I'm seeing this in my HPT logs related to a JAM base for netmail

3 Mar:29:2026:15:55:16 Linking area NETMAIL
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!
A Mar:29:2026:15:55:38 JAM ERROR: subfield is suspiciously large! (825360384 bytes)

any thoughts on how best to resolve the problem?

Best, Paul

Kerr Avon [Blake's 7] 'I'm not expendable, I'm not stupid and I'm not going' avon[at]bbs.nz | bbs.nz | fsxnet.nz

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On 29 Mar 2026 at 04:00p, Paul Hayton pondered and said...

3 Mar:29:2026:15:55:16 Linking area NETMAIL
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!

I tried hptutil fix -j /pathto/netmail

But it seemed to do nothing ... ended up removing the database and starting over :(

Kerr Avon [Blake's 7] 'I'm not expendable, I'm not stupid and I'm not going' avon[at]bbs.nz | bbs.nz | fsxnet.nz

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On 29 Mar 2026, Paul Hayton said the following...

I'm seeing this in my HPT logs related to a JAM base for netmail

3 Mar:29:2026:15:55:16 Linking area NETMAIL
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!
A Mar:29:2026:15:55:38 JAM ERROR: subfield is suspiciously large! (825360384 bytes)

any thoughts on how best to resolve the problem?

Hi Paul,

Other than sqpack and hptutil, I've not found a utility on Linux that scans and repairs JAM message bases. In the past I've moved those files to a Windows machine and used FastEcho's "feutil pack -renumber" which seemed to do the trick for me, your mileage may vary.

I haven't tried, but another thing you could do is use MK Message Utilities:

https://flisterz.throwbackbbs.com/filelist/BBS_Utilities/mkmu103.zip

To convert that base from JAM to Squish and then back to JAM again.


Jay

... Who called it a jetski and not a boatercycle?

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On 2026 Mar 29 06:28:42, you wrote to Paul Hayton:

I haven't tried, but another thing you could do is use MK Message Utilities:

https://flisterz.throwbackbbs.com/filelist/BBS_Utilities/mkmu103.zip

To convert that base from JAM to Squish and then back to JAM again.

FWIW: converting from JAM to SQU will result in data loss/change... specifically in the timestamps... SQU's timestamps are filesystem "format" and have an even-number-based 2 second granularity (eg: 0, 2, 4, 6, etc)... JAM and other message base formats use the regular timestamp format so have 1 second granularity (eg: 0, 1, 2, 3, 4, etc)... sure it isn't much but it changes more than one might expect...

messages in JAM written at (eg) 17:01:01 would be stored in SQU with 17:01:00 or 17:01:02... this not only changes the timestamp but also results in header checksums for duplicate detection failing... converting from SQU to other formats will not undo this...

BUT i also recall at least one message base format in the MK library that forced seconds to zero... i fixed many of these types of defects in my copy of the library... some of them made it back upstream to the original developer, Mark May, but not all of them did... this was back in the day before code repositories were known and used...

)\/(ark

"The soul of a small kitten in the body of a mighty dragon. Look on my majesty, ye mighty, and despair! Or bring me catnip. Your choice. Oooh, a shiny thing!"
... I am Canadian Because....I know Medicine Hat is a place, not a thing.
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Other than sqpack and hptutil, I've not found a utility on Linux that scans an
repairs JAM message bases. In the past I've moved those files to a Windows machine and used FastEcho's "feutil pack -renumber" which seemed to do the trick for me, your mileage may vary.

I haven't tried, but another thing you could do is use MK Message Utilities:

https://flisterz.throwbackbbs.com/filelist/BBS_Utilities/mkmu103.zip

To convert that base from JAM to Squish and then back to JAM again.

Does your second suggestion work on linux?

Mike


* SLMR 2.1a * if it has tires or tits, you're gonna have problems
--- SBBSecho 3.28-Linux
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On 29 Mar 2026, Mike Powell said the following...

I haven't tried, but another thing you could do is use MK Message Utilit https://flisterz.throwbackbbs.com/filelist/BBS_Utilities/mkmu103.zip

Does your second suggestion work on linux?

