea was probably to resemble the so famous in the '90s spaceshooter games.
KETM is pretty addictive just like tyrian and has santimental meaning for me since it brings me memories for my arcade gaming years 😉
The game is easy to play and has a feeling of "diversity" especially in type of weapons your ship can obtain and use against enemies.
The powerups you get is quite plenty compared to the enemy ship types you should destroy 😉 In overall the game is quite easy to play, this however is also a good thing, as you can play more smoothly without dying every few secs like it is in so many arcade games…
The game has only 4 game levels and on each level end there is a big spaceship "the boss" which is the last in line to destroy in the tradition of the 2d arcade games.
Kill Everything That Moves is available for Debian and Ubuntu as a deb installable with apt. To install the game on Debian and Ubuntu
debian:~# apt-get install ketm
...
ketm's official latest available source and binary of time of writting this article is at version 0.6 and as far as I checked it unfortunately seems like the game development is stucked and the code seems a unmaintained. I'm sure ketm has a lot of potential en hope somebody will adopt the code and will push further its development. The game runs by default in the annoying windowed mode, I don't like this so I always run it fullscreen:
debian:~# ketm -f
KETM also reminds a bit on GEKI 2 / 3, which I have previously blogged about but I found KETM to be more enjoyable than gekis. I've seen KETM has RPM ports as well so installing the game on fedora will be probably as easy as downloading the respective RPMs fulfilling the RPM package requirements and installing with rpm -i. I would be glad to hear from people who had succesfully run the game on Fedora and other RPM based Linux distributions?
The only thing that prevents the game to feel a bit more awesome (in my view) is the missing sound & music … Even though in the game settings inside the main menu there is an option for Sound On / Off the game runs by default without any sound or music (at least on my Debian). I hope you will have some fun with KETM just I like I did! 😉 Also if you haven't played Tyrian yet, then I strongly advice you download Tyrian from here and try it out with dosbox – (a dos gnu linux / bsd game emulator)
Interesting fact to mention here, while looking for the native tyrian game info , I found tyrian has an open source version under development called – OpenTyrian . I'll check the game and write on it when I have time.
I'm testing some old school arcade games, available from Debian's package repositories and quitting one of the games ended me up with a GNOME Screen Resolution of 640×480 pixels.
I wanted to revert back to the Classics resolution, so what I would normally do to do that is use >GNOME menus:
System -> Preferences -> Monitors
In that huge screen resolution on my 14 inch lenovo notebook screen, however the System menu cannot fit in 640×480 resolution. You can see the non-screen fitting System on the screenshot below:
Having this situation, I needed a way to change back to my normal daily used 1024x768px screen resolution to continue my daily work by some other way. One possible solution I thought of was Logging Off Gnome and logging again. Loggig off and log on again would usually restart the initiated GNOME session and therefore will reset the screen resolution to my default 1024×768 / 32 bit color.
Having the unobservable System gnome panel menu on my screen however made using the usual Log off procedure via System -> Log Out myusername impossible…
Another possible way to actually restart my screen and hence revert back to my original resolution is achiavable using the classical restart X server key switch CTRL + ALT + backspace (bckspc) . Though this was a possible approach to the situation, I had a bunch of programs already running on my desktop and I did not wanted to interrupt my desktop session, what I was looking for is simply change the screen resolution size .
With all said I had to look up for alternative way (preferably easy) way, to revert back my screen resolution to my desired 1024×768.
As a console guy, I was interested if there is some kind of possibility to change my GNOME resolution directly using xterm or gnome-terminal , after a bit of check up online, I've found few threads started by people who were looking just like me for a way to change GNOME / KDE screen resolution size on various distributions Linux desktops as well on Free/Net/Open/BSDs. The answer to the question on few places was the command xrandr which I had used some few years ago to initiate remote X server connections via SSH
xrandr is actually a great tool part of the x11-xserver-utils
Actually xrandr is capable of doing a few things besides setting the screen resolution size, just to name a few it supports change the screen orientation, reflection of the output of the screen, adjust brightness, set color gamma etc. etc.
It is good to mention that xrandr changes the resolution not on a GNOME level but on Xorg server level.
Using xrandr to change the screen resolution appeared to be very easy.
1. First I issued xrandr to check all the supported xrandr resolutions by my X server hipo@noah:~/Desktop$ xrandr Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192VGA1 disconnected (normal left inverted right x axis y axis)LVDS1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 304mm x 228mm 1024x768 60.0*+ 50.0 800x600 60.3 56.2 640x480 60.0 59.9 TV1 disconnected (normal left inverted right x axis y axis)hipo@noah:~/Desktop$
From the output you can see I have 3 basic resolutions configured in my Xorg, I can switch between.
2. To switch to my previous default screen resolution
hipo@noah:~/Desktop$ xrandr -s 1024x768
After using xrandr command to revert back to my default screen size, I realized there is two other (partially command line partially gui) way to change to 1024×768 pixels.3. Through launching gnome Control Center and searching for Monitors menu.
If one prefers this way he can;
i) press ALT+F2 to invoke Gnome's Run Application dialog
ii) issue gnome-control-center command:
4. By invoking gnome's Control Panel -> Monitors settings window by a command
