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HH HH PPPPPPPP 8888888 6666666 HH HH PP PP 88 88 66 HH HH PP PP 88 88 66 HHHHHHHHH PPPPPPPP 8888888 66666666 HH HH PP 88 88 66 66 HH HH PP 88 88 66 66 HH HH PP 8888888 6666666 KK KKK EEEEEEEE RRRRRRRR MMM MMM IIIIII TTTTTTTTTT KK KKK EE RR RR MMMM MMMM II TT KK KKK EE RR RR MM MM MM MM II TT KKKKK EEEEEEE RRRRRRRR MM MMM MM II TT KKKKKK EE RR RRR MM M MM II TT KK KKK EE RR RRR MM MM II TT KK KKK EEEEEEEE RR RRR MM MM IIIIII TT - 1 - ====================== HP86 KERMIT USER GUIDE ====================== Edition 1.00 This Manual applies to version 1.00 CONTENTS -------- 1. Introduction. 2. What is Kermit. 3. Running Kermit on the HP86. 3.1 Starting the HP86 Kermit. 3.2 Entering Kermit commands. 3.3 HP86 Kermit commands. 3.4 Using Kermit. 3.5 Finishing Kermit. 4. Communicating with another computer. 4.1 Setting the RS232. 4.2 Using the HP86 as a terminal. 4.2.1 The CONNECT command. 4.2.2 Differences between command mode and terminal mode. 4.2.3 Sending a break. 4.2.4 Returning to the HP86 Kermit. 5. Transferring files using Kermit. 5.1 The basic method. 5.2 File types. 5.2.1 The file type problem. 5.2.2 The data type problem. 5.3 HP86 to remote file transfer - The SEND command. 5.4 Remote to HP86 file transfer - The RECEIVE command. 5.5 Transfer problems. 5.6 File name conversion. 5.6.1 HP86 to standard conversion. 5.6.2 Standard to HP86 conversion. 5.6.3 File renaming. 6. Changing Kermit attributes. 6.1 The SET command. 6.2 The SHOW command. 6.3 Settable attributes. Appendix A - HP86 Kermit capabilities. Appendix B - HP86 Kermit error messages. Appendix C - Converting numeric variables. - 2 - 1. INTRODUCTION =============== Program: Martin Rootes, Sheffield City Polytechnic, U.K. Language: HP86 Basic. Documentation: Martin Rootes. Version: 1.00 Date: April 1986 This manual describes the Kermit program for the HP86 microcomputer produced by the Computer Services Department of Sheffield City Polytechnic. The implementation described is HP86 Kermit version 1.00. The purpose of this manual is to supply the user with the information necessary to enable them to transfer files from a HP86 microcomputer to another Kermit. As transfer will almost always be to a different system the user will also have to read the corresponding guide for the other Kermit. This manual has been divided into various chapters, dealing with various aspects of the HP86 Kermit. For users new to Kermit Chapter 2 describes what Kermit is, the way it works, and why it is better than some other methods of file transfer. Chapter 3 details the way HP86 Kermit is run, how to enter commands, brief descriptions of the commands, and how they are used. Chapter 4 deals with setting the HP86 Kermit up to communicate with another computer, and how to use it as a terminal for a mainframe. Chapter 5 gives comprehensive information on how to transfer files, and the problems associated with transfer. Following these are various chapters giving more detailed information on commands and some hints and tips. The HP86 Kermit version 1.00 is written in HP86 BASIC and needs the binary program UTIL/1 to be loaded to provide various extra commands, this program is provided with the HP86 microcomputer on the demo disk. HP86 Kermit version 1.00 was developed, written and tested on an Hewlett Packard HP86 microcomputer with a HP 82939A Serial interface and the I/O programming ROM installed. Due to being written in BASIC it will very probably work with the HP87 as long as the same I/O ROM and interface are fitted, however this has not as yet been tested. - 3 - 2. WHAT IS KERMIT ================== Kermit is a data transfer system devised by the Center for Computing Activities at the University of Columbia, New York (CUCCA). The copyright on Kermit is retained by CUCCA, however they have published full information on it and permit anyone to implement it on their machines, as long as this is not for commercial purposes. Due to this policy Kermit is now available for a large range of computers: There are implementations for nearly all mainframes and most popular microcomputers. The basic idea behind Kermit is to allow the transfer of any data between different systems, in a uniform manner, and producing a usable file on the receiving system. There are other methods of data transfer that could be used, most notably 'dumb capture', however Kermit has several advantages over this method. Most simple terminal emulator programs will allow some degree of data transfer in the form of 'dumb capture'. This is a method whereby as characters are received from the mainframe they are placed in a file, as well as being displayed on screen. The reverse process being to take characters from a file on the microcomputer, instead of the keyboard, and transmit them to the mainframe. The dumb capture method, although fast and easy to implement, has many problems associated with it. These are due to the RS232 communications system used to link the computers, and the manner in which it is used. The first problem is caused by parity, as many mainframe systems use one bit of a byte for error checking, the 'parity' bit, only the lower 7 bits of a byte can be used to transmit data, thus only characters with codes between 0 and 127 will be able to be sent. Secondly communications systems commonly use certain characters as control characters, these can therefore not be sent as part of the data without causing problems, control codes lie in the range 0 to 31 and sometimes include 127. Thirdly in a dumb capture system no error checking is performed, this means that the file received may not necessarily be the same as the file sent, due to transmission faults as well as the above problems. - 4 - Kermit overcomes these problems by encoding the data to be transferred using a standard set of rules, the Kermit 'protocol'. The rules have been designed to allow transmission of any character, regardless of any parity or control codes, with adequate error checking to ensure that the file received is the same as the file sent. The full Kermit protocol is beyond the scope of this manual, however the basic method will be described here to aid in the comprehension of following discussions, if more detail is required consult the Kermit protocol manual (5th edition). Kermit transfers data by dividing data up into individual packets, each packet containing the data itself plus some extra control information. This