File System Interface

The File System Interface (FSI) is a system to organize and track files and provide a parallel access to multiple disks.

NOTE	FSI is a somewhat ambiguous term as it refers to both a file system and the interface to that file system. Be aware that the FSI file system is a standalone file system that does not require the D3 VME. The FSI file system does not provide access to VME files if the D3 VME is present.

Some of the differences between the Virtual Machine Environment (VME) and File System Interface (FSI) are:

VME

Set of resources obtained from Windows or UNIX at initialization that display the functions and characteristics of a D3 computer system, and are shared by several D3 processes. For example, a real machine (the Windows or UNIX-based operating system) emulates a virtual machine (the D3 computer system), which then has disk space, tape drives, printers, terminals, users, and the D3 file system and language.
Only one virtual machine can exist on any given single hardware platform.
Subsystem of D3 Windows that provides an ASCII mode that is backwards compatible with previous Rocket applications.
D3 Windows VME is required in order to start and run the FSI. It acts as the front-end to the FSI.
idn correlative in VME can start from 0 (for example, id0).
The list-lockq command is supported for VME locks.

FSI

Server is a multithreaded process that can service several clients requests.
Process is more reliable because the files are distinct objects on the network, locks and disk space are handled independently of other files which limits risks.
Server also centralizes the record locks associated with the tables it manages.
idn correlative must start from 1 (for example, id1). id0 in the FSI is ignored.
The list-lockq command is not supported for FSI locks.

These topics are presented: