RFC734 - SUPDUP Protocol

NWG/RFC# 734				        MRC 07-OCT-77 08:46  41953SUPDUP Display PRotocol						    Page 1Network Working Group					      Mark CrispinRequest for Comments 734					     SU-AINIC 41953						    7 October 1977			  SUPDUP ProtocolINTRODUCTIONThis document describes  the SUPDUP protocol,  a highly efficient  displaytelnet protocol.  It originally started as a private protocol between  theITS systems at MIT to allow a user at any one of these systems to use  oneof the others as a display.  At the current writing, SUPDUP user  programsalso exist  for  Data  Disc  and  Datamedia  displays  at  SU-AI  and  forDatamedias at SRI-KL.  The author is not aware of any SUPDUP servers otherthan at the four MIT ITS sites.The advantage  of  the  SUPDUP  protocol  over  an  individual  terminal'sprotocol is that SUPDUP defines a "virtual" or "software" display terminalthat implements relevant  cursor motion Operations.   The protocol is  notbuilt on  any  particular  display  terminal but  rather  on  the  set  offunctions common to all display terminals; hence it is completely  device-independent.  In addition, the protocol also provides for terminals  whichcannot handle certain operations, such as line or character insert/delete.In fact,  it is  more than  this.   It provides  for terminals  which  aremissing any set of features, all the way down to model 33 Teletypes.The advantage over the TELNET protocol  is that SUPDUP takes advantage  ofthe full  capabilities of  display  terminals, although  it also  has  theability to run printing terminals.It is to be  noted that SUPDUP operates  independently from TELNET; it  isnot an option to  the TELNET protocol.   In addition, certain  assumptionsare made about the  server and the user  programs and their  capabilities.Specifically, it is  assumed that the  operating system on  a server  hostprovides all the display-oriented features of ITS.  However, a server  mayelect not to do certain display operations available in SUPDUP; the SUPDUPprotocol is far-reaching enough so  that the protocol allows terminals  tobe handled  as well  as that  host can  handle terminals  in general.   Ofcourse, if a host does not  support display terminals in any special  way,there is no point in bothering  to implement a SUPDUP server since  TELNETwill work just as well.A more complete description  of the display facilities  of SUPDUP and  ITScan be found by FTP'ing the  online file .INFO.;ITS TTY from ARPAnet  hostMIT-AI (host 206 octal, 134. decimal).  For more information, the  mailingaddress for SUPDUP is "(BUG SUPDUP) at MIT-AI".  If your mail system won'tallow you to use parentheses, use Bug-SUPDUP@MIT-AI.SUPDUP Display Protocol						    Page 2
                         BACKGROUNDThe SUPDUP protocol originated as the internal protocol used between partsof ITS, and between ITS and "intelligent" terminals.  Over the network,  auser host acts like an intelligent terminal programmed for ITS.The way terminal  output works  in ITS is  as follows:   The user  programtells the system to  do various operations,  such as printing  characters,clearing the screen, moving the cursor, etc.  These operations are  formedinto 8-bit characters  (using the  %TD codes described  below) and  storedinto a  buffer.   At interrupt  level,  as the  terminal  demands  output,characters are  removed  from  the buffer  and  translated  into  terminaldependent codes.  At this time  padding and cursor motion optimization arealso done.In some cases, the interrupt side does not run on the same machine as  theuser program.  SUPDUP terminals have their "interrupt side" running in theuser host.  When  SUPDUP is  run between two  ITS's, the  SUPDUP user  andserver programs and the network simply move characters from the buffer  inthe server machine to the buffer in the user machine.  The interrupt  sidethen runs on the user machine just as if the characters had been generatedlocally.Due to the highly interactive characteristics of both the SUPDUP  protocoland the ITS system, all transactions are strictly character at a time  andall echoing  is  remote.  In  addition,  all padding  and  cursor  controloptimization must be done by the user.Because this is also the internals of ITS, the right to change it any timeif necessary to provide new features  is reserved by MIT.  In  particular,the initial  negotiation  is probably  going  to be  changed  to  transmitadditional variables, and additional %TD codes  may be added at any  time.User programs should ignore those they don't know about.The following conventions are  used in this  document: function keys  (ie,keys which represent a "function"  rather than a "graphic character")  arein upper case in square brackets.  Prefix keys (ie, keys which generate nocharacter but  rather are  held  down while  typing another  character  tomodify that  character)  are  in  upper case  in  angle  brackets.   Hence"<CONTROL><META>[LINE FEED]" refers to  the character generated when  boththe CONTROL and META keys  are held down while a LINE FEED is typed.  Caseshould  be  noted;  <CONTROL>A  refers  to  a  different  character   from<CONTROL>a.  Finally, all numbers which  do not eXPlicitly specify a  base(ie, octal  or decimal)  should be  read  as octal  unless the  number  isimmediately followed by a period, in which case it is decimal.SUPDUP Display Protocol						    Page 3INITIALIZATIONThe SUPDUP server listens on socket 137 octal.  ICP proceeds in the normalway for establishing 8-bit connections.   After the ICP is completed,  the
                         user side  sends several  parameters to  the server  side in  the form  of36.-bit Words.  Each  word is  sent through  the 8-bit  connection as  six6-bit bytes, most-significant first.  Each byte is in the low-order 6 bitsof a character.  The first word is the negative of the number of variablesto follow in the high order 18. bits (the low-order 18. bits are ignored),followed by the  values of  the TCTYP,  TTYOPT, TCMXV,  TCMXH, and  TTYROLterminal descriptor variables (these  are the names they  are known by  atITS sites).  These  variables are  36.-bit binary numbers  and define  theterminal characteristics for the virtual terminal at the REMOTE host.The count is for future compatability.  If more variables need to be  sentin the future, the server should assume "reasonable" default values if theuser does not specify them.  PDP-10 fans will recognize the format of  thecount (ie, -count,,0) as being an  AOBJN pointer.  At the present  writingthere are five variables hence this word should be -5,,0.The TCTYP variable defines the terminal type.  It MUST be 7 (%TNSFW).  Anyother value is a violation of protocol.The TTYOPT  variable specifies  what capabilities  or options  the  user'sterminal has.  A bit being true implies that the terminal has this option.This variable also includes user options which the user may wish to  alterat his or her own descretion; these options are included since they may bespecified along with the terminal capabilities in the initial negotiation.See below for the relevant TTYOPT bits.The TCMXV variable specifies the screen height in number of lines.The TCMXH variable specifies the line width in number of characters.  Thisvalue is one less  than the screen width  (ITS indicates line overflow  byoutputting an exclamation  point at  the end  of the  display line  beforemoving to the  next line).  Note:  the terminal must  not do an  automaticCRLF when a  character is  printed in the  rightmost column.   If this  isunavoidable, the user SUPDUP must decrement the width it sends by one.Note: Setting either the TCMXV or  TCMXH dimension greater than 128.  willwork, but will have some problems as coordinates are sometimes representedin only  7 bits.   The main  problems occur  in the  SUPDUP protocol  whensending the cursor position after an output reset and in ITS user programsusing the display position codes ^PH and ^PV.The TTYROL variable specifies the "glitch count" when scrolling.  This  isthe number of lines to scroll up when scrolling is required.  If zero, theterminal is not  capable of  scrolling.  1 is  the usual  value, but  someterminals glitch up by more than one line when they scroll.Following the transmission of the terminal options by the user, the servershould respond with an  ASCII greeting message,  terminated with a  %TDNOPcode (%TD codes are described  below).  All transmissions from the  server
