EXT/[23], Reiser, Joliet, FAT32, HPFS..

EXT/2 Filesystem:


Second Extended File System - by Dave Poirier


"This book is intended as an introduction and guide to the Second Extended File System, also known as Ext2. Trying to implement ext2 drivers isn't always an easy task, the most difficult issue is unfortunately the documentation available. It seems like most of the documentation on the net about the internal layout of Ext2 was written to complement the Linux sources rather than be a complete document by themselves."

The Extended-2 Filesystem Overview - by Gadi Oxman


This explains how the EXT/2 filesystem is implemented under Linux. It also explains a little about the linux installable filesystem system.

Design and Implementation of the EXT/2 Filesystem - by Rémy Card


"In this paper, we describe the history of Linux filesystems. We briefly introduce the fundamental concepts implemented in Unix filesystems. We present the implementation of the Virtual File System layer in Linux and we detail the Second Extended File System kernel code and user mode tools. Last, we present performance measurements made on Linux and BSD filesystems and we conclude with the current status of Ext2fs and the future directions."

Analysis of the Ext2fs structure - by Louis-Dominique Dubeau


This document describes the ext2 filesystem (which is the defacto linux standard fs), and contains an analysis of the structure of the Second Extended File System and is based on a study of the Linux kernel source files. Some insight is provided into the design and origin of the FS.

David Robins ext2fs page - by David Robins


David's page is quite interesting, because it provides some nice source code to take apart the ext2 file system. His page focuses on the efforts that he went through to repair a partition of his...

StegFS: A Steganographic File System for Linux - by Andrew D. McDonald and Markus G. Kuhn


"Cryptographic file systems provide little protection against legal or illegal instruments that force the owner of data to release decryption keys for stored data once the presence of encrypted data on an inspected computer has been established. We are interested in how cryptographic file systems can be extended to provide additional protection for such a scenario and we have extended the standard Linux file system (Ext2fs) with a plausible-deniability encryption function. Even though it is obvious that our computer has harddisk encryption software installed and might contain some encrypted data, an inspector will not be able to determine whether we have revealed the access keys to all security levels or only those to a few selected ones. We describe the design of our freely available implementation of this steganographic file system and discuss its security and performance characteristics."

EXT2 Futures - by Theodore Ts'o


These slides focus specifically on the EXT/2 filesystem, talking about its evolution, philosophy, planned new features, and relation to other linux filesystems.

FAT/VFAT/FAT32 Filesystem:


FAT: General Overview of On-Disk Structure - by Microsoft


It seems that Microsoft was fed up with all the bits and pieces of documentation laying around on its FAT filesystem. This document seems to clear up the major problems. It does a thorough job describing the FAT12, FAT16, & FAT32 filesystems.

Long File Name Specification - by Microsoft


Again it seems that enough was not enough. Microsoft has finally provided a decent spec for their long file name mess.

Notes on the structure of the VFAT Filesystem - by Galen C. Hunt


This is a useful snippet of information regarding the VFAT system used by Microsoft in Win '95 and NT. It details how long filenames work and all of the other stuff that make it useful. This info came from the Linux kernel distribution v2.0.27.

FAT Filesystem Info - by Inbar Raz


A short document that describes the FAT filesystem.

Long Filename Structure in Windows 95 - by Jeff Prosise, PC Magazine


PC Magazine article (June 25, 1996). Fairly comprehensive description of what is happening behind the scenes, and how long filenames are made out of 8.3 names...

More Long Filenames... - by Kyle Anthony York


This doc is a post to comp.os.msdos.programmer that explains a little more about long filenames...

How does Windows 95 stores Long Filenames? - by Jozsef Hidasi


A short document that describes a little about how Microsoft implemented Long Filenames with the FAT filesystem.

HPFS FileSystem:


Inside the High Performance File System


A series of six articles on the HPFS... covers the structures in very nice detail.

"Design goals and implementation of the new High Performance File System" - by Roy Duncan


An article originally published in Microsoft Systems Journal by Roy Duncan. This is one of the few published documents about the HPFS. This was written before the IBM/Microsoft unrest.

CD-ROM Filesystems:


ISO-9660 CD-ROM filesystem specification (ECMA-119) - by ECMA


This is the official specification for the ISO-9660 CD-ROM filesystem.

