OFM Bulletin 1998

Softpanorama (slightly skeptical) Open Source Software Educational Society

May the source be with you, but remember the KISS principle ;-) Softpanorama Search

Version. 1.06, Jan 15, 1998

The Orthodox File Manager(OFM) Paradigm

By Dr.Nikolai Bezroukov

Abstract

The paper discusses Orthodox File Managers (OFMs), often called NC-style file managers. The importance of this type of file managers is connected with  a very high productivity of advanced users and the portability (OFM is the only portable file manager known to the author). OFMs can be found on a large variety of operating system including  various flavors of UNIX, OS/2,  all existing versions of DOS, Windows 3.1, Windows 95, and  Windows NT . They are an essential tool for system administrators, especially NetWare and UNIX system administrators.  The current stage of development is explored, several classical (NC5, VC, DN,FAR) and GUI-based (Windows Commander, Norton Commander for Windows 95)  implementations are reviewed and recommendations for future development are proposed. The author believes that OFMs should become an important tool for WEB masters. Another important role of OFMs is to simplify file management in Linux and FreeBSD and to help to attract new users to this very interesting and currently underutilized Oses (Midnight Commander is now shipping with both variants or UNIX mentioned).

The "Orthodoxness test" that measures the level of compliance of a particular file manager with the orthodox doctrine is proposed. It contains four parts: "Basic compatibility", "Virtual file systems support", "Modern extensions" and "Recommended extensions/Wish list".

Contents

• Abstract
  • Contents
  • Introduction
  • Overview of the OFM implementations
  • Advantages of OFMs
  • The New Direction for OFMs - WEB Administration
  • Characteristics of OFM
    • Appearance
    • Common characteristics of OFM
    • OFM and GUI-based interface
  • Milestones of the OFM paradigm.
  • NC line of the OFM
  • VC line of OFM
    • Level of compatibility
    • VC contributions
    • VC deviations from OFM paradigm
  • DN line
  • MC line
  • FAR line
    • Level of compatibility
    • FAR Contributions
    • FAR deviations
    • GUI-based implementations
    • WinCmd -- Windows Commander
    • Level of compatibility
    • Advanced features implemented.
    • WinCmd Contributions
    • Incompatibilities
    • NCW - Norton Commander for Windows95/NT
  • Sectant implementations
  • JC line - an example of sectant implementation
    • JC innovations
    • JC deviations
  • Comparative table
• About the author
• Acknowledgments
• Supplement 1.
• The Orthodoxness Test (version 0.05).
  • Part 1. Basic compatibility
  • Part 2.Virtual file systems support
  • Part 3. Modern extensions
  • Part 4. Recommended extensions/Wish list

Introduction

The Orthodox File Managers (often called NC-style file managers), are probably the most influential type of file managers of DOS heritage.  The OFMs are more than a popular type of file manager.  It is a cultural phenomenon that we ( lacking more precise definition) will call the OFM paradigm or even OFM religion (the word orthodox is more applicable to religion that paradigm;-). For a typical Windows user it looks somewhat strange that people continue to use descendants of a character-based file manager  that  was initially designed for XT. Also strange that a lot of talented programmers devote considerable time solving intricate problems of designing OFM-style manager. One of the motivations of this article is to provide some kind of framework for both OFM users and authors and to put this kind of file manager into a more general context.  The test provided in the supplement 1 also can be useful for the authors of the OFM implementations

Overview of the OFM implementations

I believe that the total number of the OFM implementations (including discontinued) is close to a hundred. This figure alone says a lot about the phenomenon. No other type of  file managers ever managed to get such a strong following.  OFMs are also parts of the hacker culture, especially European hacker culture.

Although originated in the USA,  the OFMs  became mostly a European phenomenon with a very strong following in former USSR(xUSSR) countries. The first attempt to create to generalize Norton Commander functionality (PIE Commander by Valentin Chernyak that has had four independent panels instead of two) was done in this region as early as 1989. Three major OFM implementations (VC, FAR and DN) are from Ukraine, Russia and Moldavia/Russia (Stefan Tanurkov is from Kishinev, Moldavia and  Dmitry Dotsenko is from Moscow). In the xUSSR countries OFMs are often taught at introductory university courses and books describing techniques of working with this type of file manager has been published in several millions of copies.  From the late eighties till the early nineties for entry level users in the xUSSR OFM interface was a synonym to the DOS interface. Many users never even suspected that the OFM is not a part of DOS or that regular command-line DOS interface exists. 7

In other  European countries OFMs are very popular as well.  There are many implementations of OFMs in that region (probably at least one for each European country :-) including:

• A Czech implementation ( Servant Salamander by Peter Solin);
• A Dutch implementation (Nico Commander by Nico Cuppen);
• A Denmark implementation (Crash Commander by Martin Rasmussen);
• Several German implementations ( EFC be Emil Fickel, Jet Commander by Frank Klosek,and UFO by  Hansmann/Wildgrube/Yoran GbR, (Deus Ex Machina Communications));
• A Hungarian implementation (Start Commander by Joe Forster); 
• An Italian implementation (Ramsete Commander by  Marco Varagnolo);
• A Netherlands implementation (WinNC by R.Speets and C.Hamers);
• A Swiss implementation (Windows Commander by Christian Ghisler).

The high quality Australian implementation - FC by Brian Havard is very popular in the OS/2 environment (Win95 version with support of long file names and a virtual file systems for archives is also available). This  suggests that OFMs are well known in Australia too. 

More that a dozen implementations of OFM exist for UNIX. The most popular in the UNIX environment is  Midnight Commander.

Sometimes OFM-style managers are incorrectly called NC clones - the latest incarnation of OFMs represented by Dos Navigator(DN), FAR, Midnight Commander(MC),  Volkov Commander(VC), Wincmd (Windows Commander) and others are far from being clones, since Symantec lost its leadership after NC 5.0; most of them are quite original and often introduced new features.

We will distinguish between classic OFM implementations(COFM) that use text interface and GUI-based OFM implementations (GOFM).  As with any religion along with mainstream (orthodox) implementations there are various sects that deviate in some ways from the orthodoxy  ;-).  One rather interesting sectant implementation (Jet Commander) is also discussed in the paper. 

This paper provides a short overview of features in five classic (DN, FAR, NC and MC(the latter being mainly the UNIX beast, although Win95 version is now available), two GUI-based(Windows Commander and Norton commander for Windows 95)   and one sectant implementations (Jet Commander).

Advantages of OFMs

Much like Johann Sebastian Bach's music OFM belongs both to the previous century and to the next century. The interface is more than 10 years old and is somewhat archaic. Key assignments have no rational explanation from the point of view of a typical Windows user (but that deficiency can be be easily cured by providing a key-mapping mechanism, see below).

At the same time OFMs offer a unique blend of simplicity and power. They provide a very efficient tool (and a way of thinking about performing these operation - that's why the word paradigm appears in the title of this paper) of working with large collections of file and complex file structures. People that start using OFMs seldom switch to another file manager. There are a lot of users (including the author) with more than a five years experience in one or several OFM implementations.

I see the following major advantages of OFMs:

• Better paradigm.  OFM idea of two symmetrical interchangeable panels (similar to an editor with two text windows is a more powerful model that asymmetrical model used in Windows-style GUI-based managers (the tree in the left panel and the file list in the right with the possibility of drag and drop from one panel to the other). Also OFMs have  richer variety and more flexible semantics of file operations that often permit performing tasks with fewer keystrokes and fewer mistakes. For example OFMs use concept of multiple associations - any extension in OFM can be associated not with single executable, but with multiple; selection of group of files is more flexible and number of operations on groups is bigger than in in Windows-style managers.  OFM paradigm successfully integrate several concepts from other filemanagers (Xtree and windows-style) as well as ideas originated in WEB-browsers (directory favorites or bookmarks). BTW the concept of bookmarks was present in rudimentary form in OFMs from the beginning (user menu), but now it is refined and fit naturally.
• Productivity. The productivity of the power user of OFM is really amazing. To the uninitiated it often looks like a magic - especially the speed with which advanced user can perform complex file operations. It looks much like playing piano. Availability of virtual file system(VFS) make some complex operations much simpler.  Generally it seems that complex file operations the OFM paradigm of symmetrical interchangeable panels with emphases on keyboard is more productive then Windows-style GUI interface with asymmetrical windows and strong emphases on mouse based operations (drag and drop). 
• Unique suitability to system administration tasks. OFMs are a very powerful tool for system administrators, and using them can considerably cut time needed to perform usual system administration tasks. They are very useful for troubleshooting as many implementation of OFM (Volkov Commander is a famous example) are small programs that can be used from the floppy. I believe that an OFM should be a part of the toolbox of any decent system administrator.  Sysops of FIDO BBS were probably the most active OFM adopters and some features in OFMs are generalizations of BBS maintenance experience (4DOS file description support is one such feature). Most OFMs (FAR, NC5, Norton Commander for Windows, Windows commander, etc.) provide additional system administration tools for NetWare (drive mapping,  etc.). MC provides additional UNIX management tools.
• Portability. With its simple character-based interface OFM is the only portable file manager.  OFMs managed to migrate to almost any other OS (including palmtops Oses, all flavors of UNIX, OS/2, Amiga and even IBM mainframe VM/CMS operation system).  It can be implemented on black and and white screen with limited number of shades of Gray or no shades at all. OFM is probably one of two types of file managers (the second is Xtree and its derivatives) with implementations on all four (or more, it depends on how your count them ;-) major Microsoft operating systems (DOS 2.0-6.22, Windows 3.xx, Windows 95.xx and Windows NT).
• "Small is beautiful".  OFMs are rather small programs that efficiently utilize system resources and can be developed by a single author.  Now famous Volkov Commander 4.01 is an extreme case - it's a 64K program that is blazingly fast even on the most primitive and underpowered PC. At the same time the functionality of this 64K program beats the functionality of many Windows file managers that have a size of more than one megabyte.
• Dynamic development. OFM field is not static with well known players, it is a rapidly developing culture with a lot of innovation from newcomers. For example FAR - current leader among classical implementations - is a recent introduction to the OFM family with v.1.0 released in 1996. Competition in the field of OFMs is really strong with several dozen talented programmers working on their products. The functionality of the latest generation of OFMs ("made in 1997" OFMs) is vastly superior to their predecessors made in 1993 or 1990. For example DN 1.5 introduced three new and very important VFS  - flat subtree, briefcase and findfile/list VFS.