It looks like MK Message Utilities was only released as an .exe


Jay

... Shoutout to all of the sidewalks out there for keeping me off the streets

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On 30.3.2026 0.41, Jay Harris wrote:

On 29 Mar 2026, Mike Powell said the following...

I haven't tried, but another thing you could do is use MK Message Utilit https://flisterz.throwbackbbs.com/filelist/BBS_Utilities/mkmu103.zip

Does your second suggestion work on linux?

It looks like MK Message Utilities was only released as an .exe

DOS exe, year 1994. :)

There is also a program called MBMERGE that can copy messages from msgbase to another. It runs on linux, windows and os/2.

'Tommi

---
* Origin: nntp://rbb.fidonet.fi - Finland (2:221/360.0)

Hi Tommi,

On 2026-03-30 10:27:39, you wrote to Jay Harris:

There is also a program called MBMERGE that can copy messages from
msgbase to another. It runs on linux, windows and os/2.

Or even more simple, just use GoldED to copy messages between areas... ;-)

Bye, Wilfred.

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* Origin: FMail development HQ (2:280/464)

On 29 Mar 2026, Paul Hayton said the following...

I'm seeing this in my HPT logs related to a JAM base for netmail

A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!

any thoughts on how best to resolve the problem?

I've seen others have success in using Claude AI to make them a purpose-built utility, so decided to give it a try.

I pointed Claude at JAMLib on Sourceforge and SMAPI from the Husky Project on GitHub and asked it to make me a utility that can scan & repair damaged JAM message bases. A little trial & error and it spit something out that seems to work for my limited uses. I asked it if it's easy to compile for Linux or Windows and it updated the C source code & Makefile to make sure it can do a 32 or 64 bit .exe.

For Linux you just have to run "make" in the same directory and it'll spit out an executable for you.

I tested the Linux version on some test bases (Claude also included two python scripts to generate a damaged JAM base to test). I mostly just opened up a JAM file with nano and messed it up to see if the utility can fix it, and to my surprise it did/can.

If you have a backup of that damaged base, I'd be interested to see if this works for you.

I've not thoroughly tested this utility (and I am by no means a coder), so I wouldn't run this on anything you don't already have a backup of. But hopefully someone somewhere finds this useful.


.c source and 32 & 64bit .exe's included:
https://nrbbs.net/jamrepair.zip


Jay

... If it breaks then you get to keep both pieces

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I haven't tried, but another thing you could do is use MK Message Utilit https://flisterz.throwbackbbs.com/filelist/BBS_Utilities/mkmu103.zip

Does your second suggestion work on linux?

It looks like MK Message Utilities was only released as an .exe

Thanks!

I have also been running into some JAM bases that are getting corrupted
somehow so I am on the lookout for something that might fix them. Figuring
out how they are getting corrupted to begin with might be enough. ;)

Mike

* SLMR 2.1a * A reasonable man accomplishes nothing.
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On 30 Mar 2026 at 12:34p, Jay Harris pondered and said...

I've not thoroughly tested this utility (and I am by no means a coder),
so I wouldn't run this on anything you don't already have a backup of. But hopefully someone somewhere finds this useful.

thanks Jay :)

I'll have a crack and let you know.

Thanks to all who replied... it's an interesting thread.

Best, Paul

Kerr Avon [Blake's 7] 'I'm not expendable, I'm not stupid and I'm not going' avon[at]bbs.nz | bbs.nz | fsxnet.nz

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Hello Paul!

29 Mar 26, Paul Hayton wrote to All:

3 Mar:29:2026:15:55:16 Linking area NETMAIL
A Mar:29:2026:15:55:16 JAM ERROR: wrongly sized subfield occured!
A Mar:29:2026:15:55:38 JAM ERROR: subfield is suspiciously large!

any thoughts on how best to resolve the problem?

Do not use JAM for netmail. Really. Especially for routing systems with in tranist netmail a broken indexed area could destroy many netmails. With FTS1/OPUS style one message per file (*.msg) the risk is reduced to each message only.

Regards

Kai

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