There are three stages in this process. These are:

 Qualification,
 Adaptation (also known as wrapping),
 Composition (all in the context of components).

Component qualification: examines reusable components. These are identified by characteristics in their interfaces, i.e., the services provided, and the means by which consumers access these services. This does not always provide the whole picture of whether a component will fit the requirements and the architectural style. This is a process of discovery by the Software Engineer. This ensures a candidate component will perform the function required, and whether it is compatible or adaptable to the architectural style of the system. The three important characteristics looked at are performance, reliability and usability.

Component Adaptation is required because very rarely will components integrate immediately with the system. Depending on the component type(e.g., COTS or inhouse), different strategies are used for adaptation (also known as wrapping). The most common approaches are:

 White box wrapping: The implementation of the component is directly modified in order to resolve any incompatibilities. This is, obviously, only possible if the source code is available for a component, which is extremely
unlikely in the case of COTS.

 Grey box wrapping: This relies on the component library providing a component extension language or API that enables conflicts to be removed or masked.

 Black box wrapping: This is the most common case, where access to source code is not available, and the only way the component can be adapted is by pre / post-processing at the interface level.

It is the job of the software engineer to determine whether the effort required to wrap a component adequately is justified, or whether it would be “cheaper” (from a software engineering perspective) to engineer a custom component which removes these conflicts. Also, once a component has been adapted it is necessary to check for compatibility for integration and to test for any unexpected behavior which has emerged due to the modifications made.

 Ans : The following are the similarities and the differences between the Cleanroom software engineering development and OO software engineering paradigm.

Similarities
 Lifecycle - both rely on incremental development
 Usage - cleanroom usage model similar to OO use case
 State Machine Use - cleanroom state box and OO transition diagram
 Reuse - explicit objective in both process models

Key Differences
 Cleanroom relies on decomposition and OO relies on composition
 Cleanroom relies on formal methods while OO allows informal use case definition and testing
 OO inheritance hierarchy is a design resource whereas cleanroom usage hierarchy is system itself
 OO practitioners prefer graphical representations while cleanroom practitioners prefer tabular representations
 Tool support is good for most OO processes, but usually tool support is only found in cleanroom testing, not design.

 A formal method in software development is a method that provides a formal language for describing a software artifact (e.g., specifications, designs, source code) such that formal proofs are possible, in principle, about properties of the artifact so expressed.

Mathematics supports abstraction and therefore is a powerful medium for modeling. Because they are exact, mathematical specifications are unambiguous and can be validated to uncover contradictions and incompleteness. It allows a developer to validate a specification for functionality. It is possible to demonstrate that a design matches a specification, and that some program code is a correct reflection of a design

How is the mathematics of formal languages applied in software development? What engineering issues have been addressed by their application? Formal methods are of global concern in software engineering. They are directly applicable during the requirements, design, and coding phases and have important consequences for testing
and maintenance.

They have influenced the development and standardization of many programming languages, the programmer’s most basic tool. They are important in ongoing research that may change standard practice, particularly in the areas of
specifications and design methodology. They are entwined with lifecycle models that may provide an alternative to the waterfall model, namely rapid prototyping, the Cleanroom variant on the spiral model, and “transformational” paradigms.

The concept of formalism in formal methods is borrowed from certain trends in 19th and 20th century mathematics. Formal methods are merely an adoption of the axiomatic method, as developed by these trends in mathematics, for software engineering. Mastery of formal methods in software requires an understanding of this mathematics background. Mathematical topics of interest include formal logic, both the propositional calculus and predicate logic, set theory, formal languages, and automata such as finite state machines.

 The OECD an international organization working in the area of data privacy and information security, established an ad hoc process of meetings (the first was on 1-2 July 1997 and second on 22 October 1997) on approaches being taken in major industrial countries for the regulation of content conduct on the Internet. The meeting acknowledged the primary role of the private sector in regulating the Internet. However, at the joint OECD/Business and Industry Advisory Committee forum held on 25 March 1998 in Paris, the OECD resolved to do no further work in this area. On 19 April 2006, OECD task force on spam has recommended that Governments and industry should step up their coordination to combat the global problem of spam. It calls on governments to establish clear national anti-spam policies and give enforcement authorities more power and resources. Co-ordination and co-operation between public and private sectors are critical, the report notes.

