VOGONS


First post, by vanfanel

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Hello,

I just got a relatively cheap, fanless, brand-less minipc from Aliexpress that has this old Celeron 2955U CPU.
It has Haswell graphics, apparently.

It's ALMOST good! It has some good things going for it in regards to native DOS:
-DOS boots natively: has good CSM support.
-EMS works perfectly well with EMM386 and JEMMEX!
-SBEmu works! So yeah, it has OPL and digital audio in DOS games and programs!
-Scrolling registers work well: Prehistorik 2 scrolling map is flawless, Superfrog works perfectly well, Jazz Jackrabbit also works well... That sums up my "test suite" for games which ask good DOS support to the hardware and it passes them all! Wow!

But here's the catch: it insists on using a 60Hz mode for 320x200 games, so some games like Lemmings 2, Tyrian, etc.. have slow music.

I know that there's the VGA60HZ TSR: https://github.com/wbcbz7/dos-vga-tsr-goodies … /master/VGA60HZ
...But what I would need is the opposite: I would need something that tells the CRTC registers that 320x200 IS a 70Hz video mode!
Is there such a thing? Can you guys shed some light here?

Thanks!

Reply 1 of 6, by keenmaster486

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Does your monitor natively support 70Hz? I don't know if there even is an LCD panel that supports 70Hz. Afaik they're all either 60 or 75, or something much higher.

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Reply 2 of 6, by vanfanel

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keenmaster486 wrote on Yesterday, 19:08:

Does your monitor natively support 70Hz? I don't know if there even is an LCD panel that supports 70Hz. Afaik they're all either 60 or 75, or something much higher.

I'm using an OSSC, it eats 70Hz for breakfast, so yes.
It seems to be something with the VBIOS on this PC, which as things are, insists that all DOS modes including VGA 13h (320x200@8) are 60Hz...

That's why I am looking to revert that via a TSR or similar.

Reply 3 of 6, by Falcosoft

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keenmaster486 wrote on Yesterday, 19:08:

Does your monitor natively support 70Hz? I don't know if there even is an LCD panel that supports 70Hz. Afaik they're all either 60 or 75, or something much higher.

Older LCD monitors that have analog/VGA input usually supports 70 Hz. I have 2 such monitors LG Flatron 2242T (1680x1050) and Philips 243V (1920x1080).

vanfanel wrote on Today, 07:36:

I'm using an OSSC, it eats 70Hz for breakfast, so yes.
It seems to be something with the VBIOS on this PC, which as things are, insists that all DOS modes including VGA 13h (320x200@8) are 60Hz...

That's why I am looking to revert that via a TSR or similar.

You can only get 70 Hz from Intel HD on analog/VGA output and only in text modes (720x400 70 Hz). Unfortunately all lower resolution graphics modes are scaled to 640x480 60 Hz.
In case of digital output even text modes are scaled to 640x480 60 Hz.

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Reply 4 of 6, by vanfanel

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Falcosoft wrote on Today, 09:40:

You can only get 70 Hz from Intel HD on analog/VGA output and only in text modes (720x400 70 Hz). Unfortunately all lower resolution graphics modes are scaled to 640x480 60 Hz.
In case of digital output even text modes are scaled to 640x480 60 Hz.

According to OSCC, text mode is also getting scaled to 60Hz.
This is over analog VGA output, of course: all DOS-capable computers I've seen only produce 60Hz when connected over HDMI.

But even so, shouldn't it be possible to program the CRTC so mode 13h behaves like actual 13h (70Hz)?
I mean, VGA60HZ does the opposite, so...

Reply 5 of 6, by Falcosoft

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vanfanel wrote on Today, 10:00:
According to OSCC, text mode is also getting scaled to 60Hz. This is over analog VGA output, of course: all DOS-capable computer […]
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Falcosoft wrote on Today, 09:40:

You can only get 70 Hz from Intel HD on analog/VGA output and only in text modes (720x400 70 Hz). Unfortunately all lower resolution graphics modes are scaled to 640x480 60 Hz.
In case of digital output even text modes are scaled to 640x480 60 Hz.

According to OSCC, text mode is also getting scaled to 60Hz.
This is over analog VGA output, of course: all DOS-capable computers I've seen only produce 60Hz when connected over HDMI.

But even so, shouldn't it be possible to program the CRTC so mode 13h behaves like actual 13h (70Hz)?
I mean, VGA60HZ does the opposite, so...

1. I have just checked this on my Haswell (i7-4770K) desktop and it outputs 720x400 70 Hz through analog VGA.

The attachment Haswell_VGA.jpg is no longer available

BTW, it seems to be real 70Hz. I used my retro PC with a CRT monitor as a reference and my Ivy Bridge T430 (works the same way as me Haswell desktop under DOS) and run the famous 70 Hz test program YO on both screens.
Here is the test video:
https://youtu.be/ZXDQM2MtTZE

2. Yes, but not all of them scales lower resolution modes to 640x480. E.g. Nvidia cards scales all modes to the native resolution of the LCD. This gives much better output quality for text modes. Text modes over digital output are very ugly on Intel HD.

3. The problem is the VGA BIOS does not handle it as real mode 13h. Instead you should try to force 640x480 70 Hz.

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Reply 6 of 6, by vanfanel

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@Falcosoft: Thanks a lot... It seems that the VBIOS on the mini-pc isn't good then 🙁
Time to return it. I have returned like 10 different ones already for different defects in DOS.
It seems that my dream of a modern mini-pc for DOS gaming is...well, a dream 😁