f1911

Multiple IPs can be assigned to single network Interface by one of the following methods:

1- Using the Aliases [The Old Techniques]
Create a file /etc/sysconfig/network-scripts/ifcfg-eth0 [eth0 is the name of the interface]

#File: ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=statis
IPADDR-192.168.0.1
NETMASK=225.225.225.0
BROADCAST=192.168.0.225
NETWORK=192.168.0.0
HWADDR=00.00.00.10.10.10

#File: ifcfg-eth1
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=statis
IPADDR-192.168.0.2
NETMASK=225.225.225.0
BROADCAST=192.168.0.225
NETWORK=192.168.0.0
HWADDR=    00.00.00.10.10.10

Save the files and restart the service

>service network restart

2-Using the IP technique [New and the easyone]

>ip addr addr 192.168.0.1/24 brd + dev eth0
>ip addr addr 192.168.0.2/24 brd + dev eth0

Clouds are now becoming a common phenomenon after their introduction from blue chips like Amazon , Google , Microsoft . Amzaon introduced EC2 which is based on a customized version of XEN with IaaS [Infrastrucutre as a Service], Google introduced App Engine which is moving in a different direction allowing to develop application and deploy them on app engine currently very limited language support available.
Google app engine provides vitalization as PaaS [Platfrom as a service]. Microsoft Azure is almost in the same direction as google app engine with deployment feature of .net web applications.They also provided the services as PaaS.Though all of them providing the services with following features

1- Processing vitalization
2- Storage vitalization

Though all of them are providing the support for the 2 features but in a very heterogeneous way.If a person is using Amazon for some of its linux capabilities and at the same time he needed support for some microsoft applications [ Though Amazon AWS provided support for windows using the latest XEN vitalization though needed VT enabled hardware :)] he will be in a delima which we can say is the "federated cloud". These federated clouds are so different in every aspect , in architecture , domain and even their business models.Here comes a need to have some middle-ware which provides transparency against the "Heterogeneous Clouds" and the optimum utilization of the clouds, which not only analyze the utilization of the clouds in terms of technical aspects but also in terms of financial aspects. For financial aspects we can use our own financial benchmarks , now after cloud computing there is a time coming where each processing will be rated and each additional useless processing cycle can be penalyzed not by the company but by the green house effects like the same way as [PAKISTAN SCENARIO :PEPCO advertising to use energy saver to save electricity in terms of kilo watts to avoid load shading].
So all this is some of my very very very sighted imagination may be helpful in future.

if this error comes on Amazon Webservice API


The device is not ready

Please check your EC2 home and other paths they may b
e incorrect.

Microsoft learn from Linux to predict future

Microsoft planned for MinWin ,which is the windows core for every porduct in future of microsoft.It has a size of 25 MB which only require 40 MB memory to run..


http://www.istartedsomething.com/20071019/eric-talk-demo-windows-7-minwin/


Microsoft's  open source operating system available

Microsoft releases the operating system of the future completely written in C# and run on CLR.




It is nothing more than a neat academic exercise, not a glimpse of Windows 7. 

Microsoft Singularity Step by Step

http://www.ahmed-essam.com/2008/03/preparing-building-and-denuging.html

Adding Code to Singularity

http://www.ahmed-essam.com/2008/03/adding-code-to-singularity.html


Windows 7 new OS ,release due in 2010

Joshua used the following two quotes from the web about JAVA GENERICES:

“I am completely and totally humbled. Laid low. I realize now that I am simply not smart at all. I made the mistake of thinking that I could understand generics. I simply cannot. I just can't. This is really depressing. It is the first time that I've ever not been able to understand something related to computers, in any domain, anywhere, period.”

“I'm the lead architect here, have a PhD in physics, and have been working daily in Java for 10 years and know it pretty well. The other guy is a very senior enterprise developer (wrote an email system that sends 600 million emails/year with almost no maintenance). If we can't get [generics], it's highly unlikely that the ‘average’ developer will ever in our lifetimes be able to figure this stuff out.”


Reference : http://www.artima.com/forums/flat.jsp?forum=106&thread=222021

Last night Pakistan's Day Light Saving System took more hours then save through this system. I was working in S3 bucket explorer and it was continuously giving error that it can not connect to S3.In the end I found out that my computer clock was adjusted according to new timing in Pakistan "Day Light Saving System".S3 can only accept 15 min deviation from the Zone time,but I was deviating 1 hour (Saving the day light and wasting office light).When I adjusted to the old one it worked...

Problems: server refused key

Reasons: One of the reason which I faced and that ate my two days among other reasons is :

If you change the permissions of the /root this problem occurs
By default root permissions are
    750
you can check it by ll.

