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SCIENCE AND ENGINEERING RESEARCH COUNCIL
RUTHERFORD APPLETON LABORATORY
INFORMATICS DIVISION
OS 4000 USER NOTE 105
____________________________________________
Kermit-40 for GEC OS4000(RAL), Version 3.5
issued by
M J Loach
March 1986
_________________________________________________________________________
ABSTRACT
Kermit is an error protected, asynchronous file transfer protocol
designed by Columbia University, USA, intended to work over RS232/V24
interfaces. It is widely used as a 'standard' means of file transfer
between micro-computers and other micro-computers or larger machines.
Any two machines which have Kermit implemented on them can transfer text
files, (and sometimes also binary files) provided the necessary hardware
inter-connection is provided. Kermit-40 is the implementation for GEC
4000 series computers running under RAL OS4000, and provides the means
whereby Kermit on micro (or larger) computers can transfer text and
binary files with OS4000 machines.
Kermit distribution policy requires that permission hereby be granted to
any individual or institution to copy or use this document and the
programs described in it, except for explicitly commercial purposes.
_________________
Table of Contents
1 Preface.............................................................1
1.1 Revisions for Version 3.2.......................................1
1.2 Revisions for Version 2.1.......................................2
2 Introduction........................................................4
3 Running Kermit-40...................................................7
4 The command list....................................................7
5 The commands, in detail.............................................9
5.1 To send a file, or files, to micro-kermit.......................9
5.2 To receive files from micro-kermit.............................10
5.3 To reset default parameters....................................10
5.3.1 DEBUG (off/on)...........................................12
5.3.2 EOL n....................................................12
5.3.3 STX n....................................................13
5.3.4 PAD n....................................................13
5.3.5 CHAR n...................................................13
5.3.6 SEND n...................................................13
5.3.7 RETRYS n.................................................13
5.3.8 TIME n...................................................13
5.3.9 TIMEOUT n................................................14
5.3.10 QUOTE n.................................................14
5.3.11 8BIT n..................................................14
5.3.12 BINARY (off/on).........................................14
5.3.13 REPEAT..................................................14
5.3.14 NORMAL (on/off).........................................15
5.4 To display the settings of SET parameters......................15
5.5 To switch Kermit-40 into remote Server mode....................16
5.6 To obtain on-line help on the Kermit-40 commands...............17
5.7 To exit from Kermit-40.........................................17
6 Examples of using Kermit-40........................................18
6.1 Example- Kermit-40/IBM PC (Telios).............................18
6.2 Example- Kermit-40/IBM PC (Kermit-MS)..........................20
6.3 Example- Kermit-40/ VAX/VMS (Kermit-32)........................23
7 What to do when things go wrong....................................25
7.1 Failure to be able to Connect to host..........................25
7.2 Failure of the transfer of the file(s).........................25
8 Appendix A.........................................................26
Kermit-40 Users Guide
_______
1 Preface |
|
_________________________
1.1 Revisions for Version 3.2 |
|
This version of Kermit-40 provides the following: |
|
|
Main features: |
|
* Inclusion of Server mode. |
|
* Repeat count prefixing available. |
|
* Receive command can be specified with a filename. |
|
* A file of initialising commands can be read at the start of a Kermit |
run, as provided for in some Kermits as a 'TAKE' file. |
|
* Packets of upto 94 characters can now be sent, and upto 80 characters |
can be received. |
|
|
Bugs fixed: |
|
* Overprints were still output to &KERMLOG, this has been fixed. |
|
* Error messages from the Send command were incorrect. |
|
* I/O buffers have been enlarged, to prevent overwriting problems in |
&KERMLOG. |
|
* Eight bit quoting is now handled whenever agreed, irrespective of the |
SET BINARY option. |
|
* The code has been altered so that the standard GEC version will now |
compile. |
|
* Prefix encoding and decoding is now done on file header packets. |
|
* A check has been included to prevent text file records received from |
exceeding 235 characters. |
|
|
General improvements: |
|
* The Data Management error code after a DMCONNECT is now written to |
&KERMLOG. |
|
* Conversion of file names to 'normal form' can now be switched off. |
|
* Output from the SHOW command displays off/on instead of 0/1. |
|
* In Receive, the message 'oldname receiving as newname' appears in |
&KERMLOG. |
March 1986 Page 1
Kermit-40 Users Guide
|
|
_________________________
1.2 Revisions for Version 2.1
This release of Kermit-40 is a more complete version of the Kermit
protocol. There are two added main features, eight bit quoting for
binary file transfer, and the ability to timeout failed protocol
exchanges. A number of bug fixes and other improvements are also
incorporated.
Main features:
* Binary file transfer included, with an eight bit quoting ability.
* 10 second timeout added, with SET timeout facility included.
Bugs fixed:
* Message output when number of packet retries exceeds the maximum
allowed.
* Help can be abreviated to 'h' instead of 'he'.
* Parameters can be abbreviated sensibly.
* Overprint control records no longer appear in the logfile.
* A command field consisting of only spaces is now treated as a null
command instead of causing Exit.
* ASCII character Delete is now transferred correctly.
* If a transfer was aborted by the micro-kermit, and a subsequent one
started, Kermit-40 could crash. This should be fixed.
General improvements:
* Parameter MAXTRY is renamed to RETRYS.
* Parameters IMAGE and REMOTE are redundant and therefore have been
removed.
* Parameter DEBUG now prints hex values in 8 digits instead of 6.
* Parameter SEND should be specified in seconds instead of milli
seconds.
* Checks are made for correct filetype on opening files, (types LST and
LSB ).
* Checks are made for legal timeout periods, both for those entered
Page 2 March 1986
Kermit-40 Users Guide
with SET and the one received in the initialisation exchange.
* The logfile is now called &KERMLOG instead of USER.KERMLOG, and is
not deleted by Kermit-40.
* All error packets have 'Kermit-40' prefix, and will be written to the
logfile.
