### Answer:

`0xFF00AA11`.

Little Endian
AddressContents
4003 FF
4002 00
4001 AA
4000 11
Big Endian
AddressContents
4003 11
4002 AA
4001 00
4000 FF

To answer the question, remember:

1. The address used for a group of bytes is the smallest address of the four.
2. What goes in that byte is:
• Big Endian: the big end
• Little Endian: the little end
3. The remaining three bytes are filled in sequence.

# Portability Problems

When a word is loaded from memory, the electronics puts the bytes into the register in the correct order. Operations (such as addition) inside the processor use the same order. When the register is stored to memory the bytes are written in the same order. As long as the electronics is consistent, either byte order works. Usually you don't need to think about which order is used.

However, when data from one computer is used on another you do need to be concerned. Say that you have a file of integer data that was written by an old mainframe computer. To read it correctly, you need to know (among other things):

• The number of bits used to represent each integer.
• The representational scheme used to represent integers (two's complement or other).
• Which byte ordering (little or big endian) was used.

### QUESTION 5:

Data is sent across the Internet as groups of bit patterns (of course!) Does the byte ordering matter with Internet data?