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

From: Tom Jennings <tomj_at_wps.com>
Date: Thu Jan 6 18:48:53 2005

On Thu, 6 Jan 2005, Dwight K. Elvey wrote:

> In the past when I wanted a non-block binary transfer,
> I often had some value that I used as an escape character.
> I'd choose a low frequency value to improve throughput.
> It is simple, If you want to send a command value, you
> send the escape character, first. If you just wanted the escape
> character, you'd send it twice. For 8 bit data, you
> had 255 commands. EOF could be one of those.
> It makes a simple protocol that is easy to implement in
> code.

For MSDOS etc, you have to escape SUB, and NUL. And a bunch of
others. Plus, you might not have an 8-bit channel, only 7. So now
you ahve to escape all those.

A is sent as A
Control-A is sent as &A
A with bit7 set is sent as #A
Control-A with bit7 set is sent as #&A

Wait! That's Kermit!

Machines need to pause for various tasks, like writing to slow
disks. So now you need a way to tell the sender to stop.

Ad nauseum. Hence, communications protocols. The problem is
anything BUT trivial.


But I do agree with you, I'm all in favor if one-off problem
solutions, with the caveat that many tasks expand with time.


To paraphrase the jargon file:

"That's why I love standards, there's so many to choose from!"
Received on Thu Jan 06 2005 - 18:48:53 GMT