What is a Dispatcher?

A number of types of schedulers are available that suit the different needs of different operating systems. Presently, there are three categories of the schedulers:

1. Long-term schedulers
2. Medium-term schedulers
3. Short-term schedulers

Apart from the schedulers there is one more component involved in the scheduling process and is known as the dispatcher. 

- It is the dispatcher that gives a process power to control the CPU. 

- To which process this control is to be given is selected by the short-term scheduler. 

- This whole process involves the following three steps:

1. Switching the context
2. Turning on the user code
3. Making a jump to the exact location of the program from where it has to be restarted.

- Values taken from the program counter are analyzed by the dispatcher and accordingly it fetches instructions and feeds data in to the registers. 

- The dispatcher unlike the other system components needs to be very quick since it is invoked during all the switches that occur. 

- Whenever a context switch is invoked, the processor gets in to an idle state for a very small period of time. 

- Hence, it is required that the context switches that are not necessary might be avoided. 

- The dispatcher takes some time for stopping one process and start running the other one. 

- The dispatch latency is what we call this time.

- Scheduling and dispatch are complex processes and interrelation to each other. 

- These two are very much essential for the operation of the operating system. 

- Today, architectural extensions are available for the modern processors that provide a number of banks of registers.

- Swapping of these registers in hardware is possible and therefore a certain number of tasks are capable of retaining their full registers. 

- Whenever an interrupt triggers the dispatcher, it sends to it the full set of the registers belonging to the process that was being executed at the time of occurrence of the interrupt. 

- Here, the program counter is not considered. 

- Therefore, it is important that the dispatcher should be written carefully for storing the present states of the registers on being triggered. 

- In other words, we can say that for the dispatcher itself, there is no immediate context. 

- This saves it from the same problem. 

Process of Dispatcher

Below we try to describe in simple words what actually the process is.

1. The program presently having the context is executed by the processor. Things used by this program include stack base, flags, program counter, and registers and so on. There is a possible exception of the reserved register that is native to the operating system. The executing program does not have any knowledge regarding the dispatcher.
2. For dispatcher a timed interrupt is triggered. Here the program counter jumps to the address listed in the BIOS interrupt. This marks the beginning of the execution of the dispatch sub routine. The dispatcher then deals with the stacks and the registers etc. of the program that raised the interrupt.
3. Dispatcher like the other programs consists of some sets of instructions that operate up on the register of the current program. These instructions know everything of the previously executed programs. Out of these, the first few instructions are responsible for storing the state of the program.
4. Dispatcher next determines which program should be given the CPU next for executing. Now it deletes all the statistics of the previously executed state and fills in the details of the next process to be executed.
5. Dispatcher jumps to the address mentioned in the program counter and establishes a full context on the processor.

- Actually dispatcher does not really require registers since its only work is to write the current state of the CPU in to a memory location that has been predetermined. 

- It then loads in to the CPU another process from other predetermined location. 

How test cases are generated using Testing Anywhere?

Testing anywhere software product helps you create the test cases using any of the 5 methods namely:

- Web recording

- Object recording

- Image recognition

- Smart recording and

- Editor

- While editor can be used for editing the test cases by advanced users, wizard is for those who do not have any programming skills. 

- Another facility is that the creation of the files that are executable. 

- These files are created in such a way that they can be executed on a machine that might be located in a remote location. 

- IT and business processes are created by the work flow designer and is managed by the same.

In this article we explain how the test cases can be generated using the testing anywhere product. 

How test cases are generated using Testing Anywhere?

- The testing anywhere product comes with a SMART recorder that one can use to create new tests. 

- Clicking on the ‘record’ button will drop down a list of options from which you have to select what type you are testing i.e., a web or windows application type. 

- Then you need to perform the activities on the system that you want to be recorded. 

- You can insert a checkpoint wherever you want by clicking on the check point button. 

- When you are done with recording the tests click on the stop button. 

- You can then save these activities in a test by clicking on the save button. 

- You can playback these test scripts whenever you want and any number of times by clicking on the run button. 

- In testing anywhere product, it does not matter if any change occurs between the size and location of the window of the application while the recording or replaying is in progress. 

- Testing anywhere uses a SMART automation technology that helps in automatically adjusting to those changes.

