VOGONS


First post, by Claris

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Hi hi! Im working on a early 95 era Pentium build. Iv got most of it figured out but I'm stuck on what motherboard to use and the question of PS2 ports. Specifically with mice.

First motherboard option is an Intel "Plato" socket 5 board. I have no experience with early intel boards, i assume they are quality? No PS2 port from what iv read. Next up is a QDI P5I437/250A socket 7 board. Has PS2 available. Again, no experience with QDI. Im trying to pick high quality components as i want this build to "just work".

Part of me wants the Plato board because its the most period correct, but I play mostly FPS games and my problem with serial mice is how laggy and imprecise they feel due to the low polling rate. With PS2 usually that can be fixed in Windows, no idea about DOS though and that's what this build is going to be focusing on. I know a PS2-To-Serial active adapters can be bought off Serdashop, does that do anything to fix the terrible polling rate? Is there anything i can do in DOS to get that upped? I'd rather not use Windows 95 just for PS2Rate as i want this to be my "instant-action" machine. No worrying about getting drivers or windows hogging up resources. Just DOS and go.

Reply 1 of 31, by retardware

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There is lag if you use COM ports at default 1200bps.
But you can use up to 19200 bps on serial interfaces, at least with true microsoft compatible mice.
Very low lag if any, compared to PS2.
And COM->PS2 adapters are commonly delivered with Microsoft PS2 mice , so they are basically free, unlike PS2->COM adapters.

Reply 2 of 31, by Claris

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retardware wrote on 2021-11-01, 22:36:
There is lag if you use COM ports at default 1200bps. But you can use up to 19200 bps on serial interfaces, at least with true m […]
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There is lag if you use COM ports at default 1200bps.
But you can use up to 19200 bps on serial interfaces, at least with true microsoft compatible mice.
Very low lag if any, compared to PS2.
And COM->PS2 adapters are commonly delivered with Microsoft PS2 mice , so they are basically free, unlike PS2->COM adapters.

So is that like polling rate? How would i go about changing the bps on a serial port in DOS?

Reply 3 of 31, by retardware

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There is no polling.
Both serial and PS/2 are interrupt driven.
The mouse driver catches the interrupts and processes the events directly as they happen.
Use the mode command to change the bitrate for COMx.
Officially it is necessary to send a character sequence to the mouse afterwards to alert it of the new bit rate.
But my experiments indicated that this is not necessary even with very old mid-1980s Microsoft mice or Microsoft PS2 mice on the serial port with the Microsoft serial->PS2 adapter, even the later wireless ones.

Reply 4 of 31, by Claris

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retardware wrote on 2021-11-01, 22:57:
There is no polling. Both serial and PS/2 are interrupt driven. The mouse driver catches the interrupts and processes the events […]
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There is no polling.
Both serial and PS/2 are interrupt driven.
The mouse driver catches the interrupts and processes the events directly as they happen.
Use the mode command to change the bitrate for COMx.
Officially it is necessary to send a character sequence to the mouse afterwards to alert it of the new bit rate.
But my experiments indicated that this is not necessary even with very old mid-1980s Microsoft mice or Microsoft PS2 mice on the serial port with the Microsoft serial->PS2 adapter, even the later wireless ones.

Ah, thanks! I tried it on my 486-80 machine but sadly it seems 19,200 baud isn't available there. "Function not supported on this computer".

Reply 7 of 31, by Claris

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I wouldn't mind using a USB card, although my previous experiences with USB in DOS haven't been that great. Nor have i ever tried to get a USB Mouse working in it.

Is there anyway to findout what motherboards support 19,200 baud for COM? Evidently it seems my 486 doesn't like it, but what about a Socket 5 Intel board?

Reply 8 of 31, by jakethompson1

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Claris wrote on 2021-11-02, 00:16:

I wouldn't mind using a USB card, although my previous experiences with USB in DOS haven't been that great. Nor have i ever tried to get a USB Mouse working in it.

Is there anyway to findout what motherboards support 19,200 baud for COM? Evidently it seems my 486 doesn't like it, but what about a Socket 5 Intel board?