You run an instance of the image at EC2 and change the rights of the /root folder from 750 to any other then try make connection from putty then
It will give this error

server refused key

The only solution to this problem is change back the permission of the root from any other to 750 or the one from which you created the key pair [Private key and Certificate Key].

How to deploy FoodMart dataware-house on Linux using Mondrian as OLAP Server and PostgreSQL as Database

 Legends:

1-         Commands are in Italic format.

 

Assumptions:

 

1-         Database                      foodmart

2-         Schema                        foodmart

3-         Database User Name   test

4-         Database Password      test

 

Requirements:               [In order of installations]

 

1-                                         JDK 1.5 [Mondrian XML/A can not run on version other then jdk 1.5]

2-                                         Tomcat 5.5

3-                                         Postgresql 8.1.*

4-                                         Mondrian-3.0.3.11016

 

 

Procedure:

 

1- Jdk 1.5 Deployment          [SKIP if already installed]

 

1- Download using

wget http://www.java.net/download/jdk6/6u2/promoted/b02/binaries/jdk-6u2-ea-bin-b02-linux-i586-12_apr_2007-rpm.bin

2-Change Persmissions using

                        chmod 755 jdk-6u2-ea-bin-b02-linux-i586-12_apr_2007-rpm.bin

 

3-Depploy using

                        ./jdk-6u2-ea-bin-b02-linux-i586-12_apr_2007-rpm.bin

                       

4-set Environment variable using

                        export JAVA_HOME=/usr/java/jdk1.6.0_02

 

2-Deploy Tomcat                   [SKIP if already installed]

                       

1-Download

wget http://apache.mirrors.hoobly.com/tomcat/tomcat-5/v5.5.26/bin/apache-tomcat-5.5.26.zip

 

2-Unzip

unzip apache-tomcat-5.5.26.zip -d /etc

           

3-Deploy PostgreSQL           [SKIP if already installed]

 

                       

            1-Download and install

            yum -y install postgresql postgresql-server php-pgsql 

[We can download and then install or download zip and then unzip but we have to create the postgres user for servicees]

            2-Configure them as service and set to start automatically

            /sbin/chkconfig postgresql on

            /sbin/service postgresql start

            3-To enter into the postgres account use

            su - postgres 

            4-create FoodMart Database on PostgreSQL

            createdb foodmart

createuser test CREATEUSER;

psql -d foodmart -U test -W;

 

5-Configuration for USER to access database

            for user “test ” to access the database  you have to configure following files

            vi /var/lib/pgsql/data/pg_hba.conf

 

 

# TYPE  DATABASE    USER        CIDR-ADDRESS          METHOD   # "local" is for Unix domain socket connections only local   all         all                               trust # IPv4 local connections: host    all         all         127.0.0.1/32          trust # IPv6 local connections: host    all         all         ::1/128               trust

 

define trust in the column under METHOD

since default is “for sameuser” which is used for Linux users so if we remain the default configuration we have to make each linux user for each database user in postgresql.

 

create schemea ‘foodmart’;

set serarcg_path to foomart;            

 

 

 

                        6-To generate schema and data for foodmart

 

                                    1-Download the jdbc driver for postgres

                                    download postgresql-8.3-603.jdbc3.jar and copy it into the lib folder of the mondrian

 

                                    Pentaho Installation/mondrian-3.0.3.11016/mondrian-3.0.3.11016/mondrian-3.0.3.11016

 

java -cp "/mondrian/lib/mondrian.jar:/mondrian/lib/log4j-1.2.8.jar:/mondrian/lib/eigenbase-xom.jar:/mondrian/lib/eigenbase-resgen.jar:/mondrian/lib/eigenbase-properties.jar:/mondrian/postgresql-8.3-603.jdbc3.jar"     mondrian.test.loader.MondrianFoodMartLoader     -verbose -tables -data -indexes     -jdbcDrivers=org.postgresql.Driver     -inputFile="/mondrian/demo/FoodMartCreateData.sql"     -outputJdbcURL="jdbc:postgresql://localhost/foodmart"     -outputJdbcUser=test     -outputJdbcPassword=test

 

In the above command if some jar is missing or problem in version number then check or download and give the correct file name and path 

 

            So by run the command then the FoodMart schema will be generated. J

 

4-Deploy mondrian

 

Copy mondrian.war from mondrian-3.0.3.11016/mondrian-3.0.3.11016/mondrian-3.0.3.11016/lib into the web apps folder and unwar it into the tomcat webapps folder.

