.TH INTRO 9
.SH NAME
intro \- introduction to 5620-related software
.SH SYNOPSIS
.BI PATH= stuff :/usr/jerq/bin
.SH DESCRIPTION
Section 9 of this manual lists software for running or supporting
Teletype DMD-5620 terminals.
Subsections 9.1-9.7 mirror the purposes of the preceding sections 1-7,
with 9.1 being commands, 9.6 being games, etc.
Command synopses assume that the shell search path includes
.FR /usr/jerq/bin .
.PP
Few commands deal with a 5620 in native mode.
.IR 32ld (9.1)
loads programs into the terminal and
.IR mux (9.1)
starts the characteristic `layer' or window system.
Almost all other commands in section 9 either run on
Unix or within
.I mux
layers.
.PP
A layer is technically a virtual terminal,
but is almost indistinguishable in software from a real terminal;
in particular, the interface described in
.IR ttyld (4)
applies to layers, except for the additional editing capabilities discussed in
.IR mux (9.1).
.PP
The commands in sections 9.1 and 9.6 run on Unix,
but most implicitly call
.I 32ld
to down-load a program that replaces the
default terminal process running in the layer.
To Unix the interface is still that of
a terminal; in particular
.F /dev/tty
(see
.IR fd (4))
is always connected to the layer.
The default
.I mux
terminal program implements the teletype driver function itself.
When a program is down-loaded,
there is no teletype driver;
programs that desire one
must push the teletype line discipline on the stream,
and arrange to pop the line discipline
on exit; see
.IR stream (4)
and
.IR ttyld (4).
Some commands may simply
emulate other terminals by down-loading
a terminal program (see
.IR term (9.1);
others, such as the text editor
.IR sam (9.1),
are really two programs \(em one on Unix and one in the layer \(em
communicating using standard input/output on Unix
and
.BR sendchar() / rcvchar()
in the terminal; see
.IR request (9.2).
.PP
There is an identity between bitmaps and layers
in the graphics software.
Graphic objects are bitmaps.
The 
.IR newlayer (9.2)
primitives that operate on layers are aliased to bitmap
primitives of (9.3), and the data structures are isomorphic.
When running under
.IR mux ,
a programmer need not consider layers as graphical objects
at all; the operating system checks the arguments to the graphics
primitives and dispatches the appropriate operator depending
on the type of the argument.
Except in stand-alone software, layers are an invisible
implementation detail.
.SS Teletype 630
.I Mux
and various programs that run in
.I mux
layers have been ported to Teletype DMD-630 terminals.
The ported software is not available on all machines and
is not specifically documented.
Look in
.F /usr/630/bin
to see what's there.
.SH FILES
.TF /usr/jerq/mbin
.TP
.F /usr/jerq/bin
jerq-related Unix object programs
.TP
.F /usr/jerq/mbin
terminal programs, usually down-loaded automatically
by programs in
.F /usr/jerq/bin
.TP
.F /usr/630/bin
630-related Unix object programs
.TP
.F /usr/630/lib
terminal programs
.SH SEE ALSO
.IR 32ld (9.1), 
.IR mux (9.1), 
.IR stream (4)
.SH BUGS
There are two mechanical-drawing programs,
.I cip
and
.I ped,
two `artistic' drawing programs,
.I paint
and
.I twid,
one `graphic' drawing program,
.I brush,
two pixel-level drawing programs,
.I icon
and 
.I jf,
all for working on binary images.
None dominates.