A model in which a transmitterTsends a message to a receiverRvia shared random-access memory is analyzed. In the model, the random-access memory consists ofLindividually addressable cells, each of which may be set to a value from a finite alphabet. A messagemis sent by writing values into some of the memory cells so that the memory state is consistent with some codeword form. The model differs from traditional source coding in several respects. The codeword may specify values for a noncontiguous subset of the memory cells and allow the remaining unspecified cells to be filled in by other users as they wish. Also, the transmitterTmay attempt to avoid writing a full codeword into memory by first reading some cells to determine the initial memory state partially. Thus, the cells accessed for transmission and the cells specified by a codeword may be distinct, unlike traditional noiseless source coding where the symbols sent and symbols received are identical. Here we analyze the operational characteristics of the transmitterT. It is shown that the number of accesses byTobeys a generalized Kraft inequality. Lower bounds are given for the worst case and average number of accesses.