                         after the  %TDNOP  are  either printing  characters  or  virtual  terminaldisplay codes.SUPDUP Display Protocol						    Page 4The user  and  the  server  now both  communicate  using  the  intelligentterminal protocol (described below) from the  user and %TD codes from  theserver.  The user has two commands in addition to these; they are  escapedby sending 300  (octal).  If following  the escape is  a 301 (octal),  theserver should attempt to  log off the remote  job (generally this is  sentimmediately before the user disconnects,  so this logout procedure  shouldbe done regardless of the continuing integrity of the connection).  If thecharacter following  the escape  is a  302 (octal),  all ASCII  charactersfollowing up to a null (000  octal) are interpreted as "console  location"which the server  can handle as  it pleases.  No  carriage return or  linefeed should be in the console location text.  Normally this is saved  awayto be displayed by the "who" command when other users ask where this  useris located.SUPDUP Display Protocol						    Page 5TTYOPT FUNCTION BITSThe relevant TTYOPT bits for SUPDUP usage follow.  The values are given inoctal, with the left and right 18-bit  halves separated by ",," as in  theusual PDP-10 convention.Bit name	Value		Meaning%TOALT		200000,,0	characters  175  and 176  are converted to				altmode (033) on input.%TOERS		 40000,,0	this  terminal  is capable  of selectively				erasing its  screen.  That is, it supports				the %TDEOL,  the %TDDLF,  and (optionally)				the  %TDEOF  operations.   For   terminals				which   can   only   do   single-character				erasing, see %TOOVR.%TOMVB		 10000,,0	this  terminal  is capable of  backspacing				(ie, moving the cursor backwards).%TOSAI		  4000,,0	this   terminal   has   the   Stanford/ITS				extended ASCII graphics character set.%TOOVR		  1000,,0	this terminal is  capable of overprinting;				if  two  characters  are  displayed in the				same  position, they will both be visible,				rather than one replacing the other.				Lack of this capability but the capability				to backspace (see %TOMVB) implies that the				terminal can  do single  character erasing				by overstriking with a space.  This allows				terminals without the %TOERS capability to				have display-style "rubout processing", as				this capability depends upon either %TOERS				or [%TOMVB and not %TOOVR].%TOMVU		   400,,0	this terminal  is capable  of  moving  the				cursor upwards.%TOLWR		    20,,0	this  terminal's  keyboard is  capable  of				generating lowercase characters;  this bit				is mostly provided for programs which want				to know this information.%TOFCI		    10,,0	this  terminal's  keyboard is  capable  of				generating  CONTROL and META characters as				described below.%TOLID		     2,,0	this  terminal  is  capable  of doing line				insert/delete operations,  ie, it supports
                         				%TDILP and %TDDLP.%TOCID		     1,,0	this   terminal   is   capable   of  doing				character insert/delete operations, ie, it				supports %TDICP and %TDDCP.SUPDUP Display Protocol						    Page 6TTYOPT FUNCTION BITS (continued)Bit name	Value		Meaning%TPCBS		     0,,40	this terminal is  using  the  "intelligent				terminal protocol".				 THIS BIT MUST BE ON.%TPORS		     0,,10	the server should  process  output  resets				instead of ignoring them.				 IT IS HIGHLY RECOMMENDED THAT THIS BIT BE				ON; OTHERWISE THERE MAY BE LARGE DELAYS IN				ABORTING OUTPUT.The following bits are user  option bits.  They may be  set or not set  atthe user's discretion.  The bits that are labelled "normally on" are thosethat are normally  set on when  a terminal is  initialized (ie, by  typing[CALL] on a local terminal).Bit name	Value		Meaning%TOCLC		100000,,0	convert  lower-case  input to  upper case.				Many  terminals  have  a  "shift lock" key				which makes this option useless.				 NORMALLY OFF.%TOSA1		  2000,,0	characters  001-037  should  be  displayed				using  the  Stanford/ITS  extended   ASCII				graphics character set instead of  uparrow				followed by 100+character.				 NORMALLY OFF.%TOMOR		   200,,0	the   system   should  provide  "**MORE**"				processing when  the  cursor  reaches  the				bottom  line  of  the  screen.    **MORE**				processing is described in ITS TTY.				 NORMALLY ON.%TOROL		   100,,0	the terminal should scroll when attempting				output below the bottom line of the screen				instead of wrapping around to the top.				 NORMALLY OFF.SUPDUP Display Protocol						    Page 7INPUT -- THE INTELLIGENT TERMINAL PROTOCOLNote: only  the parts  of the  intelligent terminal  protocol relevant  toSUPDUP are discussed here.  For more information, read ITS TTY.CHARACTER SETSThere are two  character sets  available for  use with  SUPDUP; the  7-bitcharacter set of standard ASCII, and the 12-bit character set of  extendedASCII.  Extended ASCII has 5 high order  or "bucky" bits on input and  hasgraphics for octal 000-037 and 177 (see the section entitled "Stanford/ITScharacter set" for more details).  The two character sets are identical onoutput since the protocol  specifies that the host  should never send  thestandard ASCII  formatting  characters  (ie,  TAB,  LF,  VT,  FF,  CR)  asformatting characters; the characters whose  octal values are the same  asthese formatting characters are never output unless the user job has thesecharacters enabled (setting %TOSAI and %TOSA1 generally does this).Input differs dramatically  between the 7-bit  and 12-bit character  sets.In the 7-bit character set, all characters input whose value is 037  octalor less  are assumed  to be  (ASCII) control  characters.  In  the  12-bitcharacter set,  there are  5 "bucky"  bits which  may be  attached to  thecharacter.  The two most  important of these are  CONTROL and META,  which
