@begin(comment) @Part(OS9KERMIT,root="USER") @Chapter @end(comment) @Begin @i(Authors:)@\Bill Catchings, Bob Cattani, Chris Maio, Columbia University@* Modified from UNIX Kermit to Os9 Kermit By Glean Seaton and Robert A. Larson@* with fixes and contributions from many others. @i(Documentation:)@\Walter Underwood, Ford Aerospace (Palo Alto, CA)@* Changed for Os9 Kermit by Robert A. Larson @i(Version:)@\1.5 @i(Date: )@\July 1985 @end @label<-kc> A sample, working implementation of the Kermit "kernel" was written in the C language, and widely distributed in the @i. This kernel was intended merely to illustrate the protocol, and did not include a "user interface", nor some of the fancy features like server support, 8-bit quoting, file warning, timeouts, etc. Several sites have added the necessary trappings to make this a production version of Kermit, usually under the UNIX operating system. Limited server functions have also been added to the Os9 version. The keyword style of user/program interaction favored by Kermit (program types prompt, user types command followed by operands, program types another prompt, etc) is contrary to the UNIX style, so UNIX implementations have a style more familiar to UNIX users. The Os9 version has retained this style of command interface. C versions of Kermit are running successfully on VAX and PDP-11 UNIX systems, IBM 370-@|compatible mainframes under Amdahl UTS, and the SUN Microsystems MC68000-@|based and other workstations. There is a new version of Kermit written in C called C-Kermit. (The current version as of July 1985 is 4c.) It is recommended for Unix and adapting to other operating systems if memory is adiquate. (It is being adapted to Os9/68000, but is probably to large for Os9/6809.) Os9 filespecs are of the form @example where the tokens delimited by slashes form a @i, and are each limited to 29 characters in length. The final token in a path is the actual file name. By convention, it is of the form name.type, but there is nothing special about the dot separating name and type; to Os9 it's just another character, and there may be many dots in a filename. In the tradition of UNIX, here's the Os9 KERMIT "man page". @begin NAME@\kermit - file transfer, virtual terminal over tty link SYNOPSIS@\kermit cl[e] line [esc] @\kermit r[ddifl] [line] @\kermit s[ddifl] [line] file ... @\kermit gl[ddif] line file ... @\kermit ql[ddif] line @\kermit h[ddifl] [line] DESCRIPTION@\@beginKermit provides reliable file transfer and primitive virtual terminal communication between machines. It has been implemented on many different computers, including microprocessors (see below). The files transferred may be arbitrary ASCII data (7-bit characters) and may be of any length. The file transfer protocol uses small (96 character) check summed packets, with ACK/NACK responses and timeouts. Os9 Kermit by defaults (changeable by compilation options) uses a fifteen "second" timeout and ten retries. The arguments to kermit are a set of flags (no spaces between the flags), three optional args (which, if included, must be in the same order as the flags which indicate their presence), and, if this is a Send or Get operation a list of one or more files. Kermit has six modes, Connect, Send, Receive, Get, Quit, and Host. Connect is for a virtual terminal connection, Send and Receive may be used to transfer files in a non-server mode, Send, Get, and Quit are used with a remote kermit server, and Host is used to make the Os9 system a server itself. These modes are specified by the first flag, which should be c, s, r, g, q, or h respectively. Exactly one mode must be specified. The d flag (debug) makes kermit a bit more verbose. The states kermit goes through are printed along with other traces of its operation. A second, third, and even fourth d flag will cause kermit to give an even more detailed trace. The i flag (image) allows slightly more efficient file transfer between Os9 machines. Normally (on Kermits defined to run on Os9 systems) return is mapped to CRLF on output, LF's are discarded on input, and bytes are masked to 7 bits. If this is set, no mapping is done on returns, and all eight bits of each byte are sent or received. The l flag (line) specifies the tty line that kermit should use to communicate with the other machine. This is specified as a regular filename, like "/t2". If no l option is specified, standard input is used and kermit assumes it is running on the remote host (i.e.. NOT the machine to which your terminal is attached). The e flag (escape) allows the user to set the first character of the two character escape sequence for Connect mode. When the escape character is typed, kermit will hold it and wait for the next character. If the next character is c or C, kermit will close the connection with the remote host. If the second character is the same as the escape character, the escape character itself is passed. An exclamation mark ('!') as the second character will cause shell to be forked. (Use your EOF character to return to the kermit connect mode.) Any character other than these two results in a bell being sent to the user's terminal and no characters passed to the remote host. All other typed characters are passed through unchanged. The default escape character is tilde ('~'). (Control-3 on the standard Coco keyboard.) The file arguments are only meaningful to a Send or Get kermit. The Receiving kermit will attempt to store the file with the same name that was used to send it. Os9 kermits normally convert outgoing file names to uppercase and incoming ones to lower case (see the f flag). If a filename contains a slash (/) all outgoing kermits will strip off the leading part of the name through the last slash. In the Get command, filenames will be sent to the remote host as is and the filenames sent back will be converted as usual for a receiving kermit. (Wildcard characters may be expanded on the remote end.) The Quit command will send a "Generic Finish" packet to the remote kermit server. The Host command has not been fully implemented and tested as of this writing. @end EXAMPLE@\@beginFor this example we will assume two Os9 machines. We are logged onto "Os9a" (the local machine), and want to communicate with "Os9b" (the remote machine). There is a modem on "/t2". We want to connect to "Os9b", then transfer "file1" to that machine. We type: @example Kermit answers: @example Now we dial the remote machine and connect the modem. Anything typed on the terminal will be sent to the remote machine and any output from that machine will be displayed on our terminal. We hit RETURN, get a "login:" prompt and login. Now we need to start a kermit on the remote machine so that we can send the file over. First we start up the remote, (in this case receiving) kermit, then the local, (sending) one. Remember that we are talking to Os9b right now. We type: @example(kermit r) (there is now a Receive kermit on Os9b) We type ~ (the escape character) and then the letter c to kill the local (Connecting) kermit: ~c Kermit answers: @example We type: @example Kermit answers: @example When the transmission is finished, kermit will type either "Send complete", or "Send failed.", depending on the success of the transfer. If we now wanted to transfer a file from os9b (remote) to os9a (local), we would use these commands: @begin kermit cl /t2 @i<(connected to Os9b)> kermit s file9 ~c @i<(talking to Os9a again)> kermit rl /t2 @end After all the transfers were done, we should connect again, log off of Os9b, kill the Connect kermit and hang up the phone. @end FEATURES@\Kermit can interact strangely with the tty driver. @\The KERMIT Protocol uses only printing ASCII characters, Ctrl-A, and CRLF. Ctrl-S/Ctrl-Q flow control can be used "underneath" the Kermit protocol, but is not currently implemented in Os9 Kermit. @\Since BREAK is not an ASCII character, kermit cannot send a BREAK to the remote machine. On some systems, a BREAK will be read as a NUL. @\This kermit does have timeouts when run under Os9, so the protocol is stable when communicating with "dumb" kermits (that don't have timeouts). DIAGNOSTICS@\@begin@i@* The file named in the line argument did not exist or had the wrong permissions. @i@* A Receive kermit could not create the file being sent to it. @i@* A Connect kermit was started without a line argument. @end @end