Re: [Freedos-user] Question about error message / redirecting AUX and PRN?

2022-07-11 Thread Eric Stein
Thanks for the reply. It turns out the software is trying to write to 
the com port on exit, which I'm assuming expects to find a modem there. 
There was a modem connected, but wasn't turned on. With the modem on, I 
don't get the error. Also if there is nothing connected to the port, the 
data is just sent out to nowhere, and there is no error. I'm not sure 
why it is accessing a modem only in certain conditions, but obviously 
this is not a FreeDOS problem.


BTW I did not specifically mention that I'm running this on old hardware 
(Pentium III based) and not a VM. I will ignore the drive messages and 
see what happens. Also it is a Gateway system, so it may have finicky 
stuff going on that a generic system doesn't.


Regards,
Eric

On 7/8/2022 16:29, Eric Auer wrote:


Hi ERIC,

the AUX device usually was the same as COM1, in the same
way that the PRN device usually was the same as LPT1.

If your program tried to read/write AUX, it either
really wanted to do something with the serial port,
or an unrelated bug made it access the wrong file.

According to the FreeDOS kernel sources, AUX is the
first item in the system file table, similar to
file handles 0 to 4 defaulting to CON as stdin,
CON as stdout, CON as stderr, "stdaux" (stdin)
and PRN, respectively.

Note that your luck may vary when it comes to access
to real or emulated serial or parallel ports in the
PC or DOS emulators you may be using today. At least,
you will have to dig into the configuration docs to
find out how to link them to the right device of your
host operating system to make them useful :-)

The message about drives and cylinders probably
refers to a mismatch between your CHS geometry
and what would be plausible based on where your
partitions start and end. The MBR partition table
should better agree with the geometry reported
by the BIOS, but if you have LBA, then DOS will
probably be using LBA instead of CHS anyway, so
warnings about geometry become less relevant.
Regards, ERIC ;-)

PS: You are right that our MODE has LPTn=COMn
redirection but not PRN/AUX redirection. The
kernel source code says MODE should be able to
redirect AUX and PRN, like CTTY redirecting CON?
In MS DOS, the first 3 system file table items
would be AUX, CON and PRN. I guess redirecting
those would involve "just" manipulating the SFT?







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[Freedos-user] Question about error message

2022-07-08 Thread Eric Stein

Regarding FreeDOS 1.3 release version:

So I get this message when I exit from a certain program: Error reading 
from device AUX: write fault.


Aside from the strangeness of getting a write fault by reading 
something, does DOS even still have an AUX device?  I think this is a 
generic device name like PRN that can be redirected to something else, 
but the MODE command doesn't seem to know what it is.


Also when I start FreeDOS, I get 4 lines of "Can't read parameters from 
drive 01" after a message that looks like it is adjusting the number of 
cylinders detected. But the system seems to work fine.


Any insights would be appreciated.

Eric




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