- Another advantage of using testing anywhere is that you can work up on any number of applications.

- You do not have to finish working up on one application before moving on to the next. 

- You can very well switch between the applications. 

- Testing anywhere even works while your computer is locked. 

- It does so because of the auto log-in capability that is unique to this software. 

- With this, you can schedule the tests and they will be executed even when your system is locked. 

- If this capability is enabled and the system is locked, it will be unlocked by the testing anywhere, the test will be executed and the computer will be locked again. 

- Auto log-in capability lets you run the tests in stealth mode when the system is locked. To do this follow:

Properties à security à run this test in stealth mode

- The execution will then be hidden. 

- Further, if you want to lock the keyboard and mouse you can use the ‘disable mouse and keyboard for this test’ option. 

- If you want to stop the execution of a test just keep holding the escape key for some time. 

- Using the pause key on the keyboard you can pause the test while it is executing. 

- Further clicking on the resume button you can continue with the execution. 

- Another thing that makes testing anywhere unique is that it can run the tests in background. 

- A number of advanced technologies lets you run the tests in background such as:

1.    Web recorder

2.    Object recorder

3.    And a number of other powerful actions

- However, there are some tests like those that are recorded through standard recorder. 

- These tests require mouse and keyboard control and therefore cannot be executed in background. 

- There are few other exceptions also such as commands such as screenshots; image comparison etc. that cannot be run in background.

What is Testing Anywhere software product? What are its uses?

Testing anywhere software product was developed by the Automation Anywhere Inc. based in San Jose. This is another software in the category of test automation tools. This software has proven to be a boon for the software testers and developers who have to test the web sites, applications, GUI front-ends, objects and controls. The product has got many uses from recording to the execution of the test cases. It is used for the following major purposes:

1. Recording of the tests
2. Debugging them
3. Scheduling their execution
4. Executing the tests

The above mentioned operations can be carried out for a number of application types such as:

1. Java
2. Silverlight
3. Mainframe
4. C++
5. .NET and so on.

Testing anywhere product provides option for automating the test case creation. Testing anywhere offers you 5 different methods for creating the test cases namely:

1. Web recording
2. Object recording
3. Image recognition
4. Smart recording and
5. Editor

- The test cases thus created using any of the above methods can be later recorded, edited, saved and can also be enhanced. 

- The editor is used for editing the test cases. 

- People who don’t have programming skills can use the wizard for creating and editing the test cases. 

- Testing anywhere software lets you create files with .exe extension i.e., the executable files which later can be deployed by the software testers on remote machines. 

- The creation of a high level IT and business processes is the responsibility of the workflow manager. 

- Further, workflow manager only takes care of the ability by virtue of which these processes are managed. 

- It supports a number of platforms:

1. Microsoft windows 7 (both 32 and 64 bit)
2. Microsoft windows vista (both 32 and 64 bit)
3. Microsoft windows XP (both 32 and 64 bit and along with service pack 2)
4. Microsoft windows server 2008 R2
5. Microsoft windows server 2003

- Testing anywhere supports the following kinds of testing:

1. Integration testing
2. Compatibility testing
3. Performance testing
4. GUI testing
5. System testing
6. Java application testing
7. Automated flex testing
8. Silverlight application testing
9. Mainframe application testing
10. WPF testing
11. Third party .NET supported testing
12. Automated software testing
13. Automated web testing
14. Regression testing
15. Distributed testing
16. Functional testing
17. Black box testing
18. Acceptance testing
19. Unit testing
20. Keyword driven testing
21. Data driven testing
22. Smoke testing

- The product has been named because of the facility that it provides for running the tests on any remote machine present in the network. 

- Further, it reduces the testing cost by a huge margin since it cut down the money being spend up on the software licenses, resources, and training and time of course.

- Testing anywhere provides you a SMART recorder for creating new tests.

What are benefits of LabVIEW(Laboratory virtual instrumentation engineering workbench)?

Laboratory virtual instrumentation engineering workbench (or labview as it is commonly known) is a platform developed for designing systems and presents a development environment.

Benefits of LabView

1. Interfacing

- The extensive support that labview provides for access to instrumentation hardware is one of the key benefits of it. 

- In addition to the drivers, a number of abstraction layers are available for inclusion for a variety of buses as well as instruments. 

- These drivers and abstraction layers are presented as the graphical nodes. 

- A standard interface is provided by the abstraction layers so that communication with the other hardware devices could be established. 

- A lot of program development time is saved by the driver interfaces that are provided. 

- That is why people having limited coding experience of writing the programs can even develop programs and easily deploy the test solutions in a time less than what it might take with the conventional programming systems. 

- DAQmxBase is a brand new driver topology.

- It comprises mostly of the G – coded components having a few register calls via national instrument measurement hardware driver development kit (DDR) functions.

- It is known to provide hardware access that is independent of the platform. 

- This access is to instrumentation devices and a number of other data acquisition devices. 

- This new driver is available for the following platforms:

a)    Windows

b)    Mac os x

c)    Linux

- An interface for .net frame work applications is also provided by the labview using    which one can use XML files and data bases in one’s automation projects.

2. Code Compilation

- When it comes to performance, labview is at its best as it provides you even a compiler that can produce a native code for platform level of CPU. 

- Firstly, the graphical code is converted in to machine executable code by passing it through an interpreter and compiler.

- The syntax of the labview is to enforced during the code editing process only and then it is compiled in to machine level code whenever execution command is given. 

- The executable code is executed by the run time engine of labview which already has some pre-compiled code that can be used to perform usual tasks that have been already defined by the G – language. 

- Also, the compile time is reduced by the run time engine. 

- In addition to this it also offers you a consistent interface that can be used for a number of following:

a)    Operating systems

b)    Graphic systems

c)    Hardware components and so on.

- The code is made portable across the platform because of the run – time environment. 

- Labview code compiles slower than the equivalent code in C and this difference gets larger with the program optimization.

3. Large Libraries

- A large number of libraries with a large number of functions such as those mentioned below are provided with the labview package:

a)    Functions for data acquisition

b)    Signal generation

c)    Mathematics

d)    Statistics

e)    Signal analysis

f)     Signal conditioning and so on.

- The package also has a number of graphical interface elements. 

- The package has numerous advanced mathematics blocks which can carry out functions such as filters, integration and so on.

- Many other specialized capabilities that are associated with the data that has been captured with the help of hardware sensors. 

- In addition to all this, labview comes with mathscript which is nothing but a text based programming component having some additional functionality such as for mathematics, analysis, signal processing and so on. 

- This component and graphical programming can be integrated together via the script nodes and using a syntax compatible enough with MATLAB.

4. Code re use

5. Parallel programming

6. Ecosystem

7. User community

Explain LabVIEW (Laboratory virtual instrumentation engineering workbench)?

Laboratory virtual instrumentation engineering workbench (or labview as it is commonly known) is a platform developed for designing systems and presents a development environment. 

- The environment it provides is for the development of visual programming language from what are known as the national instruments. 

- The graphical language that is usually used is commonly known as “G”. 

- Make sure that you do not yourselves with G code.

- This graphical language had its release for the Apple Macintosh in the year of 1986. 

Labview is used for a number of purposes few of which are:

1. Data acquisition
2. Instrument control
3. Industrial automation and so on.

All these functions can be carried out on a number of platforms including:

a)    Unix

b)    Linux

c)    Mac OS X and

d)    Microsoft windows

- Labview 2012 which is the latest version of labview has been released recently in year 2012 in the month of August. 

- 'G' is actually a data flow programming language. 

- The structure of the graphical block diagram helps in determining the execution. 

- This graphical block diagram is actually composed of the LV source code using which the different function nodes can be connected via wires. 

- Variables are propagated by these wires. 

- Any node for which all the input data is available can be put in to execution immediately. 

- It involves a number of modes simultaneously, parallel execution is very much possible in G.

- Built-in scheduler is automatically exploited through multi–threading and multi– processing hardware.

- Multiple OS threads are multiplexed by the built – in scheduler over the nodes that are ready to be executed. 

- User interfaces called front panels are created by the labview and incorporated in to the development cycle. 

- The programs or subroutines of the labview are termed as virtual instruments or VIs. 

There are 3 main components of each VI namely:

1. A block diagram
2. A front panel and
3. A connector panel

- The third component i.e., the connector panel is used for the representation of the virtual instrument in the other virtual instruments which call this one. 

