EBCDIC code 1111 1001 represents the character _______

Question

Accepted Answer

The correct option is (4):
The EBCDIC (Extended Binary Coded Decimal Interchange Code) character set is an 8-bit code used primarily by IBM mainframe operating systems. An EBCDIC code is conceptually split into two 4-bit sections: the high-order bits, known as the Zone nibble, and the low-order bits, known as the Digit nibble. For the decimal digits (0 through 9), the Zone nibble is consistently set to **1111** (Hex F). The specific value of the digit is then encoded in the Digit nibble (1001 for '9'). Therefore, the full code 1111 1001 correctly combines the numeric zone (1111) with the binary representation of the value 9 (1001), confirming that it represents the character '9'.

The incorrect option is (1):
The character 'F' (uppercase) is an alphabetic character and belongs to a different Zone class in the EBCDIC standard. The Zone nibble for the block of letters F, G, H, I is 1100 (Hex C). The Digit nibble for 'F' is 0110 (Hex 6). Thus, the correct EBCDIC code for 'F' is **1100 0110**. The provided code uses a Zone nibble of 1111, which designates a numeric or control character, not a letter in this zone, making Option 1 incorrect.

The incorrect option is (2):
The character 'R' (uppercase) is also an alphabetic character but is located in another Zone class. The EBCDIC Zone nibble for the letters J through R is 1101 (Hex D). The Digit nibble for 'R' is 1001 (Hex 9). This means the correct EBCDIC code for 'R' is **1101 1001**. Since the Zone nibble of the given code is 1111, which is the code for numeric characters and not the 1101 Zone required for the letter 'R', this option must be false.

The incorrect option is (3):
The character 'I' (uppercase) shares the same Zone nibble as 'F' in EBCDIC. The Zone nibble is 1100 (Hex C), and the Digit nibble for 'I' is 1001 (Hex 9). Consequently, the EBCDIC code for 'I' is **1100 1001**. The code in the question, 1111 1001, has a numeric Zone nibble (1111) instead of the required alphabetic Zone nibble (1100), which clearly demonstrates that it does not represent the character 'I'.