OPERATION
Copyright 2007
5-2
S SC150e HARDWARE REFERENCE
NOTE
: Virtual paging does not affect host access to shared memory. Virtual Paging
only changes the network address. The HOST-SPECIFIC logic always sees the base
address of S SC150e shared memory as zero.
If the 4 MB block were paged into the upper 4 MB, a host-specific write to a shared-
memory address of 2 MB would result in a network address of 6 MB. This translation is
bi-directional. An incoming network message with a network address of 6 MB will be
written to shared memory at 2 MB. Any write accesses to the lower 4 MB will be ignored
since there is no memory addressed there.
4MB
6MB
8MB
0
2MB
Node 1
Node 3
Node 5
Node 7
Node 9
Node 2
Node 4
Node 6
Node 8
4MB
4MB
2MB
2MB
2MB
2MB
1MB
1MB
8MB
Network
Address
7MB
5MB
3MB
1MB
Figure 5-1 Memory Sharing With Virtual Paging
To produce a network address, the host write adds the relative S SC150e
address and virtual page offset.
Relative a Virtual page offset = Network address
For example: 12340 + 400000 = 412340
This network address is transmitted to all S SC150e nodes and is written to
that address. In nodes where the address does not exist in S SC150e memory,
the write is ignored.
The example in Figure 5-1 shows the memory-sharing relationships between various
nodes in the virtual-paging mode. Node 1 shares data with nodes 3, 4, 8, and 9. Node 2
shares data with nodes 5, 6, 7, and 9. Node 8 shares data with nodes 1,3, and 9. Node 7
shares data with nodes 2, 5, and 9. Node 9 shares data with all nodes.
Summary of Contents for SCRAMNet+ SC150e
Page 2: ......
Page 79: ...OPERATION Copyright 2007 5 29 SCRAMNet SC150e HARDWARE REFERENCE Figure 5 10 Quad Switch ...
Page 82: ......
Page 94: ......
Page 108: ......
Page 121: ...D D CONFIGURATION AIDS APPENDIX D CONFIGURATION AIDS ...
Page 122: ......
Page 127: ...1 GLOSSARY GLOSSARY ...
Page 128: ......
Page 135: ...1 INDEX INDEX ...
Page 136: ......