CHAT
Chat is a program for establishing Pup Telnet connections between a
pair of cooperating parties. Its chief function is to permit Alto
users to login to Maxc and IFS servers. Chat includes an extension to
support text-display control and graphics. Chat also includes support
for attachment of IBM-PCs to the network via a DLS line.
1. Simple operation
Chat is organized so that default operation with Maxc is simple.
Simply saying "Chat" will establish a connection with Maxc and
(provided you are "logged in" on your Alto) will try to establish the
Alto as controlling terminal for a Maxc job that is logged in under
your name. Chat will perform a "login" or "attach" as appropriate. If
the simple methods fail you must deal with Maxc yourself (life is
hard).
To connect to some server besides Maxc, type "Chat name" where "name"
is the name of the desired server (Ivy, DLS, etc.) Chat will perform
the automatic login if the server is a Maxc or an IFS.
If you don't have the file Chat.Run on your disk, the Alto Executive
will boot-load it from a boot server on the network. In this case,
Chat will not use the "name" you supply on the command line but rather
will require you to type the server name directly to Chat.
If you are not logged in on your Alto at the time you start Chat, or
you booted Chat from the network, Chat will first request that you type
in your user name (if different from the one installed on your disk)
and password.
The preferred method for exiting Chat is to depress the key immediately
to the right of the "return" key on the keyboard, and then to press "q"
for Quit. The other method, <shift>SWAT, is frowned upon and is not
guaranteed to work.
If the connection fails or is broken by the server, Chat will display
an appropriate message and will ordinarily terminate. However, if you
booted Chat from the network, Chat will continue running and will ask
you for the name of a new server to connect to.
2. Command Interpreter
While Chat is running, you may wish to give various commands that alter
its operation. Depressing the key immediately to the right of the
RETURN key will cause Chat to enter a command mode. The commands are:
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Copyright Xerox Corporation 1983
Chat July 7, 1983 2
C Change control character output setting. Control characters
other than CR, LF, and Tab are normally displayed as "↑x".
Changing this setting causes control characters to be thrown
away.
D Specify a "do" file to insert now. The text of the file will be
treated as if it had been typed in at the keyboard--it will be
transmitted to the connected party. This is a simple way to
"can" Maxc procedures that you use a lot.
E Change local echo setting. Chat starts out assuming that the
connected party will echo all characters. In some instances,
Chat will want to echo your typein locally (e.g., when connected
to another Chat).
F Specify a new font. The screen will be re-initialized, which will
cause recent typeout to disappear. If insufficient core space is
available for the font, the system font will be used.
I Toggle the "input" switch for the typescript file, set by the
USER.CM entry TYPESCRIPTCHARS (see below).
M Toggle the IBM PC mode of operation, set by the USER.CM entry
PCMODE (see below).
N Permits you to establish a New connection (after breaking the
current one), without leaving Chat.
O Toggle the "output" switch for the typescript file, set by the
USER.CM entry TYPESCRIPTCHARS (see below).
Q Quit--terminate the connection.
R Receive characters and put into specified file. To terminate
capture issue the command again with a CR. Command T is reset if
this command is issued.
S Send the text of the file to the connected party. This is a
simple way to transmit program text to the IBM-PC.
T Specify a new typescript file. The old typescript, if any, is
closed. The new typescript will grow without bound, even if the
old typescript had a length limit specified in USER.CM (see
below).
X Toggle the "line feed strip" option, set by USER.CM entry
LINEFEEDS (see below).
3. Command-line options
Several options may be passed to Chat by global switches in the command
line (i.e., by typing Chat/s/t where "s" and "t" are the switches):
/A "Attach" -- meaningful only when connecting to Maxc. This
will force the Maxc attach sequence to be typed rather than
whatever Chat considers appropriate.
Chat July 7, 1983 3
/C Chat will suppress output of control characters, rather
than displaying them as "↑x".
/D See /P below.
/E Chat will cause local echoing of input characters.
