Abstract: A portable radio telephone apparatus and including a first memory and a second memory for storing variable length records and validity confirmation indicators, indicating confirmed or unconfirmed validity, associated with each record, and memory defragmentation for identifying a first record in the first memory which is adjacent an available memory fragment; providing a second record in the second memory which is a duplicate of the first record having its validity confirmation indicator set to unconfirmed validity; setting the validity confirmation indicator of the second record to confirmed validity; setting the validity confirmation indicator of the first record to unconfirmed validity; providing a third record in the first memory at the location of said available memory fragment having its validity confirmation indicator set to unconfirmed validity; setting the validity confirmation indicator of the third record to confirmed validity; and setting the validity confirmation indicator of the second record to