This paper presents storage structures and algorithms for the efficient manipulation of general-purpose large unstructured objects in a database system. The large object is stored in a sequence of variable-size segments, each of which consists of a large number of physically contiguous disk blocks. A tree structure indexes byte positions within the object. Disk space management is based on the binary buddy system. The scheme supports operations that replace, insert, delete bytes at arbitrary positions within the object, and append bytes at the end of the object. 1. INTRODUCTION The manipulation of large objects is becoming an increasingly important issue of many so called unconventional database applications such as geographical, image analysis, computeraided design (VLSI, mechanical, software engineering), office automation for document processing and publishing, and multimedia presentation. The latter are perhaps the most noticeable applications that demand efficient storage and ret...