#### What type of number “3 D“ is? Why? What do you mean by BCD and EBCDIC?

Subject | Introduction to Computer System |
---|---|

NU Year | Set: 3.(d) Marks: 4 Year: 2009 |

3D is a Hexa-decimal number.

# Binary
Coded Decimal

**Binary Coded Decimal** or BCD as it is more commonly called, is another process for
converting decimal numbers into their binary equivalents.

As we naturally live in a
decimal (base-10) world we need some way of converting these decimal numbers
into a binary (base-2) environment that computers and digital electronic
devices understand, and binary coded decimal code allows us to do that.

We have seen previously that an n-bit binary
code is a group of “n” bits that assume up to 2^{n} distinct combinations of 1’s and 0’s. The advantage of the Binary Coded Decimal system is
that each decimal digit is represented by a group of 4 binary digits or bits in
much the same way as Hexadecimal. So for the 10 decimal digits (0-to-9) we need
a 4-bit binary code.

# EBCDIC (Extended Binary Coded Decimal Interchange
Code)