The New Direction for OFMs - WEB Administration

Professionally OFMs are mostly used by system administrators (especially Novell administrators and now Linux and FreeBSD administrators), BBS sysops and professionals who perform a lot of file manipulations. Using OFM is also part of the hacker culture, especially in Europe.

But now the most important type of users of OFMs  are WEB masters. Essentially all BBSs are moving toward WEB server technology and BBS sysops were always a stronghold of OFMs. WEB masters need to perform a lot of file manipulations, and often work in the cross-platform environment.  The first important move of OFMs in this direction is the support of the FTP virtual file system(VFS). Second important feature is the ability to convert the case of filenames.

I believe that HTML-related tasks will drive the evolution of OFMs for the next decade. Several possibilities exist and some features are very easy to incorporate into the general OFM framework. Among them:

• The panel view enhancements
• The navigational enhancements;
• The viewer enhancements;
• The tools integration.

The most simple panel view enhancement is to show  the <title>  tag as a description for all HTML documents (by generating Descript.ion file on the fly,  if its time stamp is older than one of HTML documents, or using other methods).

The simplest navigational enhancement is probably the ability to use a selected document(index) as a filter to display all referenced documents in the panel. Even now this can be achieved in DN by writing simple preprocessor that converts HTML document into file list. In essence it is similar to viewing an archive and can be called a virtual HTML file system. The second useful enhancement would be to display a tree view of references from the HTML document as a specialized tree-view and navigating this tree in a usual OFM style. 

As for built-in viewer enhancements, integration of HTML stripping into viewer would be really beneficial. Also badly needed is the ability to jump from the text view to the panel view for a particular directory (jump to the directory selected in viewer or editor will probably be enough and is quite simple to implement).

Here are some recommendations for tools that can be used with OFMs to improve a WEB master productivity:

• Viewers (Lynx-like) or specialized (for example VIEWHTML v2.5 that provides   hypertext linking and colors. Also can convert HTML documents to text files. Is able to copy text to Windows clipboard. Links to web browser, see Softpanorama. vol. 9, No.3, issue B);
• Strippers - program that convert HTML to a raw text (for example HTMSTRIP.EXE - that removes HTML tags from one or several files. It is avalable from www.shareware.com. The current version is 7.10, earlier versions were published in the Softpanorama bulletin. vol.9, No.2, issue C.);
• Prettyprinters ( I do not know any standalone HTML prettyprinter right now);
• Collection viewer (ability to display on the panel only documents that belong to a particular HTML  collection);
• Link checkers (for example CHECKWEB v1.1 - HTML links analyzer that scans HTML pages, explore all the links and generate a log file with all errors (http://www.alterego.fr/develop.htm.)).
• Table of content generators (htmltoc can be easily integrated)

Characteristics of OFM

Appearance

The main window of the OFM is divided into three subwindows. Two of them called panels are identical in structure and are situated side by side. Panels contain directory listings of the current directory or a  tree representation of the current drive. One of the panels is the so-called active panel in a sense that the user can perform operations on file listed in this panel. The second one is passive and serves as a target for operations performed on the files on the active panel.

The third window contains just a command line, and is situated at the bottom of the screen. Often the toolbar with buttons for 10 functional keys is situated under the command line.  The panels can be shrunken or completely hidden.

Both panels are further divided into three subwindows - a header, a list part, and an information line. 

The header line contains the titles of the columns present in the list part. In some OFMs (for example Windows Commander) columns headers are clicklable and click on any of them changes the sorting order of the list.

The list part contains the list of directories and files from the current directory (usually including hidden and system directories and files) with some or all attributes(size, timestamp, etc.) or tree representation of the current drive.  In all OFM user can choose one of several form of the directory listing representation (the minimum is just two: a brief list and a detailed list).  In advanced OFMs the list is customizable. 

