1. A computer readable medium having stored thereon a data structure for storing data objects in a range of memory, the data structure comprising: a contiguous range of memory of the data record in which data objects are stored, the range of memory having a first end and a second end; a first list associated with the first end of the contiguous range of memory to which data objects are related, the first list increasing in length toward the second end as data objects are written to the first list; and a second list associated with the second end of the contiguous range of memory to which data objects are related, the second list increasing in length toward the first end as data objects are written to the second list.