This would be a limit of the mouse not the motherboard. Most AT motherboards late enough to have onboard serial would be 16550A serial so up to 115200 bps.
Do you have a picture of the boards? Sometimes there is a header next to the keyboard port, ready to be connected to a PS/2 mouse port.
Also, consider Rio444's PS/2-to-serial on an ISA card: Another PS/2 Mouse ISA (ISA8) card adapter It works fine for me.

Reply 9 of 31, by retardware

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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).
The only problem is the software, older DOS versions' MODE command does not support setting higher than 9600.

Regarding the PS2 header near the keyboard connector on many mobos, keep in mind that there is no standard pinout,.
You need to use a multimeter to find out +5V and GND to make sure you do not kill the mouse using a random connector that is wired the wrong way.

Reply 10 of 31, by Claris

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jakethompson1 wrote on 2021-11-02, 01:08:
This would be a limit of the mouse not the motherboard. Most AT motherboards late enough to have onboard serial would be 16550A […]
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Claris wrote on 2021-11-02, 00:16:

I wouldn't mind using a USB card, although my previous experiences with USB in DOS haven't been that great. Nor have i ever tried to get a USB Mouse working in it.

Is there anyway to findout what motherboards support 19,200 baud for COM? Evidently it seems my 486 doesn't like it, but what about a Socket 5 Intel board?

This would be a limit of the mouse not the motherboard. Most AT motherboards late enough to have onboard serial would be 16550A serial so up to 115200 bps.
Do you have a picture of the boards? Sometimes there is a header next to the keyboard port, ready to be connected to a PS/2 mouse port.
Also, consider Rio444's PS/2-to-serial on an ISA card: Another PS/2 Mouse ISA (ISA8) card adapter It works fine for me.

Guess it really doesn't like this 3 button MouseSystems mouse then. Iv attached a picture of the board in question from the seller.

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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).
The only problem is the software, older DOS versions' MODE command does not support setting higher than 9600.

I plan on using 6.22 for this build, and thats what im currently running on my 486. Does it not support higher then 9600?

Reply 11 of 31, by jakethompson1

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Claris wrote on 2021-11-02, 01:19:
jakethompson1 wrote on 2021-11-02, 01:08:
This would be a limit of the mouse not the motherboard. Most AT motherboards late enough to have onboard serial would be 16550A […]
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Claris wrote on 2021-11-02, 00:16:

I wouldn't mind using a USB card, although my previous experiences with USB in DOS haven't been that great. Nor have i ever tried to get a USB Mouse working in it.

Is there anyway to findout what motherboards support 19,200 baud for COM? Evidently it seems my 486 doesn't like it, but what about a Socket 5 Intel board?

This would be a limit of the mouse not the motherboard. Most AT motherboards late enough to have onboard serial would be 16550A serial so up to 115200 bps.
Do you have a picture of the boards? Sometimes there is a header next to the keyboard port, ready to be connected to a PS/2 mouse port.
Also, consider Rio444's PS/2-to-serial on an ISA card: Another PS/2 Mouse ISA (ISA8) card adapter It works fine for me.

Guess it really doesn't like this 3 button MouseSystems mouse then. Iv attached a picture of the board in question from the seller.
s-l1600.jpg

Looking at other Plato pictures it seems like it was offered in both dual PS/2 port and AT keyboard port configurations. If you look next to the keyboard port on that one, you can see a place for a PS/2 port.
If you're good with a soldering iron, there might be a space for a PS/2 mouse port hidden underneath the AT keyboard port if you were to try and "convert" that board to PS/2.

Otherwise, as far as a serial mouse, I'm not sure how much you could overcome your lag issue. The Logitech DOS mouse driver does have a sensitivity option. On a 286 I found the pointer moved too slowly when using the Rio444 converter but if I passed S07 or S08 to LMOUSE it worked fine. Not sure if that option might help with your own serial mouse issues. I think the bigger issue is all "native" serial mice are ball mice other than those ones that need a special pad.