/I Equivalent to the command-line entry Chat.Initial/D (see
below).
/L "Login" -- meaningful only when connecting to Maxc or an
IFS. This forces a login sequence to be typed, regardless
of what Chat considers appropriate. For example, if you
already have a detached job on Maxc and wish to create a
new job, you must use this option.
/M Equivalent to the USER.CM entry PCMODE: ON (see below).
/N Chat will not attempt any automatic login or attach.
/P or /D Chat will enable a display protocol (see below).
/S Chat will be a "Pup Telnet Server," and will respond to
requests for connection from others rather than initiate
requests itself.
/T Chat will write a typescript on file Chat.ts$, regardless
of whether or not a TYPESCRIPT entry appears in USER.CM.
/X Chat will set the LINEFEEDS option to NO (see below).
Several options may be specified with "local" switches:
string This gives the "name" of the party with whom Chat should
initiate a connection. The name may be an address constant
of the form net#host#socket, or may be a full symbolic name
like Maxc+Telnet (see "Naming and Addressing Conventions
for Pup" for details). The default socket is 1, the Telnet
socket. Thus typing "Chat Regis" will try to connect to a
Telnet server on the host named Regis.
filename/D This gives a "do" file name that is fed to the connected
party. When the last character of the file has been sent,
Chat will not close the connection.
filename/E Similar to /D, but will end the connection when end of file
is encountered.
filename/F Specifies the name of the font to use.
filename/T Specifies the name of the typescript file.
4. USER.CM Options
The USER.CM file may also contain defaults that Chat examines at
initialization. The section of USER.CM that Chat examines must begin
Chat July 7, 1983 4
with a line with the 6 characters [CHAT] on it. Thereafter, lines
begin with "labels," followed immediately by colons, followed by
arguments.
Note that Chat does not look at User.cm (or anything else on your disk)
if you boot-loaded it from the network.
In the following descriptions, square brackets enclose parameters that
are optional--you shouldn't actually type the square brackets.
BELL: [DING] [FLASH] [AUDIO]
Tells what to do when a bell character is received. If DING is
specified, a pattern that spells out DING will be displayed at
the top of the screen. If FLASH is specified, the bottom area of
the screen will flash black. If AUDIO is specified, and you have
a loudspeaker connected to your Alto's Diablo printer interface,
an audible tone will sound. Any combination of options can be
specified together (default: DING FLASH).
BORDER: BLACK|WHITE
Gives the color of the top border of the screen (default: white).
CONNECT: net#host#socket or host-name
Gives the network address constant or name of the party with whom
a connection should be initiated (see "Naming and Addressing
Conventions for Pup" for details). Default is Maxc+Telnet, the
Maxc Pup Telnet server.
CONTROLCHARS: ON|OFF
Normally, control characters other than CR, LF, and Tab are
displayed in the form "↑x". This option forces them not to be
displayed at all. Default is ON.
DISPLAYPROTOCOL: ON|OFF
This entry enables a display protocol. The same effect can be
achieved with the /P or /D command-line switches. Default is
OFF.
ECHO: ON|OFF
This option turns on local echoing. This is usually necessary
only if you are connecting to another Alto running Chat that has
used the /S option.
FONT: AltoFontName.AL [width height]
Gives the name of a font to use when displaying typeout from the
connected party (default: system font). If two numbers follow
the name, they are interpreted as the width of a line (in
characters) and the height of a page (in lines). These numbers
override the calculations made by Chat, and are shipped to the
server to set the terminal parameters.
LINEFEEDS: ON|OFF
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Normally, line feeds transmitted by the other party are included
in the typescript file. If you wish to keep line feeds out of
the file, set LINEFEEDS: OFF.
PCMODE: ON|OFF
Normally, carrage returns are not followed by line feeds in text
send to the other party. If you wish Chat to send line feeds
after carrage returns set PCMODE: ON. THis option is intended to
be used to communicate with and IBM-PC connected via a DLS line.
