Implementation of KERMIT for Version IV of the UCSD p-System Kate MacGregor / Steven Pacenka Cornell University (Test) Version 0.1, May 1984 KERMIT-UCSD4 is a program which implements the KERMIT file- transfer protocol for use under the Version IV.x UCSD p-System on various computers. The distributed version has been developed on an IBM Personal Computer under Network Consulting, Inc.'s excellent adaptation of the p-System. This implementation was done by Steven Pacenka, based largely on an implementation by Kate MacGregor of Cornell Computing Services for the Version II.0 p-System on a Terak 8510a. USING KERMIT with the NCI p-SYSTEM on an IBM PC You must have NCI release C1F or later to use this program. Earlier releases suffered from bugs in the serial interface support which caused incoming characters to be lost even at low speeds. You need to do two things with your boot diskette before trying to execute the distributed .CODE file: - Enable serial interrupts using the NCI CONFIG program; and - Place the SYSTEM.SERIAL file on your boot disk. You need to reboot to get these to take effect for the first time. Then and thereafter just eX(ecute the KERM.CODE program. - 1 - CONSTRUCTING A NEW KERMIT The program consists of several Pascal source files which need to be compiled. Also required is a REMUNIT.CODE to interface with your computer's serial port. The source files (and their short names on the distribution tape) are: UCSD Name KERMIT Contents Distribution Name -------------- ----------------- -------------------------------- KERMIT.DOC.TEXT UC4KRM.DOC This documentation KERMIT.TEXT UC4KRM.PAS Main program SETSEND.TEXT UC4STS.PAS Include file for KERMIT.TEXT RECEIVER.TEXT UC4RCV.PAS UNIT Receiver (file receiving) SENDER.TEXT UC4SND.PAS UNIT Sender (file sending) HELPER.TEXT UC4KHP.PAS UNIT Helper (online help info) KERMPACK.TEXT UC4PKT.PAS UNIT KermPack (packet utilities) KERMUTIL.TEXT UC4KUT.PAS UNIT KermUtil (misc utilities) KERMGLOB.TEXT UC4GLB.PAS UNIT KermGlob (declarations) PARSER.TEXT UC4PRS.PAS UNIT Parser (command parsing) KERM.CODE UC4NCI.COD p-code file that will run with NCI p-system release C1F on IBM PC The .PAS files are Pascal source files, and the .DOC file (obviously) contains this user documentation, instructions for building UCSD Pascal Kermit for the IBM PC, and hints on adapting it to other machines. The .COD file is a p-code file for the NCI p-System on an IBM PC. All of the .PAS modules should compile and execute on any adaptation of Version IV of the UCSD p-System, provided that an equivalent of the REMUNIT.CODE unit is available for the particular computer being used. (This file implements the UCSD Pascal Users' Society (USUS) "standard remote unit.") To generate a variant of this KERMIT for another computer running the Version IV p-System: 1. Create or obtain a REMUNIT that implements the USUS standard remote unit. Specifications and implementations for a variety of different computers are available from USUS. For communications above 300 baud, the incoming characters to REMIN: should be processed in a buffered, interrupt-driven mode. The buffer should be at least 256 characters long. - 2 - 2. Gather all of the source Pascal files onto your prefix volume along with the REMUNIT.CODE file. 3. Compile the Pascal units in this sequence: 1--KERMGLOB 2--KERMUTIL 3--KERMPACK 4--PARSER 5--HELPER 6--SENDER 7--RECEIVER 8--KERMIT. 4. At this point you can use the standard p-System LIBRARY.CODE program to combine the units (including REMUNIT) into one code file for easier and faster loading, or you can enter their individual .CODE file names into the USERLIB.TEXT file on your root disk. LIMITATIONS 1. No wild card designations of file names are allowed. Files are transmitted and received individually. 2. No eight-bit character quoting is allowed. In practice, this means that only text files can be transferred. 3. No character repeat counts are used in packets. 4. '?' and cannot be used when entering a command line. Some versions of Kermit parse commands from the keyboard character by character as they are entered. This version interprets the line after it has been terminated by a carriage return. Use the HELP command in place of '?', and type out the command names in full. 5. No server communications are supported. 