22 Nov
2007
22 Nov
'07
5:10 p.m.
ons 2007-11-21 klockan 12:00 -0600 skrev "John A.
Dundas III"
<dundas at caltech.edu>:
Yes, shared regions (libraries and others) are supported. However as a
general purpose timesharing system, RSTS insisted on direct access of the
I/O page only by the kernel.
So while it _might_ be possible to peek/poke a device CSR from user space
(I never had occasion to try but could imagine a few possible approaches),
it would not be possible to set up, e.g., an interrupt vector in user
space.
John
Jerome,
I can speak for RSTS with some authority, RSX with somewhat less
authority.
At 9:17 PM -0500 11/20/07, Jerome H. Fine wrote:
I thought RSTS/E had some way of remapping the address space as well.
Can't you remap parts of your memory to some shared region, for example? I doubt that RSX-11 or RSTS/E allow a user access
to the IOPAGE
even via PREVIOUS DATA space. Can anyone confirm this assumption?
Address space in the I/O page for RSTS jobs (processes) was not
directly available. The APRs are always controlled by the OS. It
MIGHT be possible for a privileged job to use PEEK/POKE SYS calls to
access the I/O page in the way you suggest but it would be
particularly difficult.