PC-98 – Window Accelerators « modelrail.otenko

11Apr/240

PC-98 – Window Accelerators

Thanks to the complexity of Kanji characters, early Japanese 'DOS' machines needed high-resolution text displays. This requirement resulted in the PC-98's 640x400 standard console mode. The video cards to run this were purposely-built and were never really meant to run Windows.

Due to these limitations, companies started coming out with "Window Accelerators" which provided a secondary video device, of which could produce much higher resolutions at higher colour depths. I happened to get my hands on an IO-DATA GA-1280A-2, capable of 1280x1024 @ 256 colours.

Being a secondary video device, these cards require a passthrough cable from the primary machine video output to their 'input' port. When the machine is displaying standard PC-98 graphics, accelerators will route this output straight to the monitor. Once the card is initialised, you'll hear the internal relays 'click' and video will be displayed from the card's internal ram buffer, which specific software is now sending the graphical data to.

Unfortuantely, my specimen came as-is with no cable... so a trip was made to Jaycar for a male and female set of ribbon-crimp IDC 15-pin plugs.

The card was mounted in the machine and the wiring was hooked up...

With no drivers, the card will just pass the standard video through. This is what happened until I installed the drivers for DOS and Windows 3.1. And then? Reboot... a beautiful "CLICK" from the relay on the card and...

Windows 3.1 at a ridiculous resolution.

Does it play Doom?

By default, a PC-9801 can't play doom with it's in-built EGC video card. The settings only give you the following options:

And yeah, GA-1280* is there and it works perfectly.. not even needing other drivers! Well. It runs terribly on the PC-9801VX, even with the 486 Upgrade. The shots above were taken with the card installed in my newly-acquired FC-9801K with 486-Overdrive processor and Doom runs nicely!