SuperMac ColorCard SE/30 strangeness

[bigmessowires]

I've recently acquired a SuperMac ColorCard for my SE/30. One of the quirks of this card is that it displays a monitor selection GUI on the internal monitor after the "Wecome to Macintosh" appears, presumably using some code in the card's ROM. This behavior only works when booting System 6 and causes System 7 to hang, but if you boot in System 6 and make a monitor selection, it will be saved in PRAM and then you can boot with System 7 next time.

The strangeness is that the external monitor sometimes simply mirrors the internal display instead of extending the desktop area, and it does it in a broken sort of way that seems like a bug. The Monitors control panel shows that I have two monitors with different physical sizes, but the content is mirrored between both instead of creating an expanded desktop. The external monitor is 640x480 and it shows the 512x342 internal monitor contents in the top-left corner with empty space to the right and below. It also appears to be running the internal display in color mode, so some items like the close box in the window title bar become invisible. The mouse cursor can't be moved between the monitors, and only appears on the external.





I've narrowed down the mirroring problem a little bit. It may be caused by using a locked startup disk like a ROM disk. Or it might be related to using a ROM-inator, or to the specific version of System 7 used.

• SE/30 with ROM-inator, booting System 7.1.1 from the hard disk: Color Card works normally
  
  
• SE/30 with ROM-inator, booting System 7.1 from the ROM-disk in RAM-disk mode (press A while booting): Color Card always starts out disabled and must be enabled by opening and closing the Monitors control panel. After that it displays normally until the next reboot.
  
  
• SE/30 with ROM-inator, booting System 7.1 from the ROM-disk in read-only mode (press R while booting): Color Card always starts out disabled and must be enabled by opening and closing the Monitors control panel. After that it displays a mirrored image as shown in the photos, and the internal display tries to draw in color mode.

I read elsewhere that it might be possible to upgrade this card's ROM to a SuperMac Spectrum ROM, which would unlock more video resolutions and maybe also fix this? As it stands now, it's not really usable with a ROM-inator.

 

[bigmessowires]

I'm speculating that some monitor setup info needs to be written to the startup disk, instead of saved in PRAM. When the info can't be written (read-only disk), the SuperMac card gets confused and exhibits the broken mirroring behavior. When the info is written to a RAM disk, it works temporarily but settings are lost after a reboot. When the info is written to a traditional disk, then it works OK. It was my understanding that monitor setup info was stored in PRAM though, not on disk. Anybody want to hazard a guess where this info might be saved on disk, so I could find it and examine it?

 

[cheesestraws]

Anybody want to hazard a guess where this info might be saved on disk, so I could find it and examine it?

Some of it is stored in 'scrn' resources in the System file.

 

[Phipli]

I'm speculating that some monitor setup info needs to be written to the startup disk, instead of saved in PRAM. When the info can't be written (read-only disk), the SuperMac card gets confused and exhibits the broken mirroring behavior. When the info is written to a RAM disk, it works temporarily but settings are lost after a reboot. When the info is written to a traditional disk, then it works OK. It was my understanding that monitor setup info was stored in PRAM though, not on disk. Anybody want to hazard a guess where this info might be saved on disk, so I could find it and examine it?

I believe that System 7 support with these wasn't great.

Have you installed the SuperMac control panel? Best to use the older (pre version 3) one.

Drivers for SuperMac video cards (mostly NuBus) - Macintosh Garden

This stuffed file includes an installer and various versions of the SuperVideo control panel, SuperPower extension, manuals and other bits and pieces. It allows one to configure the various SuperMac graphics cards. I have a SuperMac Thunder/24 in my IIfx at the moment. This file runs contrary to...

macintoshgarden.org

I've heard there was a bug where these cards would lose their PRAM settings. They never sold many.

 

[bigmessowires]

I have not yet tried the control panel, but I will soon. If monitor settings are stored in the System file, I'm hoping I can make a new ROM disk with a custom System file that has monitor settings already applied.

 

[bigmessowires]

I think I have this figured out. It's exactly as I said - enabling or changing the external monitor settings requires a writable startup disk, and you'll get weird behavior if you boot from a ROM disk. But the next time you boot from a standard disk everything is OK, and the old monitor settings are reapplied.

I think it's best not to include a modified System file on the ROM disk as I'd proposed. Though it might work, I couldn't ever change those settings and it might create a lot of problems and confusion in the future if I tried to use that ROM disk when the external monitor or the SuperMac ColorCard weren't present. If I keep it this way, then booting from the ROM disk will always revert to stock settings with the internal SE/30 video, which is the safest option. If I really need the external monitor while booting from ROM disk, I can press 'A' to boot with a temporary RAM disk and then configure the external monitor in the control panel. The only thing I can't do that way is use the external monitor as a primary monitor while booting from ROM disk, because that requires a restart, and then the temporary RAM disk's changes are lost.

1024x768 at 16 colors works, but the image isn't entirely stable on my Dell monitor. I suspect the sync timings are a bit non-standard. The experience of using a 1024x768 monitor and the 512x384 built-in monitor in a dual monitor setup is also a little awkward, due to the huge difference in sizes. I think I'll just stay at 640x480 at 256 colors and be happy with it. In which case there's really no need for me to experiment with alternate ROMs.

At 640x480 it's a composite sync only output like the Mac IIci and IIsi. So it will benefit from my sync-splitting Mac-to-VGA adapter, assuming I ever finish building that. It works on my Dell 2001FP but none of my other monitors.

The SuperVideo control panel works, but doesn't really offer anything that I need if I plan to stay in 640x480 resolution.

So far I've not had any problems with the card losing its PRAM settings. After setting the resolution in that strange boot-time GUI once yesterday, I've powered-down and rebooted many times, running from a mix of System 7 and System 6 disks, ROM disks, floppies, HD20, etc. I also screwed around in SuperVideo and experimented with all the versions from 2.07 to 3.1 without problems. So far, so good.

 

[Phipli]

1024x768 at 16 colors works, but the image isn't entirely stable on my Dell monitor. I suspect the sync timings are a bit non-standard.

Have you ran auto adjust? I assume so, but as long as the clock is stable, that should stabilise most images? Confuse if it doesn't.

 

[bigmessowires]

I have. At 1024x768 the picture is essentially stable, but then every so often it jumps or a black bar appears for an instant. No problems at 640x480. If it's not sync, it might be an issue cabling or power or something else. I'm not going to worry about it for now.