information is used by the receiving Kermit to give the start of packet, the sequence number of the packet, the length of packet, the type of packet and finally a check byte. Using this information the receiving Kermit can verify the data and check for missing packets. If a character needs to be sent whose code falls into one of the problem areas as mentioned above (0-32, 128-255), Kermit will convert it into a sequence of two 'legal' characters using prefix encoding. This is achieved in the following manner, if for example a control code needs to be sent as data it is first converted into a printable character, corresponding with the standard representation of these codes, for instance ASCII 13, usually called control M, is converted to the letter M. This is then prefixed with the prefix character (default - #), thus ASCII 13 will be sent as '#M'. A similar method is used to encode data with the 8th bit set using the 8th bit prefix (default - &). After sending a packet Kermit will wait for a packet from the receiving Kermit to confirm that the packet has arrived correctly, this is called the acknowledge packet (ACK). If for any reason the packet is not received correctly the receiving Kermit sends a negative acknowledge (NAK), this causes the sender to retransmit the last packet. Thus if transmission errors occur Kermit will not only detect the error it will try to remedy the situation by repeating the data. Although ensuring safe transmission of data this method can, without adequate safeguards, cause the system to become 'hung', however there two mechanisms employed to stop this, timeouts and the retry limit. The purpose of the timeout is to avoid the situation where the two Kermits are each waiting for a packet from the other, this can occur when a packet is lost in transmission. A timeout is basically a time limit on the receiving of packets, if after the limit has passed a packet has still not been received the Kermit will assume that the last one it had sent was lost and will retransmit it. - 5 - The retry limit is, as its name implies, a limit on the number of times that Kermit will try to retransmit a particular packet before giving up. This is to prevent the Kermit from endlessly sending the same packet to a Kermit that is either not replying, or is having severe transmission problems. The result of using the Kermit protocol is a simple, highly reliable system of data transfer, that can be, and has been, implemented on a wide variety of machines ranging from microcomputers to mainframes. The only requirements needed to transfer data from the HP86 and another computer are two Kermit programs, one for the HP86 and one for the target computer, and the existence of a RS232 serial interface port on both machines. The great advantage of Kermit over data transfer programs written for specific machines is its wide availability, making it possible to transfer data to many different machines using the same program. - 6 - 3. RUNNING KERMIT ON THE HP86 ============================= This section describes the general operation of the HP86 Kermit, how to start it and how to enter commands. 3.1 STARTING THE HP86 KERMIT ---------------------------- To run Kermit on the HP86 the disk containing the Kermit program and the utility programs should be inserted in the disk drive (if your HP86 has more than one disk drive insert in drive 0). The following procedure should now be taken:- LOAD "Kermit" <--- Load the Kermit program. LOADBIN "UTIL/1" <--- Load the utility program. <INIT> <--- Press the INIT button. <RUN> <--- Press the RUN button. After about 80 secs the program will display the following prompt:- Kermit-HP86 > Enter command ? If this does not happen the RUN button should be pressed again. 3.2 ENTERING KERMIT COMMANDS ---------------------------- To control the HP86 Kermit commands have to be issued to it, this is done by entering the desired command in the space underneath the Kermit prompt (note: on most implementations of Kermit the command is entered next to the prompt). Commands can be entered in either upper or lower case, and may be abbreviated to a minimum of 1 character (depending on command). Some of the commands will require parameters to be entered as well, these should be typed after the command and should be separated by at least one space, except for filenames which must be enclosed by quotes ("). The parameters can be of various types, a filename, a character, a numeric value, or an item from a list. In the case of the SET command two sets of parameters are required, firstly the item to be set, and secondly what it is to be set to. - 7 - The question mark (?) can be used to give useful information on commands, if entered as a command all the legal commands will be displayed, and if entered as a parameter the type of parameter will be displayed. send ? <- You enter. SEND "Source filename" <"Destination filespec"> <- Kermit replies. Where '<' and '>' denote an optional item. If the required parameter is an item from a list the alternatives are all displayed, also note that list items can be abbreviated in the same way as commands. set flow ? <- You enter. FLOW-CONTROL - NONE, XON/XOFF, DTR/RTS <- Kermit replies. 3.3 HP86 KERMIT COMMANDS ------------------------ The following is a list of valid commands for the HP86 with a brief description of each, they will be explained in more detail in latter chapters. Command Parameters Description CONNECT Sets the HP86 to act as a terminal to allow communication with the remote host. SEND "source filename" <"dest filespec"> Send the specified file to the remote, the file name that is used by the remote can also be specified, if required to be different from the source file name. RECEIVE <"dest filename"> Receive a file, or group of files, from the remote, changing filename if required. SET List option Parameter Set specified option to a new value, used to change communication settings, timeouts, retry limit etc. Requires extra parameter(s) after the option. SHOW List option Displays current setting of the requested option, if no option is specified all the settable parameters will be displayed. EXIT Both these commands will cause the HP86 Kermit QUIT to stop, and return the HP86 to the command state. - 8 - CAT This command will produce a catalogue of the current disk. As well as the above commands it is also possible to use the HP86 filing system commands in the following way: <PAUSE> <- Press the PAUSE key. Warning 101 at line 0 : XFR <- The HP86 gives a warning that an input transfer from the RS232 is still in progress. Any of the HP86 filing system commands can now be entered, for example: PURGE "GARBAGE" <- Erase the file called "GARBAGE" Once finished entering commands to the HP86 the Kermit program should be restarted: <CONT> <- Press the continue key ? <- The HP86 replies with this, the next Kermit command should now be entered under this prompt. 