Information line(or more correctly information windows) is in essence a separate window that shows the information about current file and current group of selected files, if any. If long file names are supported then the long file name of the current file is displayed in the window in real case(i.e. if file name in in upper case it should be displayed as such). Additional operations on the current file (for example click by the mouse on the information line can select all files with the given extension, etc.) also can be supported in this window. In case one or more files on the panel are selected the information line shows statistics on these files(the total number of selected files and the total size of the group).   In modern OFMs, an information line became an information window and bottom border line of the panel and upper delimiting line are used for displaying the number of selected files and the total number of files in the current directory.

In some OFM there are special colors for directories, executable files, hidden and system files. Traditionally at the bottom of the screen a command bar is displayed (see below).

Common characteristics of OFM

All OFM share the following characteristics:

• Two symmetrical panels that provide the same functionality (one panel is current and second is passive; switchable with the Tab key)
• Strong keyboard orientation. Unique (incompatible with usual windows assignments) keystrokes assigned to each function (traditional F1 -help, F2- user menu, F3 file view, F4 - file edit, F5 - file copy, F6 - file move/tree move, F7 - make a directory,  F8 - file delete).  Often these major keystrokes are depicted on the bottom line as buttons clickable by the mouse. Although key combinations are traditionally preserved in OFM implementations they are NOT a part of OFM paradigm. If possibility of reassigning the keys is implemented (for example in a way, similar to MultiEdit implementation (MultiEdit is a favorite Editor for many OFM users) than any other combinations (including more Windows like) can be used. Again only semantics of the operations is fixed and should be implemented "as is".
• The ability to perform most functions without mouse (that feature is especially useful on the laptops and now palmtops); mouse is supplementary, not primary input device in OFMs;
• Command line window at the bottom of the screen with the ability to execute DOS commands and select previous commands from the commands history;
• Special customizable extension files and menu that permit context-dependent invocation of scripts and programs of file click (execute), F3(view) and in F4(edit).

OFM and GUI-based interface

Although the OFM paradigm is rooted in the character text interface and classical OFM implementations are text-based, OFMs are not limited to it. It is not a type of GUI per se, it's not keystrokes(if you can reassign them), it's  the semantics of operations that matter most.  Now a lot of of OFMs successfully use GUI interface. 

GUI provide much more capabilities than restrictive character-based interface. Nevertheless the character interface is really important and considered classical from another point of view. Artists know well the saying "form liberates". In the same way puritan character interface liberate a programmer from spending too much time and effort on unimportant things and thus provide possibility to spend most of the time implementing richer set of operations. Paying too much attention/time/effort  to the "face" is characteristic to Windows developers and often  negatively influence the functionality of the product. Nevertheless several GU-based implementations exits and some of them combine drag and drop features with classical OFM features. I found almost a dozen of GUI-based implementations. Among them the following deserve attention:  

• Windows Commander by Christian Ghisler(http://www.ghisler.com/)
• Norton Commander for Windows from Symantec.
• WinNC by R. Speets and C.Hamers
• Emil Fickel Commander (EFC)
• Nico Commander by Nico Cuppen.
• Disk Haunting by Diego Sendra.  
• Servant Salamander by Peter Solin.

Milestones of the OFM paradigm.

OFMs is more that 10 years old. Milestones in the development of OFM are:

• NC 1.0 (1985???);
• NC 2.0( 1987???);
• NC 3.0 (1989???);
• NC.4.0 (1993);
• VC4.0 (1993);
• WinCmd 1.0 (1993);
• MC  (1994);
• NC5.0 (1995); 
• DN 1.50 (1997);
• WinCmd 3.03 (1997);
• VC 5.0 (alpha - 1997);
• FAR 1.50b (beta 1997).

NC line of the OFM

Norton Commander for DOS is the original line of OFMs that exists in four major version: 2.0 3.0, 4.0 and 5.0. Only versions 2.0 and 3.0 (I believe only the version 2.0 was written by NC original author John Socha, before he left the company) can be considered as a decent implementations of   the ideas of OFM (NC 2.0 was the cornerstone of OFM)  and they provide a basis of OFM paradigm. Versions 4.0 and 5.0 provide useful enhancements, but implementations look much like betas and are quite fat. 

The main enhancements introduced in NC5 are:

• The Virtual File System for archives (rather weak implementation for ZIP files only, but a very important idea);
• File attributes command  (very convenient. later was extended in VC for date and time stamps);
• Synchronize directory command (Ctrl-F8);
• Label Disk command;
• Invert Selection and Restore Selection operations;
• Customizable file name filters in the panel (via Filter menu)
• Tools menu file (Tools.MNU) for customization of the Main menu.

The Virtual File System(VFS) was the only important addition to OFM paradigm in NC 5.0. Actually  NC 4.0 also can show archive contents in panel, but unlike NC 5.0 it cannot view archived files. Initially VFS was implemented by many OFM enthusiasts as add-ons to NC 3.0 (archive viewers of different flavor with NC-like panel structure and operations were very popular addition to NC 3.0, but the level of integration was limited). The VFS provides possibilities of working with archives in a completely transparent way by viewing archives as directories.

NC 5.0 for DOS was probably the last version which really contributed to the OFM paradigm. Compatibility with NC 5 should be considered as a minimal test for contemporary OFM implementations(see suppl.1).  

Symantec essentially discontinued its line of OFMs in favor of Windows-style file managers (Norton Navigator). BTW Symantec managed to kill another interesting file manager -- Xtree. But probably due to pressure from users in Europe a European-only Norton Commander for Windows was created (or reanimated :-) in 1997. This product is much weaker than shareware alternatives and the development team seems lack a talented leader that is needed to compete with other OFM implementations. My impression was that nobody from the developers has a deep understanding of  the OFM paradigm.

Currently there are two commercially available OFM products from Symantec - NC 5.0 for DOS (an old hat by today's standards) and NC for Windows 95 and NT (see overview below).

VC line of OFM - masterpiece of assembler programming

Volkov Commander(VC) was the first OFM that beat NC-line to the punch. VC 4.0 was a masterpiece of assembler programming, small (v. 4.xx is a COM program and is less than 64K), but extremely powerful. In 1994 it took the world by storm at it implemented a dozen of important enhancements that later became part of the OFM paradigm (for example Ctrl-[ and Ctrl-]).  Even now with strong competition from FAR, VC is still  probably the most popular OFM. I have used VC from late 1992 (Volkov Commander was first published in the Softpanorama bulletin in the December 1992). In the 1993 the development of Volkov Commander were partially supported by the grant from the Softpanorama bulletin and Vsevolod Volkov make a couple of presentations on the Kiev Softpanorama seminar.

Level of compatibility

We will discuss version 5. It's still in alpha(4.99.03), but the alpha is amazingly bug free and pretty much usable. Despite absence of several features(Find file, etc.) this alpha version is more powerful than 4.0. It supports long file names and the archive VFS. And it still is the smallest OFM among the leading OFM implementations (beta is 78K zip archive ! It's refreshing to see that program under 100K can perform more that a just "Hello world" with a couple of options ;-).

This version corrects VC 4.0 major deviation from the orthodox NC paradigm that was connected with the way it treats "Alt-F10". VC 4.0 does not keep the results of scanning on the disk (I believe only the last tree structure is available and often pressing Alt-F10 initiate time consuming rescan of the whole drive, that makes the feature almost unusable).  This is now fixed and a file TREEINFO.VCX is used as a cache for the drive directory info.

VC contributions

VC version 4.xx was a milestone in OFMs. It make a lot of important contributions to the OFM paradigm, like "Ctrl-[", "Ctrl-]",  generation of the selected file list to the command line (Ctrl-I), enhanced attribute command that can change timestamp of the file as well as attributes, etc.  Most of them are now firmly incorporated in the OFM doctrine (BTW Ctrl-I, Ctrl-[ and Ctrl-] functionality was recommended by the Softpanorama bulletin).  Also its tiny size makes it an excellent troubleshooting tool and the best OFMs to carry with when servicing customer PCs. There are more that a dozen of various add-ons for VC 4.01 (see for example ftp://ftp.elf.stuba.sk/pub/pc/utilfile/ in the USA the best is to use its Walnut Cdrom mirror ftp://ftp.cdrom.com/pub/sac/). This attests the popularity and the value for the programming community of  this OFM implementation.

Version 5 preserve VC 4.xx unique advantages as it is still the smallest and the fastest of the of leading OFM implementations.  If provides several contributions to the orthodox doctrine:

• Ability to specify shell options like /e:2048 for additional environment space;
• Quick view tree navigation: navigating the tree in one panel will make current(highlighted) directory current on the second(passive) panel.
• Uniform syntax for both user menu and the extension table with the possibility to include files both to the user menu and extension table, so that the same included files can be used in the user menu.
• Macro substitution symbols for the passive panel.

VC deviations from OFM paradigm

Quick view was not available in 4.0. It is still absent from the beta, but is present in the panel menu, so it will be implemented in a final version.

Like in v.4.0 file operations using the passive panel tree view are impossible. For example there is no possibility to copy file from one directory into another directory using the tree representation of the disk on the second panel.

Navigating the tree in one panel will make current(highlighted) directory current on the second(passive) panel. This is an interesting kind of quick view function for the tree representation and although useful in its own way it does not substitute the functionality of selecting the target directory on the tree representation. 

Clicking on Name, Size, Date and Time options does not resort the directory with this key.

DN line - breakthrough in VFS

The DOS Navigator (DN) is an extremly interesting and influential implementation of OFM. v.1.5 released in April 1997 opened a new generation of OFMs. It should be considered as an ultimate DOS-based classic implementation of OFM and  currently it is difficult to compete with DN featurewise.

