What is the main purpose of the National Electrical Code?

What is the main purpose of the National Electrical Code?

The NEC (the National Fire Protection Association’s NFPA 70) is a widely-adopted model code for the installation of electrical components and systems. Its purpose is to safeguard persons and property from hazards arising from the use of electricity (NEC 90.1(A)).

What are the two basic types of conventional framing?

Two basic methods are used for framing a house: platform and balloon-frame construction. Platform construction is much more common than balloon framing, though balloon framing was employed in many two-story houses before 1930.

What are different types of framing method?

Types of Framing Framing can be of two types, fixed sized framing and variable sized framing. Here the size of the frame is fixed and so the frame length acts as delimiter of the frame. Consequently, it does not require additional boundary bits to identify the start and end of the frame. Example − ATM cells.

What is framing and its need?

Framing is a point-to-point connection between two computers or devices consists of a wire in which data is transmitted as a stream of bits. However, these bits must be framed into discernible blocks of information. It provides a way for a sender to transmit a set of bits that are meaningful to the receiver.

What are the disadvantages of character count method?

Character Count The disadvantage is that if the count is garbled by a transmission error, the destination will lose synchronization and will be unable to locate the start of the next frame. So, this method is rarely used.

How can the receiver detect the start and the end of the frame?

That is, how can the receiver recognize the start and end of a frame? Length Count: Make the first field in the frame’s header be the length of the frame. That way the receiver knows how big the current frame is and can determine where the next frame ends.

Which one of the following is the multiple access protocol for channel access control?

CSMA

Which one is better either byte or bit stuffing?

Byte – Stuffing − A byte is stuffed in the message to differentiate from the delimiter. This is also called character-oriented framing. Bit – Stuffing − A pattern of bits of arbitrary length is stuffed in the message to differentiate from the delimiter. This is also called bit – oriented framing.

Why is stuffing used?

Bit stuffing may be used to synchronize several channels before multiplexing or to rate-match two single channels to each other. Another use of bit stuffing is for run length limited coding: to limit the number of consecutive bits of the same value in the data to be transmitted.

What is bit stuffing and why is it used?

Bit stuffing is the process of inserting noninformation bits into data to break up bit patterns to affect the synchronous transmission of information. It is widely used in network and communication protocols, in which bit stuffing is a required part of the transmission process.

What is bit padding?

Bit padding is the addition of one or more extra bits to a transmission or storage unit to make it conform to a standard size. Some sources identify bit padding as a type of bit stuffing. It also refers to the term “bit stuffing”.

What is the advantage of structure padding?

Padding increases the performance of the processor at the penalty of memory. In structure or union data members aligned as per the size of the highest bytes member to prevent the penalty of performance.

Why do we need structure padding?

In order to align the data in memory, one or more empty bytes (addresses) are inserted (or left empty) between memory addresses which are allocated for other structure members while memory allocation. This concept is called structure padding.

What is structure padding How do you avoid it?

So, to avoid structure padding we can use pragma pack as well as an attribute. Below are the solutions to avoid structure padding: Program-1: Using pragma pack. // C program to avoid structure. // padding using pragma pack.

What is structure padding?

Structure padding is a concept in C that adds the one or more empty bytes between the memory addresses to align the data in memory.

What is actually passed if you pass a structure variable to a function?

5) What is actually passed if you pass a structure variable to a function.? Explanation: Yes. If you pass a structure variable by value without & operator, only a copy of the variable is passed.

What is basic difference between padding and packing?

So a packed structure is a structure without padding. Since the size of char is 1, the padding for a and c is 4 – 1 = 3 bytes while no padding is required for int b which is already 4 bytes. It works the same way for mystruct_B .

What do you mean by structure member alignment padding and data packing?

Data structure alignment is the way data is arranged and accessed in computer memory. Data alignment means putting the data at a memory address equal to some multiple of the word size, which increases the system’s performance due to the way the CPU handles memory. …

What is Pragma pack?

The #pragma pack directive modifies the current alignment rule for only the members of structures whose declarations follow the directive. It does not affect the alignment of the structure directly, but by affecting the alignment of the members of the structure, it may affect the alignment of the overall structure.

How are structure members stored in memory?

1. How structure members are stored in memory? Always, contiguous(adjacent) memory locations are used to store structure members in memory. Consider below example to understand how memory is allocated for structures.