Subject: [FreeVMS] Re: New release 0.0.14
Date: Tue May 07 2002 - 11:32:51 CEST
On Mon, May 06, 2002 at 08:40:46PM -0400, Glenn and Mary Everhart wrote:
> Where DMA is done, VMS resolves process space during FDT processing
> to get it into addresses that can be used from kernel mode. Drivers
> may go further if there are additional adapters.
> For buffered I/O (mainly terminal I/O) there is a kernel buffer
> in nonpaged pool allocated when you start that can get freed when
> i/o posting is done. Copying from process space occurs during fdt
> time. Copying to process space occurs during the final special
> kernel AST, same time as the IOSB gets filled in.
> Hope this helps.
I see it in the Internals, but then it is the matter of using it.
Getting nonpaged buffers for buffered I/O may be done with kmalloc (or even
vmalloc), but with direct I/O the irp$l_svapte shall contain the system
virtual address of the first pte that maps the buffer.
The address of that pte is gotten with mmg$svaptechk, but I have not got
that routine or know what it's equivalent is.
Maybe buffered I/O could be used until we get Memory Management going.
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