                         form a 9-bit character set.  TOP  is used to distinguish between  printinggraphics in the extended character set and ASCII controls.  The other  twoare reserved and should be ignored.  Since both 7-bit and 12-bit terminalsare commonly in use, 0001, 0301, and 0341 are considered to be  <CONTROL>Aon input by most programs, while 4001 is considered to be downwards arrow.MAPPING BETWEEN CHARACTER SETSMany programs and hosts do not process 12-bit input.  In this case, 12-bitinput is folded down to 7-bit as follows: TOP and META are discarded.   IfCONTROL is on, then if the 7-bit  part of the character specifies a  lowercase alphabetic it is converted to upper  case; then if the 7-bit part  isbetween 077 and 137 the  100 bit is complemented or  if the 7-bit part  is040 the 040 bit is suBTracted  (that's right, <CONTROL>?  is converted  to[RUBOUT] and <CONTROL>[SPACE] is  converted to [NULL]).   In any case  theCONTROL bit is discarded,  and the remainder is  treated as a 7-bit  ASCIIcharacter.  It should be noted that  in this case downwards arrow is  readby the program as standard ASCII <CONTROL>A.Servers which expect 12-bit input and are told to use the 7-bit  characterset should  do  appropriate unfolding  from  the 7-bit  character  set  to12-bit.  It is up  to the individual server  to decide upon the  unfoldingscheme.  On ITS, user programs that use the 12-bit character set generallyhave an alternative method for 7-bit; this often takes the form of  prefixcharacters indicating that the next character should be "controllified" or"metized", etc.SUPDUP Display Protocol						    Page 8INPUT -- THE INTELLIGENT TERMINAL PROTOCOL (continued)BUCKY BITSUnder normal circumstances, characters input from the keyboard are sent tothe foreign host as is.  There  are two exceptions; the first occurs  whenan octal 034  character is to  be sent; it  must be quoted  by being  senttwice, because 034 is used as  an escape character for protocol  commands.The second  exception occurs  when  %TOFCI is  set  and a  character  withnon-zero bucky bits is to be sent.  In this case, the character, which  isin the 12-bit form:Name	Value	Description%TXTOP	4000	This character has the [TOP] key depressed.%TXSFL	2000	Reserved, must be zero.%TXSFT	1000	Reserved, must be zero.%TXMTA	 400	This character has the [META] key depressed.%TXCTL	 200	This character has the [CONTROL] key depressed.%TXASC	 177	The ASCII portion of the characteris sent as three bytes.  The first  byte is always 034 octal (that is  why034 must be  quoted).  The next  byte contains the  "bucky bits", ie,  the%TXTOP through %TXCTL bits,  shifted over 7 bits  (ie, %TXTOP becomes  20)with the 100  bit on.   The third  byte contains  the %TXASC  part of  thecharacter.  Hence the character <CONTROL><META>[LINE FEED] is sent as  034
                         103 012.OUTPUT RESETSThe  intelligent  terminal  protocol  also  is  involved  when  a  networkinterrupt (INR/INS) is  received by  the user program.   The user  programshould increment a count of received network interrupts when this happens.It should not do any output, and if possible abort any output in progress,if this count is greater than zero  (NOTE: the program MUST allow for  thecount to go less than zero).Since the server  no longer  knows where the  cursor is,  it suspends  alloutput until the user informs it of the cursor position.  This also  givesthe server an idea of how much was thrown out in case it has to have  someof the aborted output  displayed at a later  time.  The user program  doesthis when it  receives a  %TDORS from the  server.  When  this happens  itshould  decrement  the  "number  of  received  network  interrupts"  countdescribed in the previous paragraph and then send 034 followed by 020, thevertical position,  and  the  horizontal  position  of  where  the  cursorcurrently is located on the user's screen.SUPDUP Display Protocol						    Page 9OUTPUT -- DISPLAY PROTOCOL (%TD CODES)Display output  is  somewhat  simpler.   