MS-DOS aux file -- what that is??

luserdroog

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Jul 5, 2021, 8:30:12 PM7/5/21

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I've been reading up on MS-DOS programming and the various file functions
as they evolved from 1.0 to 2.0 to 3.0 from Norton's Guide to the IBM PC.
In the DOS 2.0 functions there are 5 file handles already opened and reserved.

0 = stdin
1 = stdout
2 = stderr
3 = stdaux
4 = stdprint

What in the heck is a "standard auxiliary file (or device?)"? Is there any lore
on what this was used for? Would you plug an extra gizmo into the computer
and install a device driver and hook it up as the aux file and do what ...
blinkenlights, 7 segment displays, warp coil polarity control?

Carlos E.R.

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Jul 5, 2021, 9:08:08 PM7/5/21

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It was the serial port, by default.

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J. Clarke

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Jul 5, 2021, 9:58:45 PM7/5/21

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My guess would the audio recorder, which on the PC wasn't used to
record sound but as an I/O device.

luserdroog

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Jul 5, 2021, 11:01:27 PM7/5/21

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Interesting. Do you a need a modem in there somewhere or A/D or D/A convertors?

Grant Taylor

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Jul 6, 2021, 12:56:27 AM7/6/21

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On 7/5/21 9:01 PM, luserdroog wrote:
> Interesting. Do you a need a modem in there somewhere or A/D or
> D/A convertors?

The original IBM PC included a Cassette port.

Link - Nobody ever used the IBM PC with cassette tape port.
- https://www.youtube.com/watch?v=G_8CXyF5M1Q&t=129s

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Bob Eager

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Jul 6, 2021, 7:11:45 AM7/6/21

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No, it was the first serial port. The AUX: device.

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Carlos E.R.

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Jul 6, 2021, 7:16:08 AM7/6/21

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Nope, sorry. The tape recorder thing wasn't a device, not a pseudo file
you could write to.

No, AUX was the serial port.

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Cheers, Carlos.

Juergen Nickelsen

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Jul 8, 2021, 12:01:41 PM7/8/21

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"Carlos E.R." <robin_...@es.invalid> writes:

[AUX:]

> It was the serial port, by default.

And there was a MODE command to set the port parameters (among other
things), so this could actually be useful.

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Ted Nolan <tednolan>

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Jul 8, 2021, 12:13:34 PM7/8/21

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In article <87a6mw2...@lith.ni.w21.org>,

Juergen Nickelsen <n...@w21.org> wrote:
>"Carlos E.R." <robin_...@es.invalid> writes:
>
>[AUX:]
>> It was the serial port, by default.
>
>And there was a MODE command to set the port parameters (among other
>things), so this could actually be useful.
>

Except it still wasn't useful because DOS didn't use interrupts to
drive the UART iirc. You still needed a program that could do that
directly to get any useful speed out of the com port, and that bypassed
the whole AUX: interface entirely.
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