Karen,
granted I was intending to connect my friend in California with Joseph
Norton, he wants to run freedos, but use a USB speech synthesizer.
If I follow what you say here, in theory at least, he could use this
Linux USB drivers for the actual hardware, but in an emulator, tell say
his screen reading program to use the simulated serial port?
Depends on the nature of the USB speech synth. You can do it
if the USB version of the synth in fact is just the serial
one with an USB serial bridge chip added, or maybe even just
an USB serial adapter cable to plug it to USB-only computers.
In that case, you need nothing specific to the USB device.
You only need a generic way to make the underlying serial
communications visible to DOS. This can be done 1. by a DOS
USB driver supporting your or generic USB serial bridges.
Or 2. by running DOS in an emulator on an operating system
with support for USB serial bridges, configuring only the
emulator to make the right serial thing visible as if it
were connected to the emulated RS232 port, even if it is
not physically RS232 in the outside world. It could be USB,
IrDA or Bluetooth, for example, depending on bridge chips.
If, however, your USB speech synth has no serial port roots
at all, it will probably need a quite different driver.
One may write something which connects any speech synth your
Linux or Windows supports to an emulator in a way which looks
like a fixed, classic DOS compatible synth from the DOS side.
That would be a very generic solution, but also more complex.
It would be similar to having an ESC/P printer data capture
thing connected to your emulator, creating a PDF of whatever
DOS is printing, to give you flexibility on how to print the
contents later, in the Linux or Windows hosting the emulator.
Joseph has a build of freedos that uses something internal for speech.
What does "uses something internal" mean here in technical terms?
still I was wondering how Freedos itself would, or if it could simulate
the same thing?
DOS itself does not simulate things in that sense. But as
said, you may get drivers for DOS which simulate for example
RS232 ports from a BIOS or UART chip perspective, or tell an
emulator to do that, without needing a DOS driver.
The modern DOS drivers which simulate soundblaster hardware
while using AC97 or HDA hardware for actual sound output are
an impressing example of direct simulations without emulators.
In the decades before those, you had to run the entire DOS in
an emulator to get a simulated soundblaster, while the actual
sound output worked via any sound device of your host system.
provide the DOS floor, add in a good USB dos driver,
like the Panasonic
one I use, but simulate the serial port?
I believe the Panasonic driver has a focus on block
oriented storage (USB flash, USB card reader, USB
floppy, USB CD, USB DVD, USB harddisk, USB SSD etc.)
but more modular drivers like those of Bret and Georg
may have support for serial (bridge) class devices.
Another popular class is HID, human interface devices,
which includes keyboard, mouse, joystick and similar.
the serial port is needful, because the screen reader program uses it,
not necessarily a physical port, but the serial port address.
If you need a port with an address, make sure that the
USB driver or emulator you use has UART level realism.
Some might only support BIOS level, not realistic enough.
Regards, Eric
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