Saturday, 10 December 2011

Windows Domain Controller and their Roles

I really favour Linux/Unix working environmental but sadly commercialism has engulfed our societies as the likes of Windows platforms while the former one doesn't matter how much is rated high still lives in the shadows. And now I have to grasp the Windows lingo all along to fit in an organization. So lets learn something about Windows Domain Controller and their roles.

Before going into any details first its important to understand the differences between the following terms.

  • Active Directory: is a directory service that serves as a central location for network administration and security which is responsible for authenticating and authorizing all users and computers within a network of windows domain.
  • Forest: is the top-level container of Active Directory (AD) infrastructure. Can contain one or more domains. These domains are interconnected trough a transitive trust. A forest shares a single schema database.
  • Domain: is one level below AD forest. Can consist of one or more Organizational Units (OU). A domain shares a single administrator group and same set of objects.
  • Domain Controller: A domain can consists one or more domain controllers (DC). A DC holds a directory DB of its perspective domain. The directory DB consists of user, objects, computer objects or more.
  • Organizational Unit: is a container within a domain and is used to organize set of users and computers. It is helpful in implementing set of policies to a group, user or computer within a domain.
  • Windows DC: A server running the version of Windows Server OS and has AD installed on it and is responsible for allowing host access to Windows Domain resources.

Now coming to the roles; there are specialized DC roles that perform specific roles in Active Directory Domain Services (AD DS) environment. The specialized roles are:

  • Global Catalog Servers: A DC designated as a global catalog server stores the objects from all domains in a forest. This is usually the first DC in a forest. Later on other DC can be specified as global catalog servers.
  • Operations Master: This is a DC that is designated to perform specific tasks to ensure consistency and to eliminate the potential for conflicting entries in the AD DB.

AD DS defines five operation master roles called:

  1. Schema Master: Responsible for propagating changes to all DCs within a forest. Changes regarding schemas required throughout forest should be made on DC serving as schema master. There can be only one schema master in a forest at any time.
  2. Domain Naming Master: It is required to keep track of all the domains within an AD forest. The DC with domain naming master is accessed whenever domains are address/removed from a tree or forest. There can be only one domain naming master per forest. It ensures that no two domains have the same name existing in the same tree.
  3. Relative Identifier (RID): Allocates blocks of RIDs to each DC in a domain. When a DC creates a new security principal (user, group etc.) it assigns the object a unique security identifier SID. The SID contains a domain SID which us same for all the security principals created in the domain and a RID which uniquely identifies each security principal created in the domain.
  4. Primary Domain Controller (PDC) Emulator: PDC receives prefential replication of password changes that are performed by other DCs in the domain and is the source for latest password information. It's also the default time source.
  5. Infrastructure Master: is responsible for updating object references in the domain that point to object in another domain. It updates object references locally and uses replication to being all other replicas of domain up to date. Object reference contains GUID global unique identifier, distinguished name and possible a SID. The distinguished name and SID on object reference are periodically updated to reflect changes made to actual object.

- Schema Master and Domain Naming Master performs operations that must occur on only one DC in the forest.

- PDC, RID, Infrastructure Master perform operations that must occur on only one DC in a domain.

Monday, 4 April 2011

HEC Dissolution to Provincial Level.

The Higher Education Commission of Pakistan (HEC) in now dissolved to provincial level. Former chairman of HEC and the pioneer of lucrative educational policies Dr. Atta Ur Rehman is terming this as a "National Disaster." In an interview on a private news television channel he mentioned some the most obvious reasons for this dissolution which are:

1. To avoid degree scrutiny by our political leaders as member of the parliament needs to hold a graduate degree. The verification of these degrees was given to the HEC and as a result created a rift between the commission and the political circles.

2. To get illegal access to huge lands owned by different universities around Pakistan.

3. To further practice corruption within the education sector and to nurture respective political ideologies. As after this, it will be the provincial regulatory committees responsible for the provision of scholarships, grants and to oversee state and private universities. As a result, it would be soon that one would be able to find two-room universities in different corners of the country nurturing different political ideologies.

