Record Management Services (RMS) are procedures in the VMS, RSTS/E, RT-11 and RSX-11Moperating systems that programs may call to process files and records within files.[1][2] Its file formats and procedures are similar to of those in some IBM access methods[a] for several of its mainframe computer operating systems[b] and by other vendors for file and record management. VMS RMS is an integral part of the system software; its procedures run in executive mode. (RMS was not initially integrated into RT-11 and RSTS/E, but was available as an added charge "layered product". It was later added to RSTS/E and was a part of its standard documentation set.)