Introduction to ISO 9660 - by Disc Manufacturing Inc


This is an excellent document that describes just about everything you'd want to know about ISO 9660. It describes the file system layout, different implementations of the file system (DOS, Mac, unix), and extensions to the file format (Apple extensions and the Rock Ridge extensions). Overall, a must have, especially if you don't have the official (non free) spec.

Joliet CD-ROM Specification - by ISO


"While the CD-ROM media provides for cost-effective software distribution, the existing ISO 9660 file system contains a number of restrictions which interfere with simple and efficient distribution of files on a CD-ROM.

The general design approach used in the Joliet specification is to relax restrictions and resolve ambiguities in the ISO 9660:1988 specification so the practical goals can be met."

ISO-9660 Information - by Philip J. Erdelsky


This file documents the ISO 9660 filesystem, which is the basis of almost all filesystems stored on CD-ROMs. It is suprisingly difficult to find information on this fundemental standard. If you know of any that I'm missing, please let me know.

Information Specification for Bootable CD-ROMs - by SFF Committee


"This document defines how CD-ROM manufacturers can package several floppy and hard disk images on a single piece of media with the ability to catalog these images and selectively boot from any single image."

Slides from the Linux Storage Management Workshop '99:


The Kernel and the VFS - by Stephen Tweedie


"A filesystem Engineer's Perspective," discusses the evolution of the filesystems provided by linux, new stuff, and stuff coming soon to a kernel near you...

Buffer Management for XFS under Linux - by William J. Earl, SGI


These slides are very high quality slides that discuss all manners of buffering, and how the XFS buffering mechanism was integrated into the linux kernel. Although XFS is still vaporware at the time of the writing, it does appear that they are integrating some cool technologies.

Others:


Large File Support


X/Open Large File Support Standard Draft - by X/Open


"As UNIX systems have become increasingly powerful, a number of system vendors have developed a requirement to access files that contain more information than can be addressed using a signed long integer. A number of major system vendors and users have been meeting at the "Large File Summit" (LFS) for over a year to develop a set of changes to the existing Single UNIX Specification (SUS) that allow both new and converted programs to address files of arbitrary sizes.

Large Files in Solaris: A White Paper - by Solaris OS group


This document describes Sun's implementation of the Large File Summit's standard for 64 bit file access... including the User level experience of converting existing applications to the new standard.

The NFS Filesystem - by Sun Microsystems


The NFS filesystem is the standard for fileshares in the Unix world. This filesystem is documented by a number of RFC's: NFS v2, NFS v3, NFS v4(in progress), and Web NFS.

File System Usage in Windows NT 4.0 - by Wemer Vogels


This paper discusses real world traces of filesystem usage. It shows how certain real world behaviors are important to optimize for and shows how NT succeeds (partially) at providing good filesystem performance.

The BFS Filesystem Structure - by Martin Hinner


"The UnixWare Boot FileSystem (BFS) is a filesystem used in SCO UnixWare. It contains all files necessary for UnixWare boot procedures (such as unix). Because the object of the bfs filesystem type is to allow quick and simple booting, BFS was designed as a contiguous flat filesystem. It is not intended to support general users. The only directory bfs supports is the root directory. Users can create only regular files; no directories or special files can be created in the bfs filesystem."

The Amiga floppy disks format - by Laurent Clevy


"This document purpose is to describe the Amiga floppy disk format. I don't found any document which explains this format in details. Because I wish this machine to be supported a long time, including via emulators, I decided to write this file, and supply C routines as examples."

Adaption of the System V/386 Filesystem for Linux - by Paul Monday


"Compatibility between operating systems and filesystems is an essential item when creating a robust operating system. The Linux operating system is taking the filesystem compatibility issue to a new level with its modular integration of filesystems into the Linux kernel. The project which accompanies this paper exploits the robust Linux filesystem to integrate System V/386 filesystem compatibility into Linux kernel. This paper will discuss issues relative to the integration of the System V/386 filesystem support."

A Class Hierarchy for Building Stream-Oriented File Systems - by Madany, Campbell, Russo and Leyens


"This paper describes the object-oriented design and implementation of a family of stream-oriented file systems under UNIX and under an object-oriented operating system called Choices. A class hierarchy provides an object-oriented taxonomy of the algorithms and data structures used in the design of this family. The family includes the System V file system, the 4.2 BSD file system, and the MS-DOS file system."