Like MC it is a team effort. Initial design was by Stefan Tanurkov and Dmitry Dotsenko. Several programmers participated in the development on a different stages. After v. 1.37 Slava Filimonov (he now author of MRP Navigator - a file shell, designed for use for Win95/NT) and Ilya Bagdasarov were in charge for DN coding. Then Stefan Tanurkov and Max Masytin continued the development.  The version 1.5 was authored by Stefan Tanurkov and Max Masytin. 

Although it is a text based,  the latest version seems to be more close to GUI-based OFM counterparts as it is using Borland Turbo Vision for the interface implementation. The size of DN distribution is also more close to GUI-based OFMs (1M). Although it seems to be a little bit overloaded with additional utilities, the core OFM functionality is really impressive.

Disclaimer: The author has a very limited experience working with DN and tested only the demo of v .150.  The demo does not provide some advanced features. In this case documentation was used.

DN Contributions

DN 1.5 should be considered as a milestone in the OFMs virtual file system implementations. It had made a very important contributions in this area. The feature set and flexibility of DN in this area are really amazing. Among a long list of DN innovations I would like to single out the following three VFS:

• Flat subtree VFS -- the ability to view a directory with all subdirectories as a single virtual directory. Drive a directory can then be viewed as a flat list of  files. this idea was pioneered in Xtree file manager and is a natural and very important extension of the OFM paradigm.

• Briefcase VFS that links to files and directories on existing drives into single virtual directory(or drive). Semantically it is an implementation of the link operation in UNIX, so a briefcase should be a standard feature in all UNIX implementations of OFMs. It is possible to copy files from different directories to the briefcase drive and then work with this links as if they are were stored on this drive. All file operations are supported.  Of course implementation of briefcase on a regular FAT file system is not as simple as in UNIX, but this is a Microsoft fault ;-).  For drives on some versions of MS DOS and all version of PC DOS join operation was available (strange mix of link and mount operations), so limited capability of creating briefcase was present even in DOS.

• Findfile/list based VFS - the panel will show only files that are results of the search or present in the text-file list. This is a very important generalization of the find file function and panel filters. Using  Panel|Read file user can read a list of files from a text file, for example, files.bbs and DN will search for each of them. The panel will display the list of files found. Files can be in different directories and different drives.  Essentially filters present in NC line of OFM should be considered as a very primitive implementation of this concept: essentially each filter find and displays result of search with a particular mask or group of masks.

This three new types of VFS are really a milestone in OFM development.  The flat subtree VFS is an important productivity enhancement tool. It was first introduced in Xtree (as early as in 1987) and this capability probably was the single most important reason of  XTree popularity. This VFS should be a standard in all modern OFMs, as it provide really superior functionality to any known to me Windows-style file manager. With Xtree-line of file managers discontinued (by the way by Symantec :-(), it can became a distinctive mark of OFMs.

Three other innovations are also very important:

• The ability to have several sets of panels and switch between them like in a real multi-windows editor.
• DN was probably the first OFM implementation that introduced keyboard macrorecoder in OFMs. DN     permits to record a key sequence and replay it.
• History lists for directory visited, selection masks, etc. 

Usefulness of the ability to have several sets of panels is proved by attempts by other authors to add similar features to OFM (for example early attempts to introduce 4 panels in the PIE Commander by Valentin Chernyak) and  experience with Windows-style file managers where multiple windows are a standard feature.

As I already mentioned DN introduced many other innovations. Among them:

• The first (although not the best, see FAR below) correct implementation of the information windows concept. Information windows in DN is a three line entity with a current file as the first line, the number of selected files is the second and number of files in the directory in the third line

• Movable panel delimiter can make the panels asymmetric so that one can view descriptions and additional columns on the single panel.
• Custom video modes (30-line panel view implementation).
• Drag and drop implementation for groups of files and single files (from information window) !
• Compare directories operation (permits comparing contents);
• Collapsible tree views (although I did not find the key to return to regular tree view);

• Directory tree has expand/collapse options:
• + : Expands/reads the tree starting at the current directory for one subdirectory level
• - : Collapse the subdirectory tree below the current directory.
• * : Expands/reads all subdirectories starting at the current directory.
• Advanced file search. It is possible to search files using a list of selection masks (e.g. *.bak; *.$$$; *.tmp ), by text string, by date, size and attributes. File Find in DN can work in background.

• Rudimental selection mask language (several masks can be entered using semicolon as a delimiter, ">" serves as inversion symbol. Although regular expressions are better way to go method of combining them used in DN deserves attention. for example it is possible to specify   *.c; *.h  directory in the selection menu. In PC world is is easier than *.[c h]. More complex example is much difficult to convert to a regular expression (*.txt; *.bat; *.inf; *.doc) and they are more natural to construct.  
• Operations with floppy images;
• Additional operations on selection lists and use of multiple selections lists
• The ability to edit commands history;
• New keys for selection of all files irregarding current selection mask, selecting all files with extension equal to the extension of the file under cursor, etc.