3.4 USING KERMIT ---------------- To use Kermit to transfer data you will need a Kermit program for both the HP86 and the other computer, the actual procedure to be used depends on whether the other computer is a microcomputer with its own keyboard, or a minicomputer or mainframe that needs a terminal to communicate with it. For HP86 to microcomputer transfer the method is very simple, after making any connections load and run the Kermit programs in both computers, then using the SET command the RS232 interfaces should be set to appropriate values (see chapter 4). Once all the settings are correct transfer can begin, enter the RECEIVE command on the computer to which the data is to be sent, then enter the SEND command on the sending computer, the transfer will now take place. For HP86 to minicomputer or mainframe transfer a slightly different approach is needed, after physically connecting the HP86 to the computer the HP86 Kermit is run and any communication settings made. The HP86 should now be put into terminal emulator mode using the CONNECT command, then using the HP86 as a terminal you should log on to the computer and run its Kermit program. To transfer data you enter the required command on the remote, either SEND or RECEIVE, then escape back to the HP86 Kermit (using k1 - see chapter 4), and issue the complimentary command. - 9 - After the transfer is completed connect back to the remote, if no more transfers are required exit from the Kermit program, log off, escape back to the HP86 and exit from its Kermit program. Both these methods will be discussed in more detail in chapter 5 'Transferring files by Kermit'. 3.5 FINISHING KERMIT -------------------- Once you have finished using Kermit for your file transfers you should exit from the program by using either the EXIT or the QUIT command, either of these will halt any RS232 transfers that are active, close any open files and leave the HP86 in a suitable state for further use. If you wish to enter a new program via the keyboard you should use the SCRATCH command to clear the memory, as the Kermit program is still present. - 10 - 4. COMMUNICATING WITH ANOTHER COMPUTER ====================================== This section describes how to set up the HP86 Kermit so that it can communicate with another computer, the remote host. it will also outline how to use the terminal emulation facility when the remote is a mainframe computer. 4.1 SETTING THE RS232 --------------------- Once the HP86 is physically connected to the remote (if you are unsure of how to do this contact your system support personnel), you should now set up the RS232 interface so that it can communicate with the remote host. There are four separate settings that may have to be changed these are Baud rate, parity, duplex and flow control or handshake (depending on duplex setting). All the changes are made using the SET command and the existing settings can be determined using the SHOW command. BAUD RATE 110, 300 Default 300 This is the rate that the data is transmitted along the RS232 link, at present only two rates are allowed 110 or 300 baud. PARITY NONE, ODD, EVEN, MARK, SPACE Default MARK This is the parity that will be used by the RS232 interface, this can be none, odd, even, mark or space, if none is chosen all 8 bits of a byte will be sent, otherwise only the bottom 7 are used. DUPLEX FULL, HALF Default HALF This defines whether the remotes communication equipment can receive at the same time as it is transmitting, full duplex operation, or can only receive whilst not transmitting, half duplex. Setting this will also change the local echo setting, if set to full duplex local echo will be switched off, is set to half duplex it will be switched on, this can be changed with SET LOCAL-ECHO. FLOW-CONTROL NONE, XON/XOFF, DTR/RTS Default NONE Defines the method the remote uses to stop the HP86 transmitting any more data, to stop its buffers overflowing. The possible settings are none, XON/XOFF for software flow control using control codes 17 and 19 (XON,XOFF), and DTR/RTS for hardware flow control using the DTR and RTS control lines. Setting this to any setting other than none will set handshake to none. - 11 - HANDSHAKE NONE, BELL, LF, CR, XON, XOFF Default XON Defines the character to be used as a handshake character for half duplex communications, the handshake character is used by both computers to indicate that they have finished transmitting and that the other can now transmit, this is sometimes called the line turnaround character. The possible option are none, bell (ASCII 7), linefeed (ASCII 10), carriage return (ASCII 13), XON (ASCII 17) and XOFF (ASCII 19). To change any of these settings use the SET command in the following manner: KERMIT-HP86 > Enter command ? <- Underneath the prompt type in set set flow-control xon/xoff followed by the options. FLOW-CONTROL - XON/XOFF <- Kermit will respond with the new setting if it is accepted. Note that the options can be abbreviated for ease of typing, for instance the above could have been entered as set flow xon. The settings can be determined using the SHOW command, if no option is specified the screen will display the settings of all the set options, otherwise specify the particular option: KERMIT-HP86 > Enter command ? show parity <- Enter command PARITY - MARK <- Kermit responds with the current setting. The actual settings needed will depend on the machine that you wish to communicate with, you will need to know what its settings are. If you are linking to another microcomputer you will need to set the RS232 options to the same on both machines. The simplest method is to set the options on one machine to the default settings of the other, depending if this can be done, for instance if the other micro has a default Baud rate of 1200, which can not be set on the HP, set its Baud rate to 300. An alternative approach is to set each option to the 'best' that can be set on both machines, ie the highest Baud rate, full duplex, hardware flow control, and no parity (to allow 8 bit data communication with no encoding). When connecting to a mainframe computer you will be limited to the standard operating on that computer, the default settings are designed to operate with an IBM 4341 on a 300 baud line, your Systems Support staff should be able to tell you what settings are needed for your installation. - 12 - 4.2 USING THE HP86 AS A TERMINAL -------------------------------- As mentioned before when transferring files between the HP86 and a minicomputer or mainframe you will need to communicate with the remote by using the HP86 as a terminal, to achieve this you should use the CONNECT command. 