- Front panel comprises of the indicators and controls, thus allowing the operator to input or extract data from an active virtual instrument. 

- Another feature of the front panel is that it also serves as a programmatic interface. 

Thus, a virtual instrument can be run in either of the two ways:

1. As a program: The front panel serves as a user interface.
2. As a node on to the block diagram: The inputs and outputs for a particular node are defined by the front panel through the connector panel.

- Any of the virtual instruments can be tested very easily before it is embedded in to the main program as a subroutine. 

- Even non-programmers can take the benefit of the graphical approach since using it, they can build programs by just dragging and dropping the lab equipment’s’ virtual representation with which they have some familiarity. 

- Advantage is that the labview programming environment comes with documentation and some included examples which can be used to work out small applications very easily. 

- There is one disadvantage also which is that one might underestimate the expertise required from implementing high quality G – programming.

- Also, as far as complex programming or large scale programming is concerned it is a must for the programmer to have an extensive knowledge regarding the labview syntax and the topology it uses for the management of memory. 

- The advanced development system of the labview lets you create stand –a lone applications also.

How to run a test automatically in Test Director?

The whole testing process revolves around the execution of the tests. As the changes are introduced in to the software system or application, running tests either manually or automatically becomes mandatory so that the defects can be located and quality can be assessed. 

How are tests run?

- One starts the testing process with the creation of the tests and adding these tests to a test set. 

- Tests are grouped into test sets by the test director so that some specific goals can be achieved. 

- Execution process of the tests can be controlled via the various controls provided by the test director. 

- Along with these controls, there are certain conditions and settings which need to be configured for the execution of the tests as desired by the tester. 

- The date and time can also be scheduled when the tests will be executed. 

- Once the tests have been defined the tester can begin with the execution of the tests. 

- Whenever the tests are executed manually, it is basically the test steps that were defined earlier during the test planning which are executed one by one. 

- The steps are passed or failed by the tester depending up on whether there is a match between the expected results and the actual results. 

- For the automatic run of a test, the selected tool is directly opened by the test director and the test is run. 

- The result hence obtained is exported to the test director. 

- Setting conditions and specifying date and time for the execution of a test both can be done with the help of the execution flow tab.

- In the execution, one thing should be noticed which is that the condition is always dependent on the result of some other specified test in the same flow. 

- Also, the sequence in which the tests are to be executed can be specified. 

In this article we shall see how the test execution can be automated. The tool selected for the execution of the tests is opened directly by the test director and the tests are run on either local or remote machine. It is either choice if you want to run all the tests or some specified ones. 

For running the tests automatically one of the following tools must be installed on the system:

a)   Astra quick test

b)   Quick test professional

c)   Winrunnner

Follow the below mentioned steps:

1. Clicking on the test lab tab will display the test lab module. This is a must for the automation of the tests.
2. The test set you want to execute automatically should be displayed in the execution grid. For doing this click on the execution grid tab and select the required test from the test sets tree.
3. Select a test. For running the winrunner test select the required test or if you want to run an astra quick test or QTP test select the required one. Next clicking on the run button will open up the execution dialog box and the test will be displayed.
4. Configure the test run settings and select the ‘run all tests locally’ option for running the tests on the local machine.
5. For running the tests click on run tests and the tool will be opened automatically by the test director and the tests will be run. The execution progress can be viewed in the status column.
6. Once the execution of the test is complete close the execution dialog box by clicking on the exit option.
7. Also the summary of the test results can be viewed in the execution grid.

When do you use Break Points? What is Toggle Break Points? How it differ from Break points?

What you got to do when you are in need of pausing a test run in between its execution? 

- Break points are used to mark such points in the test script where you want the test to be paused. 

- Break points have proved to be a very useful tool in the discovery of the flaws that might be present in a test script. 

- A break point marker marks the break point present in the test script. 

- This break point marker resides in the left margin of the test scripts.

- The test run is paused by the winrunner whenever it encounters a break point. 

- On a particular break point following tasks can be carried out:

1. The effects of the test run can be examined.
2. The current value of the variables can be viewed.
3. Any necessary changes can be made.
4. Test can be continued to further execution.

How to use Break Points?

