Editing NetWare (section)

=== File service instead of disk service ===
When first developed, nearly all LAN storage was based on the disk server model. This meant that if a client computer wanted to read a particular block from a particular file it would have to issue the following requests across the relatively slow LAN:

# Read first block of directory
# Continue reading subsequent directory blocks until the directory block containing the information on the desired file was found, could be many directory blocks
# Read through multiple file entry blocks until the block containing the location of the desired file block was found, could be many directory blocks
# Read the desired data block
NetWare, since it was based on a file service model, interacted with the client at the file API level:
# Send file open request (if this hadn't already been done)
# Send a request for the desired data from the file
All of the work of searching the directory to figure out where the desired data was physically located on the disk was performed at high speed locally on the server.
By the mid-1980s, most NOS products had shifted from the disk service to the file service model. Today, the disk service model is making a comeback, see [[Storage area network|SAN]].