Codes less  than  200  octal  areprinting characters and  are displayed  on the terminal  (see the  sectiondescribing the "Stanford/ITS character set").  Codes greater than or equalto 200 (octal) are known as "%TD codes", so called since their names beginwith %TD.  The %TD codes that are relevant to SUPDUP operation are  listedhere.  Any other code  received should be ignored,  although a bug  reportmight be sent  to the server's  maintainers.  Note that  the normal  ASCIIformatting characters (011 - 015) do NOT have their formatting sense underSUPDUP and should not occur at all unless the Stanford/ITS extended  ASCIIcharacter set is in use (ie, %TOSAI is set in the TTYOPT word).For cursor  positioning operations,  the  top left  corner is  (0,0),  ie,vertical position 0, horizontal position 0.%TD code	Value		Meaning%TDMOV		200		General cursor position code.  Followed by				four bytes;  the  first  two are the "old"				vertical  and horizontal positions and may				be  ignored.    The  next  two are the new				vertical  and  horizontal  positions.  The				cursor  should be moved  to this position.				On printing consoles (non %TOMVU), the old				vertical position may differ from the true				vertical position;  this  can  occur  when				scrolling.  In this case, the user program				should set  its  idea of the old  vertical				position to what the %TDMOV says and  then				proceed.  Hence a %TDMOV with an old  vpos				of 20. and a new vpos of 22. should always				move the "cursor" down two lines.  This is				used to prevent the vertical position from				becoming infinite.%TDMV1		201		An  internal  cursor  motion  code   which				should not be seen;  but if it is,  it has				two  argument bytes after it and should be
                         				treated the same as %TDMV0.%TDEOF		202		Erase  to  end  of  screen.   This  is  an				optional function  since many terminals do				not support this.   If  the terminal  does				not  support this  function,  it should be				treated the same as %TDEOL.				%TDEOF does an erase to end of line,  then				erases  all lines lower on the screen than				the cursor.  The cursor does not move.%TDEOL		203		Erase  to  end  of  line.  This erases the				character position the  cursor  is at  and				all  positions  to the right on  the  same				line.  The cursor does not move.SUPDUP Display Protocol						   Page 10OUTPUT -- DISPLAY PROTOCOL (%TD CODES) (continued)%TD code	Value		Meaning%TDDLF		204		Clear the character position the cursor is				on.  The cursor does not move.%TDCRL		207		If the cursor is not on the bottom line of				the screen, move  cursor to  the beginning				of the next line and clear that line.   If				the  cursor is at the bottom line,  scroll				up.%TDNOP		210		No-op; should be ignored.%TDORS		214		Output reset.   This code serves as a data				mark for  aborting  output much as  IAC DM				does in the ordinary TELNET protocol.%TDQOT		215		Quotes the following  character.   This is				used  when sending 8-bit codes  which  are				not  %TD codes,  for instance when loading				programs  into  an  intelligent  terminal.				The  following  character should be passed				through intact to the terminal.%TDFS		216		Non-destructive forward space.  The cursor				moves right one position;  this  code will				not be sent at the end of a line.%TDMV0		217		General cursor position code.  Followed by				two bytes; the new vertical and horizontal				positions.%TDCLR		220		Erase the screen.   Home the cursor to the				top left hand corner of the screen.%TDBEL		221		Generate an audio tone, bell, whatever.%TDILP		223		Insert blank lines at the cursor; followed				by a byte containing a count of the number				of blank lines to insert.   The  cursor is				unmoved.   The line the cursor is  on  and				all lines below it move down;  lines moved				off the bottom of the screen are lost.%TDDLP		224		Delete lines at the cursor;  followed by a				count.  The cursor is unmoved.   The first				line  deleted is the  one the cursor is on.				Lines below those deleted move up.  Newly-				created lines  at the bottom of the screen				are blank.SUPDUP Display Protocol						   Page 11OUTPUT -- DISPLAY PROTOCOL (%TD CODES) (continued)%TD code	Value		Meaning%TDICP		225		Insert  blank  character  positions at the				cursor;  followed by  a count.  The cursor				is unmoved.   The character the  cursor is				on and all characters to the right  on the				current line move to the right; characters				moved off the end of the line are lost.%TDDCP		226		Delete characters at the cursor;  followed				by a count.   The cursor is unmoved.   The