- To continue the execution of the test after completing the task to be carried out on the break point the “run from arrow” command can be given and the test will restart from the break point. 

- Once, it gets in to the execution process again it will continue to execute until and unless it encounters another break point or till the test is complete. 

- One thing that should always be taken care of is to make sure that the winrunner is out of batch mode otherwise it won’t pause. 

- For winrunner to pause on break points, it is mandatory that it comes out of the batch mode. 

- If it is not, it is sure to ignore the break points. 

- There are 3 main uses of the break points:

1. They are used to suspend the test run at a particular point so that the state of your software system or application can be inspected.
2. They are used for monitoring the entries that are there in the watch list.
3. They are used to mark certain points throughout the test script for the stepping purpose by using the step commands.

Types of Break Points

We have two types of break points as mentioned below:

1. Break at location point: This break point makes the test to stop at some line number specified by the user in a test script and
2. Break in function point: This break point makes the test to stop whenever a functioned specified by the user is called in a loaded compiled module.

The break points that you define in a session remain active for that particular winrunner session only. Once you terminate that particular winrunner then you must redefine the break points to continue the debugging of the test script in the successive session.

Toggle Break Point and how they differ from normal break point

- Toggle break point command is used whenever you have to set a break at the location break point. 

- For doing this, you just need to move the point of insertion to that line of the test script where according to your desire the test must stop executing. 

- Now go to the debug menu and click on the option “toggle break point” or you can simply go for the button entitled toggle break point. 

- Once you have clicked on this you can observe a symbol of break point towards the left margin of the current window of the winrunner. 

- This break like other break points is also listed in the break points list.

- There is just one simple difference which is that the toggle break points automatically make use of the pass count of 0 and if some other pass count is required these break points can be easily modified. 

What is meant by Step and Step into in WinRunner?

Winrunner provides certain run commands commonly known as the winrunner run commands which help in the execution of your test cases. Whenever a test is in the process of running, it is marked by an execution arrow in the left margin of the test scripts indicating that particular TSL statement has been interpreted. 

The winrunner provides 6 typical run commands which have been mentioned below:

1. Run from top: There is also a button corresponding to this command called the “from top” button and clicking on this will cause the active test to start running from the first line of its test script. If another test is called by a test then the test script of the called test is also displayed by the winrunner. The execution takes place till the last line in the test script has been entered.

2. Run from arrow: There is also a button corresponding to this command called the “from arrow” button and clicking on this will cause the active test to start running from that line of the test script which has been marked by an execution arrow. In rest of aspects, this command shares a lot common with the previous mentioned command.

3. Run minimized commands: These commands help in making sure that the entire screen is available to the software system or application that is being tested. Actually, when you use the minimize commands the winrunner window is shrunk to an icon while the test keeps on executing. When the test comes to an end or is paused or stopped the winrunner grows back to its usual size. The following are the available run minimized commands:

        a)   Run minimized > from arrow command and

        b)   Run minimized > from top command

    4. Stop command

   5. Pause command: This command is used whenever there is a need for the temporary suspension of the test run.

   6. Step commands: These commands help in the execution of a single TSL statement in a test script. Buttons called step buttons are also available for these step commands. Step commands available are:

           a)   Step command

           b)   Step into command

           c)   Step out command

           d)   Step to cursor command 

   

   We shall now discuss these step commands in detail. 

    - After a test has been created, it should be checked that whether or not it runs smoothly without giving any errors in logic as well as in syntax. 

   - The step commands come very handy for the detection and isolation of the defects present in the test script. 

    

    With the help of step command, a single line of the test script can be executed. You can either choose the step command or go for step button for the execution of the current line of the script which has been marked by the execution arrow.

- With the help of step into command, another user defined function as well as test can be called and displayed as well. 

- If a function is called by the current line of the active test script then the function settings and startup applications are not implemented. 

- Later, the step out or step commands can be used for a continuous run of the test.

   - The step out command is often applied in conjunction with the step into command i.e., it is used only after you have entered the user defined function or test and thus completes the execution of the user defined function or the called test. 

   Now what if you want to run a particular portion of the test script? Here in such cases you can use the step in to cursor command. 

   - This command helps in executing a portion of the test script that has been selected by the user.