 

            1- Mondrian Configuration for the assumptions specified above

            In  /WEB-INF/datasources.xml makes changes specified in bold

 

<?xml version="1.0"?> <!--   == $Id: //open/mondrian/webapp/WEB-INF/datasources.xml#5 $   == This software is subject to the terms of the Common Public License   == Agreement, available at the following URL:   == http://www.opensource.org/licenses/cpl.html.   == (C) Copyright 2005-2006 Julian Hyde and others.   == All Rights Reserved.   == You must accept the terms of that agreement to use this software.   --> <DataSources>     <!--          A data source is a collection of logically related Mondrian          catalogs.            The XMLA specification allows an XMLA provider to have          multiple data sources, but some clients, particularly ones          based on ADOMD.NET such as Simba's O2X client and Pentaho          Spreadsheet Services, can only connect to the first declared          data source. Therefore, we recommend that you use a single          data source, containing multiple catalogs if necessary.      -->     <DataSource>         <!--              Name of the data source.         -->         <DataSourceName>Provider=Mondrian;DataSource=MondrianFoodMart;    </DataSourceName>           <!--              Description of the data source.         -->         <DataSourceDescription>Mondrian FoodMart Data Warehouse </DataSourceDescription>           <!--              The URL of the servlet.         -->         <URL>http://localhost:8888/mondrian/xmla</URL>           <!--              Mondrian connect string for the data source. If this data              source contains multiple catalogs, omit the 'Catalog'              property, and specify the URI of the schema.xml file in              the catalog's <Definition> element.                Catalogs can override the connect string with their own              <DataSourceInfo> element.           -->           <DataSourceInfo>Provider=mondrian;JdbcUrl=jdbc:postgresql://localhost/foodmart; JdbcUser=test;JdbcPassword=test;JdbcDrivers=org.postgresql.Driver;</DataSourceInfo>           <!--              Provider name must be 'Mondrian'.         -->             <ProviderType>MDP</ProviderType>           <!--              Authentication mode. Allowable values are              'Unauthenticated', 'Authenticated', 'Integrated'.         -->          <AuthenticationMode>Unauthenticated</AuthenticationMode>           <!--              A data source contains one or more catalogs.         -->         <Catalogs>             <!--                 Catalog names must match the name inside the                 schema.xml file, and must be unique across all data                 sources defined in this datasources.xml file.             -->             <Catalog name="FoodMart">                 <!--                      Mondrian connect string for the data source. This                      element is optional; if specified, it overrides the                      data source's <DataSourceInfo> element. Typically,                      you would use this element if the catalogs have                      different JDBC data sources.                  -->                   <DataSourceInfo>Provider=mondrian;Jdbc=jdbc:postgresql://localhost/foodmart; JdbcUser=test;JdbcPassword=test;JdbcDrivers=org.postgresql.Driver;</DataSourceInfo>                     <!--                     URI of the schema definition file.                 -->                 <Definition>/WEB-INF/queries/FoodMart.xml</Definition>             </Catalog>         </Catalogs>       </DataSource>   </DataSources>

 

 

 

            In WEB-INF/ mondrian.properties file makes changes specified in bold

 

 

# For XML/A JSPs mondrian.test.connectString=Provider=mondiran;Jdbc=jdbc:postgresql://localhost/foodmart?user=test&password=test;JdbcDrivers=org.postgresql.Driver;Catalog=/WEB-INF/queries/FoodMart.xml;

 

            In the following files change <jp:mondrianQuery>  to

 

arrows.jsp  

colors.jsp  

testquery.jsp 

fourhier.jsp 

mondrian.jsp  

mondrianXMLA.jsp 

testrole.jsp  

xmla.jsp

 

<jp:mondrianQuery id="query01" jdbcDriver="org.postgresql.Driver" jdbcUrl="jdbc:postgresql://localhost/foodmart?user=test&password=test" catalogUri="/WEB-INF/queries/FoodMart.xml">

 Copy the following files:

·                     If needed, copy your JDBC driver JAR to TOMCAT_HOME/common/endorsed

·                     Copy xalan.jar to TOMCAT_HOME/common/endorsed

Note: in case any problem first check and restart postgres and tomcat

Reference:

 1-http://mondrian.pentaho.org/documentation/installation.php

2- Searched a lot on www.google.com so can not specify all the names of the websites.

 

 

 

 

 

 

In any case first Change try to  change permission of the files

Singleton is a deign pattern used to minimize the memory foot prints , mostly used in stateless and service providing objects, but does following the rules to make singleton objects make it singleton.These rules usually are,

1- Making the constructor private
2- Providing  a Factory Method for the object
3- Providing a Factory Method Synchronized
4- In some cases making the class  un-override-able
                 in java Making Class  final
                 in .net Making  Class  sealed [C#]
5- Defining Class level securities

But just following the above rule ca we make it singleton or multiton.

No, there are ways which stop them from from being single or multiton.

1- Serialization
            If we make them transient


Through Serialization
Through Reflection