6. Instead of using a clock to time out when waiting for a packet, KERMIT-UCSD has a limit on the number of times it will look for a response before giving up. 7. All linefeed characters received during file transfer are stripped from the local file that is being created, since the p-System does not recognize them in text files. This may cause difficulties in files received from certain other computers which omit carriage returns at the ends of lines, particularly blank lines. - 3 - COMMANDS The commands recognized by KERMIT-UCSD are listed below. CONNECT To make a "virtual terminal" connection to a remote system. The CONNECT command may be abbreviated to 'C'. When in CONNECT mode, all typed characters are sent to the serial interface except the escape character (see SET ESCAPE, below). The escape character may be followed by another character which is interpreted as follows: c Break the connection and "escape" back to the micro b Send a "break" signal over the communications line; this is only useful on mainframes such as the IBM 3081/370/4341 et. al. s Same as the "show all" command in command mode; displays the current parameter settings for the local KERMIT. ? Displays the possible characters to follow the escape code Two consecutive escapes are required to send one such character to the communications line EXIT To return to main p-System command level. HELP To get a list of KERMIT commands. HELP can be followed by any command, in which case the help will refer only to that command. RECEIVE To accept a file from the remote system. Note that ".TEXT" will be concatenated onto the end of the received file name if it is not already present. - 4 - SEND To send a file to the remote system. Takes a filename as a parameter. In creating a file name for the remote Kermit, all periods in the name except the rightmost are deleted. This is for compatibility with most other operating systems. SET To establish system-dependent parameters. The SET options are as follows: BAUD To set the communications baud rate to 110, 300, 1200, 2400, 4800, or 9600 (default is 1200). DEBUG To set debug mode ON or OFF (default is OFF). EMULATE To set DataMedia 1520A screen control code interpretation ON or OFF (default is OFF). END-OF-LINE To change the character used at the end of packets to something other than the default of CR. It must be a digit between 0 and 31. ESCAPE To change the escape sequence that lets you return to the PC Kermit from the remote host. The default is CTRL-] c. FILE-WARNING ON/OFF, default is OFF. If ON, Kermit will rename an incoming file so as not to write over a file that currently exists with the same name. IBM ON/OFF, default is OFF. This flag should be ON only when transfering files between the PC and an IBM VM/CMS system. It also causes the parity to be set appropriately and activates local echoing. LOCAL-ECHO ON/OFF, default is OFF. When on, this causes characters typed at the keyboard during connect mode to be echoed to the screen. - 5 - PARITY EVEN, ODD, MARK, SPACE, or NONE. NONE is the default but if the IBM flag is set, parity is set to MARK. This flag selects the parity for outgoing and incoming characters during CONNECT and file transfer to match the requirements of the remote computer. SHOW To see the values of parameters that can be modified via the SET command. SHOW ALL shows all parameters; SHOW followed by a parameter listed under SET will show the value of only that parameter. WISH LIST FOR FUTURE VERSIONS If anyone tries these, please consider portability and share your work with the rest of the p-System community. 1. Increased memory buffering of sent and received packets. Now only the standard 512 character buffers provided by the operating system are utilized. On floppy disk systems the throughput is slowed considerably by frequent disk access. 2. Timing of file transfers using the system clock to determine the effective transmission rate. 3. More intelligent handling of received linefeed characters. 4. Implementation of the immediate '?' (help) and (abbreviate) commands in the parsing routines; 5. A DIR command to list a local volume directory. 6. Text file capture with memory buffering, and XON/XOFF protocol. (For remote computers not supporting Kermit.) 7. Text file transmission without protocol. 8. Eight-bit quoting for sending and receiving data and code files. 9. Timeouts during send and receive using the hardware clock, and a related SET TIMEOUT command. - 6 -