Level of compatibility

Despite a lot of enhancements semantically DN is very compatible with OFM doctrine. All operations that I tested were implemented semantically correct although many of them used different (e.i. non-standard) hot keys.

Neither Alt-<letter> not Crtl-Alt <letter> quick search works and I have an impression(may be wrong - I use only a demo version) that this important part of OFM paradigm was not implemented at all.

Sometimes (like in case of switching from quick view windows to full windows view) no key was available at all and the operation need to be performed by the mouse. That is a deviation from the OFM doctrine that stress availability of all (or most) operations via hot keys. For other operation hot keys were different, so the major problem is that keyboard remapping is not supported. 

The current version of DN supports archive VFS, but does not support DOS 7 long file names and FTP VFS.  No 32 bit version of DN exists yet.  I strongly recommend to make a GUI-based version as well.

MC line -- power to UNIX

MC is the part of GNU project. It is the only OFM implementation known to the author that have source available.  It was originally developed for Linux in Mexico by Miguel de Icaza.  Interestingly enough the initial version (released  in late 1994) was called MouseLess Commander. Later  name was changed to Midnight Commander and people from other continents joined the original developer. The current team includes Andrej Borsenkow, Radek Doulik, Ching Hui, Jakub Jelinek, Janne Kukonlehto, Fred Leeflang, Mauricio Plaza, Dugan Porter, Paul Sheer and Norbert Warmuth.  Its major contribution was FTP integration (this was really a milestone and now this feature has found its way into FAR 1.50).

MC is not the first OFM-style manager for UNIX and not the only one. At least a dozen of other implementations exist. But MC is definitely the most popular one. The main contribution of MC is not to OFM doctrine as such, but its role in the popularization of Linux and FreeBSD platforms among PC users and understanding of important Unix concepts by the advanced PC users community and developers. As it is included in all major Linux and FreeBSD distributions it proved to be an important cross-fertilization device for DOS-related skills to UNIX-related skills in file manipulation. 

UNIX is a much better platform for some OFM-style VFS. For example briefcase VFS can be implemented via links. But the most important is that MC makes PC user instantly productive in Linux or FreeBSD and thus serves as an important tool for the popularization of UNIX (the second, largely overlooked tool is THE editor that provides for UNIX users with mainly PC background convenient escape from Vi/Emacs mentality ;-).

MC also influenced several PC implementations of OFMs started in late nineties including JC and FAR. MC implementation on Win95 platform currently is not very impressive. MC main achievement is to bring OFMs to UNIX, not vice-versa. But it does bring several UNIX ideas back to DOS/Windows. I still have pretty rudimentary understanding of MC, but other that FTP VFM I can mention the following innovations:

• Directory favorite lists. The idea is borrowed from WEB browsers and fit naturally OFM paradigm. The user can add current directory to the directory favorites.
• Regular expressions in selection masks.
• Command completion.

I beleave that TCL is in best position to integrate TCL into OFM implementation and that would be yet another important contribution to the OFM paradigm.

FAR line

Although still in beta FAR 1.50b is a very impressive OFM 32 bit implementation. It was definitely influenced by VC, DN and MC. At the same tile is it very clean implementation with its own "face" and an excellent compatibility with OFM doctrine. Currently it can be considered as a leader among the 32-bit classic OFM implementations. 

Level of compatibility

FAR v. 1.50b currently has the best score on my "The Orthodoxness Test". It also has probably the best archive virtual file system implementation, as Eugene Roshal is the author of RAR - a leading achiver.  FAR supports the quick view feature (important part of OFM paradigm).  FTP support is very impressive and now becomes an standard by which the other OFM implementations will be judged.

Far is compatible with requirements of considerable part of the Orthodoxness test(parts 1,2 and 3). for example it is the second OFM (after DN) that implements history of visited folders, viewed and edited files, etc.

Among advanced features that FAR support are:

• Panel, directory and selection histories.
• Ability to work with UNIX-style regular expressions in selections, for example [c-f,t]*a.?xt.
• Supports of keyboard macros (several enhancements in FAR, for example using Del key instead of F8 for deleting files, were implemented using keyboard macros; see Add-ons\Macros directory for details).
• Ability to execute a command for selected files.
• Customizable file highlighting scheme;
• Ability to insert the list of selected files into the command line. That operation that VC perform with a single keystroke (Ctrl-I) FAR can do it using Windows clipboard and standard Windows key combinations: Ctrl-Ins to copy selected files (or command line, if it is not empty) to clipboard. Ctrl-Shift-Ins always copies selected files to clipboard,regardless command line state. Shift-Ins to paste clipboard contents to command line. Such behavior is probably more flexible, because allows to insert selected file names to any other program, which can work with clipboard, but VC Ctrl-I capture the most frequently use case. Jury is still out about which implementation is better.

