Did you know? Bridgeboards can run ext roms from amiga side

[fgh]

Hi there, any Bridge board users here?

Did you know you can load BIOS extensions like XTIDE Universal Bios, SCSI boot roms, etc from the amiga side?

The file pc.boot (or pc.boot.2386sx) is the Janus BIOS extension.

If you don’t need Janus, just replace the Janus file with your rom.
If you want Janus, join the two files together (on 8kb limits), and both will load.

I’m even booting off the IDE port on my Plug and Play AWE64, by using a modded XTIDE rom that initialize the card. (which was never intended to be bootable, as PnP cards are initialized from autoexec.bat)

It’s well known that you can run BIOS extensions from the ROM socket of network cards, etc, but this is easier.

XTIDE Universal Bios is quite nice, with unlimited drive capacity and great compatibility, and the ability to boot from IDE 2/3/4 addresses like used on sound cards

Perhaps this could save you an ISA slot, so you can do silly things like in the image attachment? (AWE64+Gravis Ultrasound+VGA)

[Calabazam]

I'm flabbergasted to read this! Amazing!
Could you share your rom file so i can give it a try on my A2386?
Or explain how you aggregate the ROM?

[fgh]

You can download XTIDE Universal BIOS from their website:
www.xtideuniversalbios.org

The regular 386 version should work, and be the fastest option. [EDIT: 386 version confuses the bios, use 286 aka AT version instead!)
You have to run xtidecfg.com to configure it (it will save it with exactly 8kb length and required checksum)

With an a2386sx just replace pc.boot.2386sx with the prepared xtide rom, or rename it to say ‘janus.bin’ and then do ‘join janus.bin ide_at.bin as pc.boot.2386sx’ in amiga shell. (original pc.boot.2386sx is 16kb so no padding required)

By the way:
I found that you need to use D000 address and turn BIOS shadowing ON in PCPrefs for this to work. (Edit: D000 is probably required already with a VGA card, as that ROM usually occupies A000)
On A2386sx, the file pc.boot is not used but it still fails if you delete it. (Having a 0 byte file named pc.boot works..)

It’s possible that XTIDE can interfere with Janus, depending on how you configure it. I’ve read some people had trouble but for me it worked fine at least.

Oh, and that’s a Gravis Ultrasound in the middle there. I should hook up the MT32 as well for a really silly bridgeboard config

Edit: I’m on a work trip and didn’t bring the files but you can figure it out I’m sure.

[Calabazam]

Thanks. Will give it a try.
I don't have an IDE port on my soundcard as it is the very modern MK8330 from Keropi/Mames but will try it another way.

[slaapliedje]

I keep thinking ai need to find my SBC and put it into my towerized Amiga with some ISA cards, though being able to bridge it to run AmigaOS at the same time would be phenomenal, I wouldn't think that would be possible, right? Though I do have an Emplant...

[fgh]

ISA SBC cards work fine if they fit. (they are often very low in front of the ISA connector, and might interfere with amiga motherboard components and zorro slots.

Usability would not be more integrated than a standalone pc though.

[fgh]

I was a bit disappointed by the speed of my CF card in this setup, at ~400kB/s.

Turns out the Bridgeboard BIOS has shadow RAM features for the BIOS and VGA but not for extension ROMs.
So I went looking for third party shadow RAM software without luck, until a friendly soul at vogons.org told me it’s right there under my nose - EMM386 can do RAM shadowing!

My XT-IDE ROM is 8KB and landed at D800h, so I ended up with this setup:
EMM386.exe RAM ROM=D800-D9FF, and now I get ~1800KB/s from my soundblaster IDE. (Edit: 2,6MB/s with the newer version, see below)

[fgh]

Another discovery (from an a1k user): The mouse driver ‘amouse.com’ often fails to load, but starts working if you disable the ‘stacks swapping’ feature of ms dos by putting stacks=0,0 in config.sys.

(This degrades stack handling to simple DOS <=3.1 method though so may introduce stack overflow problems, etc)

[fgh]

For anyone interested, I've attached the merged Janus + XT-IDE file I'm using now. (For A2386sx)

I bought a non-PNP sound card with IDE, so now I can use the current version (r625) instead of the older hacked PNP version I was using before with the PNP sound card.

It's also the 'AT' build of XT-IDE, instead of XT before, and it's set to boot from secondary IDE (170h address).

And it's a bit faster than the older XT build I was using - getting 2,6MB/s now