Designing File Systems for Digital Video & Audio - by Rangan and Vin


"We address the unique requirements of a multimedia filesystem such as continuous storage and retrieval of media, maintenance of synchronization between multiple media streams, and efficient manipulation of huge media objects. We present a model that relates disk and device characteristics to the recording rate, and derive storage granularity and scattering parameters that guarantee continuous access. In order for the filesystem to support multiple concurrent requests, we develop admission control algorithms for determining whether a new request can be accepted without violating the realtime constraints of any of the requests."

Filesystems in Development:


Reiserfs Balanced Tree Filesystem - by Hans Reiser


This is an exciting new filesystem that is using some new ideas to provide linux with a faster file system than the Ext2fs. Using balanced trees to hold the files themselves, instead of just the filenames, rieserfs claims big performance improvements over conventional FS's. It is released under the GPL, with commercial exceptions.

The SGI XFS Filesystem - by SGI Inc.


With SGI's recent news of embracing open source projects, it seems that they are releasing their journalling, 64 bit filesystem into the public domain, and porting it to linux. Although it is still in beta form, it looks like it progressing quite well.

EXT/3 Filesystem - by Stephen Tweedie


The EXT/3 Filesystem is an improved version of the EXT/2 filesystem, and is currently under development. This filesystem extends EXT/2 by adding journaling information to the metablock, thus aiming for full backward and forward compatibility. Here is an installation page. My feeling is that in the JFS war, Reiser will probably come out on top... but competition is a great thing!

Journaling the Linux ext2fs Filesystem - by Stephen C. Tweedie


"This paper describes a work-in-progress to design and implement a transactional metadata journal for the Linux ext2fs filesystem. We review the problem of recovering filesystems after a crash, and describe a design intended to increase ext2fs’s speed and reliability of crash recovery by adding a transactional journal to the filesystem."

The LinLogFS - A Log-Structured Filesystem For Linux - by Christian Czezatke


"This thesis discusses the design and implementation of dtfs, a log-structured filesystem for Linux. dtfs features a generic core providing logging facilities that are filesystem-independent and a "filesystem personality" that borrows heavily from the Linux ext2 filesystem. Furthermore, the dtfs design supports the placement of multiple filesystems (even of different filesystem personalities) on top of one dtfs filesystem device and the creation of snapshots and different versions for these filesystems."

The Steganographic File System - by Ross Anderson, Roger Needham, Adi Shamir


"In this paper, we present the steganographic file system. This is a storage mechanism designed to give the user a very high level of protection against being compelled to disclose its contents. It will deliver a file to any user who knows its name and password; but an attacker who does not possess this information and cannot guess it, can gain no information about whether the file is present, even given complete access to all the hardware and software. Homepage available.

GFS: The Global File System - by The GFS Group


"The goal of the Global File System research project is to develop a serverless file system that fully exploits new interfaces like Fibre Channel that allow network attached storage. This approach allows all client computers to have full access to all storage devices on the network, making access more efficient and more reliable. Scalable networked storage interfaces like Fibre Channel will allow computer architects to design systems with many shared storage devices, increasing the performance and reliability of the design."

An Overview of the Global File System - by David Teigland, Ken Preslan, Matthew O`Keefe


As the title suggests, these slides discuss the global file system and the feature set it supports... It gives interesting coverage to issues that they encounter and the direction the project will be taking in the future.

xFS: Serverless Network File Service


"We are currently designing a serverless file system called xFS which will attempt to provide low latency, high bandwidth access to file system data by distributing the functionality of the server among the clients. The typical duties of a server include maintaining cache coherence, locating data, and servicing disk requests."

Frangipani: A Scalable Distributed File System - by Chandramohan A. Thekkath, Timothy Mann, Edward K. Lee


"Frangipani is meant to run in a cluster of machines that are under a common administration and can communicate securely. Thus the machines trust one another and the shared virtual disk approach is practical. Of course, a Frangipani file system can be exported to untrusted machines using ordinary network file access protocols."

(new!) sections have been updated in the last week... (recent) sections have been updated in the last two weeks...