@chapter TCP/IP Applications
@label[chapter-doc-tcp-app]

Note that many of the TCP/IP functions documented below
which take as an argument the name of a remote host
will also accept an Internet address.
@cindex[host arguments]
This permits communication  with a host that is
not specified in the loaded site information.

@section FTP - TCP File Transfer Protocol
@label[section-ftp]

The FTP specification specifies that a command interface
be provided to make conventional FTP commands available at the user level.
On the Lambda, it is generally not necessary to use the command interface;
@cindex[file access]
rather, the normal file system commands --
@l[copy-file], @l[viewf], etc. --
and utility interfaces --
@l[ZMacs], @l[Dired] --
will go through FTP as required.
This ``transparent'' access provided by the Lambda software is an important
feature of the networking software.

The command interface is also provided, with the LISP function @l(ftp:cmd).
It is useful on the Lambda if, for example, the normal Lambda file access functions
are not working because of pathname parsing problems.
@cindex[pathname problems]
Pathnames are passed without translation from @l(ftp:ftp) to the remote FTP server.

@defun ftp:ftp &optional remote-hostname

The File Transfer Protocol command.

Optionally connects to specified @l(REMOTE-HOSTNAME).
@end(defun)

@ref[figure-ftp] illustrates an example FTP session.

Type ``@i(?)'' to see the help on each command.
In the help listing, optional arguments are enclosed in brackets, after
any required arguments.
If a command is entered without arguments,
the user is prompted for every one;
enter @return@  to skip options.

The most commonly used commands include:

@itemize @bullet
@item @i(? [command]) -
help information on all commands (or a specific @i(command))
@item @i(OPEN to) -
open a connection to a remote host.
@item @i(CD remote-directory) -
change remote working directory to @i(remote-directory).
The working directory is used to apply pathname defaults
to relative pathnames or where @i(remote-directory) is optional.
@item @i(PWD) -
display current working directory on remote host.
@item @i(DIR [remote-directory] [local-file]) -
list directory contents of current directory or @i(remote-directory);
optionally, save listing in @i(local-file).
@item @i(STATUS) -
show current status of environment commands.
@item @i(USER [username] [password] [account]) -
login and send new user information.
@item @i(SEND local-file [remote-file]) -
transfer @i(local-file) from local system to @i(remote-file) on remote system.
@item @i(RECV remote-file [local-file]) -
transfer @i(remote-file) from remote system to local system as @i(local-file).
@item @i(CLOSE) -
terminate FTP session.
@item @i(QUIT) -
terminate FTP session and exit.
@end(itemize)

@figure
@setq figure-ftp figure-page
@smalllisp
@include ftplog
@end(smalllisp)

@caption Example @l[FTP:FTP] session
@end(figure)

@section Telnet - TCP Terminal Network Access Protocol
@label[section-telnet]

There are four different ways to access the Telnet program from LISP.
@cindex[terminal access]
The Kermit interfaces provide H19 terminal emulation,
which is supported by many other Telnet servers.
The other Telnet and ``glass tty'' interfaces provides only the most basic
``dumb terminal'' capability.

The primary Telnet interface in LISP is through the Kermit program.
Within @b(Review Parameters), the user selects @mouseditem(TCP Telnet)
to specify Telnet for future connections.
The @b(Connect) command is then used to connect the H19 terminal emulation window
to the remote host's Telnet server.
Use the keystroke @neton[K] to disconnect after logging out.
@c @b???test-VAX flaky, 'connection refused' most of the time

@defun kermit:telnet-h19 &optional to-host
Connect to @l(TO-HOST).
Substantially the same as the Kermit window interface,
but can be invoked from LISP.
@end(defun)

@defun tcp:telnet host
Open a Telnet connection to the remote @l(HOST)
with no special terminal emulation.
@end(defun)

@defun telnet:telnet-glass-tty address &optional  (port "TELNET") (HALF-DUPLEX NIL)
This glass TTY works well enough for testing purposes.