4.2.1 THE CONNECT COMMAND ------------------------- The CONNECT command needs no parameters and can be abbreviated to 'C', once entered the HP86 will clear the screen and display the following information: HP86 Kermit - Terminal emulation mode Function key Escape character Action -------------------------------------------------- k1 C Return to Kermit k7 B Transmit break k14 Enable transmit The above display indicates the action of various function keys, and the corresponding escape key sequences (Ctrl-] + character). At the bottom of the screen a cursor will be displayed, this is where any keyboard input will appear. The HP86 will now act like a 'glass' teletype, characters typed on the keyboard will be sent directly to the remote via the RS232 interface, and characters received from the RS232 will be displayed on the screen. 4.2.2 DIFFERENCES BETWEEN COMMAND MODE AND TERMINAL MODE -------------------------------------------------------- There are important differences in the way the keyboard and screen are handled in the terminal mode compared to the normal HP86 entry mode, these are as follows. All of the special keys, cursor keys and screen control keys cease to have any effect, except for the ENTER key, RESET key, and the defined function keys. Pressing the ENTER key sends a carriage return (Control M) to the remote, in addition if a handshake character is specified it will also be sent and the transmitter will be disabled. The RESET key performs its normal function of halting the program and resetting interfaces. - 13 - The delete key may not have any effect, depending on the remote system, even if accepted the action on the screen will differ, instead of the last character typed being removed from the screen, a delete character will be displayed after it. Some remotes will use a different key for this purpose, for instance the IBM uses '_' as a delete character, you will be able to find this from the user documention on using terminals. If there is any handshake or flow control specified there will be times when the keyboard does not respond due to the transmitter being disabled, with half duplex systems this will occur immediately after pressing the enter key and will remain until the remote finishes transmitting data and sends the handshake character. If the keyboard is not responding and the remote is not transmitting, or about to transmit, the transmitter can be re-enabled by pressing function key 14. 4.2.3 SENDING A BREAK --------------------- Many mainframe computers may need to be sent a 'Break' signal for certain reasons, usually to interrupt the current program and return to the command state. You can send a break from the HP86 Kermit either by pressing function key 7, or by typing control ] followed by B. 4.2.4 RETURNING TO THE HP86 KERMIT ---------------------------------- When you have finished issuing the required commands to the remote Kermit or you have finished your session on the remote, you will need to return to the HP86 Kermit's command mode, this is achieved using function key 1, or control ] plus 'C'. On returning the screen will be cleared and the standard Kermit prompt will be displayed. If you are unsure what mode you are in examine the prompt, if it is not 'KERMIT-HP86 > Enter command ?' then you are in terminal mode. - 14 - 5 TRANFERRING FILES USING KERMIT ================================ The main purpose of the HP86 Kermit is to enable file transfer between the HP86 and another computer, the remote host. The basic method will not vary from one system to another as this is defined in the Kermit protocol, however certain details will be different. Before attempting any file transfer you should consult the user guide for the remote system to familiarise yourself with any differences. This section describes in detail how to transfer files between the HP86 and the remote computer. 5.1 THE BASIC METHOD -------------------- To transfer files using Kermit you will need another Kermit program running in the remote host, and you will need to issue commands to it. For HP86 to microcomputer transfers this can be done simply by typing the required commands on the respective keyboards, however for HP86 to mainframes or minicomputers a more complex approach is needed. 1. Load and run the HP86 Kermit, change any RS232 settings to enable the HP86 to communicate with the remote, and set any other parameters needed for the transfer. 2. The HP86 is put into terminal mode using the CONNECT command. Now with the HP86 acting as a terminal the user should log on to the mainframe in the normal manner. 3. The Kermit program on the remote should now be run, and any SET commands entered. 4. To transfer files the relevant command should now be entered, RECEIVE for HP86 to remote, SEND for remote to HP86. After entering the command return to HP86 Kermit command mode using k1 and enter the complimentary Kermit command, SEND for HP86 to remote, RECEIVE for remote to HP86. 5. After the transfer is complete re-enter terminal mode to set the remote's Kermit for any further transfer, or if you have finished all your transfers you should log out from the remote. The above description is only a guide to the sequence of actions to be taken, you may not need to set any parameters, or you may wish to run some other program on the remote using data transferred by Kermit. - 15 - 5.2 FILE TYPES -------------- Before any discussion of file transfer it is necessary to outline the types of files that can successfully be transferred with HP86 Kermit version 1.00. Due to version 1.00 being written in HP86 BASIC the ideal of being able to transfer any file cannot be implemented. The restrictions imposed by HP86 BASIC are quite severe and can only be overcome by various forms of file conversion. Because of the limitations it is advisable to thoroughly read this section before attempting any file transfer. 