Now as a graduate myself in Pakistan and hoping to pursue my doctorate studies here; What do students like me fear? To start with, HEC now working as cells around Pakistan would lose its centralized transparent structure as we already have seen how incompetent our provincial structure is. Thanks to the 18th amendment of Pakistan constitution; which is dubbed to be the best thing happened to Pakistan since the 1973 constitution but only if we had a reliable strong political structure. Given the present scenario everyone is aware how dire this step is and what consequences we would be visible in few years time.

I also fear the the different grants and scholarships available to the Pakistani students from different governments and organizations around the would would be stopped. Its has been only few hours since the news of HEC dissolution is announced and already we had a statement from the present HEC chairman Dr. Javaid Laghari that the USAID and World Bank has stopped their aid which sums up to about $550 billion that was to be used by HEC for the coming 5 years to carry out different projects. Apart from these future promises, the present structure of the commission in question is also uncertain of its future like the HEC Digital Library and HEC e-learning.

Now the interesting thing would be to see how the nation responds to this. Dr. Atta-Ur-Rehman and Dr. Javed Leghari are already appearing on different news channels to sum up these mentioned facts to the nation. What matters now is would there be someone to carry out any action on this unfolding situation. I hope and I pray that there would be some patriotic Pakistanis among us that would stand up to this matter and do justice with it.

Sunday, 3 April 2011

Mobile Communication Technologies for Dummies.

Different communication technologies and then the different standards between countries and upon it the non-stop introduction of wireless gadgets often makes me confused and eventually I mix up the concepts. Now I decided to make myself a simple/easy to understand table for a quick review of these technologies.

Generation Name Year Frequency Data Rate
1G AMPS – Advanced Mobile Phone System (using FDMA) 1980’s 800 – 900 MHz
1G D-AMPS – Digital AMPS (adding TDMA to AMPS) 800 – 900 MHz
2G IS-95 (using CDMA) 1990’s 800 MHz
2G GSM – Global System for Mobile Communication (using TDMA) 1990’s 900 – 1800 MHz
2G GSM GPRS – General Packer Radio Services (by 3GPP*) 2000 144 Kbps
2.5G 1xRTT – One Time Radio Transmission Technology (by 3GPP2**) 2002 144 Kbps
2.5G EDGE – Enhanced Data GSM Environment (by 3GPP) 2003 384 Kbps
3G UMTS – Universal Mobile Telecommunication System 2002 1885 – 2025 MHz 1.92 Mbps
3G UMTS HSDPA – High Speed Downlink Packet Access 2002 14.4 Mbps
3G EV-DO – 1x-Evolution-Data Optimized (using CDMA) (by 3GPP2) 2.4 Mbps
3G EV-DO Rev. A (by 3GPP2) 3.1 Mbps
3G EV-DO Rev. B (by 3GPP2) 4.9 Mbps
4G UMB *** – Ultra Mobile Broadband (by 3GPP2) 288 Mbps downstream
4G LTE – Long Term Evolution (by 3GPP) 2009 1920 Mhz – 3600 Mhz 100 Mbps downstream 30 Mbps upstream

* - 3GPP 3rd Generation Partnership Project. Body responsible of up-gradation of GSM networks in Europe, Japan, North America, South Korea.

** - 3GPP2 3rd Generation Partnership Project. Body responsible for up-gradation of CDMA networks in US (also South Korea and Japan.)

*** - Instead of adopting UMB, it has now been decided favoring LTE instead by the service providers.

4G is currently implemented in Sweden and South Korea. UK has recently declared licenses for 4G service provision. While in Pakistan 2.5G EDGE is currently implemented but not a single provider has upgraded to 3G. Huawei did implemented a couple of experimental 3G sites but its not sure where some operator would adopt it in near future.

P.S: Stuff here has been collected from various online resources and there might be some errors. So please do point them out so I can correct them.

Thursday, 10 February 2011

Executable Bit: Wine error in Ubuntu 10.10

If you are bothered by the Windows .exe files execution under the Wine in Ubuntu 10.10 and getting this error:

Blocked: wine start/unix
The file '/media/My Passport/Softwares/Setup.exe' is not marked as
executable. If this was downloaded or copied from an untrusted source, it may be dangerous to run. For more details, read about the executable bit.

