🚀 go-pugleaf

Does anyone have any experience with user-written drivers on the Alpha?

I am hearing conflicting information on the availability of documentation
for user written drivers, and hope that someone in this news group can clarify
the situation.

A specific concern for me is porting my home grown pseudodriver. On VAX/VMS,
this driver processes a series of QIO's from application programs,
originally written to control a CAMAC serial highway driver. For compatibility
with existing systems, these applications cannot be rewritten. The QIO's
come down from the application specifying (in p1-p6) three buffers in 
user space. The driver locks these pages in memory, using the usual
exe$write/read/modify routines, and then passes the request off to a
user-written ACP using EXE$QIOACPPKT.
The ACP interprets the information (in this case, generating network requests
to uVAXIII systems running VAX/ELN), returns information and status into the
buffers in the requesting user process, and then completes the request
using COM$POST.

So this driver/ACP combination is relatively simple (no hardware access, except
via supported network drivers), but it _does_ do some things which I would have
thought would require some (possibly extensive) code changes when running on
the Alpha.

For example, the ACP uses system page table entries to map the original
user request.

Anyone done such a thing, or know about available documentation?

Thanks

Tony Cox, Stanford,CA
TCOX@SSRL01.SLAC.STANFORD.EDU(INet)	SSRL01::TCOX (HEPNet)
TCOX@SSRL750 (BitNet)