Com port question

Com port question

[Bernie Gardner]

I am trying to get CT, an amateur radio logging program to work in
dosemu.  Everything seems to be ok except for keying through the com
port.  The program has a feature to key the radio using the DTR line
from the com port, and this sort of works except that it is much to slow
to keep up.  Is there a way to speed up the com port?  Thanks for any
suggestions!

Bernie Gardner
w1az@arrl.net

Re: Com port question

[Stas Sergeev]

Hello.

Bernie Gardner wrote:
> slow to keep up.  Is there a way to speed up the com port?
Probably no - emulation is an emulation.
It works quite fast in a FIFO mode
(buffering), but when there is no
buffering and each operation must
be performed immediately, if falls
down with a perforance.
You can always try to use a direct
access to the com ports (bypassing
an emulation) but it is not something
that is recommended for the real use.
Try setting $_hogthreshold to 0, maybe
that will help a bit.
Btw, what dosemu version do you have?
The latest ones shold perform a little
better under some conditions.

Re: Com port question

[Ged Haywood]

Hi there,

On Sun, 17 Nov 2002, Stas Sergeev wrote:

> Bernie Gardner wrote:
> > slow to keep up.  Is there a way to speed up the com port?
> Probably no - emulation is an emulation.
> It works quite fast in a FIFO mode (buffering),

I do not think FIFO buffering will help a program which manipulates
the DTR line directly, as the UART is not actually sending data in
the normal way - it's just being used as a 1-bit data latch.

[snip]

> You can always try to use a direct access to the com ports
> (bypassing an emulation) but it is not something that is recommended
> for the real use.  Try setting $_hogthreshold to 0, maybe that will
> help a bit.

Unless you can get the source for the program and recompile it for
Linux, I think direct access is the best way to go in this case.

73,
Ged.

Re: Com port question

[Stas Sergeev]

Hello.

Ged Haywood wrote:
> I do not think FIFO buffering will help a program which manipulates
> the DTR line directly, as the UART is not actually sending data in
> the normal way - it's just being used as a 1-bit data latch.
Right, that's what I implied to actually.
It works quite fast in a FIFO mode [only
when the actual data transfer is concerned
of course]. In all other cases it falls
down with perforance [and the DTR case
is the one of those].

Re: Com port question

[Bernie Gardner]

On Sun, 2002-11-17 at 11:33, Ged Haywood wrote:
> Hi there,
> 
> > You can always try to use a direct access to the com ports
> > (bypassing an emulation) but it is not something that is recommended
> > for the real use.  Try setting $_hogthreshold to 0, maybe that will
> > help a bit.
> 
> Unless you can get the source for the program and recompile it for
> Linux, I think direct access is the best way to go in this case.
> 
> 73,
> Ged.
> 
> 

Thanks to you and Stas Sergeev for the thoughts. I am using dosemu
version 1.0.2.0 on SuSE 8.1 if it matters.  It's possible if I have to
ask I shouldn't do it, but can you give me a hint how to set up for
direct access to the serial port?

Thanks and 73,

Bernie
w1az@arrl.net