• It is faster than stream cipher.
• If any block contains any transmission error then it will not have affect on other blocks.
• It is not sufficient in hardware but may be used to connect keyboard to CPU (central process unit)
• Block ciphers can be easier to implement in software, because there is no bit manipulation like in stream cipher which is time consuming process and treats data in computer-sized blocks
• Block Cipher is more suitable in trading applications.
• Short blocks at the end of a message can also be added with blank or zero status.

 If you need to line up the cells next to each other you can resize and move the layout cells as you need. You can change the size of a layout cell by using one of its resize handles.

You cannot click and drag a cell to move it to a new position. If you need to move a layout cell to reposition it in a document, follow these steps

1. Click the border of a layout cell to select it.
2. To move the layout cell, do one of the following:
   
   1- Use the arrow keys.
   2- Hold down Shift and use the arrow keys to move a layout cell 5 pixels at a time.

• With no arguments and with no return value.
• With no arguments and with return value
• With arguments and with no return value
• With arguments and with return value

 Besides three storage class specifications namely, Automatic, External and Static, there is a register storage class. Registers are special storage areas within a computer’s CPU. All the arithmetic and logical operations are carried out with these registers.

For the same program, the execution time can be reduced if certain values can be stored in registers rather than memory. These programs are smaller in size (as few instructions are required) and few data transfers are required. The reduction is there in machine code and not in source code. They are declared by the proceeding declaration
by register reserved word as follows:

register int m;

Points to remember:

• These variables are stored in registers of computers. If the registers are not available they are put in memory.
• Usually 2 or 3 register variables are there in the program.
• Scope is same as automatic variable, local to a function in which they are declared.
• Address operator ‘&’ cannot be applied to a register variable.
• If the register is not available the variable is though to be like the automatic variable.
• Usually associated integer variable but with other types it is allowed having same size (short or unsigned).
• Can be formal arguments in functions.
• Pointers to register variables are not allowed.
• These variables can be used for loop indices also to increase efficiency.

 In case of single file programs static variables are defined within functions and individually have the same scope as automatic variables. But static variables retain their values throughout the execution of program within their previous values.

Points to remember:
• The specifier precedes the declaration. Static and the value cannot be accessed outside of their defining function.
• The static variables may have same name as that of external variables but the local variables take precedence in the function. Therefore external variables maintain their independence with locally defined auto and static variables.
• Initial value is expressed as the constant and not expression.
• Zeros are assigned to all variables whose declarations do not include explicit initial values. Hence they always have assigned values.
• Initialization is done only is the first execution

 These are not confined to a single function. Their scope ranges from the point of declaration to the entire remaining program. Therefore, their scope may be the entire program or two or more functions depending upon where they are declared.

Points to remember:
• These are global and can be accessed by any function within its scope.
Therefore value may be assigned in one and can be written in another.
• There is difference in external variable definition and declaration.
• External Definition is the same as any variable declaration:

            • Usually lies outside or before the function accessing it.

• It allocates storage space required.
• Initial values can be assigned.
• The external specifier is not required in external variable definition.
• A declaration is required if the external variable definition comes after the function definition.
• A declaration begins with an external specifier.
• Only when external variable is defined is the storage space allocated.
• External variables can be assigned initial values as a part of variable definitions, but the values must be constants rather than expressions.
• If initial value is not included then it is automatically assigned a va

 The variables local to a function are automatic i.e., declared within the function. The scope of lies within the function itself. The automatic defined in different functions, even if they have same name, are treated as different. It is the default storage class for variables declared in a function.

Points to remember:
• The auto is optional therefore there is no need to write it.
• All the formal arguments also have the auto storage class.
• The initialization of the auto-variables can be done:

           • in declarations
           • using assignment expression in a function

• If not initialized the unpredictable value is defined.
• The value is not retained after exit from the program.

 LCDs are the screens of choice for portable computers and lightweight screens. They consume very little electricity and have advanced technologically to quite good resolutions and color support. They were developed by the company RCA in the 1960s. LCDs function simply by blocking available light so as to render display patterns.

LCDs can be of the following types:

1. Reflective LCDs: Display is generated by selectively blocking reflected light.
2. Backlit LCDs : Display is due to a light source behind LCD panel.
3. Edgelit LCDs : Display is due to a light source adjacent to the LCD panel.

