I'm having trouble with google searches finding the real differences between AVE and BVE. Will a BVE card fit in an AVE slot? What are the differences between the slots?
Also, any idea why IBM chose to make the AVE slots 16-bit on 32-bit systems like the Model 70 and 80? Seems like a curious decision.
So you could take an XGA-2 and put it in a 32-bit MCA non-AVE slot? Some search results say the onboard VGA will be disabled if there is no monitor attached, but wouldn't the XGA/XGA-2's VGA emulation (assuming it has one?) interfere with it, or are they compatible, and if so, how does the BIOS decide which to initialize for the console?
Can I put an XGA/XGA-2 in a 55SX at all?
Auxiliary Video Extension on the Ardent Tool. A BVE card will NOT fit into an AVE slot. -BUT- it will work just fine in a normal 32-bit slot with the little video extension hanging free.
Why is AVE on a 386 bit system on a 16-bit slot? Uh, you are pumping the raw, screaming power of 256 color VGA over the AVE, which has -EIGHT- data lines. IBM decided that the Auxiliary Video Extension would provide Base Video [on-board VGA in most cases] to "accelerator" cards like the 8514/A.
XGA-2 in 8590 / 9590 answers XGA-2 in a 32-bit slot without a BVE extension slot. In short, yes you can.
As to running a planar VGA w/o monitor while running an XGA/XGA-NI adapter with a monitor, or running two monitors [VGA and XGA] that is a bit more complex. You can't run XGA / XGA-NI inserted into a Auxiliary Video slot on a system that has on-board VGA. There are no systems that would physically allow this.
In this case, both the XGA and XGA-NI ["XGA-2" for mere commoners] do not use the Auxiliary Video extension. I have run an XGA-2 in a Model 90, and it just works. Fun fact, the Model 9590 is just a Model 8590 with an XGA-2 card added.
So, let's look at
Announcement Letter Number 192-228 for the XGA-NI
To quote from the Holy Text:
"MACHINE REQUIREMENTS:
System Units Supported -- The IBM PS/2 XGA-2 Display Adapter/A can be installed in any Micro Channel (R) Architecture PS/2 386, 386SX, 386SLC (TM), 486SX, 486 or higher IBM PS/2 system unit. Supported systems include IBM Personal System/2 Model 55 SX and SLC"
Further:
"The XGA-2 Display Adapter/A can be installed in either a 16-bit or 32-bit Micro Channel connector that does not have an auxiliary video extension (AVEC). Up to eight XGA-2 display adapters may be installed in a system unit. XGA-2 Display Adapter/A can
coexist with the following video subsystems:
o VGA on a PS/2 planar.
o XGA chipset on a PS/2 planar.
o XGA-2 chipset on a PS/2 planar.
o Adapters that utilize the AVEC."
Caveat: While the XGA-NI on-board VRAM will be accessed by the XGA-NI controller in 32-bit mode, communication or memory accesses to the 55SX system will be 16-bit only. Bet you saw that coming...