Then you are at the right place. Just do the following:

1. Copy the .exe file to your system (home/desktop: Just to make it sure the file is not on a removable media.)
2. Right click on the .exe file. Click Properties.
3. Click Permissions tab.
4. Check the option: Execute: Allow executing file as program.
5. Close and run it.

You would able be execute it without any errors this time with Wine.

Saturday, 1 January 2011

"Mapping of User Quality-of-Experience" published.

So it is official now. My research findings are now published by Lambert Academic Publishing. So super excited to receive my first copy any day soon. If you are interested in this area of study you can get your self a copy here.

ISBN-13: 978-3-8433-8978-5
ISBN-10: 3843389780
EAN: 9783843389785

Monday, 15 November 2010

Research Findings.

I started this blog to share my academic achievements I endured during my Masters studies back at Sweden. I wanted to share some interesting results here but due to lack of time I was not able to. Now finally I have decided to give it some time daily and share a topic or two which has some research potential on this platform. I will follow a step by step procedure here based on my research findings in my Master Thesis. Once completed, I will share my ideas on how the work can be extended and carried on. Some of the upcoming blog posts would be:

- The need for mapping user experience to application perceived performance.

  • - The plan and what aspects were considered.
  • - The implementation and experimentation.
  • - The results (which would be divided into many sub posts.)
  • - Future work.

Am excited and hopeful that not only this blog will catch interest of QoE/Ux enthusiastic but will also polish my skills and help me get recognized on other platforms I sought for my career.

Wednesday, 24 February 2010

Social Categorization – Visibility and Invisibility

She just stood there at the front, pointing to the power points slides lit by a projector. The participants were just listening, many of them dozing just like me while the beautiful mid thirties lady just went on discussing the different aspects of social categorization. While discussing one of the aspects of whether social categories can be visible or invisible, she proceeded with a personal example. She just told it to out face. “I was a prostitute for one year in Dubai in the mid nineties.” These very words from the elegant lady mouth landed like a spell on fellow participants. All were just staring at the face of this lady who was just scrolling her eyes around the room with her mouth closes, her face color turned red with sparkling eyes as if tears would start flowing from them any moment. The next 10 to 15 seconds turned the seminar room of almost 40 participants into complete quietness that you could hear the sound of wall clock perking through your ear drums. She was the first one to break the ice by saying “No I was not!” which came as a relief to everyone that as figuring from how sweet this lady was, it would be such a cruel injustice of her being a social taboo. She went on clarifying that she was considered to be a prostitute when she was on her own working for a firm in Dubai in the mid nineties which saw a peak in prostitute business when the local Sheikhs were pretty much fond of getting the taste of blondes from the Europe. She went on explaining on how she learnt few words in Arabic to woo passersby away when cards used to stop for her on the road. And how she would lower her gaze when people used to stare her being as the scum of the society. She explained this one incident that brought her to tears when showing her love to a small kid at a shopping mall, the kid’s mother came around and pulled the child away from her and kept on babbling in Arabic that not to socialize with her as if her invisible social taboo is like a contagious disease that would spread even by affection. She called that year the worse she has ever felt in her life and this made her to resign from her job and leave the country.

She asked whether we have been victims of such invisible social categorization being entrusted upon us. She only had to ask this question for a sea of responses that were to unravel from the participants. We being the social victims? Of what part of our 2 plus years of stay in Europe has made us felt socially acceptable? The conditions might have changed in Dubai at the month for European blondes to be considered prostitutes. In present years a lady with blonde hair would be most likely to be taken for a touring and the only exploitation she would be getting would be from shopkeepers looking for a healthy bargain. But on the other hand brown skinned people like us would find the situation deteriorating day by day in this part of the words. Called by names such a garlic people or paki –whatever you can add with that is been a routine situation which browned skinned people like us have to live through. The very fact that you have to hide your green passport while standing in airport queues just to avoided unnecessary attention you might get from the security. So invisible social categories, where do we fit in now?

Sorry for sounding so naive but I needed to get this out of my system.

Pictures are from Pic 1 and Pic 2.