Dos (assuming you mean MsDos) can share IRQs perfectly well. The
thing that can't, due to poor design, is the original ISA bus,
which prevents sharing across cards. It is perfectly possible to
design hardware on a single card which uses only one IRQ to handle
multiple channels.
I think I should clarify my comment. My understanding of dos is that
it makes no attempt to manage hardware esp not HW
addresses/assignments. That being said yes devices _can_ share IRQ's
under DOS as long as the drivers are written according to standards
and where a hardware register is used to pass the interrupt
sequentially to the linked drivers until the correct device is
reached. However this is usually not the case esp for very old HW (in
dos/ISA terms) & very new HW where little attention is paid to this
obsolete environment.
RAID cards are generally not intended for their primary use to be in
dos. There are multiple compatibility issues which reflect this.
IRQ's aside in actual use some work perfectly in dos without
additional software or effort, others need a driver or correct aspi
drivers, still others appear to work in dos easily but may have
problems with certain disk utility apps (which altering environment
variables may or may not help). This is also sometimes firmware level
related. Picking a card and asking users for specific experiences
with dos, ghost, etc may go a long way in helping to separate the
wheat from the chaff & ensure the greatest possibility of success.
From what I've seen simply having a PCI card will not guarantee
perfect & optimal operation in native dos - both including and beyond
potential IRQ & BIOS issues.
