Most Model T file transfer programs use an old non TCP/IP protocol called 
Xmodem...

-----Original Message-----
From: M100 [mailto:[email protected]] On Behalf Of Brian K. 
White
Sent: Thursday, February 25, 2021 9:56 PM
To: [email protected]
Subject: Re: [M100] Why not transfer with Telcom?

On 2/25/21 9:08 PM, AvantGuard Systems wrote:
> I can use Telcom and connect to BBS's. When on a session you have the 
> options to (I forget the exact terminology on the screen) UPLOAD, DOWNLOAD.

TELCOM has no file transfer ability. All it can do is capture text from the 
serial port to a file and it can read a file and send it out the serial port.

That is missing too many things. No binary data, no machine language programs, 
not even 8-bit text, no error detection, let alone error correction, it can't 
even tell when a file begins or ends out of any other data coming in the serial 
port, nor can tell the host side when sending a file.

You have to do all those kinds of things yourself with separate programs in a 
dozen laborious, inefficient, error-prone steps before and after the actual 
transfer, to manage to get a file transferred that way. 
(encode the file with some kind of utility, generate a checksum of either the 
original file or maybe the encoded file, start the capture on one end, start 
sending from the other end, somehow arrange to ensure that there is not a 
single byte of other junk included in the capture before or after the file 
contents, run a decoder program on the receiving end to unpack the encoded file 
back into it's real form, run a checksum program to verify that, delete the 
encoded version, have an empty machine so that the ram can all be used up on 
having both the file you want and the 2x size encoded copy of it and the 
decoder app all in ram at the same time (so no big files), and then how did you 
get the encoder or decoder app onto the 100 in the first place? Manually type 
it in? Cassette? TELCOM capture an ascii format BASIC program and just hope it 
wasn't corrupted?

You only do that once per reset simply because the system rom provides no other 
option besides the cassette interface (for instance TELCOM has no xmodem), and 
you physically have no choice. So you do that once, just to bootstrap some kind 
of software to do that job for real the rest of the time, until the next time 
you wipe the machine.

> So if I can upload and download files, why can't I build my own FTP 
> SERVER? or whatever server, put the program files on it and download 
> them to the Model100?

I'm not sure what exactly is the question. Yes you can place files on a 
computer and download them to the 100. That's exactly all a TPDD emulator (akak 
tpdd server) does is exactly that.

It's not FTP though. FTP is a tcp/ip protocol. There is no such thing as tcp/ip 
on a 100.

--
bkw

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