vogons - very old games on new systems Last Visit : never :: 2010-8-01 @ 01:48 am : Now
?FAQ sSearch mMemberlist uUsergroups
rRegister pProfile "Messages lLog in
View posts : unanswered
Forum Index :: DOSBox Development ::
up MCGA already supported in dosbox
Reply with quote MCGA already supported in dosbox :: 2006-1-09 @ 05:36 pm
zbiggy
Zbigniew Luszpinski
no avatar
Joined: 2004-07-29
Posts: 90
Location: Poland, Pultusk 		It looks MCGA is compatible with VGA so dosbox also supports MCGA. However I did not find any informamtion dosbox supports MCGA. Maybe it could be good to add such informaton to supported harware list?
Post new topicReply to topic
Offline
Reply with quote Re: MCGA already supported in dosbox :: 2006-1-09 @ 07:58 pm
Kippesoep
Met lettertjes!
[avatar]
Joined: 2005-05-04
Posts: 994
Location: Netherlands 		MCGA and VGA are not strictly compatible. MCGA is a subset of VGA (well, almost). VGA's commonly used (for games) resolution of 320x200 in 256 colours is available on MCGA, though. When games have MCGA support, it's usually a version of this mode, so it also works on VGA.
Post new topicReply to topic
Offline
Reply with quote Re: MCGA already supported in dosbox :: 2006-1-09 @ 11:33 pm
vasyl
Oldbie
no avatar
Joined: 2005-03-27
Posts: 680
 In a sense, VGA emulates MCGA. The emulation is so good that I am not even sure if there is anything that can be done on MCGA that wouldn't work on VGA. The opposite is not true -- so popular ModeX won't work on MCGA.
There were not that many real MCGA adapter in existence. PS/2 Model 25 came with one, I think you could get it for Model 30 (option?) at some point but that's about it. I never heard about MCGA clones.
Post new topicReply to topic
Offline
Reply with quote Re: MCGA already supported in dosbox :: 2006-1-10 @ 10:19 am
`Moe`
Barkeeper
[avatar]
Joined: 2004-04-29
Posts: 1180
Location: Oldenburg, Germany 		A friend of mine owned a PS/2 with genuine MCGA. Slow as hell - he played Eye of the Beholder in CGA mode because the game was crawling with MCGA output.

MCGA is somewhere between EGA and VGA - it has 256-color modes from VGA, but not the hi-res 16-color modes from either EGAor VGA. It has CGA compatibility.
Post new topicReply to topic
Offline
Reply with quote Re: MCGA already supported in dosbox :: 2006-1-10 @ 03:49 pm
Servo
Newbie
[avatar]
Joined: 2005-09-28
Posts: 49
Quote:
The emulation is so good that I am not even sure if there is anything that can be done on MCGA that wouldn't work on VGA.
correct, VGA implemented the two MCGA modes identically. Most all early VGA games were really just MCGA. DOSBox doesn't "support" MCGA in that if it was truly in MCGA mode, EGA games would fail, mode x games would fail, and so on...

The PS/2 model 25 and 30 both did indeed come with MCGA, though some later versions of the model 30 switched to VGA.

`Moe` wrote:
A friend of mine owned a PS/2 with genuine MCGA. Slow as hell - he played Eye of the Beholder in CGA mode because the game was crawling with MCGA output.


I also had an MCGA machine; 256 color mode was definitely slower than CGA 4 color (as would be expected), but probably a slow processor was the issue here. (the PS/2 25 and 30 both initially came with 8mhz 8086).
Post new topicReply to topic
Offline
Reply with quote Re: MCGA already supported in dosbox :: 2006-1-11 @ 01:01 pm
jal
Member
[avatar]
Joined: 2004-01-02
Posts: 477
Location: Amersfoort, Netherlands
zbiggy wrote:
It looks MCGA is compatible with VGA so dosbox also supports MCGA. However I did not find any informamtion dosbox supports MCGA. Maybe it could be good to add such informaton to supported harware list?


DOSbox emulates the MCGA emulation of the VGA. So strictly speaking, it's just a side-effect.


JAL
Post new topicReply to topic
Offline
Reply with quote Re: MCGA already supported in dosbox :: 2006-1-11 @ 04:15 pm
Great Hierophant
Oldbie
[avatar]
Joined: 2003-04-27
Posts: 853
 I believe the main differences between VGA and MCGA, when it comes to the modes they have in common is the way they deal with memory. Mode 13h is well-suited to MCGA's linear memory mapping. The VGA uses planar memory, so it must emulate the memory map in hardware.

Also, in another sense DosBox is closer to MCGA than to VGA. The text resolution in DosBox's VGA mode is 640x400, which is what MCGA used (8x16 text box.) Proper VGA used a 720x400 text mode (and a 9x16 text box.)

Quote:
correct, VGA implemented the two MCGA modes identically. Most all early VGA games were really just MCGA. DOSBox doesn't "support" MCGA in that if it was truly in MCGA mode, EGA games would fail, mode x games would fail, and so on...

The PS/2 model 25 and 30 both did indeed come with MCGA, though some later versions of the model 30 switched to VGA.


Originally, the PS/2 Models 25 and 30 came with MCGA and an 8088 @ 8Mhz. However, both were upgraded to VGA and a 80286 @ 10MHz.
Post new topicReply to topic
Offline
Reply with quote Re: MCGA already supported in dosbox :: 2006-1-11 @ 05:50 pm
ih8registrations
Oldbie
no avatar
Joined: 2003-07-25
Posts: 864
 Historical note; model 30 was the first system with MCGA; model 25 came a few months later.
Post new topicReply to topic
Offline
page 1 of 1
All times are GMT
Moderate
Quick Reply & Options
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
Powered by phpBB © 2001-2003 phpBB Group.
vogons and vogons site design and content herein is under a creative commons license 2002-2003 zetafleet.dom.
This site hosts no abandonware. There is no material that is knowingly illegal here.
zetafleet.dom will not be held responsible for users' posts.
This disclaimer is brought to you thanks to the BSA.