mdj wrote:
On Jun 21, 2:18 pm, Polymorph <polymorp...@hotmail.com> wrote:On Jun 21, 2:00 pm, mdj <mdj....@gmail.com> wrote:On Jun 20, 7:46 pm, Linards Ticmanis <ticma...@gmx.de> wrote:Polymorph wrote:I don't have a //c or //c+, but that image that Bill posted works fine on my ROM03 IIgs, so there must be some incompatibility specific to the //c+ (maybe even the //c?). Do you have problems with any other programs/games on your //c+?Hmmmm... are there any Soft Switches or hardware registers peculiar to the //c+ ? Mabye one of them gets hit by accident in this game?Or maybe this has to do with interrupts? Interrupts normally occur in a //c but not in a //e, right?I can confirm choplifter works just fine on a ROM04 //c, which pretty close to a IIc+. Since interrupts are probably disabled during the game anyway, I'd imagine it's some incompatibility with the accelerator hardware. I assume you guys are testing this with the accelerator disabled ?This is going to one of those problems where finding the culprit is a bit like looking for a tiny piece of hay in a massive stackful of needles. The solution once it's found, is probably trivial.MattMatt, I ran Choplifter on my ROM03 IIgs with a Zip GSX installed - but with the control panel speed set to "normal" (ie. 1Mhz). I don't know if this has any relevance to the //c+ though? I thought it might, as isn't the //c+ accelerated by an onboard ZIP chip? I can try running it with the Zip GSX enabled, however, it will be pretty freaky trying to play the game running at 8Mhz. ;-)Yeah - the IIc+ has the equvalent of a 4Mhz Zip Chip installed, but it's implemented with a 4Mhz 65C02, ASIC, and seperate SRAMs for the cache. Apparently Apple believed that the integrated chip as shipped by Zip would be unreliable. Since I've had one die on me, I tend to think they may have had a point.
Actually, the Zip Chip is just a multi-chip package consisting of exactly a 65C02, a crystal oscillator, an ASIC, and two SRAMs. Apple just didn't trust Zip (or Zip's supplier) to manufacture the potted multi-chip module in sufficient quantities and with sufficient reliability. Zip did choose SRAMs for some of their manufacturing runs that became unreliable after a few months. Apple was much more particular about qualifying its suppliers. Or maybe the problem was just the manufacturing process--overheating during manufacture, residual flux inside the potting material, etc.... Since Apple had board space, they took the easy way and put the separate chips on the board instead of into a multi-chip package.
Unless there's an errata list for known Zip anomolies, it seems doubtful. I know that Publish It! used to trigger a Zip bug, and later Zip's were modified to work around it.
I have encountered very few programs that behaved differently with a Zip Chip, but then I don't run a large variety of programs. ;-) One whose "menu" misbehaved was IIGIF, for reasons that I never got to the bottom of. -michael NadaNet file server for Apple II computers! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it's seriously underused."