"PDP-11 UNIX/RT ldp" files ?

[Mikko Nahkola]

I wonder ... is UNIX/RT still alive? Or is someone else just using data
formats close enough to fool the popular "file" command and associated
magic data file, consistently?

I saw a certain piece of networking gear stuff its own configuration in
a file that looks like binary (not much ASCII in there) to someone like
me who's only used to having binary and human-readable files ...
and gets recognized as "PDP-11 UNIX/RT ldp".

After a bit of searching I found that other people had gotten similar
stuff out of other makers' network equipment too. And that still more
people mention PDP and UNIX a lot in the Linux Documentation Project ;-(

A certain Martin McCormick tried to read such a floppy that came out of
a 3Com device, apparently; mine's a Zyxel and drops files across the
network with FTP.

Anyone care to enlighten me as to what the "UNIX/RT ldp" part means, at
least? Surely someone around here has seen it before...?

Anyway, the file structure doesn't look all that complicated - which
probably means that there isn't enough information in there to make any
real sense of the contents...

[Scott Lurndal]

Post by Mikko Nahkola
I saw a certain piece of networking gear stuff its own configuration in
a file that looks like binary (not much ASCII in there) to someone like
me who's only used to having binary and human-readable files ...
and gets recognized as "PDP-11 UNIX/RT ldp".

All that means is the file starts with the 16-bit value 0x0401.

scott

[Mikko Nahkola]

Post by Scott Lurndal

Post by Mikko Nahkola
I saw a certain piece of networking gear stuff its own configuration in
a file that looks like binary (not much ASCII in there) to someone like
me who's only used to having binary and human-readable files ...
and gets recognized as "PDP-11 UNIX/RT ldp".

All that means is the file starts with the 16-bit value 0x0401.

Yes, about that much I could figure out too. I've seen 'file' produce
all kinds of weird results over the years, this wouldn't be the first.

It's just that ... some of these file formats seem to stay around for
ages. And all the googling couldn't find anything _but_ networking
equipment, which would be a _really_ funny coincidence (if it isn't
accompanied by a statistical artifact in the distribution of that
particular line in the magic file).

[rpl]

Post by Mikko Nahkola

Post by Scott Lurndal

Post by Mikko Nahkola
I saw a certain piece of networking gear stuff its own configuration in
a file that looks like binary (not much ASCII in there) to someone like
me who's only used to having binary and human-readable files ...
and gets recognized as "PDP-11 UNIX/RT ldp".

All that means is the file starts with the 16-bit value 0x0401.

Yes, about that much I could figure out too. I've seen 'file' produce
all kinds of weird results over the years, this wouldn't be the first.
It's just that ... some of these file formats seem to stay around for
ages.

No reason to change perhaps.

Post by Mikko Nahkola
And all the googling couldn't find anything _but_ networking
equipment, which would be a _really_ funny coincidence (if it isn't
accompanied by a statistical artifact in the distribution of that
particular line in the magic file).

well DEC was pretty heavily into networking, you might say. Hardly any
different from all PC sound cards having a "Creative SoundBlaster 16"
default or fallback mode or the many hw knockoffs that emulate the
"standard"'s configuration/commandset-wise.



rpl