____________________
Binary file transfer
OS4000 files with an attribute of type LSB have a concept of variable
length records. Records are normally of a length determined by the size
of data block written by each Babbage write statement in a particular
program. Most other operating systems treat a binary image as a stream
of bytes with no record terminators, hence Kermit cannot be used to
transfer binary files while retaining this record information.
Whilst transfer of binary image streams from other computers to
OS4000 and back again will involve the use of records in the GEC file, a
correct binary image without records will be returned to the computer
receiving the files back again. However, if an LSB file originating from
OS4000 is sent away to another machine with Kermit, and then returned to
a GEC machine, the record structure will not be preserved in the original
fashion. Thus such a file will no longer be useable in the orginal sense
under OS4000.
Since the binary transfer facility is expected to be used for the
movement of binary images between machines other than GECs, where the GEC
machine is purely acting as carrier, this is not expected to be of
concern. It seems very unlikely that anyone would want to use Kermit-40
for the transfer of OS4000 image files, but if they did then it would be
possible to use COPY with OPT BTOT to create a text listing of the file,
which could then be transferred to another machine via Kermit, and then
rebuilt in the same way using OPT TTOB.
March 1986 Page 3
Kermit-40 Users Guide
____________
2 Introduction
Kermit-40 is the RAL GEC implementation of the Kermit file transfer
protocol as devised by Columbia University Centre for Computing
Activities, USA. It is written to run under OS4000(RAL modified) and
enables transfers between a GEC machine and any asynchronously attached
micro, also running Kermit. To transfer files, a version of Kermit must
be present on both machines involved. There is a version available for
most current computer systems, many of which can be obtained all together
on magnetic tape from Columbia University. However, some sites in UK
maintain a current on-line version of the tape, often including other
extra versions which are too new to be included on the Columbia tape. It
is useful to look at the filestore of one of these sites, and possibly
even to register on their electronic mailing list, particularly if you
are going to use Kermit a lot. The exchange of experience, ideas and
talk of new versions is worth following.
The protocol is based on the use of packets, which are chunks of data
with leading and trailing information added indicating the type of packet
and helping with error protection. Packets are often about the length of
one line on a display terminal, and they can be accepted or rejected by
the receiving Kermit. There are different types of packets, not all
contain file data, some are for acknowledgment/rejection purposes only,
others may contain initialisation parameters or error messages. Data
packets contain sequential fragments of the file, often of about 70-80
characters in length, with some protocol information appended 'around'
them. There is a checksum character, which is calculated from the whole
of the data in one packet, and appended to the end of that packet. If
errors occur in transmission, then the checksums will be different and
the packet would be rejected for re-sending.
By means of this protected packet system, errors can rarely occur in
files. However users should be aware that there are ways it can fail,
even though the file may appear to transfer correctly. This can happen
as the result of multiple separate errors occuring which are opposite in
effect in the same packet, which then preserve the correct value of the
checksum.
All Kermit packets are made up from printable characters only. There
are no control characters used by the protocol, except for the beginning
of packet marker and the end-of-line (end-of-packet) character, by
default ASCII 1 and 13 respectively. Kermit transforms any control
characters which appear in data, into printable representations, using a
technique called control-quoting. When data is to be transferred with
eight bit values then 'eighth bit quoting' will also be used. Repeat |
count prefixing is available in order to provide data compression and |
therefore greater efficiency over communication lines. |
Kermit-40 can operate as a remote Server, and once in this mode, the |
user is able to send and receive files at will by issuing commands only |
from the local Kermit, without having to 'Connect' back to the remote |
Kermit. |
Page 4 March 1986
Kermit-40 Users Guide
____________
Reading note
In any documentation on the use of Kermit, it is convenient to be
able to refer separately to the two Kermits which are to talk to each
other. Therefore, from here onwards, the Kermit running on the GEC
machine will be referred to as Kermit-40, and that on your micro/mini
will be referred to as micro-kermit.
In addition, this guide particularly refers to the version of Kermit
known as Kermit-40, written for use on the GEC MUMs in SERC, and should
be regarded as supplementary to the fuller versions of the Kermit
documentation as distributed by Columbia University. They provide two
documents, the protocol manual, and the user manual, in addition to other
supplementary documents. Recent versions are available on line, and full
details of how to read them can be obtained from ICF User Support. All |
queries relating to Kermit-40 specifically should be addressed to |
|
Martin J Loach |
|
Mail addresses NSIN12 @ UK.AC.RL.GB or via SUPPORT @ UK.AC.RL.GB, |
|
or at |
|
ICF User Support, |
Rutherford Appleton Laboratory, |
Chilton, |
Didcot, |
Oxon, |
OX11 0QX. |
|
Telephone Abingdon (0235) 446252. |
______________________________
Kermit-40 implementation notes
Version 3.2 of Kermit-40 is not a full implementation of any
particular version of the Kermit protocol, but has been based on Version
2 and the structure of the prototype program followed that of the UNIX C
listing. It embraces most of the essential parts needed to transfer text
and binary files successfully with other Kermits of any generation, since
Kermits should always be upward-compatible.
There are a number of restrictions which the user familiar with other
Kermits should be aware of. Kermit-40 works in REMOTE mode only, and
therefore has no CONNECT command. No Image mode is possible due to the |
restrictions of the RAL OS4000 communications format using even parity. |
However 8-bit quoting is available for binary transfers. There is no '?' |
help facility, although a limited 'HELP' command is available. Error |
checks are done with single character checksumming, no other type is |
supported. |
March 1986 Page 5
Kermit-40 Users Guide
Kermit-40 Capabilities at a glance: |
|
Local operation: No |
Remote operation: Yes |
Transfers text files: Yes |
Transfers binary files: Yes |
Wildcard send: No |
^X/^Y interruption: No |
Filename collision avoidance: No |
Can time out: Yes |
8th-bit prefixing: Yes |
Repeat count prefixing: Yes |
Alternate block checks: No |
Terminal emulation: No |
Communication settings: No |
Transmit BREAK: No |
IBM mainframe communication: No |
Transaction logging: Yes |
Session logging: No |
Raw transmit: No |
Act as server: Yes |
Talk to server: No |
Advanced server functions: No |
Advanced commands for servers: No |
Local file management: No |
Handle file attributes: No |
Command/init files: Yes |
Command macros: No |
Page 6 March 1986
Kermit-40 Users Guide
_________________
3 Running Kermit-40
Normally micro-kermit will be invoked on the local machine, using the
procedures given in the documentation for that version. Once the
hardware connection has been established to the remote GEC computer, then
the CONNECT command will be used on the micro-kermit, enabling login to
the GEC in the usual manner, the micro emulating a terminal.
Once logged in Kermit-40 is started on the GEC machine by the command
RARESYS.KERMIT . The proforma is:
RARESYS.KERMIT IN = stream 1 (*) - |
OUT = stream 2 (*/NEW) |
WITH = stream 5 (SINK) |
|
Arguments: |
|
IN The input stream for commands and reception from the micro-Kermit. |
|
OUT The output stream used for messages and for transmission to the |
micro-kermit. |
|
WITH The input stream used for initialisation purposes, which may contain |
Kermit commands, and is read when Kermit-40 first starts up. |
|
Other streams: |
|
3 The input stream used for reading OS4000 files being sent to |
micro-kermit. |
|
4 The output stream used for writing files received by Kermit-40. |
|
6 The output stream used for writing &KERMLOG, the log file. |
The prompt will appear thus:
KERMIT-40>
________________
4 The command list
A number of commands are available to set up, and initiate file
transfers.
____
SEND
Initiate the sending of a file(s) from the GEC to micro-kermit
_______
RECEIVE
Initiate the reception of a file(s) to be sent from micro-kermit.
March 1986 Page 7
Kermit-40 Users Guide
___
SET
Alter various default parameters which MAY need to be set according
to the micro and communications hardware etc in use.
____
SHOW (also STATUS)
Display the current values of all parameters.
______
SERVER |
|
Switch Kermit-40 into Server mode, further commands are taken from |
the micro-kermit. |
____
HELP
Obtain help by listing the commands available and/or by giving
further information on a particular command.
____
EXIT (also QUIT/END/BYE)
End the Kermit program.
All commands can be safely abbreviated to the least number of
characters required to make the command unique. However, abbreviating to
less will not produce an error message, the command chosen will be
according to the priority given above. Case has no significance, and any
parameters are separated by one or more spaces. There may appear to be
some similarity to CAMTEC PAD commands, but any such duplication is
purely coincidental.
Page 8 March 1986
Kermit-40 Users Guide
_______________________
5 The commands, in detail
__________________________________________
5.1 To send a file, or files, to micro-kermit.
SEND command
Format:
SEND[ filename][ filename filename...]
where 'filename' is a valid OS4000 filename (default %C),
For example:
send .klog me.mjl.text
will send the two files, .klog in the current directory, and
.mjl.text in the top directory.
Each file will be sent separately, but automatically. Unless Set |
Normal Off has been specified, Kermit-40 will form a simple filename |
from each file identifier, which will be sent to micro-kermit at the
start of each file transfer, and used by micro-kermit as the local
filename to be created. The full OS4000 identifier is stripped of
all leading directory structures including the leading full-stop.
Thus, for example, NSIN99.MACRO.TEST will become TEST, which is the
simplest form of file name which should be useable by most
micro-kermits.
There will be, by default, a 15 second delay before the first
packet is sent, during which period the user should escape back to
micro-kermit (ie escape from CONNECT mode on the micro-kermit,
generally something like control-] C ), and switch that Kermit to
RECEIVE. The transfer should then take place, and on completion, the
user should return the micro-kermit to CONNECT mode, whereupon
further commands can be given to the outstanding KERMIT-40 prompt on
the GEC machine.
It is possible that if the user is too slow returning to
micro-kermit at the start of sending then the first packet from
Kermit-40 could be missed. If this happens, then the transfer should
eventually proceed normally after micro-kermit or Kermit-40 has timed
out and sent some NAK (negative-acknowledgment) packets. Be patient,
don't give up 'till Kermit does, as indicated on your screen by a
message something like, 'Too many retries'. If the transfer does
really fail, then use CONNECT to return to Kermit-40, which may still
be in SEND mode. If so, indicated by the failure of the prompt to
appear when pressing <RETURN>, then control Z <RETURN> should allow
Kermit-40 to be aborted, which must then be restarted before further
attempts can be made.
Wildcards are not allowed in file specifications on Kermit-40.
March 1986 Page 9
Kermit-40 Users Guide
Binary files:
To send files containing binary images, it is necessary to use
the SET BINARY ON command, (see 5.3.12) before carrying out the above
instructions. The micro-kermit must be capable of doing eight bit
quoting. (See preface, 'Binary File Transfer')
___________________________________
5.2 To receive files from micro-kermit.
RECEIVE command |
|
Format: |
|
RECEIVE[ filename] |
This command switches Kermit into receive mode, after which
Kermit-40 will sit and wait for the first valid packets to arrive
from micro-kermit. At this stage, escape and return to the
micro-kermit and use a SEND file(s) command to start the transfer.
If a filename is given to this command, then that will be used as the |
received filename regardless of the name sent by micro-kermit. If |
however there is no filename given, then the name supplied by |
micro-kermit will be used. The filenames given by micro-kermit may |
not be valid OS4000 names. Provided Set Normal Off has not been set, |
then this will not matter since Kermit-40 will hash any name given to |
it into an acceptable name. Firstly any non alpha-numeric characters
will be removed, and if the result is longer than eight characters,
then the name will be truncated to the last eight. Secondly a period
will be added to the front, and finally the /ADD attribute will be
added, which implies that any existing file in the current catalogue
with the same name will be appended to, (as in FTP).
On completion of sending files, use CONNECT to return to
Kermit-40 and proceed with the next command, which could be to EXIT,
SEND or RECEIVE more files. If the transfer fails in any way, and
the process is not properly completed, it is possible that, on return
to Kermit-40, no prompt appears on pressing <RETURN>. This means
that Kermit-40 is still in Receive mode, and pressing control Z
<RETURN> should allow Kermit-40 to be aborted, which must then be
restarted before further attempts can be made.
Binary files:
To receive files containing binary images, it is necessary to use
the SET BINARY ON command, (see 5.3.12) before carrying out the above
instructions. The micro-kermit must be capable of doing eight bit
quoting. (See preface, 'Binary File Transfer')
____________________________
5.3 To reset default parameters.
There are a number of parameters which start with a default
value. For many cases these defaults will be satisfactory to
inititiate and continue file transfer. If, however, problems are
experienced, then alteration of some of these values may be needed.
Page 10 March 1986
Kermit-40 Users Guide
For example, if your micro-kermit should require a line-feed
character to terminate input, instead of <RETURN>, then parameter EOL
would need to be reset to ASCII code 10.
When first trying to use Kermit-40 it may not be necessary to be
concerned about the SET command, except for binary file transfer, but
if you understand communications and think that some parameter may
need to be reset, then reading this section could save some
frustration. Obviously, if file transfers do fail to take place then
it will be neccessary to establish why and use this command to alter
any suspect parameters.
SET command
Format:
SET[ param][ value][ param[ value]...]
For example:
set binary on time 20
will set binary file transfer to send or receive a LSB file, and tell
micro-kermit to time me out after 20 seconds.
This command allows tailoring of the communications protocol to
your micro-kermit and hardware, as well as allowing setting of some
useful switchable options such as DEBUG and BINARY. Some of these
communications parameters are set during an initial exchange of
agreement which takes place automatically before each transfer
begins, but some parameters may need to be set by hand before even
this initial exchange can take place, for example if EOL needs to be
set to some character other than the default ASCII 13. If this is
wrong then the initial packets will be terminated with the wrong
end-of-line character, and may therefore not be recognised by the
micro-kermit. Although some parameters may be set by hand, or left
at the default value initially, they could later be overwritten by
the agreed values provided by micro-kermit at the start of transfer.
The following is a list of the parameters set by the initial packet
exchange.
Received by Kermit-40 from micro-kermit:
Maximum size of packet to send
Period after which to time-out micro-kermit (** TIMEOUT)
Number of pad characters to send (** PAD)
Pad character to send (** CHAR)
End-Of-line character to send (** EOL)
Character to receive for control quoting
Character to receive for 8 bit quoting
Type of checksum to receive, (only one allowed in Kermit-40)
Character to receive for repeat quoting |
March 1986 Page 11
Kermit-40 Users Guide
Sent by Kermit-40 to micro-kermit:
Maximum size of packet I receive
Period after which Kermit-40 is to be timed out (** TIME)
Number of pad characters to receive, (not required)
Pad character to receive
End-of-line character to receive
Character I send for control quoting (** QUOTE)
Character I send for 8 bit quoting (** 8BIT)
Type of checksum I send, (only one done in Kermit-40)
Character I send for repeat quoting (** REPEAT) |
Those parameters which can be set in advance with the SET command are
marked (** parameter-name)
The parameters adjustable, and their functions are listed below.
They can all be abbreviated sensibly. Further explanation may be
found by reference to the KERMIT protocol manual.
5.3.1 DEBUG (off/on)
Switch debugging mode. Whenever Kermit-40 is run a file
called &KERMLOG is opened. This normally will contain a minimum
of information logging the use of Kermit-40, such as the commands
given and the result, success or failure. However, the command
SET DEBUG ON, will cause much more data to be logged to this
file, enabling failures and errors to be tracked down. If
&KERMLOG already exists it will be appended to.
The additional details logged are as follows:
* All characters received and sent, which will include all
packets and any other spurious data which may arise.
* The results of decoding each packet received, giving length,
packet number, type and data buffer.
* The encoding details of each packet sent, giving length,
packet number, type and data buffer, and also the packet
itself.
* Changes of state within the program state table switcher,
(see Kermit Protocol Guide, 5th ed, p17, 5.8)
Default, Debug off
5.3.2 EOL n
SETs the packet end of line terminator character sent to
micro-kermit as ASCII value n (in decimal).
Default, 13 (<RETURN>)
Page 12 March 1986
Kermit-40 Users Guide
5.3.3 STX n
SETs the start-of-packet synchronising character to ASCII
value n (in decimal). Some micros or communications systems may
respond incorrectly when the normal STX character is sent, so
this enables it to be changed, (provided the same change is set
on the micro-kermit.)
Default, 1 (SOH)
5.3.4 PAD n
This will cause n CHAR characters (see below) to be sent
before each packet. These padding characters are sometimes
required to give time for the micro-kermit, or the communications
line, to 'turn-around' after each packet. The actual character
used is as defined by SET CHAR n . (see below)
Default, 0 (no characters sent)
5.3.5 CHAR n
This parameter defines the padding character sent when PAD
(above) is set to n>0. n is the ASCII value (in decimal) of the
required character.
Default, 0 (null)
5.3.6 SEND n
When sending files to micro-kermit, there is a delay period
before the first packet is sent, to allow the user to return to
micro-kermit to switch to receive mode. The period can be
altered with this command and is specified in seconds and must be
greater than or equal to zero.
Default, 15 seconds
5.3.7 RETRYS n
This defines the maximum number of times to retry sending a
packet that is rejected by micro-kermit. The number must be in
the range 0 - 50 times.
Default, 10 times
5.3.8 TIME n
This parameter, sent out at initialisation, requests the
number of seconds after which micro-kermit should timeout
Kermit-40. It must be greater than or equal to one second.
Default, 5 seconds
March 1986 Page 13
Kermit-40 Users Guide
5.3.9 TIMEOUT n
This specifies the period after which Kermit-40 will timeout
the micro-kermit if there has been no packet received when
expected. It is given in seconds, and must be greater than or
equal to one second.
Default, 10 seconds
5.3.10 QUOTE n
Control-quoting, when sending data to micro-kermit, is
normally carried out using the ASCII '#' character. This
character will be inserted into sent data preceeding any byte
which has an ASCII value less than 32, and also preceeding a
delete character, hex FF. It has to be agreeable to the
micro-kermit and will be checked in the initial exchange
agreement. The character can be altered by setting this
parameter to a new ASCII code (in decimal) for the required
character.
Default, 35 ('#')
5.3.11 8BIT n
Eight bit quoting is intended for use when transfering binary
files, and is carried out normally with the '&' character. This
character will be inserted into the sent data preceeding any byte
in which the eigth bit is set to one. It has to be agreeable to
the micro-kermit and will be checked in the initial exchange
agreement. In this way, 8 bit bytes can be transfered over
7-bit-plus-parity asynchronous lines. The character can be
altered by setting this parameter to a new ASCII code (in
decimal) for the required character.
Default, 38 ('&')
5.3.12 BINARY (off/on)
This parameter must be switched on if transfer of a LSB file
is to take place. When this is set then Kermit-40 will ask the
micro-kermit to do eight bit quoting. If this is not agreed,
(not all Kermits can do this) then Kermit-40 will abort with an
error message, and binary files cannot be transferred.
Default, off (LST textfiles only)
5.3.13 REPEAT |
|
Repeat quoting is used when agreed, and allows data |
compression by expressing, for example, sequences of 4 or more |
similar characters in terms of only three characters. The quote |
character used is normally the '~', and must be agreed by |
micro-kermit in the initial exchange agreement. The character |
Page 14 March 1986
Kermit-40 Users Guide
can be altered by setting this parameter to a new ASCII code (in |
decimal) for the required character. |
|
Default, 126 ('~') |
|
5.3.14 NORMAL (on/off) |
|
Normal mode refers to the conversion of filenames to |
'Normal-form'. When filenames are sent from micro-kermit to |
Kermit-40, they are not always likely to be valid names for |
OS4000. Similarly, when sending a filename to micro-kermit, |
Kermit-40 does not know anything about the rules of filenames on |
that system. Thus the filenames will be hashed by Kermit-40 as |
described under SEND and RECEIVE commands described previously, |
providing NORMAL is set On. |
|
If however, NORMAL is set Off, then no hashing will occur at |
all, and whatever micro-kermit sends for filenames will be |
offered to OS4000 for the Kermit-40 filenames. Obviously they |
will be rejected by OS4000 if not valid. If the RECEIVE command |
has been used with an argument, then the name given in the |
argument will be used anyway, regardless of whatever micro-kermit |
sends. When micro-kermit is receiving files from Kermit-40, it |
will similarly have to be able to cope with the full OS4000 names |
given in the Kermit-40 SEND command. |
This option therefore allows full directory structures to be |
used if required. |
|
Default, on |
__________________________________________
5.4 To display the settings of SET parameters.
SHOW
The SHOW command displays the current settings of the parameters
as defined by SET, or as over-written by the initialisation sequence.
March 1986 Page 15
Kermit-40 Users Guide
eg: |
|
Kermit-40> show |
|
KERMIT file transfer utility, Version 40/3.2 for GEC 4000 |
Status of SET parameters- |
Debug is set to OFF |
Eol is set to 13 |
Stx is set to 1 |
Pad is set to 0 |
Char is set to 0 |
Send is set to 15 |
Retrys is set to 10 |
Time is set to 5 |
Timeout is set to 10 |
Quote is set to 35 |
8bit is set to 38 |
Binary is set to OFF |
Repeat is set to 126 |
Normal is set to ON |
|
____________________________________________
5.5 To switch Kermit-40 into remote Server mode. |
|
SERVER |
|
If this command is given then Kermit-40 will immediately go into |
remote server mode, after which it will wait in 'Receive-Idle' state, |
for commands from the micro-kermit. The message shown below will be |
displayed: |
|
Kermit-40: Server running, Now type local escape sequence- |
|
The Server commands supported which may be issued from the |
micro-kermit, assuming it is capable of giving commands to a remote |
server, are: |
|
SEND |
Files will be sent from the micro-kermit to Kermit-40, the normal |
rules for Kermit-40 RECEIVE will apply. |
|
GET |
|
Files will be sent as requested from Kermit-40 to micro-kermit, |
and the normal rules for Kermit-40 SEND will apply. |
|
FINISH |
|
Kermit-40 Server mode will close down, Kermit-40 will still be |
active and will be awaiting input to it's usual prompt, Kermit-40>. |
Note that this is not standard Kermit practice, since Kermit-40 |
should close down completely. However, especially since this Server |
recognises no command to change Kermit-40 SET parameters, it is |
useful to be able to come back to this Kermit to change parameters |
and then continue server mode again. See BYE below. |
Page 16 March 1986
Kermit-40 Users Guide
|
BYE, or LOGOUT |
|
Kermit-40 will close down completely. It is not possible nor |
desirable to logout a user under GEC OS4000, therefore there is no |
_______________
further effect of this command. The user will stay logged in. |
_________________________________________________
5.6 To obtain on-line help on the Kermit-40 commands.
HELP
Format:
HELP[ command command....]
Typing HELP alone will display the version number of Kermit-40
and the commands available. Typing HELP 'command' will give full
information on that command.
_______________________
5.7 To exit from Kermit-40.
EXIT
Type EXIT to leave Kermit-40 when transfers are finished.
March 1986 Page 17
Kermit-40 Users Guide
___________________________
6 Examples of using Kermit-40
__________________________________
6.1 Example- Kermit-40/IBM PC (Telios)
Below is given an example of file transfers between Kermit-40 and the
IBM PC, using TELIOS (Genasys Corporation) in Kermit emulation mode. In
this example the PC is connected to the GEC via a RAL PAD line.
Note- Comments are (in parenthesis)
______
A: telios (Invoke Telios on the PC, from logged-on disc A:)
_________
> baud 4800 (set speed, full duplex, and Kermit protocol)
________
> echo off
_______________
> protocol kermit
________
> <RETURN> (carriage return causes Telios to resume CONNECT mode)
________
<RETURN> (carriage return awakes PAD)
* RAL Atlas PAD RLCG (Vn 2.1R) DTE=1106 line 9 speed 4800
____________
PAD>controlchars (allow control characters through the pad)
_________
PAD>call rlgb (logon to RLGB)
**** This is the Rutherford GEC 4090 - RLGB ****
OS4000+Rlix V25 RAL Atlas
Logging in
_____
user notu2
password
ID last used Wednesday, 30 January 1985 11:24
Started - Wed 30 Jan 1985 11:27:39
ready
______________
raresys.kermit (start Kermit-40)
KERMIT file transfer utility, Version 40/3.2 for GEC 4000 by M J Loach, RAL.
Kermit-Copyright Columbia University Centre for Computing Activities, 1986
________
Kermit-40> help set (use help command to check if parameters need setting)
SET COMMAND
***********
(SET) allows certain parameters to be switched on and off, or set to a
value. The ones available at present are- (s-on/off, n-value)
DEBUG s- If on, debugging information is logged to .KERMLOG, default off
EOL n- set END-OF-LINE character, to ascii value n, default 13(CR)
STX n- set start of packet text sync char to ascii n, default 1
PAD n- set number of pad characters to preceed each packet, default 0
CHAR n- set pad character to be ascii n, default 0 (null)
SEND n- set delay before first SEND packet to n secs, default 15
RETRYS n-set maximum number of sending retries before abort,default 10
TIME n- set number of seconds before micro-kermit times me out, def 5
TIMEOUT n- set number of seconds for Kermit-40 timeout, default 10
Page 18 March 1986
Kermit-40 Users Guide
QUOTE n- set the ASCII value of the character I send for quoting,def 35
8BIT n- set ASCII value of the character I send for 8bit quoting. (38)
BINARY s-If on, LSB files are sent and received, via 8bit quote. (off)
REPEAT n-set ASCII value of the character I send for repeat quote.(126)
NORMAL s-If on, filenames are converted to a 'normal form', default on
____________
Kermit-40> set debug on ( decide to set debugging mode, into file &kermlog)
_____________
Kermit-40> send .kermdoc ( going to send .kermdoc to the PC)
_______
(alt-H) (get back to PC command level)
____________
> pcapture k.k (tell PC to capture the file about to be sent to it,)
Recvd #00001 (as k.k . 'P'rotocol 'Capture' refers to Kermit, as)
Recvd #00002 (chosen at the start, above)
......
Recvd #00212 (last packet received)
#7YU (last packet from Kermit-40, superfluous)
_
Kermit-40>q (quit Kermit-40)
ready (GEC prompt)
_______
(alt-H) (return to PC Telios command mode)
________
> type k.k (type file captured, to see if OK.)
.......
________
<RETURN> (return to CONNECT mode)
ready (GEC prompt)
______________
raresys.kermit
KERMIT file transfer utility, Version 40/3.2 for GEC 4000 by M J Loach, RAL.
Kermit-Copyright Columbia University Centre for Computing Activities, 1986
___
Kermit-40> rec (switch kermit-40 to receive a file from the PC)
_______
(alt-H)
______________
>psend demo.fil (ask PC to send demo.fil from disc A: to GEC)
Sent #00001 (sends ok)
Sent #00002
......
Sent #00031
_
Kermit-40> q (finished)
ready (GEC prompt)
_____________
type .demofil (check file is on GEC)
.......
ready (GEC prompt)
__
lo (logout)
CPU used: 1 ieu, Elapsed: 2 mins, IO: 772 units, Breaks: 20
Budgets: this period = 15.400 AUs, used = 0.010 AUs, left = 14.303 AUs
User NOTU2 terminal 14 logged out Wed 30 Jan 1985 11:26:47
PAD>clear
*** Cleared
March 1986 Page 19
Kermit-40 Users Guide
_____________________________________
6.2 Example- Kermit-40/IBM PC (Kermit-MS)
Below is given an example of file transfers between Kermit-40 and the
IBM PC, using Kermit-MS. In this example the PC is connected to the GEC
via a RAL PAD line.
Note- Comments are (in parenthesis)
______
C> kermit (invoke kermit on PC, from logged-on disc C:)
IBM-PC Kermit-MS V2.27
Type ? for help
_______________
Kermit-MS> set parity even (even parity for GEC MUM)
_______
Kermit-MS> connect
[Connecting to host, type Control-] C to return to PC]
________
<RETURN> (awake PAD at RAL)
* RAL Atlas PAD RLCG (Vn 2.1R) DTE=1106 line 9 speed 4800
____________
PAD>controlchars (allow control characters through the pad)
_________
PAD>call rlgb (logon to RLGB)
**** This is the Rutherford GEC 4090 - RLGB ****
OS4000+Rlix V25 RAL Atlas
Logging in
_____
user notu2
password
ID last used Wednesday, 30 January 1985 12:19
Started - Wed 30 Jan 1985 17:27:01
ready
______________
raresys.kermit (start Kermit-40)
KERMIT file transfer utility, Version 40/3.2 for GEC 4000 by M J Loach, RAL.
Kermit-Copyright Columbia University Centre for Computing Activities, 1986
(firstly receive a binary file from the PC)
_____________
Kermit-40> set binary on
_______
Kermit-40> receive (receive a LSB file into the current catalogue)
____________
<Control-]C> (return to PC)
______________
Kermit-MS> send a:char256 (tell it to send a file from disc A)
(now the screen will show the following display:)
Page 20 March 1986
Kermit-40 Users Guide
File name :
KBytes transferred :
Sending : In progress
Number of packets : 0
Number of retries : 0
Last error : None
Last warning : None
(this display updates as the transfer takes place, and will appear thus,
when finished:)
File name : CHAR256
KBytes transferred : 0
Percent transferred : 100%
Sending : Completed
Number of packets : 12
Number of retries : 0
Last error : None
Last warning : None
_______
Kermit-MS> connect (now go back and send file back to PC)
[Connecting to host, type Control-] C to return to PC]
________
<RETURN> (get Kermit prompt on GEC)
_____________
Kermit-40> send .char256 (send the LSB file back to the PC again)
____________
<Control-]C> (return to PC)
___
Kermit-MS> rec
File name :
KBytes transferred :
Receiving : In progress
Number of packets : 0
Number of retries : 0
Last error : None
Last warning : None
(this display updates as the transfer takes place, and will appear thus,
when finished:)
March 1986 Page 21
Kermit-40 Users Guide
File name : CHAR256
KBytes transferred : 0
Receiving : Completed
Number of packets : 13
Number of retries : 0
Last error : None
Last warning : None
_______
Kermit-MS> connect
[Connecting to host, type Control-] C to return to PC]
________
<RETURN> (get Kermit prompt on GEC)
____
Kermit-40> exit (finished)
ready (GEC prompt)
__
lo (logout)
CPU used: 1 ieu, Elapsed: 4 mins, IO: 1043 units, Breaks: 20
Budgets: this period = 15.400 AUs, used = 0.010 AUs, left = 14.303 AUs
User NOTU2 terminal 14 logged out Wed 30 Jan 1985 17:35:15
PAD>clear
*** Cleared
Page 22 March 1986
Kermit-40 Users Guide
_______________________________________
6.3 Example- Kermit-40/ VAX/VMS (Kermit-32)
Below is given an example of file transfers between Kermit-40 and the
VAX 11/750, using Kermit-32. Kermit-32 is run from terminal NVA1:, to
which has been allocated terminal TTA2: . A connection has been wired
from a PACX line connected to TTA2: , to another PACX line which has
already been connected to, and logged in to RLGB.
ie:
NVA1 to Kermit-32 to TTA2 to PACX to PACX to RLGB
It is unlikely that anyone would want to use this method of file
transfer between VAX/GEC, especially since transfer via SERCNET is
easier. However, it is a useful example showing the versatility of
Kermit.
Note- Comments are (in parenthesis)
(logging into VAX...)
Central Computing Division Vax 11/750
______
Username: Anyone
Password:
Welcome to RLVE running VMS V3.7
If you are connected to this Vax via PACX please hit the PACX key
after you have logged off.
________
$ all tta2 (allot another port to connect to GEC)
TTA2: allocated
________________________
$ set term tta2/speed=4800 (set its speed accordingly)
______
$ kermit (start Kermit)
VMS Kermit-32 version 3.0.051
Default terminal for transfers is: NVA1:
_____________
Kermit-32>set line tta2 (tell kermit which port)
_______________
Kermit-32>set parity even (set its parity)
______________
Kermit-32>local host dir (DIR command to VAX)
Directory DUA0:[ANYONE]
0R.DOC;1 COM.DOC;1 CONTROL.EXE;1 CONTROL.FOR;1
CONTROL.OBJ;1 FILE.TXT;4 FLY.DOC;1 INITB.;1
INITK.;3 INITK.;2 INITK.;1 KERMIT.DIR;1
LOGIN.COM;3 MAIL.MAI;1 MAILMAI.;1 TEST.FDL;1
VER.DOC;1
Total of 17 files.
March 1986 Page 23
Kermit-40 Users Guide
_______
Kermit-32>connect (connect to GEC)
[RLVED::Connecting to TTA2:. Type ^]C to return to VAX/VMS Kermit-32]
________
<RETURN> (get prompt, already logged in)
ready (GEC prompt)
______________
raresys.kermit (run Kermit-40)
KERMIT file transfer utility, Version 40/3.2 for GEC 4000 by M J Loach, RAL.
Kermit-Copyright Columbia University Centre for Computing Activities, 1986
___
Kermit-40> rec (prepare to receive file from VAX)
____________
<Control-]C> (return to VAX)
[RLVED::Returning to VAX/VMS Kermit-32]
____________
Kermit-32>send ver.doc (ask VAX to send file to GEC)
Sending: DUA0:[ANYONE]VER.DOC;1 as VER.DOC (this is displayed when sending)
(when finished the word OK is added thus:)
Sending: DUA0:[ANYONE]VER.DOC;1 as VER.DOC[OK]
_______
Kermit-32>connect (return to GEC)
[RLVED::Connecting to TTA2:. Type ^]C to return to VAX/VMS Kermit-32]
________
<RETURN>
__________
Kermit-40> send .inik (now send a file to VAX)
____________
<Control-]C>
[RLVED::Returning to VAX/VMS Kermit-32]
___
Kermit-32>rec (switch VAX to receive)
Kermit-40: Cannot open file: .INIK (message from GEC Kermit)
_______
Kermit-32>connect (return and try again)
[RLVED::Connecting to TTA3:. Type ^]C to return to VAX/VMS Kermit-32]
________
<RETURN>
___________
Kermit-40> send .initk
____________
<Control-]C>
[RLVED::Returning to VAX/VMS Kermit-32]
___
Kermit-32>rec
Receiving: INITK as DUA0:[ANYONE]INITK.;4 (this time transfer starts ok)
(display is as below when finished:)
Receiving: INITK as DUA0:[ANYONE]INITK.;4[OK]
____
Kermit-32>quit
$
Page 24 March 1986
Kermit-40 Users Guide
_______________________________
7 What to do when things go wrong
______________________________________
7.1 Failure to be able to Connect to host.
Check the following:
* micro-kermit set for even parity
* micro-kermit set for correct baud rate
* communications medium, eg PAD, set to allow control characters
through
* micro-kermit set to use correct port on micro
* cable correct to link micro to comms port
* micro-kermit set to operate in full duplex(no-echo)
______________________________________
7.2 Failure of the transfer of the file(s)
There are two ways in which failure may be indicated.
1. Transfer completes but on inspection the file has not been
transferred correctly
2. Transfer aborts, or just halts, with or without a failure
message
In the first instance a rare combination of errors has led to the
error checksum being corrupted and then corrupted back to the correct
value for the corrupted packet. This has then been accepted as a valid
packet. The chances of this sort of problem occuring are small unless
there are a lot of short bursts of corruption on the link, leading to
many packets being repeated. Trying the transfer again may well lead to
a successful result.
In the second case it is worthwhile trying a second time to make sure
a spurious error did not occur. If problems are encountered then check
the following:
* All the possible causes in 7.1, above
* Check the SET parameters, particularly if the failure is at the
start, both on Kermit-40 and on micro-kermit (see 5.3)
Note that if you return to Kermit-40 to find it is no longer running,
but you have a GEC OS prompt instead, then Kermit-40 has probably
crashed. If so, please report with as much information as possible to |
NSIN12 @ UK.AC.RL.GK
March 1986 Page 25
Kermit-40 Users Guide
__________
8 Appendix A
____________________________________
Error messages and their explanation
_________________________
There is a checksum error
This is written to the log file each time a checksum error is
encountered in the incoming packets. It is a warning only and a
negative-ackknowledgement will be sent to the micro-kermit until a
correct packet is received or the maximum number of retries is
exceeded.
_________________________________
File being opened for sending is:
This gives the name of the next file obtained from the file list
given on the send command.
__________________
Closing input file
This is output when the currently sent file is completed.
___________________________
looking for next file......
This is output after the above message and indicates that Kermit-40
is looking for the next filename from the SEND filelist.
____________
New file is-
This gives the name of the next file obtained from the filelist given
on the SEND command.
____________
Send command
This indicates that the SEND command has been given
_______________
Receive command
This indicates that the RECEIVE command has been given
Page 26 March 1986
Kermit-40 Users Guide
______________
Receive failed
This means that receiving a file has failed. This could be
accompanied by any of the following messages-
Eight bit quoting not agreed.
Number of retries exceeded.
Packet number is out of sequence.
Failed to connect to file.
File is wrong type, compared to existing file, ie not LSB or not LST.
_____
done.
Output on completion of the SEND or RECEIVE command.
___________
Send failed
This means that sending a file has failed. This could happen due to
any of the reasons given under Receive Failed (above).
_____________________________________________
File already exists with different attributes
An attempt has been made to receive a file which already exists
having a different type, eg receiving a binary file when a CAT or LST
file exists with the same name.
__________________________________________________________
Kermit aborting with the following error from remote host:
This accompanies a message which has been received from micro-kermit
in an error packet.
______________
Cannot create:
Receiving a file has been aborted because an attempt to connect to
the file specified for creation failed. Could be due to trying to
receive to an existing LSB file (/ADD attribute cannot be used with
LSB).
___________________________
Cannot open file:(binary?):
On receiving a text file a LSB file has been found to already exist
with the same name, or, on sending a text file, the file specified is
in fact a LSB file.
_____________________________
Cannot open file:(textfile?):
On receiving a binary file a LST file has been found to already exist
March 1986 Page 27
Kermit-40 Users Guide
with the same name, or, on sending a binary file, the file specified
is in fact a LST file.
___________________________
Cannot open file:(not LS?):
On receiving a file a non logical sequencial file has been found to
already exist with the same name, or, on sending a file, the file
specified is in fact a non logical sequential file (eg, attempt to
transfer a catalogue).
_______________________
DM Error, RA= @hexvalue |
|
This gives the Data management error code associated with attempting |
to connect a filename to a stream(DMCONNECT), and is written to |
&KERMLOG. |
__________
Sending as
Kermit-40 takes the catalogue name of a file and removes all the
catalogue structure, leaving just the filename without a '.'
character, to give as the name for the file to be sent. This shows
the name which has been constructed.
____________
Receiving as |
|
This shows the name being given to the received file under OS4000, |
which will normally be as hashed from the name supplied by |
micro-kermit, but could be as specified by a RECEIVE filename |
command. |
______________________________________
Timeout retries exceeded, press return
This message will appear on the terminal stream when Kermit-40 has
aborted due to timeout retries exceeding the maximum. This is most
likely to be due to a failure in the communications between the two
Kermits. In this situation, the timeouts occured due to no records
being received by Kermit-40 from the terminal stream. The result is
that there is still an outstanding GET which must be satisfied before
Kermit-40 can continue with any more commands successfully. Hence
the reason to have to press return once before the prompt will
appear. In most situations the user will probably not see this
message on the screen, and will have pressed return anyway to get a
Kermit-40 prompt.
__________________________________
Too many retries, transfer aborted
This means that Kermit-40 has given up retrying to send or receive a
packet which is either corrupted in transmission or incorrect for
some reason. It is most likely due to a failure in the
communications between the two Kermits.
_____________________________________________________
8 bit quoting not agreed, so can't do binary transfer
The micro-kermit rejected the request to do 8 bit quoting, so
Page 28 March 1986
Kermit-40 Users Guide
Kermit-40 will not be able to transfer a binary file. The
micro-kermit presumeably has no eight bit quote facility.
______________
Kermit aborted
This message is output when control-Z is used to jump out of Kermit.
_______________
Invalid command
A command typed in to the Kermit-40 prompt was un-recognised.
_________________
Excess parameters
More than the allowed number of parameters have been typed after a
command.
_________________
Invalid parameter
A parameter typed after a command is not recognised or is missing
when required.
______________
No information
Output by the Help command if the help requested is not available, ie
the command given does not match any Kermit-40 command.
______________________
Parameter out of range
A parameter given to the SET command is invalid, eg a negative or
zero timeout, or an excessively large number of permitted retries.
____________________________
Unimplemented server command |
|
In Server mode, an unsupported command has been received from |
micro-kermit. The command subset allowed currently is, GET, SEND, |
FINISH, BYE and LOGOUT. |
|
________________________________
Taking commands from With stream |
|
An argument has been supplied for the WITH stream for this run, and |
Kermit-40 is reading commands from this file. |
|
___________________
End of command file |
|
Kermit-40 has read all the commands from the WITH stream, and is now |
expecting terminal commands again. |
March 1986 Page 29
Kermit-40 Users Guide
References
1. Kermit Protocol Manual, Fifth edition, Frank da Cruz, Columbia University
Centre for Computing Activities, New York 10027, 3 April 1984.
2. Kermit Users Guide, Fifth edition, Rev 1, Frank da Cruz, Columbia
University Centre for Computing Activities, New York 10027, 27 July 1984.
3. Access to Kermit Distribution at Lancaster, M J Loach, October 1985. |
Page 30 March 1986
