1520 INT 15 - MultiDOS Plus v4.01 - CHECK IF MULTITASKING ENABLED
152000 INT 15 U - DOS 3.0+ PRINT.COM - DISABLE CRITICAL REGION FLAG
152001 INT 15 U - DOS 3.0+ PRINT.COM - SET CRITICAL REGION FLAG
152010 INT 15 - OS HOOK - SETUP SYSREQ ROUTINE (AT,XT286,PS50+)
152011 INT 15 - OS HOOK - COMPLETION OF SYSREQ FUNCTION (AT,XT286,PS50+)