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This is a page of "How to" solve some computer problems that may happen. P = problem; S = solution #contents ** P: (2018.08.07) New Windows 10 cannot access Samba server [#g0cc2a5b] *** S: Check this answer: [#dd29725f] https://support.microsoft.com/de-ch/help/4046019/guest-access-smb2-disabled-by-default-in-windows-10-server-2016 ** P: (2016.03.10) A new FLEX user cannot receive e-mail. [#k2861b15] *** S: Don't forget to restart dovecot and postfix after creating the user [#m70339cb] $ sudo service dovecot restart $ sudo service postfix restart ** P: (2015.08.06) Sometimes CPU RAM disc is occupied by unused memory and it isn't deleted or moved automatically. (Particularly in the case we calculated by Quantum espresso in local disc.) [#jdc235c1] *** S: We can free up by following command. [#l5bf5994] We can check our current memory usage using this command: $ watch -n 1 free -m or $ watch -n 1 cat /proc/meminfo We can free up unused memory under Ubuntu/Linux Mint using this command: $ sudo sysctl -w vm.drop_caches=3 or $ sudo sync && echo 3 | sudo tee /proc/sys/vm/drop_caches Please check this site, too: http://www.upubuntu.com/2013/01/how-to-free-up-unused-memory-in.html ** P: (2014.10.17) SSH Error with GSSAPI unsupported options [#dcdad085] When we login to TUBE systems, the following message appears: /etc/ssh/ssh_config line 53: Unsupported option "gssapiauthentication" /etc/ssh/ssh_config line 54: Unsupported option "gssapidelegatecredentials" *** S: Modify /etc/ssh/ssh_config of FLEX [#aa42db8a] Give comment sign to the following lines (or remove them completely) # GSSAPIAuthentication yes # GSSAPIDelegateCredentials no Try again to login to TUBE systems. ** P: (2014.10.14) HTML helper mode by emacs does not work for updating the timestamp [#cd3ed372] *** S: The hhmts code should be in one line and with a proper spacing in order for emacs to change the HTML time-stamp automatically. [#y6963d13] Therefore, <!-- hhmts start --> Last modified: Tue Oct 14 16:58:36 JST 2014 <!-- hhmts end --> is a CORRECT syntax. But: <!-- hhmts start --> Last modified: Tue Oct 14 16:58:36 JST 2014 <!-- hhmts end --> is a FALSE syntax. ** P: (2014.8.22) DVI file does not show figures after compiling latex files. [#sd09166d] *** S: Do not use any additional option in graphicx package [#o987b86d] - In the past, people usually add: \usepackage[dvipdfmx]{graphicx} - In the current latex system, excluding any options is sufficient: \usepackage{graphicx} ** P: (2014.8.20) Thunderbird connection to flex does not work. [#x6f6c6f9] *** S: Edit /etc/dovecot/conf.d/20-imap.conf [#ve3be4db] add mail_max_userip_connections = 10 and then sudo service dovecot restart ** P: (2014.8.19) NFS in new FLEX Ubuntu 14.04 is very slow [#dc220b13] *** S: This is a known bug for the latest ubuntu. We should fix nfs-common and blacklist kerberos configuration. [#o465c4f7] - In /etc/default/nfs-common: NEED_GSSD="" should be modified to be NEED_GSSD=yes - In /etc/modprobe.d/blacklist.conf add the following line # Blacklist rpcsec_gss_krb5 kernel module; needed for quick NFSv4 mounts blacklist rpcsec_gss_krb5 - Restart nfs daemon: $ sudo service nfs-kernel-server restart Check also this reference: https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/1270445 ** P: (2014.8.18) Samba sever cannot be accessed in the new FLEX (Ubuntu 14.04) [#y2761e31] *** S: We found that the location of passdb.tdb should be different to the old FLEX [#k99e6bbb] - In old FLEX, passdb.tdb is put under /var/lib/samba/passdb.tdb - In new FLEX, passdb.tdb should instead be put under /var/lib/samba/private/passdb.tdb - After putting passdb.tdb in the correct location, don't forget to restart the samba services: # sudo service