The fourth component in the memo pad system is the INMEMO subroutine file (INMEMO.SBR). The routine is reentrant, so it may be loaded into system memory or into user memory. If not previously loaded into either one, it will be fetched from the disk when needed. The routine has several parameters which tell it the position on the screen, the auxiliary file channel, and various options. This is described in greater detail in the following sections.