TYPESCRIPT: filename [length]
Gives the name of a file on which to record a typescript of the
session. If length is specified, the file will be treated as a
"ring" buffer of that length (in bytes; 65535 maximum). The file
will be created at the beginning of the session, so that the user
can be certain the disk will not overflow when recording
typescript information. The characters "<=>" will mark the end
of the ring buffer, which will be updated periodically. If
length is not specified, the file will grow without bound and
"<=>" will not be appended. In this case, if the disk becomes
full the typescript will be closed and a warning message
displayed.
TYPESCRIPTCHARS: [ON|OFF] [ON|OFF]
This entry governs the selection of characters that are included
in the typescript file. The first on/off switch controls
characters typed on the Alto keyboard: if the switch is "on,"
these characters will be entered in the typescript file. The
second switch controls characters sent from the other party to
the Alto: if the switch is "on," these characters will be entered
in the file. Default is OFF ON.
5. Display Protocol
Chat allows a remote program to control carefully the entire Alto
display. The interactive facilities of the Alto can thus be used by
MAXC programs and others. A set of Interlisp-10 functions has been
written to ease use of the display from LISP. These functions are
documented in "Raster Graphics for Interactive Programming
Environments," by R.F. Sproull, CSL-79-6, and are contained in
<SPROULL>ADIS.COM; the symbolics (should you need them) in
<SPROULL>ADIS.
"Display Chat" is almost completely different from "teletype Chat";
they are loaded as one program largely for convenience. To exit
display Chat, use the <shift><Swat> convention. Be very careful when
attaching and detaching jobs that have Chat display connections open.
If you re-attach to a LISP job that previously had connections open,
and CONTINUE your LISP job, the connections are no longer usable
because the Pup executive has timed them out. ADISCheck should be
called to verify the state of the connection. After this call, it may
be necessary to invoke ADISInit again. If this procedure is not
followed, you may get traps with "IO Data Error" or some such message
coming out of your LISP program!
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Fonts are declared in User.Cm as follows: a line of the form "DISPLAY-
FONT: FileName" is a font declaration. Numbers are associated with the
fonts by the order in the file: the first is font 0, the second font 1,
etc. The fonts must be in "strike" format; several fonts in this
format are saved on the <ALTOFONTS> directory with extension .STRIKE.
The number of "regions" available to Chat can be altered by including a
line of the form "DISPLAY-REGIONS: 6" in User.Cm.
Two functions for making hard copies are not documented in the CSL
report:
ADISPress[file] (Flush). This function writes a one-page Press file of
the given name on your Alto disk. The page contains a bit-map for the
current contents of the Chat display area. WARNING: This function
requires considerable quantities of disk space (about 130 pages per
file), and may lead to errors while writing the file. Best use it only
when your state is safe.
ADISPressMaxc[file;scaleFactor] (Flush). This function is similar to
ADISPress, but the file will be written on the connected MAXC
directory. The scaleFactor defaults to 1.0, but can be set to any
fraction. It will cause the Press file to contain directives to reduce
the size of the image of the screen when it is printed.
Efficiency and space. The ADIS protocol operations cost a certain
amount in LISP function call and Tenex JSYS overhead; they also have a
cost determined by the number of bytes of protocol commands that are
sent to Chat. Thus we can express the communication cost in terms of
the number of "characters" we could display by transmitting the same
number of bits. Here are approximate numbers:
ADISRegion 4
ADISLimits 16
ADISSetX,ADISSetY,ADISFont 5
ADISBold,ADISItalic,ADISSetCR,ADISSetLF 5
ADISLineTo 6
ADISRegionOp 13 or 21
ADISScroll 34 in most cases
ADISButtonEnable 16
ADISTypeOnEvent 4
ADISCursor 43
ADISCursorMove 7
Space in the Alto is at a premium. At present, about 6700 words must
be shared among all fonts and region descriptions. Note that font
sizes vary. Sizes are:
Region 34 words (always)
Helvetica8.Strike 570 words
Helvetica10.Strike 630 words