As part of my daily sysadmin job I had to unlock the user of a colleague who had been locked on some obscure AIX UNIX machine. IBM AIX Operating System is used mainly for corporate crtical applications within Airports, Financial institutions Banks, U.S Army, Navy, the Stock Exchange etc.
Due to its complexity and price and the lack of people with any expertise, it is now only used for a critical businesses for its great possibilities of Native Application clustering etc.
But enough rant if you happen to come around AIX and need to reset failed login counter which is part of AIX integrated Login Security and blocks the user after a preset count number here is how.
1. Become superuser
# su – root
2. Check the number of previous unsucessful logins for the account to confirm it is blocked
# lsuser -a unsuccessful_login_count <userid>
i.e.
# lsuser -a unsuccessful_login_count hipo hipo unsuccessful_login_count=10
3. Reset unsucessful login counter
# chsec -f /etc/security/lastlog -a unsuccessful_login_count=0 -s hipo
4. Unlock the locked account
# chuser account_locked=false hipo
5. Lock account
If for some reason you need to lock some old and no longer used user (instead of completely deleting it).
7. How to reset failed login counter on RedHat / CentOS Linux
Corporate Linux distributions like RHEL / CentOS and SLES have also a similar security feature that allows the sysadmin to block user after a number of unsucessful login count. To unblock a prohibited to login user, less say due to multiple failure to remember his own password do:
I've recently installed Debian GNU / Linux 9.1 Stretch and on Ubuntu 16.10Yakkety Yak and as an old school true gameraddict decided to play some games to recall the good old memories from the past of the glorious DOS games times, when all was simple people was real and there was no terrible people dividers such as Facebook / GooglePlus, no skype fuzzy craziness and no people watching all time at their mobile smart phones like zoombies .
Well anyways, so I wanted to play my favourite DOS games Terminal Velocity, StarGunner, Raptor, Heroes of Might and Magic 2, Doom II, Duke 3d etc. etc. the list goes on and on – BTW What's your favourite old school DOS Game??
So I issues in Terminal:
$ dosbox TV.EXE
DOSBox version 0.74 Copyright 2002-2010 DOSBox Team, published under GNU GPL. — CONFIG:Loading primary settings from config file /home/zetathon/.dosbox/dosbox-0.74.conf MIXER:Got different values from SDL: freq 44100, blocksize 512 ALSA:Can't subscribe to MIDI port (65:0) nor (17:0) MIDI:Opened device:none DOSBox switched to max cycles, because of the setting: cycles=auto. If the game runs too fast try a fixed cycles amount in DOSBox's options. Exit to error: DRC64:Unhandled memory reference
So what is the solution to Exit to error: DRC64:Unhandled memory reference error and why it happens?
Well, as the error clearly states the whole problem comes from a default dosbox dos emulator configuration, that's the setting:
cycles=auto
Perhaps the CPU beat of a Core I7 CPUs is too strong for some of the old games which are expecting a slower PC with less memory that's why the exception
Exit to Error: DRC64:Unhandled memory reference is spit out by Dosemu.
So how to solve DRC64:Unhandled memory reference dosemu error?
By default DOSBOX places its configuration at Linux / BSD / *nix-es at home folder /dosbox – e.g. ~/.dosbox/ the naming of dosbox.conf might differ according to dosbox version and the respective Linux / BSD distro, on Debian and Ubuntu Linux usually the naming includes a version number.
On Debian 9 Strecth Linux dosbox config is at ~/.dosbox/dosbox-0.74.conf
Edit the file
$ vim ~/.dosbox/dosbox-0.74.conf
and change inside the value for:
core=auto
to
core=normal
Then give dosbox with the erroring game another try, it worked for me for me and everything seemed to run fine.
I've only run a handful of games but so far it seems to be working well.
If it does work but performance is degraded and tooks a huch hit on Gameplay you better try to substitute
core=normal
to
core=simple
AND HOORAY IT WORKS AGAIN! THE GAME RUN SUCCESSFULLY JOY TO THE WORLD! 🙂
While deploying an environment called "Interim" which is pretty much like a testing Java application deployed from a Java EAR (Enterprise Archive) file from within a Tomcat Manager GUI web interface after stopping the application and trying to start it, the developers come across the error:
FAIL – Application at context path /application-name could not be started
The error puzzled me for a while until I checked the catalina.out I've seen a number of thrown Java Eceptions errors like:
Okt 01, 2015 10:48:46 AM org.springframework.web.context.ContextLoader initWebApplicationContext
Schwerwiegend: Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.sun.xml.ws.transport.http.servlet.SpringBinding#2' defined in ServletContex
t resource [/WEB-INF/pp-server-beans.xml]: Cannot create inner bean ‘(inner bean)’ of type [org.jvnet.jax_ws_commons.spring.SpringService] while setting bean property
'service'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#33': FactoryBean threw exception on
object creation; nested exception is java.lang.OutOfMemoryError: PermGen space
I've googled a bit about the error:
"FAIL – Application at context path /application-name could not be started"
and come across this Stackoverflow thread and followed suggested solution to fix web.xml tag closing error but it seems there was no such error in my case, I then also tried solution suggested by this thread (e.g. adding in logging.properties) file:
org.apache.catalina.core.ContainerBase.[Catalina].level = INFO org.apache.catalina.core.ContainerBase.[Catalina].handlers = java.util.logging.ConsoleHandler
unfortunately this helped neither to solve the error when it is tried to be started from tomcat manager.
After asking for help a colleague Kostadin, he pointed me to take a closer look in the error (which is a clear indication) that the reserved space is not enough (see below err):
java.lang.OutOfMemoryError: PermGen space
And he pointed me then to Solution (which is to modify the present tomcat setenv.sh) settings which looked like this:
The default GNU / Linux top command does allow to see statistics on servers and systems with multiple CPUs. This is quite beneficial especially on Linux systems which are not equipped with htop which does show statistics to the multiple-core system load.
To examine the multiple CPUs statistics with the default top command available on every Linux system and part of the procps – /proc file system utilities
1. Start top:
linux:~# top
When the top system load statistics screen starts up refreshing,
2. press simply 1 You will notice all your system cpus to show up in the top head:
As I have started talking about top, a very useful way to use top to track processes which are causing a system high loads is:
linux:~# top -b -i
This command will run top in batch mode interactively and will show you statistics about the most crucial processes which does cause a server load, look over the output and you will get an idea about what is causing you server troubles. Moreover if you’re a Linux console freak as me you will also probably want to take a look at tload
tload command is a part of the procps – /proc file system utilities and as you can read in the tload manual tload – graphic representation of system load average
Here is a picture to give you an idea on the console output of tload :
Another tool that you might find very usefel is slabtop it’s again a part of the procps linux package. slabtop – displays a listing of the top caches sorted by one of the listed sort criteria., in most of the cases the slabtop kernel cache monitoring tool won’t be necessary for the regular administrator, however on some servers it might help up to the administrator to resolve performance issues which are caused by the kernel as a bottleneck. slabtop is also used as a tool by kernel developers to write and debug the Linux kernel.
ffmpeg is the de-facto standard for Video conversion on Linux and BSD platforms. I was more than happy to find out that ffmpeg is capable of converting an .ogv file format to .flv (Flash compressed Video). Ogg Vorbis Video to Flash’s conversion on Linux is a real piece of cake with ffmpeg . Here is how to convert .ogv to .flv:
Conversion of a 14MB ogg vorbis video to flv took 28 seconds, the newly produced converted_ogg_vorbis_video_to_flash_video.flv has been reduced to a size of 9MB. This is on a system with 2 GB of memory and dual core 1.8 Ghz intel CPU.
