jakethompson1 wrote on 2021-11-02, 02:13:

Logitech DOS driver (mouse.exe)...
...It has a "9600" option to set the rate to 9600 "if possible" and apparently isn't possible on the mouse I'm using.

You can read a quite detailed technical explanation here... this 9600bps option is supported only by a few Logitech mice.

maxtherabbit wrote on 2021-11-02, 02:30:

Yes I didn't mean to imply it was a physical limitation of RS-232 serial. But other than some specific logitech hardware (and their specific bespoke drivers) there is basically zero support for faster serial mouse interfacing

My personal experience with my mice (serial and PS2 compatible, various models, with and without cord) is different.

I only changed the serial port speed to 19200 bps using the DOS MODE utility, and mice just accepted that new speed, even without echoing the according "*<char>" speed selection code to the mouse port.

I did not like Logitech mice since their inception, because they were so jerky, and they stopped working when setting the serial port to a higher speed.

jakethompson1 wrote on 2021-11-02, 02:13:

I just downloaded a later Logitech DOS driver (mouse.exe) from inside ftp://ftp.logitech.com/pub/techsupport/mouse/m83setup.exe […]
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retardware wrote on 2021-11-02, 01:50:

So I really prefer just using a MS (or sufficiently compatible) mouse that can do 19200... this results in about 400 "mice baud", definitely sufficient for smooth mouse control.

I just downloaded a later Logitech DOS driver (mouse.exe) from inside ftp://ftp.logitech.com/pub/techsupport/mouse/m83setup.exe
It has a "9600" option to set the rate to 9600 "if possible" and apparently isn't possible on the mouse I'm using.
But potentially something for the OP to try from DOS. Mouse.exe /? shows a lot of options to tweak for the desirable speed.

Nope, gave it a try and it didn't change a thing. Still choppy mouse movement.

Anyone have any experience with QDI P5I437/250A Chariot? or QDI as a brand in general? Are they good quality? Any suggestions for a good quality 1995 era Pentium board with a PS2 mouse port? The Intel Plato has a soldered on RTC battery so there's another excuse to switch motherboards.

Claris wrote on 2021-11-02, 02:43:

jakethompson1 wrote on 2021-11-02, 02:13:

I just downloaded a later Logitech DOS driver (mouse.exe) from inside ftp://ftp.logitech.com/pub/techsupport/mouse/m83setup.exe […]
Show full quote

retardware wrote on 2021-11-02, 01:50:

So I really prefer just using a MS (or sufficiently compatible) mouse that can do 19200... this results in about 400 "mice baud", definitely sufficient for smooth mouse control.

I just downloaded a later Logitech DOS driver (mouse.exe) from inside ftp://ftp.logitech.com/pub/techsupport/mouse/m83setup.exe
It has a "9600" option to set the rate to 9600 "if possible" and apparently isn't possible on the mouse I'm using.
But potentially something for the OP to try from DOS. Mouse.exe /? shows a lot of options to tweak for the desirable speed.

Nope, gave it a try and it didn't change a thing. Still choppy mouse movement.

Anyone have any experience with QDI P5I437/250A Chariot? or QDI as a brand in general? Are they good quality? Any suggestions for a good quality 1995 era Pentium board with a PS2 mouse port? The Intel Plato has a soldered on RTC battery so there's another excuse to switch motherboards.

It looks like that is a ball mouse. I don't know if you might be happier with an optical PS/2 mouse going through a converter (the Rio444 ISA card is specifically supposed to reduce the latency of conversion overhead) or not.
I don't have a QDI motherboard, but the QDI QD6580 VLB IDE controller is considered a good card. That board looks like an Intel Triton board which would be a high end board for 1995. Hopefully your board will have 512K (or 1M) cache and come with the PS/2 mouse connector ready to go so you don't have to worry about the pinout.

retardware wrote on 2021-11-02, 02:41:

I only changed the serial port speed to 19200 bps using the DOS MODE utility, and mice just accepted that new speed, even without echoing the according "*<char>" speed selection code to the mouse port.
when setting the serial port to a higher speed.

Are all your serial mouses Microsoft brand?

maxtherabbit wrote on 2021-11-02, 03:01:

Are all your serial mouses Microsoft brand?

Yes...
well, to tell the truth, I also have some old Genius and Logitech ball mice, but on my retro computers I only use Microsoft mice.
I prefer the cordless serial/PS2 ball mouse. It is a very good mouse, works very fine on most surfaces, and large enough to rest the hand on it.

But I still have a few 1980s serial ball mice, but they are a bit more surface-sensitive in spite of the fact that they have the biggest and heaviest balls. I suppose it is a problem with their metal rolls, these seem prone to slip, like with the GM-6[000] mice.

I very much prefer optical mice to ball mice.

