The suggestions are based on observations and comments by people who are experienced in operating data processing installations. It is recommended that organizations control access to the system area and define responsibilities for the security of data, systems, and programs. Other suggestions are to involve several people in sensitive functions, to indoctrinate personnel with the importance of security and their individual responsibilities in achieving it, and to maintain a data inventory or other measure of the value of the organization's data holdings. Organizations are also advised to take prompt and decisive corrective action when security is jeopardized or lost to protect themselves against the destructive activities of disgruntled data processing personnel. Further recommendations are the establishment of emergency security procedures and avoidance of identifying data processing centers. Additional recommendations are that exterior glass walls and windows not be placed in vulnerable locations, that the system be protected against smoke damage through the use of dampers and plastic covers, and that the system be protected against water damage from leaking pipes or sprinkler systems. Further areas covered in the recommendation include relationships with the local fire department, protection against power failures, keys and passwords, portable transceivers, backup files and processing facilities, trash, supplies, programs, and personnel. Brief explanations and further suggestions accompany each of the 42 major points.