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MS-DOS Boot Disk Help

T

TandyMan100

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Jan 7, 2009
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Hello. I am trying to get my boot disk to do the following: CTTY, TELNET, Use COM1 and COM2. What files (besides the defaults) are needed on the boot disk? It says that it cannot write to COM1 when I CTTY it. Any help?
 
My guess is that you have one or more of the following problems:
Wrong cabling so CTTY doesn't think there is a connected device.
Wrong COM port. Are you sure it is COM1?
Wrong syntax. Does CTTY require the : after the device name? Are you using the : e.g. ctty com1:

To test for 1 or 2 above, try running something simple like telix on the PC and open the com port. Connect up the device you're trying to use (I think it is a model 100 or similar) and see if you can see in telix what you send out the serial port on the model 100.
 
It's not cabling, I'm just using the standard full-null modem cable. It works with hyperterminal. I'll try the colon thingy, but I think the problem is that I don't have the drivers. If anyone has MS-DOS drivers, it would help.
 
There are usually no drivers for serial ports in MS-DOS unless they are USB or PCI. Then they will probably not work at all.

If they are built into the motherboard or are on ISA/EISA/VESA boards then they are usually recognized and set up by the BIOS.

What version of ms-dos are you using? What kind of motherboard? Can you run MSD on that machine and see if it recognizes the serial ports? MSD is a part of DOS 6.22. It may even appear earlier.

There is also a program called "port finder" for ms-dos. Download that and run it in dos mode. It will enumerate all ports the computer knows about.

If you have PCI or USB serial ports and are trying to run all of this as a client of XP or VISTA (in a window) then you can probably forget about it working at all. You could try DosBox and see if that works.
 
CTTY internal

CTTY internal

TandyMan100 said... Does anyone have the "CTTY" internal file command download anywhere?
Click to expand...
Internal means its part of command.com and loads when command.com loads.
What version of DOS are you using ?
patscc
 
You have to put the M100 in terminal mode before running the ctty command, then the dosprompt should appear on the M100 screen shortly after the ctty is executed as above. That's when the real fun begins.

I'm not sure what you mean by 'standard' null modem, as there are several standards. The ones they sell at RadioShack work, but some that are designed for IBM-compatibles don't always.

--T
 
If rolling your own:

Code: 
1 ---- 1
2 ---- 3
3 ---- 2
4 ---- 5
5 ---- 4
7 ---- 7
6--\
      -- 20
8 --/
         - 6
20 -- /
       \ - 8

NOTE: This is from memory, I'll look it up later to confirm.

--T
 
@ TandyMan100:
You seem to be a little confused about how DOS works. :) There are three basic files, command.com, and two hidden system files. Thats ALL. Everything else is optional and may or may not come with any particular distribution or be on any computer. A number of commands, such as DIR and COPY etc. are compiled into command.com, everytining else is a utility and you can chose whichever you want from a huge selection available. So, when people talk about a particular utility, they are not nescessarily refereing to something compiled into command.com nor something distributed by MicroSoft, or whoever.

Example is Telnet. There are a numbe of differnt ones available and NCSA has been suggested, and is a good one. The simplest that I know of is MiniTel and you can find it on this page under TCP/IP.

If you want to get more functionality than your personal collection of utilities already offers, then you can go to many sites which specialize in DOS. Two of the best are Simtel and Garbo.

BTW, if you have a "normal" MS distribution with the help.com and help.hlp files, then you can type "help", or "help command". That offers very detailed information about the MS utilities and general DOS functionality.

Good luck!
 
Terry Yager said:
You have to put the M100 in terminal mode before running the ctty command, then the dosprompt should appear on the M100 screen shortly after the ctty is executed as above. That's when the real fun begins.

I'm not sure what you mean by 'standard' null modem, as there are several standards. The ones they sell at RadioShack work, but some that are designed for IBM-compatibles don't always.

--T
Click to expand...

That's what I did, but I didn't have the STAT parameters right because I don't know what they are.
 
CTTY works through the ROM BIOS routines, no drivers. The command is part of DOS COMMAND.COM.

To set the COM port operating parameters, you'll also need the MODE.COM command file . So, to set the COM1: port for 2400 bps, no parity and 8 data bits and one stop bit, you run:

MODE COM1:2400,n,8,1

To see if you've got what you need, leave your terminal hooked to the PC's COM1 port, take a text file (let's call it FILE.TXT) and try this:

COPY FILE.TXT COM1:

If your terminal doesn't start spewing text, the problem isn't with DOS, it's with your BIOS setup. If it works, then try:

CTTY COM1:

FWIW, the BIOS handling of a COM port is downright brain-dead--no interrupts, buffering or anything fancy, just plain old poll-mode I/O.
 
What Chuck(G) said, except, don't set the speed at anything over 1200bps, as the M100 screen can't keep up. Just make sure the settings match on both ends. On the M100, 'Line Status' (X-On/X-OFF) should be set to 'E' (Enable).

--T
 
Last edited:
Okay, I had CTTY working for a little while, but the baud rate was off, now that the baud rate is correct, nothing works at all. Even how it was originally, all I get is "abort, retry, ignore". BIOS is correct, reading the COM1 and COM2 ports, but MS-DOS just ignores them.
 
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