Write(x)
DSM + OS coop x -> twin, original writable
Write project after release Twin, X’ diff run length
Non-page-based DSM
shared r/w -> dsm software -> <-data
library-based
-annotate shared variables
-coherence achons
inserted at point of access
API calls lang runtime
structured DSM
-APU for struct
-coherence action on app calls
DSM and speedup
LAN - DSM library - p -> mem
First NFS
-SUN, 1985
Client, LAN, Servers(student), file cache
DFS
no central server
-each file distributed across several nodes
DFS implemented across all disks in the network
Preliminaries: Striping a file to multiple disks
-increase I/O bandwidth by striping to parallel disks
-Failure protection by ECC
Log Structured File System
– Buffer changes to multiple files in one contiguous log segment data structure
– log segment to disk once a file up or periodically solves small write program
mods to x, mods to y, log segment written the disk
Eebra File System(uc-berkeley)
-combines LFS + RAID
use commodity hardware
-stripe by segment on multiple nodes’ disks in software
xFS – a DFS
-log based striping, cooperative caching, dynamic manageent of data, subsetting storage servers, distributed log cleaning
Traditional NFS with centralized server(s)
– memory content
* metadata, file cache, client caching divectory
