Resolve RUNDLL error

The below error may come up when you boot up the computer or when you open an application.

Here is how you will solve this.

Go to Start >> Run >> Type Regedit and hit enter.

This will open the windows registry.

Expand: HKEY_CURRENT_USER >> Software >> Microsoft >> Windows >> Current Version >> highlight Run >> Delete the value which includes "rundll" and delete it.

Reboot the machine.

If you do not find this under HKEY_CURRENT_USER try the same location under HKEY_LOCAL_MACHINE.

Let me know if this was helpfull :-)

Kill a process which is hung

Many a time while troubleshooting issues with various applications I have had troubles with services going to a hung state. When the service is in a stopping state you can simply go ahead and kill it from the task manager but what when it is hung at "starting" ? Also not all services run as processes in task manager. For instance, if Exchange POP3 service is stuck in a 'stopping' state. You cant go into task manager and kill the process because its not there. And there isnt a way to force a service to stop in the service manager.

The following commands had been a great help for me.

To kill any process be it hung at "stopping" or "starting" state do the following :-

Open command prompt in elevated mode ie; right click on command prompt and "Run as Administrator".

Enter the following command:
sc queryex (service name)

This will give you the PID(process id) To get the service name, right click on the service under general tab you can see Service Name listed.

Then enter the following command:
taskkill /f /pid (Process id)

Hope you found it usefull.

Note: The process id will keep changing, hence always check the process id before running the taskkill command.

SAN zoning

In any network when a switch is initiated, a connection is established between all devices connected to it. So is in a SAN network. A "Fabric" in a SAN environment is referred to a SAN switch. A network without any restrictions to the storage unit compromises on security, availability and management of storage. This problem can be solved by "Zoning" which is a feauture in fabric switches. Zoning creates rules restrictions as in what FC device can see what other devices connected on the fabric. This is similar to a V-LAN.

Below figure illustrates Zoning on a Fabric.

Types of Zoning

• Hardware zoning.
• Software Zoning.

Hardware Zoning

Fabric port number is used to configure hardware zoning. The physical ports of the fabric are the members. Hardware zoning provides the highest security.

Dissadvantage: Zoning has to be re-configured if the device is connected to a different port.


Software zoning

An HBA card has WWNN(World wide node name) and WWPN(World wide port name). Just like a MAC address goes to ethernet card, WWN goes to HBA card. You don't have to worry about the port on the fabric were the device is connected if it is a software zoning.

For an initiator(servers) WWNN starts with 20:_, WWPN starts with 10:_.
For targets WWNN starts with 50:_.


WWN spoofing

A device can change it's WWN rather using the one given by it's manufacturer. An unknown device can gain trust of a storage device and can access it by spoofing the WWN number.

Commands to mount and open files in a cdrom on Linux

Many of the administrators who are new to linux have problem with opening file from a cdrom or to install application from a CD on a linux platform. The below steps must help you.

# mount /dev/cdrom /cdrom

This will show following result:

mount: mount point /cdrom does not exist.

Now change the directory to / if you are not there:

# cd /

Here create a directory to mount the CD using the following command:

# mkdir cdrom

To mount the D to the "cdrom" directory use the following command:

# mount /dev/cdrom /cdrom

Now change directory to /cdrom:

# cd /cdrom

browse the CD with the "ls" command.

To unmount the CD, change directory back to / followed by the unmount command.

# cd /

# umount cdrom.

Hope that helps...

Cloud Computing Models

While cloud computing is still a relatively new technology, there are generally three cloud service models, each with a unique focus. The American National Institute of Standards and Technology (NIST) defined the following cloud service models:


Software as a service (SaaS)

This capability that is provided to the consumer is to use the applications that a provider runs on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface, such as a web browser (for example, web-based email). The consumer does not manage or control the underlying cloud infrastructure, including the network, servers, operating systems, storage, or even individual application capabilities. One possible exception is for the consumer to continue the control of limited user-specific application configuration settings.

Platform as a service (PaaS)

This capability that is provided to the consumer is to deploy consumer-created or acquired applications onto the cloud infrastructure. Examples of these types of applications include those that are created by using programming languages and tools that are supported by the provider. The consumer does not manage
or control the underlying cloud infrastructure, including the network, servers, operating systems, or storage. But, the consumer has control over the deployed applications and possibly application-hosting environment configurations.

Infrastructure as a service (IaaS)

This capability that is provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software. These resources can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure, but has control over operating systems, storage, and deployed applications. The consumer might also have limited control of select networking components (for example, hosts).

Below figure shows these cloud models:

Cloud Computing Deploying Models:


Private cloud

The cloud infrastructure is owned or leased by a single organization and is operated solely for that organization.

Community cloud

The cloud infrastructure is shared by several organizations and supports a specific community that shares (for example, mission, security requirements,policy, and compliance considerations).

Public cloud

The cloud infrastructure is owned by an organization that sells cloud services to the general public or to a large industry group.

Hybrid cloud

The cloud infrastructure is a composition of two or more clouds (internal, community, or public) that remain unique entities. However, these entities are bound together by standardized or proprietary technology that enables data and application portability (for example, cloud bursting).

Below figure shows cloud computing deploying models: