KERMIT for RSX180 and RSX280

Here you can find the CP/M Kermit-80 ported to the RSX180/280 OS.

Kermit-180 has been tested on a P112 (Z180) machine running RSX180 and on a Z280RC (Z280) machine running RSX280.

Kermit-180 Capabilities at a glance

Capability	Implemented
Local operation	Yes
Remote operation	Yes
Login scripts	Yes, limited
Transfer text files	Yes
Transfer binary files	Yes
Wildcard send	Yes
File transfer interruption	Yes
Filename collision avoidance	Yes
Can time out	Yes
8th-bit prefixing	Yes
Repeat count prefixing	No
Alternate block checks	Yes
Terminal emulation	Yes, limited
Communication settings	If supported by the terminal driver
Support for dial-out modems	No
Transmit BREAK	If supported by the terminal driver
IBM communication	Yes
Transaction logging	No
Debug logging	No
Session logging	Yes
Raw file transmit	Yes
Act as server	Yes
Talk to server	Yes
Advanced commands for servers	Yes
Command/init files	Yes
Command macros	No
Local file management	Yes
Handle file attributes	No
Long packets	No
International Character Sets	No
Sliding Windows	No
Printer control	No

Quick start guide

1. Start Kermit at the PC side and setup it accordingly, the following settings were used with C-Kermit 9.0.302 under Linux:
   set line /dev/ttyUSB1 (or whatever line your machine is connected to)
   set speed 19200 (this is the default for the Z280RC quad-serial board under RSX280)
   set attributes off
set parity space (or set parity none)
   set file type binary
set carrier-watch off
set flow-control none
set control-character prefixed all
set file patterns off
set transfer mode manual
   To avoid having to type the above commands every time, you can save them into a text file and then use the Kermit's take command to execute them.

2. Start Kermit-180 on the RSX180/280 side:
   run $kermit (if Kermit-180 is not installed)
   ker (if Kermit-180 is installed as ...KER)
   Once it is running, setup the communication parameters. The following settings were used on a Z280RC running RSX280:
   set line tt3: (or whatever line the Z280RC is connected to the PC)
   set parity space (or set parity none, but must match the PC settings above)
   set file-mode binary
   As with the PC Kermit, you can save the above command sequence into a text file for later execution via the take command. If you name the file kermit.ini and place it into your user's directory, Kermit-180 will execute it automatically on startup.

3. You can now use the send command on the PC side and the get command on the RSX280 side to transfer a file from the PC to the Z280RC. Do the opposite to send a file from the Z280RC to the PC.

4. Best is just to put the PC Kermit in server mode. Then, you can send and receive files by only entering commands at RSX180/280 terminal. E.g.
   send examp.cmd to send a file to the PC
   get kermit.tsk to fetch a file from the PC
   remote dir to browse the PC directory
   dir to browse the local RSX180/280 directory
   etc.

Bugs and Limitations

Kermit-180 is built by default as a non-privileged task, meaning that in local mode it cannot change the characteristics of the terminal used for communications unless the terminal has been set to public by the system administrator. Specifically, Kermit-180 needs to set the terminal mode to slave with echo disabled, and those are privileged operations for terminals other than the user's current one. Remote mode does not suffer from that limitation, as it uses the user's current terminal for communications.

The filename completion (e.g. for DIR or ERA commands) is not working fully correctly yet: pressing ESC or TAB a second time appends part of the file extension again to the completed file name, etc.

The current version of Kermit-180 is not able to process file attribute information, and therefore the correct file type (text or binary) has to be set manually at both ends before starting the transfer.

Some modern Kermit programs (e.g. C-Kermit 9.0 on Linux) don't prefix all control characters by default as the protocol specifies, and therefore file transfers the PC to the Z280RC may fail randomly. The solution is to use the set control-character prefixed all command at the PC side. I'd recommend using set file patterns off and set transfer mode manual as well, otherwise C-Kermit will try to switch automatically to ascii mode when transferring text files in binary mode without Kermit-180 being aware of the change. The result is a text file with duplicated carriage return characters being received at the RSX180/280 side if the file at the PC side already had CR/LF line endings.