                         				first  character  deleted  is the  one the				cursor is on.  Newly-created characters at				the end of the line are blank.%TDBOW		227		Display black characters on white screen.				HIGHLY OPTIONAL.%TDRST		230		Reset %TDBOW and such any future options.SUPDUP Display Protocol						   Page 12STANFORD/ITS CHARACTER SETThis section describes the extended  ASCII character set.   It  originatedwith the character set developed at SAIL but was modified for 1968 ASCII.This character set only  applies to terminals with  the %TOSAI and  %TOFCIbits set in its TTYOPT word.  For non-%TOSAI terminals, the standard ASCIIprinting  characters  are  the  only  available  output  characters.   Fornon-%TOFCI terminals, the standard ASCII characters are the only availableinput characters.PRINTING CHARACTERSThe first table describes the printing characters.  For output, the  7-bitcode is sent (terminal operations are performed by %TD codes).  For input,the characters with values 000-037 and 177 must have the %TXTOP bit on  toindicate the graphic is intended rather than a function or ASCII control.Value	Character 4000	centered dot 4001	downward arrow 4002	alpha 4003	beta 4004	logical AND 4005	logical NOT 4006	epsilon 4007	pi 4010	lambda 4011	gamma 4012	delta 4013	uparrow 4014	plus-minus 4015	circle-plus 4016	infinity 4017	partial delta 4020	proper subset (left horseshoe) 4021	proper superset (right horseshoe) 4022	intersection (up horseshoe) 4023	union (downward horseshoe) 4024	universal quantifer 4025	existential quantifier 4026	circle-X 4027	double arrow 4030	left arrow 4031	right arrow 4032	not-equal 4033	lozenge (diamond) 4034	less-than-or-equal 4035	greater-than-or-equal 4036	equivalence 4037	logical OR 0040	first standard ASCII character (space)  ..		. . . 0176	last standard ASCII character (tilde) 4177	integralSUPDUP Display Protocol						   Page 13STANFORD/ITS CHARACTER SET (continued)FUNCTION KEYS AND SPECIAL CHARACTERSIn addition, the following special characters exist for input only.  Thesecharacters are  function keys  rather than  printing characters;  however,some of these  characters have some  format effect or  graphic which  theyecho as; the host, not the SUPDUP program, handles any such mappings.Value	Character	Usual echo		Usual Function 0000	[NULL] 0010	[BACK SPACE]				text formatting 0011	[TAB]					text formatting 0012	[LINE FEED]				text formatting 0013	[VT]					text formatting 0014	[FORM]					text formatting 0015	[RETURN]				text formatting 0032	[CALL]		uparrow-Z		escape to system 0033	[ALTMODE]	lozenge or $		special activation 0037	[BACK NEXT]	uparrow-underscore	monitor command prefix 0177	[RUBOUT]				character delete 4101	[ESCAPE]				local terminal command 4102	[BREAK]					local subsystem escape 4103	[CLEAR] 4110	[HELP]					requests a help messageBUCKY BITS
                         For all input characters, the following  "bucky bits" may be added to  thecharacter.  Their interpretation depends entirely upon the host.  <TOP> isnot listed here, as it  has been considered part  of the character in  theprevious  tables.<CONTROL> is different from ASCII CTRL, however, many programs may requestthe operating system to map such  characters to the ASCII forms (with  the<TOP> bit off).  In this case <META> is ignored.Value	Key 2000	Reserved 1000	Reserved 0400	<META> 0200	<CONTROL>SUPDUP Display Protocol						   Page 14ACKNOWLEDGEMENTSRichard M. Stallman (RMS@MIT-AI)  and David A.  Moon (Moon@MIT-MC) of  theMIT-AI and MIT-MC  systems staff  wrote the source  documentation and  thewonderful ITS terminal support that made this protocol possible.  It  mustbe emphasized  that  this is  a  functional  protocol which  has  been  inoperation for some years now.In addition, Moon,  Stallman, and Michael  McMahon (MMcM@SRI-KL)  providedmany helpful comments and corrections to this document.For further reference, the sources for the known currently existing SUPDUPuser programs are available online as:[MIT-AI] SYSENG;SUPDUP >		for the ITS monitor,[SU-AI]  SUPDUP.MID[NET,MRC]		for the SAIL monitor,[SRI-KL] <MMcM>SD.FAI			for the TOPS-20 monitor.The source for the known currently existing SUPDUP server program is:[MIT-AI] SYSENG;TELSER >		for the ITS monitor.These programs  are written  in  the MIDAS  and  FAIL dialects  of  PDP-10assembly language.