Reply 12 of 31, by Claris

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jakethompson1 wrote on 2021-11-02, 01:35:
Looking at other Plato pictures it seems like it was offered in both dual PS/2 port and AT keyboard port configurations. If you […]
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Claris wrote on 2021-11-02, 01:19:
jakethompson1 wrote on 2021-11-02, 01:08:

This would be a limit of the mouse not the motherboard. Most AT motherboards late enough to have onboard serial would be 16550A serial so up to 115200 bps.
Do you have a picture of the boards? Sometimes there is a header next to the keyboard port, ready to be connected to a PS/2 mouse port.
Also, consider Rio444's PS/2-to-serial on an ISA card: Another PS/2 Mouse ISA (ISA8) card adapter It works fine for me.

Guess it really doesn't like this 3 button MouseSystems mouse then. Iv attached a picture of the board in question from the seller.
s-l1600.jpg

Looking at other Plato pictures it seems like it was offered in both dual PS/2 port and AT keyboard port configurations. If you look next to the keyboard port on that one, you can see a place for a PS/2 port.
If you're good with a soldering iron, there might be a space for a PS/2 mouse port hidden underneath the AT keyboard port if you were to try and "convert" that board to PS/2.

Otherwise, as far as a serial mouse, I'm not sure how much you could overcome your lag issue. The Logitech DOS mouse driver does have a sensitivity option. On a 286 I found the pointer moved too slowly when using the Rio444 converter but if I passed S07 or S08 to LMOUSE it worked fine. Not sure if that option might help with your own serial mouse issues. I think the bigger issue is all "native" serial mice are ball mice other than those ones that need a special pad.

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. I had the same problem with games in Windows 95/98 where the mouse movement felt choppier VS the actual frame-rate of the game. Upping the Hz of a PS2 mouse using a program called PS2Rate fixed that, im trying to see if there's anyway i can do that in DOS because honestly its my biggest pet peeve with DOS only systems. Idk if upping the baudrate would fix that, or im stuck using a PS2 mouse in Win95 with PS2Rate for smooth mouse movement in DOS games.

Reply 13 of 31, by retardware

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Claris wrote on 2021-11-02, 01:19:

Guess it really doesn't like this 3 button MouseSystems mouse then.

MouseSystems mice are fixed to 1200 bps and are "dumb" in the sense that there is no two-way communication like with the Microsoft Mouse.

Claris wrote on 2021-11-02, 01:19:

I plan on using 6.22 for this build, and thats what im currently running on my 486. Does it not support higher then 9600?

No idea, as I don't use that. I don't see a point in doing so, as the 2GB partition size limit annoys me too much.

Reply 14 of 31, by retardware

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

Its the choppyness.

Think about it... 1200bps are 120 byte/sec, and a mouse systems word is 5 byte.

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

Idk if upping the baudrate would fix that, or im stuck using a PS2 mouse in Win95 with PS2Rate for smooth mouse movement in DOS games.

And now we come to the real meaning of "baud"... it really means "data word".
120 bytes / 5 byte word means only 24 mice words/sec, or 24 baud in the true meaning of "baud".
So you know why the mouse jerks down all things 😀

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.

Reply 16 of 31, by retardware

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

PS/2 mice are "smooth" in DOS without any special rate adjustment software

because their transfer rate is 10-16kbit/s

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

serial mice suck

...at least at the default 1200bps

Reply 17 of 31, by jakethompson1

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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.

Reply 18 of 31, by Claris

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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.

I'll give this a quick try.

It sounds like it'd be easier to just get a proper PS2 board though. I don't "have" to use the Intel Plato, although it would be more period correct for my uses. My other option would be a QDI P5I437/250A Chariot. I have no idea how good QDI boards are. I'm assuming the intel would be of higher quality, and i do want quality with this build. Although im sorta restricted by what my budget can afford

Reply 19 of 31, by maxtherabbit

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retardware wrote on 2021-11-02, 02:12:
maxtherabbit wrote on 2021-11-02, 02:03:

serial mice suck

...at least at the default 1200bps

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