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RT11 kermit and minicom

J

jay cotton

Member
Joined
Apr 1, 2023
Messages
38
Hi Guys:

I have been climbing the learning curve on rt11 and finding a lot of boulders in the way.

The rt11 kermit I have is freshly boot strapped from CSU web site.

Kermit-11 for EIS RT-11XB,XM,ZB,ZM/TSX-Plus V03.63 Last edit: 27-Sep-97
771. words free to load handlers
Link device is TT: S/W Parity: NONE

I have my console setup via minicom on a linux system.

When I attempt to transfer a file from the linux machine to the pdp11 via kermit with debug on I get

<<< RPACK - Paknum 0 Type T Length 0
>>> SPACK - Paknum 0 Type N Length 0
<<< RPACK - Paknum 0 Type T Length 0
>>> SPACK - Paknum 0 Type N Length 0
<<< RPACK - Paknum 0 Type T Length 0
>>> SPACK - Paknum 0 Type N Length 0
<<< RPACK - Paknum 0 Type T Length 0
>>> SPACK - Paknum 0 Type N Length 0
<<< RPACK - Paknum 0 Type T Length 0
>>> SPACK - Paknum 0 Type N Length 0
>>> SPACK - Paknum 0 Type E Length 19
Retry limit reached

I have done a few kermit transfers in the past, but not with the "age gap" of this magnitude.

Has anyone been able to make this work? what is the setup etc.

Thanks
JC
 
It can be made to work, I did RT11 / linux transfers a couple months back. Use "robust" transfer mode, and I think I also tried "set attributes off" but not sure if that was actually seen by both sides.
 
I don't find anything that says "robust". I did set attributes off. This made no difference.

Still hunting.
JC
 
With ckermit 9.0.305 running on linux, you should be able to just say "robust" at the prompt to make it use that mode. Your V03.63 on the RT11 probably only has robust mode. I just went as far as bringing up kermit on the linux box, it's a bit more work to get the RT11 end up, I can do that, but tomorrow or Sunday.
 
Progress so far.
I found that c-kermit must be installed on the linux system else minicom can't start it.

Here is the command set issued to start a transfer.

.kermit
Kermit-11 for EIS RT-11XB,XM,ZB,ZM/TSX-Plus V03.63 Last edit: 27-Sep-97
771. words free to load handlers
Link device is TT: S/W Parity: SPACE
KRT> set file type binary
Binary mode set
Caution: Binary files will require 8-bit prefixing
KRT> receive
(exit to minicom ctrlA z and start a file send then select kermit)
KRT> exit

All of that is good. However, no file shows up on the disk. More digging is required.

JC
 
I ran a transfer of an ascii file. That works !

So, it looks like the main issue is with binary files (or large files)
Need to figure out how to encode a file in hex.....

jc
 
The documentation for Kermit-11 says it can transfer binary files, so encoding them before transfer shouldn't be necessary as long as the settings at both ends are correct.
 
I am putting the kermit issue to bed for now. I managed to transfer a text file of modest size.
Binary is no start. I found 2 instances of developers stating that there is a problem with rt11 and
the serial ports WRT binary file transfer.

I decided to try again with tu58fs and got that to work with file sizes up to 15mb.

Thanks for your help on this issue
I will update latter when I work out the real kermit bugs.

jc
 
Hi Jay, thanks for the progress updates - I will be looking at this again soon as well - you mention about the apparent 8-bit issue, and this rings a bell, the ports are 8 bit capable (if so configured) - but I do recall having to set an option to not use 8-bit transfers like 8-bit-prefixing or similar... sorry it's all a bit vague. It sounds like Kermit is using a system call rather than driving the ports directly if this is an issue.

Robin
 
WRT system call. There is the source code. It might be worth a hack to get at the I/O port directly.

JC
 
jay cotton said:
.kermit
Kermit-11 for EIS RT-11XB,XM,ZB,ZM/TSX-Plus V03.63 Last edit: 27-Sep-97
771. words free to load handlers
Link device is TT: S/W Parity: SPACE
KRT> set file type binary
Binary mode set
Caution: Binary files will require 8-bit prefixing
Click to expand...

https://www.columbia.edu/kermit/pdp11.html
http://www.columbia.edu/kermit/ftp/b/k11mit.pdf

I wonder why the parity is set to SPACE. The manual says that the default parity is NONE. Is the behavior any different if you do "SET PARITY NONE" before the "set file type binary"?

SET PARITY

Syntax: SET PARITY {EVEN, ODD, MARK, NONE, SPACE}

This is used with the SET LINE and CONNECT commands to specify the type of parity for the remote link. It
defaults to NONE and can be any of ODD, EVEN, MARK or SPACE.

All parity generation is done via software, no special hardware is used. The use of software parity generation is
restricted to 8 bit links only. The character format, if parity is set to anything but NONE, will be 7 bits of data
followed with high bit set or cleared to indicate the parity. If you set parity to anything but NONE (the default),
Kermit-11 will be forced to request 8bit prefixing from the other Kermit-11, which is a method by which Kermit can
’prefix’ eight bit characters with a shift code
Click to expand...
 

Attachments

Here's how I am doing binary transfers from Windows to RT-11 with Kermit...

So I am using k95.exe - Kermit95 with this in the k95.ini file from Windows 10:

set line 2
set carrier-watch off
set serial 8n1
robust

I connect to the RT-11 host - here you can see the settings:
1737922375966.png

Alt-X returns kermit to local control, then for example type "get transf.sav":


When you press <CR> you get the file transfer progress:

1737922730630.png

Likewise for "send trans1.sav"
1737922789375.png

(I renamed transf.sav to trans1.sav on the windows box)

type "fin" to end server mode on the remote host and c to connect back to it and then exit to get back to RT-11:

1737922959100.png


For TSX, there is KRTTSX.SAV with works in the same way, but you can do more clever things in the KRTTSX.INI file...

This seems to work OK, but I welcome coments and suggestions..

Robin
 
CKW Beta 5 is getting a bit old! As it turns out, I just put out beta 7. Additionally, k95g.exe superseded the old console-mode version of Kermit 95 (k95.exe) way back in 2002 and doesn't suffer from the glitches like those on the file transfer status screen. I mostly continue building the old console-mode version for non-interactive use (eg, in scripts), and for old versions of windows were its a little less glitchy (though the GUI version is always better behaved where ever it is available).
 
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