smbd restart # sudo service nmbd restart ** P: (2014.8.14) E-mail sent through aliasing system (all, slab, etc) always repeats itself around every half an hour [#tb401f0d] *** S: Check the routing policy is correct [#n8662d9c] - Check /etc/hosts is set correctly - Execute again /root/flexroute.sh on old FLEX and /root/tuberoute.sh on new FLEX - If the problem still exists, restart both old FLEX and new FLEX and execute again above scripts. - Make sure other computers do not share the same hostname. ** P: (2014.8.13) Evince does not work well on Ubuntu 14.02 [#j6d6a1a5] *** S: Do the following way[#y4f17e9c] sudo ln -s /etc/apparmor.d/usr.bin.evince /etc/apparmor.d/disable sudo /etc/init.d/apparmor restart and add export NO_AT_BRIDGE=1 to /etc/environment ** P: (2014.8.13) How to change mouse focusing policy. [#td824c72] *** S: System --> Preferences --> Window then find a panel "Behaviour" and click: "Select windows when the mouse moves over them" [#p7f69563] ** P: (2014.8.13) How to change desktop language [#je602ad6] *** S: - for all users: edit /etc/default/locale and add: [#w3261038] LANG = "ja_JP.UTF-8" I've done this for new FLEX - for a particular user (corresponding user should do by himself): edit ~/.dmrc and add under [Desktop] section: Language="ja_JP.UTF-8" (If we want English, just change above line by Language="en_US.UTF-8") [#t91ab972] ** P: How to zip-file in win8.1 with password which is compatible with all users unzip programs: [#n48b5a05] *** S: Download and install 7-zip[#w6e3f853] 1. Download the 7-zip installer for your computer from www.7-zip.org. Run the program and install 7-zip to your computer. 2. Choosing your files. 3. Right-click on items and choosing 7-Zip, then Add to archive. 4. choose your format from Archive format `zip`. 5. Enter password. 6. Finally, OK to create the compressed archive. ** P: (2014.08.04) FLEX can be accessed from Xlaunch (local), but global component such as website and e-mail seem doesn't work [#iptable] *** S: If you have such a symptom, probably iptable was accidentally modified. We should recover the routing rule to a normal way. [#iptablesol] - Run the following script: $ sudo /root/route4flex.sh ** P: (2014.07.24) Xming is no longer good for Windows 8.1 [#xming] *** S: Install Vcxsrv, which is a clone of Xming, and remove Xming itself. [#xmingsol] - Download Vcxsrv from the following: http://sourceforge.net/projects/vcxsrv/files/latest/download?source=files - After installation, do these steps: -- Open Xlaunch. -- Choose "One large window" and press Next. -- Select "Open sesson via xdmcp" and press Next. -- Connect to host: 172.17.4.135 and press Next. -- Give the following additional parameters for Vcxsrv: -from <your_working_ip_address> for example (please change the address, the following is Nugraha's example): -from 172.17.4.181 -- Push Next button, Save Configuration, and Finish. ** P: (2014.01.17) NIS in tube 60 does not work, although NFS works [#f406f2e1] *** S: Activate ypbind with the following command [#ud86344d] # sysv-rc-conf ypbind on # reboot ** P: (2013.10.24) X-windows does not work, cannot connect to Flex using X-windows (Xming, NX, etc.) [#ad84a9d5] *** S: restart X-windows service in Flex [#lbe3cf63] #sudo service lightdm restart ** P:(2013.08.26) E-mail does not work after shutting down the Flex [#k721797e] *** S: restart dovecot and postfix [#ecca53b8] #service dovecot start #service dovecot stop #service dovecot restart #sudo /etc/init.d/postfix restart ** P:(2013.06.05) how to customize GDM login screen [#h77ecb82] *** S: using ubuntu-tweak [#ha11b2d2] Install ubuntu-tweak #sudo add-apt-repository ppa:tualatrix/ppa #sudo apt-get update #sudo apt-get install ubuntu-tweak Launch ubuntu-tweak from terminal and customize the login screen ** P: (2013.06.03) xdvi doesn't put period and comma correctly when reading Japanese documents. [#s135a004] *** S: Check a tutorial created by other people [#p867b0fd] http://d.hatena.ne.jp/tama_sh/20120505/1336197629 Install xdvi-ja # apt-get install xdvik-ja Font map file: /etc/texmf/vfontmap.d/ Do the following: # cd /etc/texmf/vfontmap.d/ # mv 20ptex-jisfonts.map 20ptex-jisfonts.map.org # mv 20xdvik-ja.map 20xdvik-ja.map.org # mv 30morisawa.map. 30morisawa.map.org Next, check the fc-list the name of the Japanese font to use. $ fc-list | grep Takao Takao P??,TakaoPMincho:style=Regular Takao????,TakaoGothic:style=Regular Takao P????,TakaoPGothic:style=Regular TakaoEx????,TakaoExGothic:style=Regular TakaoEx??,TakaoExMincho:style=Regular Takao??,TakaoMincho:style=Regular Add the following lines to a file takao.map (create new if not exist) under the directory /etc/texmf/vfontmap.d/ @TakaoMincho-Regular@ rml JIS-H % ASCII pTeX rmlv JIS-V % ASCII pTeX dm JIS-H % NTT jTeX rml-jis JIS-H % ptex-jisfonts @TakaoGothic-Recular@ gbm JIS-H % ASCII pTeX gbmv JIS-V % ASCII pTeX dg JIS-H % NTT jTeX gbm-jis JIS-H % ptex-jisfonts Finally, update the registration information of the font # update-vfontmap ** P: (2012.10.02) How to remove Ubuntu welcome notes [#m70a5bf7] Welcome to Ubuntu 11.10 (GNU/Linux 3.0.0-25-generic x86_64) * Documentation: https://help.ubuntu.com/ New release '12.04 LTS' available. Run 'do-release-upgrade' to upgrade to it. *** System restart required *** *** S: Please check /etc/update-motd.d/ folder [#l0d990ed] Then change the permission sudo chmod 600 * ** P: (2012.09.26) Warning: File `Makefile' has modification time 38 s in the future [#ycb06c28] warning: Clock skew detected. Your build may be incomplete. Such warning appears in TUBE50 ***S: TUBE50 clock is not synchronized to ntp.tohoku.ac.jp [#j265a3b5] - [[Download ntp:http://howto.eyeoncomputers.com/ubuntu/install-ntp/]] - Configure ntp by folowing [[this step:http://flex.phys.tohoku.ac.jp/english/pukiwiki-e/index.php?Computer%20Problem-Solution%20%28Open%29#p100119]] ** P: (2012.09.25)"yes" command appears every time we restart TUBE50 [#p20120925] *** S: check file /etc/default/nfs-common [#s20120925] - before: NEED_IDMAPD= yes - after: NEED_IDMAPD=yes important to note: <space> has meaning to separate the variable in sh script. ** P: (2012.08.29) Changing default text editor [#vf206db3] *** S: run this command: [#p639256c] sudo update-alternatives --config editor ** P: (2012.03.29) Segmentation fault when login tube [#j9c1a221] *** S: run this command /rsaito/bin/no-passwd [#d2e289e1] Then press Enter anytime the statement appears ** P: (2010.04.29) set-pathname-coding-system function does not exists in new xemacs lisp which existed in flex. [#t79f4d54] ** P: (2010.01.19) Managing ntp [#p100119] *** S: ntp and ntpdate package have to be configured in some tricky ways [#s100119] - ntp.conf file [root@tube40 ~]# emacs /etc/ntp.conf The /etc/ntp.conf file is the main configuration file for Linux NTP in which we place the IP addresses of the servers we want to use. Here we only use one server: server ntp.tohoku.ac.jp # A stratum 1 server at tohoku.ac.jp #server ntp.redhat.com # A stratum 2 server at redhat.com We have to restart the NTP process every time we make a change to the configuration file for the changes to take effect on the running process. - To get NTP configured to start at boot, use the line: [root@tube40 ~]# chkconfig ntpd on - To start, stop and restart NTP after booting, follow these examples: [root@tube40 ~]# /etc/init.d/ntpd start [root@tube40 ~]# /etc/init.d/ntpd stop [root@tube40 ~]# /etc/init.d/ntpd restart - For the synchronization, ntpd should be stopped and ntpdate should be run at least three times, then ntpd can be run again: [root@tube40 ~]# /etc/init.d/ntpd stop Shutting down ntpd: [ OK ] [root@tube40 ~]# /usr/sbin/ntpdate -u ntp.tohoku.ac.jp 19 Jan 16:11:08 ntpdate[23079]: adjust time server 130.34.11.117 offset 0.016601 sec [root@tube40 ~]# /usr/sbin/ntpdate -u ntp.tohoku.ac.jp 19 Jan 16:11:09 ntpdate[23080]: adjust time server 130.34.11.117 offset 0.015737 sec [root@tube40 ~]# /usr/sbin/ntpdate -u ntp.tohoku.ac.jp 19 Jan 16:11:13 ntpdate[23081]: adjust time server 130.34.11.117 offset 0.014081 sec [root@tube40 ~]# /etc/init.d/ntpd start Starting ntpd: [ OK ] ** P: (2010.01.13) The problem of 2010.1.6 is solved but response is slow. [#cc7513d1] *** S: The problem is due to the fact that /etc/mtab is on root (not snapshot) [#j127f4e3] Since we do not know what is the process of mount the file. we can not change mtab to snapshot. For a moment, we force mount /home1 and /rsaito on /tmp/home1, /tmp/rsaito /etc/rc5.d/S28autofs stop mkdir /tmp/home1 mkdir /tmp/rsaito mount -n 192.168.2.100:/home1 /tmp/home1 mount -n 192.168.2.100:/rsaito /tmp/rsaito df /rsaito/bin/pxe-mount ** P: (2010.1.6) /rsaito is not automountd on PXE client. [#m92944ad] *** S: edit and add flexS:/rsaito information on [#q5d5939e] tube30:/nfsboot/root/etc/mtab ** P: (2009.10.10) Gnorm logout is slow for Xming etc. [#y54d795e] This is a firewall problem of windows. *** S: Open port 16001 tcp [#c4bf3cc3] control panel -> firewall -> add new port -> Name Esound Port 16001 TCP ** P: (2009.07.17) Load average of FLEX is very high. [#ba0d0fa4] This is due to mounting problem again (mount NFS). After checking mount status, it is found that a network harddisk was not unmounted nicely before turning off. *** S: Re-mount (turn on) the harddisk, and do some safety procedure. [#l1c8b137] - check mount status: # mount - umount once (assuming mount point is /mnt/backup): # umount -f /mnt/backup - synchronize several times: # sync # sync # sync - check df or mount status again - if the harddisk has been nicely unmounted, then it is safe to turn it off. ** P: (2009.07.02) Flex is unstable for logining or e-mails. [#ac90f02f] *** S: mount to tube:/home1-old was not allowed any more. [#e2a3634b] comment out one line in /etc/auto.misc # home1 172.17.4.134:/home1-old ./S28autofs forcerestart I also delete in /etc/exports the requests from 172.17.4.184 (nuguraha) 172.17.4.188 (mahabubu) and 172.17.4.127 (furu). exportfs -a we also need to restart nfs /etc/rc5.d/S60nfs restart ** P: (2009.06.03) Today we were failed to run ether-wake command on new-PXE server/client machines using new Hub/router. [#m53007b8] *** S: We manually turn those on and off. After that ether-wake (wake-on-Lan) command was successful. [#a08cf22e] ** P: PXE (network boot) is now installing 2009.5.1 [#e8f71204] *** S: finished. status [[PXE Server (Open)]] [#p74ace39] ** P: We move /etc/passwd then we can not be root. No more even shutdown. [#oaefbc51] *** S: cntl-alt-del and reboot. Then when OS selection, push any arrow. [#v36584e8] Then many selection of OS appears. Select one of OS, and press E. Then select kernel and press E again. Then you can edit the command for starting kernel and add "single" in the last of the command. Finally select "b" for booting and single user mode appears. Make /etc/passwd files and exit and runlevel 5 is recovers. Even if we used NIS, we should not delete /etc/passwd /etc/group and /etc/shadow. ** P: linux emacs ispell error (no language "eu") 2009.4.24 [#xf61128d] *** S: solved. "M-x ispell-change-dictionary" and select english [#t33f8f93] *** S: solved. Edit .emacs to add (setq ispell-dictionary "english") [#l1a50648] ** P: How to update the files of remote to the files of local [#lb59159d] *** S: solved. "rsync -avc -e ssh saito@remote:/home/saito/book09/ /rsaito/book09"[#f25e1654]
