- The added line is THIS COLOR.
- The deleted line is THIS COLOR.
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: PEX (network boot) is now installing 2009.5.1 [#e8f71204]
** P: PXE (network boot) is now installing 2009.5.1 [#e8f71204]
*** S: finished. status [[PXE Server (Open)]] [#p74ace39]
** P: NIS (network information services) will be moved from tube to flex 2009.5.1 [#mb7aa695]
*** S: not yet finished. status [[Network Information System]] [#t46d19f5]
----
The following problems are solved.
----
** 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: Flex was in a trouble today (2009.06.01). Problem was, we were failed to log-in to the flex. NIS is not running. Finally we solved it. See solution [#e62b9d19]
*** S: We found the graphics card is very unstable on Tube machine (172.17.4.134). May be accidentally we pull the card out and tube machine was failed to boot properly. As Flex uses NIS from Tube that is why we were unable to log on to Flex. [#l1e69691]
** 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]
![[PukiWiki]](image/c60.png "[PukiWiki]")
