| Title: | ase |
| Moderator: | SMURF::GROSSO |
| Created: | Thu Jul 29 1993 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2114 |
| Total number of notes: | 7347 |
Hi:
Perhaps this can be a naive question.
In all books about memory channel functionality said literaly:
"Cluster member systems communicate over the MC via write-only
transactions.The systems reserve from 128 to 512Mbytes of pci I/O bus
address space for transmitting data to the pci Mc adapter,and a
separate 128 to 512Mbytes of bus address space for receiving data"
My questions is:
Is there any piece of physical memory reserved ONLY for MEMORY CHANNEL
transactions?
Thank you
Txemi
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 2057.1 | COMICS::CORNEJ | What's an Architect? | Wed May 14 1997 08:44 | 6 | |
Well, there is no physical memory in the MC hardware (buffers aside),
so it must be physical memory in the hosts. It is not a block of
"shared memory" as such though.
Jc
| |||||
| 2057.2 | Correct. | NNTPD::"cherkus@buff.zk3.dec.com" | Dave Cherkus | Wed May 14 1997 13:13 | 9 |
Every host creates a 128 MB transmit region in PCI space. The receive memory comes from the host. It is only allocated as needed, so there is no waste of memory. The dma scatter gather table is programmed with the proper information so that data written from the memory channel ends up in the right page of physical memory. Dave [Posted by WWW Notes gateway] | |||||