Rasterbars in 64 colours in 640x350 sounds nice 😀
A 286 should have no problems with that. An 8088 at 4.77 MHz might show a bit of noise on the left side of the screen if you implement it with polling (even the original CGADEMO suffered from that, and 350 lines require 75% faster processing than 200 lines).
Cycle-counting would work, but is far more difficult, and requires a fixed platform (so only one type of CPU, chipset and EGA card, much like 8088 MPH).

Combining a mod player with time-critical effects like rasterbars is going to be difficult, unless you synchronize the two. Eg, output one sample at every scanline. You have 350 visible scanlines, but also a bunch of invisible ones. CGA/EGA for example has 262 scanlines in 200-line mode, so you'd get 60*262 = ~15.7 KHz if you do a sample per scanline.
In 350 line mode you probably have around 400 total scanlines, so you'd get around 60*400 = 24 KHz that way.

I've been using a Trident TVGA8900C in this bad boy for a while now and while it does a great VGA image and has an excellent CGA mode, I noticed some screen corruption in a couple of games (e.g Double Dragon III, Silpheed). Thinking it must be this particular card I tried a TVGA8900D, Tseng ET4000AX, Cirrus Logic CL-GD5420, and even the original Ahead AVGA Deluxe this machine came with - they all did it! But at the bottom of my ISA stash I found a sad looking Diamond Speedstar 24X which I'd picked up for a few bucks a while back but never tested, because it didn't have a backing plate.

Turns out that it's a gem of a card - crystal clear output with rich colours, no image corruption in any games I've tried, and a very solid CGA mode via a command line util (I happened to have the disks and manual for another WD90C31 based card handy).

I'm very happy with this discovery and it's another nice improvement to this 286. Below are the results of trixter's CGA compatibility tester (http://www.oldskool.org/pc/cgacomp) for this card, and a couple of pics.

1Color Select Register
2   Border/Overscan: OK
3   Med-Res. background: OK
4   Hi-Res. foreground: OK
5   Med-Res. palettes: OK
6
7Textmode Manipulation
8   40-column display: OK
9   Text Mode Hicolor: OK 	
10   Cursor control: OK
11   8x8 font display: OK
12
13M6845 Compatibility
14   Vertical retrace: FAIL (~70Hz where should be 59.9)
15   Horizontal retrace: OK
16   Textmode row reprog: OK
17   Textmode row/col reprog: OK
18   Interlaced video mode: OK
19   Display positioning: FAIL (nothing happens)
20   Start Address reprog: OK

WD90C31 is quite good. It's an overkill for 286 as it has Windows acceleration that only 386+ supports. Regular WD90C30 would be best for 286.

I don't have a 286, but got the Diamond Speedstar 24X as well. Great card, my fastest ISA graphics card, tied with the ET4000 😀

Great card indeed!

kixs wrote:

Regular WD90C30 would be best for 286.

I do have an WD90C30 but unfortunately the image quality isn't acceptable. It might be faulty or just a poor implementation but from time-to-time there's a a fine but annoying 'wobble' to what should be sharp lines, particularly in high contrast situations like white text on a dark blue background. The Speedstar is rock solid though so gets the gig despite not quite being period correct.

This is the second time now I've been impressed by a WDC Paradise based VGA card, the first being the WDC Paradise WD90C33 I use in my VLB 486. I don't remember WDC being a 'hot' VGA chip-set back in the day but maybe they just didn't advertise, more of an OEM thing maybe?

its one of the fastest cards in 320x200 VGA Mode 😀

badmojo wrote:

This is the second time now I've been impressed by a WDC Paradise based VGA card, the first being the WDC Paradise WD90C33 I use in my VLB 486. I don't remember WDC being a 'hot' VGA chip-set back in the day but maybe they just didn't advertise, more of an OEM thing maybe?

In my experience they were considered to be among the best, especially in the early days of VGA clones (I have a PVGA from 1988 in one of my XTs).
When there were video-card reviews in magazines, the Paradise was generally one of the 'benchmarks' to compare others against.
You'd often find them in more high-end/performance-oriented PC clones. Eg, my Commodore 386SX-16 came with a Paradise card as standard. Which is probably no coincidence, given where Commodore came from (C64, Amiga etc). It set its performance apart from the average 386SX-16 clone with a Trident, Oak or Realtek card.
In fact, when I upgraded to a 486DX2-66 a few years later, I bought a motherboard first, and had to save some money to get a good VLB card later. In the meantime I used the Paradise 16-bit ISA card, and it actually performed quite well. Even Doom ran quite acceptably in full screen. Not bad, especially for such an early 16-bit VGA card.

Good to know thanks Scali. My mis-remembering something isn't at all unusual but thinking about it, I only really started reading reviews, etc in the mid to late 90's, before that I just took whatever cast-off hardware I could get my hands on and made the most of it. I'll need to track down some mags from the early 90's and see what I missed out on.

Here's a good starting point: https://books.google.nl/books?id=PA3RA3f6mi0C … epage&q&f=false

Scali wrote:

Here's a good starting point: https://books.google.nl/books?id=PA3RA3f6mi0C … epage&q&f=false

A great read. It's amazing how quickly things developed from from this point onward. In '88 a 286 was a hot machine, "zero wait states" was a notable feature, and an Adlib was your sound option - a music card. In '98 we had mature 3D graphics, positional audio, and CPU clock rates approaching 500MHz.