The host's Internet @l(ADDRESS) is specified as a string,
for example, "101.0.0.10".

@end(defun)

The @l(TELNET-GLASS-TTY) function is particularly useful
for debugging purposes.
@cindex[network debugging]
You can verify the ability to connect to specific TCP services on a
remote host by specifying the @l(PORT) argument.
And, as noted previously, specifying an Internet address, rather than a host name,
effectively bypasses the site file information (or lack thereof)
regarding the particular host.
For example, to test whether a remote host is accessible, and to
verify that it provides FTP, execute the following (specifying the actual address):

@lisp
(telnet:telnet-glass-tty "101.0.0.10" "FTP")
@end(lisp)

@section SMTP - TCP Simple Mail Transfer Protocol
@label[section-smtp]

@section Imagen Printer Driver
@label[section-imagen]

The networking and printer software provide a driver for 
stand-alone Imagen laser printers
(model IP/II and compatibles)
that are accessed remotely via TCP/IP.
@cindex[Imagen printer]
This is a popular printing device, since much of the printing processing is
done off-line by the Imagen.

@subsection Defining an Imagen Host

An Imagen host is defined with system type and machine type @l(IMAGEN).
The following @l(HOSTS.TEXT) entry defines a stand-alone Imagen printer:

@lisp
HOST OUR-IMAGEN, INTERNET 101.0.0.202,SERVER,IMAGEN,IMAGEN,[IMA]
@end(lisp)

In @l(SITE.LISP) you can define an Imagen printer
by name.
You can optionally specify a stand-alone Imagen as the default printer for text and/or graphics.
The following entries define the Imagen host "IMA" 
and make it the default for all printing:

@lisp
(DEFSITE ...
 ...
  (:PRINTER-NAMES '((("DOC-PRINTER") (:IMAGEN "IMA"))
                    (("LABEL-PRINTER") (:TI855 "XTRA-HOST"))))
  (:DEFAULT-PRINTER "DOC-PRINTER")
  (:DEFAULT-BIT-ARRAY-PRINTER "DOC-PRINTER")
 ...)
@end(lisp)

@subsection Setting Imagen Hardcopy Options

The following function allows you to set Imagen options for hardcopy requests:

@defun tcpa:set-imagen-print-options &key copies form-length form-width line-wrapping forms-per-page left-margin line-numbers page-headings ok-wait ok-wait-tries notifications
If any Imagen print option(s) is(are) specified, set it(them);
otherwise, bring up a choose-variable-values menu for specifying options.
@end(defun)

These options set global variables which specify
default options for hardcopy requests going to the
Imagen printer(s).

This function can also be invoked by selecting @mouseditem[Imagen Options] from the System Menu.
@subsection Printing to the Imagen

If the Imagen is specified as the default text printer,
hardcopy functions such as @l(hardcopy-file)
will automatically route to the Imagen.
If the Imagen is specified as the default bit-array printer,
bit-array printing functions such as the @termon[Q] screen-dump program
will route to the Imagen.

If some other type of printer is the default,
you can still specify the Imagen 
to functions such as @l(hardcopy-file)
by using the name you provided in @l(SITE.LISP):

@lisp
(hardcopy-file "lm:keith;myfile.text" :printer "doc-printer")
@end(lisp)

The Imagen routing software knows how to handle IMPRESS format files;
for example,

@cindex Impress format
@lisp
(hardcopy-file "lm:keith;myfile.impress" :printer "doc-printer"
               :format :impress)
@end(lisp)

@section DISK - TCP Lambda Disk Protocol
@label[section-disk]

The TCP DISK protocol is provided for compatibility with Chaosnet network disk functions such as
@l(print-disk-label) and @l(si:copy-disk-partition)
over TCP.
These functions will ``prefer'' to go through Chaosnet
with the default value of @see[net:*network-protocols*][var].
If this variable is modified -- if its value, a list, is reversed --
DISK functions will prefer TCP over Chaosnet.

See Section @ref[section-generic-disk] for the syntax of specifying disk units.

















@c end tcp-app2