That means that I prefer computers with PS/2 interfaces, and I wire them up to a PS/2 port.

jakethompson1 wrote on 2021-11-02, 02:50:

Claris wrote on 2021-11-02, 02:43:

jakethompson1 wrote on 2021-11-02, 02:13:

I just downloaded a later Logitech DOS driver (mouse.exe) from inside ftp://ftp.logitech.com/pub/techsupport/mouse/m83setup.exe
It has a "9600" option to set the rate to 9600 "if possible" and apparently isn't possible on the mouse I'm using.
But potentially something for the OP to try from DOS. Mouse.exe /? shows a lot of options to tweak for the desirable speed.

Nope, gave it a try and it didn't change a thing. Still choppy mouse movement.

Anyone have any experience with QDI P5I437/250A Chariot? or QDI as a brand in general? Are they good quality? Any suggestions for a good quality 1995 era Pentium board with a PS2 mouse port? The Intel Plato has a soldered on RTC battery so there's another excuse to switch motherboards.

It looks like that is a ball mouse. I don't know if you might be happier with an optical PS/2 mouse going through a converter (the Rio444 ISA card is specifically supposed to reduce the latency of conversion overhead) or not.
I don't have a QDI motherboard, but the QDI QD6580 VLB IDE controller is considered a good card. That board looks like an Intel Triton board which would be a high end board for 1995. Hopefully your board will have 512K (or 1M) cache and come with the PS/2 mouse connector ready to go so you don't have to worry about the pinout.

If i can turn up the baudrate with those adapters to fix the mouse choppyness, then yes, id probably prefer to buy one of those then spend another $100+ on a new motherboard with PS2.

Only other issue is this plato board had a soldered RTC battery, and i don't personally known enough to solder it off. I guess i could learn to take a Dremel to it and piggyback a coin battery holder?

Claris wrote on 2021-11-02, 01:40:

Its the choppyness. Playing a game like Wolfenstein for example, which runs butter smooth on a 486, when controlling with a mouse the movement feels all choppy. Like it was running at a lower framerate.

Check if your motherboard suffers from this issue: Moving Mouse dramatically slows down CPU

It can be resolved by using Microsoft Mouse Driver v9 but that one takes up around 25KB of conventional memory.

Joseph_Joestar wrote on 2021-11-02, 05:25:

Claris wrote on 2021-11-02, 01:40:

Its the choppyness. Playing a game like Wolfenstein for example, which runs butter smooth on a 486, when controlling with a mouse the movement feels all choppy. Like it was running at a lower framerate.

Check if your motherboard suffers from this issue: Moving Mouse dramatically slows down CPU

It can be resolved by using Microsoft Mouse Driver v9 but that one takes up around 25KB of conventional memory.

I found 9.01 which i gave a quick test here, nope no difference. Mouse movement still felt like game was running at a lower frame rate.

retardware wrote on 2021-11-02, 01:12:

It is the hardware determined by IBM, the basic RS-232 interface is based on the 8250 and its maximum bit rate is 115200 bps (the word "baud" is often used incorrectly).

Actually baudrate is used correctly on RS-232: "If there are precisely two symbols in the system (typically 0 and 1), then baud and bit per second (bit/s) are equivalent." (Wikipedia)
Where I'm not sure is when apps return a modem carrier speed. That, as I recall, was reported as "baudrate" but should be "bitrate".

mathew7 wrote on 2021-11-02, 14:17:

Where I'm not sure is when apps return a modem carrier speed. That, as I recall, was reported as "baudrate" but should be "bitrate".

Regarding modem baud, this page has a nice explanation.

Regarding the mouse choppiness, I find the baud definition (symbols/sec) really helpful.
The mentioned Mouse Systems mouse transmits a maximum of ~24 symbols, actually "5-byte mouse words" respective movement updates, per second.
This results in easily noticeable coarse movements.

On the other hand, a Microsoft (or truly compatible) mouse can theoretically at 19200bps 7E1 transmit up to roughly 2000/3 = ~700 3-byte position updates ("mouse symbols)/sec, which one could express with 700 mouse baud.
Personally, with this update rate, I cannot notice a difference to a modern USB mouse, no movement lag, no choppiness at all.

Regarding the mouse driver, for best compatibility I recommend the latest MS driver, too.
If RAM is scarce, the Genius mouse driver can be a good alternative, it supports the Microsoft protocol, too, and has a minuscule memory footprint.

retardware wrote on 2021-11-03, 05:41:

On the other hand, a Microsoft (or truly compatible) mouse can theoretically at 19200bps 7E1 transmit up to roughly 2000/3 = ~700 3-byte position updates ("mouse symbols)/sec, which one could express with 700 mouse baud.

Just call them reports/s. Not "mouse symbols" or "mouse baud". The packet still contains "individual" X-change and Y-change, therefore it's not "1" symbol per report.
I even like the PS/2 100"Hz" better.