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There are 6 main meta-data files share between 3 categories.
All of theses file are locked by the kernel when parsing and serializing using the reader/writer algorithm. This ensure the different processes will not read and modify the same ressource at same time.
The 3 shared collection files are processed to build the same browsable HTML index on each servers (see misc).
Local server files: | ||
---|---|---|
• mdtx.conf: | mdtx.conf | |
• supports.txt: | supports.txt | |
Local collection file to index the cache content: | ||
• mdtxCOLL.md5: | mdtx-COLL.md5 | |
Remotely shared collection files: | ||
• catalog.txt: | catalog.txt | |
• extract.txt: | extract.txt | |
• servers.txt: | servers.txt |
Relational schema:
Below entities are all dupplicated for each collection:
File | PUBLISHER | CLIENT | cgi | SERVER |
---|---|---|---|---|
mediatex.conf | rw | rw | r | r |
supports.txt | r | rw | - | r |
md5sums.txt | r | r | - | rw |
catalog.txt | rw | rw | - | - |
extract.txt | rw | rw | - | r |
servers.txt | rw | rw | r | r |
diseased
data remains on disk (file is up to date)
loaded
the file is loaded into memory
modified
changes on data only remains in memory
load
from <diseased> to <loaded>:
a Process tells it needs the file to be load
modify
from <loaded> to <modified>:
a Process tells it has modified the data
save
from <modified> to <loaded>:
an ACTIVITY saves all modifications on disk
free
from <loaded> to <diseased>:
an ACTIVITY ends or will reload the data
diseased
data remains on disk (file is up to date)
loaded
the file is loaded into memory
modified
changes on data remains in memory
load (n+=1)
from <diseased> to <loaded> if n==0 or
from <inUse> to <inUse> if n>0
a Process tells it needs the file to be load
release (n-=1)
from <inUse> to <inUse>:
a Process tells it no more need the file
modify
from <loaded> to <modified>:
a Process tells it has modified the data
save
from <modified> to <loaded> if n==0:
an ACTIVITY saves all modifications on disk
disease
from <loaded> to <diseased> if n==0:
an ACTIVITY that needs place on memory unloads the data
Code:
Next: Conceptual model, Previous: Invoking Mediatex, Up: Top [Contents][Index]