kilobyte (1024 bytes) not 1000 as you might expect (1 meg
= 1024 kilobytes (k for short)  This stems from the
computers binary mode of  operation. This number system is
based on the number 2 and powers of 2. We will not go
furhter into this either. Other number systems
 are used in computer programming such as Hexadecimal
and some decimal.

Some explanations
_________________

BIT - This is a single binary digit , 1 or 0 (off/on)

BYTE - a byte is represented as a number between 0 - 255
(dec) 2^8 (bin) and 0 - FF (hex) (8 bits)

WORD - a number between 0 - 65536 (dec (two bytes or 16
bits)) FFFF (hex) etc (16 bits)

LONG WORD - a number between 0 - 4294967295 (dec (four
bytes or 32bits)!!!!

The computer's main processor has things called registers.
These are used to store memory addresses and data. In fact
your computer will  probably have registers for both. E.g:
lets assume 8 data ,D0 - D7 and 8 address  A0 - A7 . You