5.2.1 THE FILE TYPE PROBLEM --------------------------- When a file is created by the HP86 it is assigned a particular type depending on its use and method of generation, these are as follows:- PROG - BASIC program created using the STORE command. BPGM - Binary program. DATA - Data file. GRAF - Screen dump. **** - Extended file. Of these only those of type DATA can be sent using version 1.00 of Kermit, this being the only type that can be accessed by HP86 BASIC. Fortunately a utility program 'GETSAVE' exists on the HP86 demo disk which will save BASIC programs from memory as DATA files, and load DATA files as BASIC programs (or sections of programs). The file type can be discovered using the CAT command either before running Kermit or whilst in the command mode. KERMIT-HP86 > ? cat <- Enter catalogue command .. HP replies with Name Type Bytes Recs ------------------------------ MYFILE DATA 256 4 PROGRAM PROG 256 9 UTILITY BPGM 256 7 If the type displayed is not DATA then the file cannot be transferred using HP86 Kermit version 1.00, if this is attempted Kermit will return with an error. - 16 - 5.2.2 THE DATA TYPE PROBLEM --------------------------- As previously mentioned only files of type DATA can be sent via the present implementation of Kermit, however there is a second factor that can affect the success of any transfer, that of data types. The HP86 like many other microcomputers stores data on its disks in two different formats depending on the variable type, either numeric or string data. This causes problems when sending data to a remote kermit for the following reasons: All data to be transferred via Kermit has to be either ASCII data, or binary data that can be converted to ASCII by 8-bit prefixing. HP86 BASIC is unable to access data on disk as bytes, it must be read either as a string variable or as a numeric variable. Therefore if data in the numeric format is encountered it has to be converted into ASCII before it can be sent. There is a mechanism to do this in the HP86 Kermit program, however this method is not satisfactory for most transfers for the following reasons: The numeric variable will be converted to a string of characters, the number of which depends only on the number of significant digits in the variable (for instance '1 ','10 ' and '10.04 '). The resulting file will therefore have a irregular format that will make its use, by other computer systems or languages, very difficult. There is no method in the Kermit program of converting this data back into numeric variables, therefore a file sent using this conversion and then received back will be of a different format and almost definitely unusable. For these reasons it is advisable to convert any files to be sent by kermit so that any numeric variables are stored as, or in, ASCII strings. You should attempt to do this so the numbers are stored in a fixed format based on their range, this will enable the data to be reconverted easily, and allow it to be used as input to programs written in other languages, or on different computers. For example if the data was a list of temperatures between 0 and 200 measured with and accuracy of 2 decimal places, a sensible choice of format would be XDDD.DD (where D is a digit or space if a leading zero, X is a space), 10 of these numbers could then be placed in one string, producing records with the following format: 12.15 54.72 112.39 23.54 178.01 107.10 93.42 121.34 154.81 133.04 This would produce a file that could be used by many high level languages, for instance it could be read by a FORTRAN program using the following format statement - FORMAT (10(1X,F6.2)). - 17 - For a simple method of storing numeric data as formatted strings see appendix C. Please note that there is no way that you can determine whether a file contains data of the correct type until you actually attempt to transfer it. The default condition for the HP86 Kermit is to do no conversion of numeric data, if a numeric variable is encountered then the transfer will be halted and an error message displayed. To use the inbuilt conversion facility issue the following command: SET SEND-CONVERT ON It must be emphasized again that using this method produces unpredictable results, also in some circumstances an type error can still be produced. For these reasons it is suggested that it should be used vary rarely, for files containing only a small proportion of non crucial numeric data. 5.3 HP86 TO REMOTE FILE TRANSFER - THE SEND COMMAND --------------------------------------------------- To send a file from the HP86 to the remote Kermit you use the SEND command, however before you issue this command you should set the remote in to receiving state. To set the remote up to receive a file you use the RECEIVE command, the manner in which this is done depends on the type of remote. If the remote is a microcomputer simply enter RECEIVE using its keyboard then enter the SEND command using the HP86's keyboard. For a mainframe or minicomputer remote host you will have needed to have logged on and started Kermit using terminal mode. While still in terminal mode issue the RECEIVE command. You should now return to the HP86 Kermit command mode by using function key 1 and enter the HP86 Kermit SEND command. Once the remote is in a state to receive files you should enter the SEND command, this has the following format: SEND "source filename" <"dest filespec"> Where: "source filename" Is the name of the file to be sent in standard HP86 format. "dest filespec" Is the name that you wish the file to be stored as on the remote computer. If only the source filename is specified the HP86 Kermit will send this name converted into a 'legal' Kermit format. - 18 - The HP86 will now start to send the named file to the remote Kermit the following screen display will be seen: ---------------------------------------------------------------- I HP86 Kermit sending file I I ------------------------ I I I I Sending 'myfile dat' as 'MYFILE.DAT' I I I I Current action : Sending initialise Retries : 0 I I Packets sent : 0 NAKs received : 0 I I Bytes sent : 0k Timeouts : 0 I I Bad packets : 0 I I I The file will now be sent packet by packet to the remote Kermit. The progress of the transfer will be displayed on the screen. When completed the message 'Transfer successful' will be displayed and you will be returned to command mode. 5.4 REMOTE TO HP86 TRANSFER - THE RECEIVE COMMAND ------------------------------------------------- Before discussing the method used to transfer files from the remote to the HP86 a serious problem needs to be highlighted. Unlike most filing systems the HP86 BASIC filing system is incapable of creating a file without knowing its size. Unfortunately there is no way for the HP86 Kermit to know the size of the file it is receiving. Due to this problem it is necessary to inform the HP86 Kermit of the size of the file that it is to receive, to do this use the SET FILE-SIZE command. SET FILE-SIZE size Where size is the desired file size in kilobytes, the default setting is 10. If FILE-SIZE is not set correctly one of two problems can arise. Firstly if FILE-SIZE is set far larger than the actual size you will be wasting disk space. Secondly and more seriously if FILE-SIZE is smaller than the actual size then the transfer will be aborted when the file on the HP86's disk becomes full. To avoid both problems before receiving files find the actual file size by using the relevant command on the remote system, you can find this from the user documentation. You may have to calculate the size in kilobytes from the record size and number of records, round this figure up to the nearest kilobyte. Setting FILE-SIZE to this value will usually be sufficient. Occasionally though this can be less than actually needed as the HP86 requires an extra 3 bytes per record stored, so for added safety when transferring large files increase the file size by 1. - 19 - As you would expect, to receive files from the remote you use the RECEIVE command on the HP86 Kermit and the SEND command on the remote. The order the two commands are entered will depend again on the type of remote. For microcomputer to HP86 transfer: Issue the RECEIVE command on the HP86, then the SEND command on the remote. For transfer from mainframe or minicomputer: First issue the SEND command to the remote whilst in terminal mode, then return to HP86 command mode, and enter RECEIVE. The RECEIVE command has the following format: RECEIVE <"dest filename"> Where "dest filename" is the file name that the received file will be stored as, if not supplied the name sent by the remote Kermit will be converted to a legal HP86 name. Once entered the HP86 screen will clear and the following will be displayed: ---------------------------------------------------------------- I HP86 Kermit receiving file I I -------------------------- I I I * I I I I I Current action : Wait for initialise Retries : 0 I I Packets received : 0 NAKs sent : 0 I I Bytes received : 0k Timeouts : 0 I I Bad packets : 0 I I I * Note the name of the file being received will not be displayed until that information has been received from the remote. When the HP86 Kermit receives the file header it will attempt to create a file with either the name supplied after the RECEIVE command, or with the name contained in the header (converted to HP86 form). If the file already exists on the disk then Kermit will rename the file and attempt to store it again, the new name will be displayed. Receiving 'MYFILE.DATA' as 'MYFI00 DAT' The actual way the file is renamed depends on whether the name was supplied as a parameter to the RECEIVE command, or contained in the file header, see the section on file name conversion for more details. - 20 - 5.5 TRANSFER PROBLEMS --------------------- After the transfer has completed the HP86 Kermit will display the 'Transfer successful' message, however if an error has occured and the transfer has been halted a suitable message will be displayed. Timeout - Time limit exceeded on sending or receiving a packet, increase timeout and re-run. NAK received - A negative acknowledge packet was received from the remote that caused the retry limit to be exceeded. Checksum error - A garbled packet was received from the remote. Check communication settings and physical connections. Incorrect packet - The remote Kermit has sent a packet which is not the type that the HP86 expects. This should only happen if both Kermits have been set to SEND files, try again being careful to enter the correct commands. Error message from remote - The remote Kermit has sent an error packet the contents of which will be displayed. Transfer aborted - Function key 1 was pressed during transfer. Other messages - The rest of the messages generated by Kermit will be errors produced by the filing system for instance 'File does not exist', these are mostly self explanatory, however the error no is displayed so users can check the HP86 manual for more detailed descriptions (see also Appendix B). Sometimes on connecting back to remote, especially after an error, garbage is printed on the screen. This indicates that the remote Kermit is still in receive or send mode, having missed the relevant error or break packet. To rectify this situation press the enter key until the remotes prompt reappears. 5.6 FILE NAME CONVERSION ------------------------ The Kermit protocol specifies that the file name of the file being sent should be transmitted in the file header packet, to provide the receiving Kermit with a name to store the file under. However the file name has first to be converted to a standard format, although different from the HP86 format it is very similar to many mainframe file specifications being of the following form: filename.filetype where filename and filetype can be of any length but can only be composed of digits or uppercase letters. - 21 - HP86 file specifications are of the form "XXXXXXXXXX", or "XXXXXXXXXX.volume", or "XXXXXXXXXX:msus", where XXXXXXXXXX is a filename of up to 10 characters. volume is the volume label of the disk containing XXXXXXXXXX. msus is the device specifier of the disk drive containing XXXXXXXXX (E.G. D700). HP86 file names may contain upper or lower case letters, digits, special characters, excluding period and colon, and imbedded spaces. Upper and lower case letters are not equivalent. Due the differences in the format of filenames it is necessary to convert names used on the HP86 if they are to be sent to the remote, and likewise convert names received from the remote if they are to be used on the HP86. 5.6.1 HP86 to standard conversion --------------------------------- When sending a file to the remote and a destination file name has not been specified the HP86 Kermit will convert the source filename into a 'legal' Kermit name. The way this conversion takes place is as follows: All lowercase characters are converted to uppercase. If the name contains one or more spaces then the first space will be converted to '.', else if name contains one or more '_' characters then the first '_' will be changed to '.'. The name is now scanned for legal characters (0-9,A-Z & first '.') if any illegal character is found it will be removed from the name. If the resulting name contains no '.' the filetype '.DATA' will be added to the end. For example Statistics would be converted to STATISTICS.DATA TEST FILE '' '' '' '' TEST.FILE Tst File 1 '' '' '' '' TST.FILE1 TEST#1-00 '' '' '' '' TEST100.DATA The name that Kermit sends to the remote will be displayed on the screen along with the source file name. - 22 - 5.6.2 Standard to HP86 conversion --------------------------------- When receiving files without specifying a destination file name then a reverse conversion occurs. First the name is scanned for the '.' marker, if this does not exist then the name is used as it is. The HP86 name is then constructed using the first 6 characters of the filename, a space and then the first 3 characters of the filetype. Thus: STATISTICS.DATA would be converted to STATIS DAT TEST.FILE '' '' '' '' TEST FIL Note that a filename converted to Kermit format and then converted back will not necessarily be the same. 5.6.3 File renaming ------------------- When receiving files from the remote the situation can arise that the file name supplied, or the converted file name from the remote will clash with a file already on the disk drive. To avoid losing data by overwriting the existing file the HP86 Kermit will attempt to rename the file. The method used for renaming depends on whether the name was supplied as a parameter for the RECEIVE command, or converted from the file header sent by the remote. For a supplied name the method is to add a two digit number to the end, keeping the total length to 10 characters, this may involve writing over the last two characters. The numbering will start from 00 and will continue until 99 after which an error message will be generated. For example:- MYFILE would be renamed MYFILE00 STATISTICS '' '' '' STATISTI00 If MYFILE & MYFILE00 existed then MYFILE would be renamed MYFILE01 If the file name is one that has been received and converted from the file header packet then the renumbering is done at the end of the part that was the filename, keeping it to 6 characters or less. For example MYFILE.DATA is converted to MYFILE DAT and renamed MYFI00 DAT TEST.BASIC '' '' '' TEST BAS '' '' TEST00 BAS The result of either of these methods will be displayed on the screen, however the results should not be too radically different from the original to enable correct identification. - 23 - 6. CHANGING KERMIT ATTRIBUTES ============================= At various points throughout this manual it has been mentioned that certain attributes have needed to be changed, the specific cases being described. This chapter gives a more detailed description of the command used to change these attributes, the SET command. 6.1 THE SET COMMAND ------------------- The SET command has the following format: SET option parameter(s) Where option The attribute that you wish to change. parameter(s) The value(s) to set the option to. The parameter types will depend on the option specified, and can be a character, a numeric value, or an item from a list. The option name can be abbreviated, as can the parameter if it is a list item. Kermit will respond with the new setting or with an error message if an illegal value is entered. SET RETRY 7 <- Enter set command RETRY - 7 <- Kermit replies SET RETRY # <- Set command with incorrect value. Illegal value - # <- Kermit replies. If a question mark is entered instead of the parameter then Kermit will display either the expected parameter type, numeric or character, or display the list from which the parameter should be chosen. SET RETRY ? <- Set command query. Numeric value <- Kermit replies SET FLOW ? <- Set command query. FLOW-CONTROL - NONE, XON/XOFF, DTR/RTS <- Kermit replies. - 24 - 6.2 THE SHOW COMMAND -------------------- This command is used to display the current settings of the attributes, if entered with no option then all settable attributes will be displayed, otherwise the setting of the specified option is shown. SHOW DEBUG <- You enter. DEBUG - OFF <- Kermit responds. 6.3 SETTABLE ATTRIBUTES ----------------------- There now follows a list of the attributes that can be set and displayed using the SET and SHOW commands. OPTION PARAMETER TYPE DEFAULT TIMEOUT Numeric value Default - 10 secs The length of time the HP86 Kermit will wait for a packet from the remote before causing a timeout. RETRIES Numeric value Default - 10 retries The number of times the HP86 Kermit will try to resend a packet. SEND-CONVERT OFF, ON Default - OFF Defines whether numeric variables are to be converted and sent as string data, if off numeric variables will cause the transfer to abort. DEBUG OFF, ON Default - OFF If set to on then packets sent and received will be displayed on the screen. PREFIX Character Default - # Defines the character to be used for prefix encoding. END-OF-LINE Numeric value Default - 13 The ASCII value of the end of line character that should be sent after each packet. RECORD-END Numeric value(s) Default - 13 10 Defines the sequence of control characters that indicate the end of a record. This will be added to strings when sending files, searched for and removed when receiving files. FILE-SIZE Numeric value Default - 10 - 25 - The size of the file (kilobytes) that will be created when receiving files. RECORD-LENGTH Numeric value Default - 256 The record length that will be used by the HP86 when creating files, if matching record lengths on remote systems add 3 bytes, the HP86 needs these extra bytes when storing strings. NO-OF-RECORDS Numeric value Default - 40 The number of records of the file created by the RECEIVE command, setting this will override the file-size, the resulting size being the record length times the no of records, setting file-size will change this value. DUPLEX FULL, HALF Default - HALF The duplex setting of the remote, setting this value alters the setting of the local echo, FULL - OFF, HALF - ON. LOCAL-ECHO OFF, ON Default - ON Defines whether characters typed on the keyboard will be displayed on the screen (ON), this only applies to terminal mode. FLOW-CONTROL NONE, XON/XOFF, DTR/RTS Default - NONE Specifies the flow control method to be employed, setting this to any value other than NONE sets HANDSHAKE to NONE. HANDSHAKE NONE, BELL, LF, CR, XON, XOFF Default - XON Defines the handshake character to be used for line turnaround, setting this to anything except NONE will set FLOW-CONTROL to NONE. PARITY NONE, ODD, EVEN, MARK, SPACE Default - MARK The parity to be used by the RS232 interface. - 26 - Appendix A : HP86 KERMIT Capabilities ===================================== The following is a list of Kermit capabilities, with information as to whether they are supported by HP86 Kermit version 1.00. Local operation: Yes Remote operation: No Transfers text files: Yes Transfers binary files: No Wildcard send: No ^X/^Z interruption: Yes Filename collision avoidance: Yes Can time out: Yes 8th-bit prefixing: No Repeat count prefixing: No Alternate block checks: No Terminal emulation: Yes Communication settings: Yes; duplex, parity, handshake, flow control Transmit BREAK: Yes IBM communication: Yes; default settings Transaction logging: No Session logging (raw download): No Raw upload: No Act as server: No Talk to server: No Advanced commands for servers: No Local file management: Yes; CAT Handle file attributes: No Command/init files: No Printer control: No - 27 - Appendix B : HP86 error messages ================================ The following is a list of error messages that Kermit version 1.00 will give if a transfer is aborted. Timeout receiving The HP86 has timed out whilst waiting for a packet from the remote. NAK received The remote has sent a NAK causing the retry limit to be exceeded. Checksum error The last packet received was garbled. Incorrect packet The wrong packet type has been received from the remote. Timeout sending The HP86 has timed out whilst trying to send a packet. Cannot rename file The file being received has the same name as an existing file, but it cannot be renamed as the number suffix is past 99. Disc write protected The disk has a write protect label attached, the file cannot be stored. File does not exist The file cannot be found on the disk. Incorrect file type The file cannot be sent as the file type is not DATA. Read error There has been a read error on the disk. Record does not exist The file has become full before all the data has been received. No M.S. device No mass storage device has been specified. Directory full No more files can be stored on the disk as the directory has become full. Volume not found The specified volume name can not be found. MSUS not found The specified mass storage device (disk drive) can not be found. Read verify error The data written to disk has been corrupted. - 28 - Disc full The disk has become full, or does not contain enough space to create a new file. Medium damaged The disk is faulty. Disc drive fault The disc drive is not functioning correctly, can be caused by leaving the latch on the disc drive up. Data type error The variable just read was a numeric variable and the data conversion facility is off. Transfer aborted Function key 7 was pressed aborting the transfer. - 29 - Appendix C : Converting numeric variables ========================================= As mentioned in the section on file transfer numeric variables cannot be sent to the remote without conversion. Although a very basic conversion method is included as part of the HP86 Kermit, it is advisable not to use it but to convert the whole file into one usable by Kermit and the remote. To convert the file you will need to know the manner in which the data is arranged in the source file, and decide on a format for the converted file. The structure of the source file can usually be determined by examining the program that created it, with a well documented program this task should be fairly easy. However if the creating program is not available, and the structure is unknown, use the HP86 BASIC TYP command. Once you have determined the structure of the file(s), and have decided on a logical format to convert them to, you will need to write a short program to achieve this. The easiest way of converting the numbers into a useful format is to use a facility provided by the HP86 I/O ROM. The method involves defining a dummy I/O buffer, output the numeric variable to this buffer using the formatting facilities (USING), and reading it back in as a string with the ENTER command. For example 10 DIM dummy$"88" <- Dimension variable to 8 bytes more than required size. 20 IOBUFFER dummy$ <- Set it up as an I/O buffer . . . 500 OUTPUT dummy$ USING "X,M4D.DD"; N <- Output number using the specified format. 510 ENTER dummy$ USING "K" ; N$ <- Read it in as a string. - 30 - After converting the number to a string it can either be stored separately, or placed into another string along with others to form a record. The OUTPUT command can be used to construct records by outputting more than one variable at once, or by outputting without end of line. 500 OUTPUT dummy$ USING "XM4D.DD" ; N1,N2,N3,N4 or 500 FOR I=1 TO 10 510 OUTPUT dummy$ USING "#,X,M4D.DD" ; N(I) <- Output without EOL 520 NEXT I . . As there is now no EOL sequence at the end of the buffer the . following statement would be needed to read this back. . 530 ENTER dummy$ USING "#,#K" ; R$ <- Enter without EOL The complete record string can now be written to the disk file. As can be seen this is a very simple method of producing formatted files which can be sent using the HP86 Kermit. Also with a bit of care these files could be used as input to programs written in other languages than BASIC. The reverse conversion is also easy to perform using the ENTER command: 500 OUTPUT dummy$ ; R$ <- Output the string to the dummy buffer 510 FOR I=1 T0 10 520 ENTER dummy$ USING "#,X,M4D.DD" ; N(I) <- Get number 530 NEXT I All the above conversion techniques can of course be included in other programs, if it is invisaged that the data files produced by the program will be transferred to another system using Kermit. Including an option to produce files in 'Kermit' format is more efficient than having separate conversion programs. The above discussion does not include any details of image specifiers and other related matters, if you wish to use this method of data conversion you are strongly advised to read the section on Formatted I/O operations in the HP86 I/O Programming guide. - 31 -