aitotat and jakethompson1, thank you for this clarification. So...
XTIDE address + a 4-bit left-shift = MB's BIOS address, where the XTIDE address is referred to as the "segment register" and the MB's BIOS address is referred to as the "x86 real mode address". Is this right?
To me, a 4-bit left shift from a shift register might be easier observed like:
C800h = 1100100000000000, left shift 4 bits = 11001000000000000000 = C8000h , which is 20-bits.
C800h = 51200 * 16 = 819200 = C8000h. I cannot really visualise HEX multiplication.
Your example of C800 + 3FFF = CBFFF had me confused because those two hex numbers when added equal 107FF, not CBFFF. I think you meant C8000 + 3FFF = CBFFF.
The r614 ide_386l BIOS is 10119 bytes in size, which is 2787h. Thus the MB's shadow ROM range needs to be C8000 + 2787 - 1 = CA786 in hex, which easily fits. It looks like each shadow range region can accommodate 16 Kbyte ROMs. So for fitting the shadow range, it only matters the amount of data inside the EEPROM, not the EEPROM size used? If I use a 32 Kbyte EEPROM on a 3c515tx ISA card, I still only need to shadow 10119 bytes, not C8000-CBFFF and CC000-CFFF, right?
I will try it on C8000 instead of D0000. Your comment on continuous unused UMB locations does feel cleaner.
What is this 32 GB limitation for Win95 that you are referring to? I am using Windows 95 OSR 2.5 and have not had any issues with 100 GB partitions. Maybe the limitation you are referring to is with Windows 95a?
I currently have the system setup with a 120 GB Maxtor Diamond Max 10 going through a Promise Ultra100 PCI IDE controller. In order to free up that PCI slot, I am switching to using the MB's onboard IDE controller. I don't want to format my Maxtor HDD and reinstall all my software, which is what I would have to do if I wasn't using the XTIDE BIOS because the MB's BIOS is limited to 8 GB, or 32 GB if I want to give up my existing partitioning. With XTIDE loaded, I am able to boot that same 120 GB maxtor IDE HDD using the MB's onboard IDE controller and I don't have to reinstall everything. The existing LBA translation scheme seems to work once XTIDE is loaded.
I have Win95c installed on several machines, usually along side NT4 or NT 3.5 and all my HDDs are 120 GB.