Hi oha , I am very grateful to you and the other people who have shared their insights with me regarding the question I posed earlier today . I hope that those other than oha will also receive this thank you note , I am just learning how to get around at this time , within this amazing forum . In my initial code , I thought that because I was pushing anonymous arrays into @X , somehow , in the undef of @X the anonymous arrays still existed somewhere and took up MEM . With your code oha , you create and initialize a 1d array , and it seems as though undef behaves differently when the array elements have been initialized to some value / string as opposed to being unitialized. In my previous coding work , I had always assumed , undef -ing an array which say took up 100 MB , would release the 100 MB back to the system . I am still trying to assimilate the information you have all provided. Thank you . Nova .