Editing Michigan Terminal System (section)

==System architecture==
{| class=wikitable style="float: right;" border=1 align="center"
|+ MTS Architecture<ref>[http://archive.michigan-terminal-system.org/discussions/figure-1-from-mts-lecture-1/1original/mts-lecture-1-original MTS Lecture 1], a transcription of the first in a series of lectures on the internals of the Michigan Terminal System given by Mike Alexander, Don Boettner, Jim Hamilton, and Doug Smith, c. 1972</ref>
!
!State
!Mode<ref name=Protection1977/>
!VM
!Interrupts
|-
|align="center" |User programs
|align="center" rowspan=3|problem
|align="center" |user
|align="center" rowspan=2|on
|align="center" rowspan=3|on
|-
|align="center" |Command Language Subsystems (CLSs),<br>Device Support Routines (DSRs),<br>System Subroutines
|align="center" rowspan=2|system
|-
|align="center" |Job programs (MTS, PDP, DMGR, RM or HASP, ...)
|align="center" |on or off
|-
|align="center" |Supervisor (UMMPS)
|align="center" |supervisor
|align="center" |n/a
|align="center" |off
|align="center" |off
|-
|align="center" |S/360-67 or S/370 hardware
|align="center" colspan="4"|
|}

{{main|MTS system architecture}}

UMMPS, the supervisor, has complete control of the hardware and manages a collection of job programs.<ref name=Alexander1972/> One of the job programs is MTS, the job program with which most users interact.<ref name=MTSVol1/> MTS operates as a collection of command language subsystems (CLSs). One of the CLSs allows for the execution of user programs. MTS provides a collection of system subroutines that are available to CLSs, user programs, and MTS itself.<ref name=MTSVol3/> Among other things these system subroutines provide standard access to Device Support Routines (DSRs), the components that perform device dependent input/output.