 

LCD Technology
The technology behind LCD is called Nematic Technology because the molecules of the liquid crystals used are nematic i.e. rod-shaped. This liquid is sandwiched between two thin plastic membranes. These crystals have the special property that they can change the polarity and the bend of the light and this can be controlled by grooves in the plastic and by applying electric current.

Passive Matrix
In a passive matrix arrangement, the LCD panel has a grid of horizontal and vertex conductors and each pixel is located at an intersection. When a current is received by the pixel, it becomes dark. This is the technology which is more commonly used,

Active Matrix
This is called TFT (Thin Film Transistor) technology. In this there is a transistor at every pixel acting as a relay, receiving a small amount and making it much higher to activate the pixel. Since the amount is smaller, it can travel faster and hence response times are much faster. However, TFTs are much more difficult to fabricate and are costlier

 We have discussed about resolutions and vertical and horizontal refresh rates in the section on Video Cards. Let us refer to them from the monitor point of view. So, we have the following definitions (from the manual of a monitor available in the market):

Horizontal Frequency: The time to scan me line connecting the right edge to the left edge of the screen horizontally is called the horizontal cycle and the inverse number of the Horizontal cycle is called Horizontal Frequency. The unit is KH Kilo Hertz),

Verticals Frequency: Like a Fluorescent lamp, the screen has to repeat the same Image many times per second to display an image to the user, The frequency of this repetition is called Vertical Frequency or Refresh Rate.

If the resolution generated by the video card and the monitor resolution is properly matched, you get a good quality display. However, the actual resolution achieved is a physical quality of the monitor. In color systems, the resolution is limited by Convergence (Do the beam of the 3 colors converge exactly on the same dot? ) and the Dot Pitch. In monochrome monitors, the resolution is only limited by the highest frequency signals the monitor can handle.

 3D Accelerator is no magic technology. It is simply an accelerator chip that has built-in ability to carry out the mathematics and the algorithms required for 3-D image generation and rendering. A 3-D imaging is simply an illusion, a projection of 3-D reality on a 2-D screen. These are generated by projection and perspective effects, . depth and lighting effects, transparency effects and techniques such as Ray-Tracing (Tracing the path of light rays emitting from a light source), Z-buffering (a buffer strong the

 The other popular way Ls to attach a disk drive to a PC via a SCSI interface. The common drive choice for servers or high-end workstations with drive capacities ranges from 100MB to 20GB and rotation speed 7200RPM, It is w common 110 interface between the adapter and disk drives or any other peripheral, I.@., CP; ROMs drives, @pe drives, printers etc.

 DE devices art connected to the PC motherboard via a 34-wire ribbon cable, The common drive used today for workstations has capacities of 40MB to 100MB and rotation speed 72QORPM. The controller is embedded on the disk drive Itself, It is an interface between the disk controller and an adopter located on the motherboard. It has good access time of 20ms and data transfer rates of about 1 Mbps under ideal conditions, Drives are reasonably cheap, The latest version of the IDE specification enables four IDE channels: each one Is capable of supporting two JDE devices.

 The debugger is a program that allows the user to test and debug the object file. The user can employ this program to perform the following functions.

1. Make changes in the object code.
2. Examine and modify the contents of memory.
3. Set breakpoints, execute a segment of the program and display register contents after the execution.
4. Trace the execution of the specified segment of the program and display the register and memory contents after the execution of each instruction.
5. Disassemble a section of the program, i.e., convert the object code into the source code or mnemonics.

In summary, to run an assembly program you may require your computer:
1. A word processor like notepad
2. MASM, TASM or Emulator
3. LINK.EXE, it may be included in the assembler
4. DEBUG.COM for debugging if the need so be.

 Loader is a program which assigns absolute addresses to the program. These addresses are generated by adding the address from where the program is loaded into the memory to all the offsets. Loader comes into action when you want to execute your program. This program is brought from the secondary memory like disk. The file name extension for loading is .exe or .corn, which after loading can be executed by the CPU

 For modularity of your programs, it is better to break your program into several sub routines. It is even better to put the common routine, like reading a hexadecimal number, writing hexadecimal number, etc., which could be used by a lot of your other programs into a separate file. These files are assembled separately. After each file has been successfully assembled, they can be linked together to form a large file, which constitutes your complete program. The file containing the common routines can be linked to your other program also. The program that links your program is called the linker.