Importing binary files without removable storage nor non-bundled software (was: TKermitFTP

From: Tom Jennings <>
Date: Thu Jan 6 14:09:49 2005

>> "Binary reads from a device are not
>> allowed" is the message at 8753 in DR-DOS 3.41.

On Wed, 5 Jan 2005, Vintage Computer Festival wrote:

> The question I haven't seen answered yet is, "Well, why the hell not???"

The real answer is: there is no out-of-band signalling, so one of
the 128 in-band symbols (SUB, 26 decimal) is chosen to mean "END
OF FILE". It's borrowed from CP/M-80; I don't know where DR got
it; it seems un-DEC-ish.

("Out of band" signalling is, for RS-232 et al, the hardware
handshake lines. No one likes them, everyone complains like
babies, so they have essentially been deprecated.)

The practical answer is: COMMAND.COM does something to the effect:

         while ( byte available from the COM port)
                 read byte
                 is it Control-Z?
                         TERMINATE COPY COMMAND
                 is it Null?
                         --> bit bucket
                 is it Character MSDOS Doesn't Like?
                         --> bit bucket

                 copy byte to file
                 is DISK FULL?
                         TERMINATE COPY COMMAND
Received on Thu Jan 06 2005 - 14:09:49 GMT

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