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C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002			SUPer-DUPer Display TELNET to ITS
C00005 00003	 SUPDUP FEATURES:
C00008 ENDMK
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		SUPer-DUPer Display TELNET to ITS
			  Mark Crispin

 INTRODUCTION:

SUPDUP is the SAIL implementation of the ITS SUPDUP program, which
is used for TELNETing between ITS sites.  This program uses the
internal ITS display codes for highly efficient communication and
full use of ITS display programs over the ARPAnet.  It runs on Data
Discs only.

When SUPDUP is run, it will prompt for the host name.  Type one or
two characters to identify the name of the ITS system you wish to
TELNET to (ie, either "A", "D", "MC", and "ML").  SUPDUP will then
establish a connection with the specified ITS site, and after that
you will effectively be a display on ITS, with full bucky bit
capability.

Some mappings in input and output are made due to the differences
between the SAIL and ITS ASCII character sets.  Most of these mappings
are transparent to the user.  The design philsophy behind the mappings
was to cause characters typed on the Stanford keyboard to be seen by
ITS as the character appears on the key tops, and for characters
received from ITS to be displayed as they would be at a console at MIT.

 NOTE!!!:

One thing that I should mention: you MUST NOT do a :TCTYP on ITS that
will set your terminal type.  SUPDUP's operation depends upon the
terminal type being SOFTWARE and things will not work correctly if
it is set to anything else.  It is alright to set certain other TCTYP
options such as SAIL character set enable, however, in general you
probably will not want to do any TCTYP at all.  SUPDUP sets the line
length and page size to the maximum possible on the screen.  In
addition, you can NOT set scroll mode and hope to win.
 SUPDUP FEATURES:

  Visible OUTPUT MAPPINGS:

Caret is mapped to AND sign (∧) since there is no code in the SAIL
character set for caret.  There is no way to tell between AND sign and
caret.

  Visible INPUT MAPPINGS:

αz and αZ are mapped to [CALL], αβz and αβZ are mapped to α[CALL];
α_ is mapped to [BACK NEXT] and αβ_ is mapped to β[BACK NEXT]. ↑ is
mapped to caret.  VT will send the uparrow character, but without the
[TOP] bit; there is no way to send the [TOP]ified ↑ other then by using
[BACK NEXT]4013. Also, there is no way to send β[CALL] or αβ[CALL] other
than by using [BACK NEXT]432 and [BACK NEXT]632.

  COMMANDS:

[ESCAPE]I is used to enter a SUPDUP command.  The following commands
are defined:

	F	Use Fast display mode (discussed below)
	H	Type a help text
	K	Kill the job on ITS and break network connections
	L	Same as K command
	P	Temporarily restore the page printer.  Typing any
		character will return your screen to ITS.
	Q	Quit out, close network connections, detach the job
		on ITS if there is one.
	S	Use Slow display mode (see below)
	?	Same as H

In addition, in [ESCAPE]I mode, αz, αβz, αZ, αβZ, α_, and αβ_ are
sent as themselves without being mapped.  Maybe someday if β[CALL]
and αβ[CALL] become readable by a program then the mappings on z's will
be removed.

DISPLAY MODES:

SUPDUP has two display modes; fast and slow, which are set by the F and S
commands.  Fast mode, which is the default, is highly optimal on network
input and very fast on display.  On the other hand, it can be disconcerting
to have the screen flash as suddenly as it does with no semblance of line-
per-line output (it sort of comes out as chunk-per-chunk), therefore, there
is a slow mode which causes SUPDUP to output in the old-fashioned manner
which just does normal optimization but not line/screen optimization.