We are doing a research project about implement dual cpu near-fault-tolerance
. The situation is roughly described as following:
X.25 ---| |-------------HP9000/700 ----------|
| BOX |------------| |
RS232---|_______| Line2 | SHARE MEMORY |------Disk Array
Sorry for the awkward drawing. Basically, we want to get data from X.25
and RS232, through the "BOX" to split the data souces to both two HP9000/700
board. (that means line 1 & 2 has idental data, and HP9000/700 is a board
with CPU, two HP9000/700 and one share mem all access to same VME bus).
The two HP9000/700 will be master/slave modle, althought both get datas,
only master HP9000/700 can write to Disk Array. If master HP9000/700 is crash
, the slave HP9000/700 will take over the action continue write data to
Disk Array. (before crash, both HP9000/700 are active). The two HP boards
can use their own local memory or use share memory.
What we need help is how to write a program using the share memory to
do the switch-over. (so far, two conditions need to switch over, line1 or
line 2 is disconnected, or, master HP9000/700 crash).
Our first idea about this program is a daemon keep on checking the
connection status of line1&2, and status of master HP board, writting flag
to share memory, another daemon check this flag to determine whether
switch over or not.
We are looking for any source codes, hints, suggestions. No commercial
products please, our dspartment doesn't has the budget, we even make
the "BOX" by ourselves.
Please E-mail me directly, thanks in advance.