Re: Write-only devices (Was read only devices)

[gdonl () gv ssi1 com (Don Lewis)]

On Jun 21,  4:40pm, Paul C Leyland wrote:
} Subject: Write-only devices (Was read only devices)
} I do not know of any readily available write-only output device other
} than printers these days.  There were advantages to paper tape and
} punched cards which we have since lost.

I shudder at the thought of logging to cards ...

} It would probably be of general
} interest to hear of large-capacity unoverwriteable devices.  Note that
} CD-R is *not* acceptable as currently implemented as it is too easy to
} destructively overwrite what is already there.
}
} Clarification for pedants: by write-only, I mean something which is
} not readable, by the system performing the writing or, indeed, any other
} connected system without having to physically remove the device and
} re-connect it to a reading system.  Printer paper can be OCR'ed, but
} unless the output is fed into an OCR system, it is unreadable.
}
} Further, it must not be possible for anything to be deleted once
} written, either by the writing system or by anything connected to it,
} without having to physically remove, reconfigure and reconnect the
} write-only medium.

I think that if you substitute a cheap PC reading from its serial port
and writing to the medium of your choice for a serially connected
printer it will meet your criteria.  The PC's serial and power
connections should be its only connections to the outside world.  The
host writing the logs is not able to read the data back from the PC and
is not able to overwrite an previously written log entries.  What would
be cool is if the PC hooked to something like a floppy disk duplicator.
As the floppies were filled, they would be ejected and new blank floppies
would be loaded.  The filled floppies could be physically write protected
after they were ejected.

                        ---  Truck