• Case conversion for files (this is a very nice feature; actually it was first implemented in FC)
• Selection enhancements
  • Shift-Gray+/Shift-Gray- for selecting deselecting all files regardless of current selection (was first implemented in DN, but is "forgotten" in v.150; FAR consistently has this feature since v. 1.20)
  • Option of changing case to the lowercase of all files in copy and move operations
  • Ctrl-Gray+/- can be used to select files with same extension as current  (the same story)
  • Alt-Gray+/- can select all files with same name as current (the same story)

FAR Contributions

Althouth the feature list in FAR 1.50b is less impressive that in DN (flat subtree VFS, briefcase VFS and filefind/filelist VSF are not supported) it is the best 32-bit OFM implementation with text-based(classic) interface. The most important contributions of v. 150b to the OFM paradigm are:

• Strong support of archive Virtual File System. Shift-F1 and Shift-F2 operation were introduced by DN, but FAR provide more consistent semantics. For example if second panel is not a file panel (or if the second panel is hidden) them FAR propose to create directory with the same name as archive and extract achieve into this directory. This is IMHO the only correct semantics for archive extraction.  Self extracting archives can be entered via Ctrl-PgUp !
• Integration of windows clipboard with built-in editor with the ability to select text in command line windows and paste it in GUI-window.
• The best implementation of the information windows concept. Information windows in Far is a three line entity. regular line in the second. FAR use the panel bottom border as the third line of the information windows (for displaying the number of files in the current directory) and upper delimiter of the information line as the first line (for showing the number of selected files). current file name is displayed in real case. if length of the file in more then a length of the column in the listing part of the panel them full name is displayed (or in case the name is too long just tail from the last symbol displayed in the information panel).
• Ability to save command history;
• Useful  treatment of Ctrl-0..Ctrl-9 key sequences as a selectors of 10 predefined panel templates (panel templates are customizable). DN-style capability of moving the panel border so that panels became asymmetrical is missing, but selector can be generalized as for position of the border between panels too.

FTP VFS is a really extremely important feature and although it is not the first implementation (the first was in MC) it is a major achievement. 

Another enhancement is the method of selecting of the sort order by clicking on the special letter in upper left corner of each panel.

After using FAR for a week or so I now understand it would be nice if you can click on current file in the panel information line (last line in the panel) OFM should select all files with this extension and place extension in the select history list.  Also regretful that 30-line mode is not supported.

FAR deviations

FAR 1.50b deviates from OFM paradigm is several minor ways.  It merged 3 extension tables (execute (Enter), view(F3) and Edit(F4) into one and does not provide a way to migrate other OFM association tables into the new format.

The idea of merging the association tables, so that one can see all three associations at once (as well as of using Windows association table as a default association) deserve attention, although the loss of flexibility of having separate tables in a simple text format probably outweigh all benefits. For example the ability to include the same subtables into both extension menu and the user menu is lost.

The main point is that in OFM there should be a possibility of dynamic association when user is presented with several choices. The classic example when one can benefit from that feature is the  use of extension .DOC. It is so overused (text, RTF, MS Word native format contents are common), that the correct choice of viewer is often impossible without examining the first bytes of the file.

Click on name, size and date does NOT change the sort order, etc. as OFM paradigm requires although FAR provides a symbol in the upper left corner of each panel clicking on which provide user with the menu, that contains most of the options. But this solution is less elegant that using column headers as buttons.

GUI-based implementations

GUI present a lot of difficulties for the implementing OFM as creation of decent interface and implementation of drag and drop are very time consuming. I know much less about GUI-based implementations that about text-based implementation, so this part of the article is still very raw. 

WinCmd -- Windows Commander

Windows Commander by Christian Ghisler is probably the most well known example GOFM. Windows Commander 1.0 was released in the autumn of 1993. I have tested the version  3.03 that was released in July 1997. I personally consider it to be the best GUI-based OFM implementation and prefer it to the   Norton Commander for Windows (NCW).  Currently is can be viewed as a reference GOFM implementation and it is much better deal for long time OFM users than NCW (see below).

The next version of WinCmd (v. 3.5, currently  in beta, will be released in the second quarter of 1998) will have three major enhancements (ftp VFS; the directory hotlist similar to favorites in a WWW browser; history list similar to a WWW browser; start menu with sub-menus and shortcut keys). Other features in the v. 3.5 includes: The direct access to Network Neighborhood without mapping a drive; ability to unpack Microsoft CAB files and CAB self extracting archives; button bar will be configurable; the ability to put Wincmd to the system tray.

Level of compatibility

The current version (3.03) fairy well conforms to the level 1 of  "The Orthodoxness Test"(suppl.1). It also well conforms to the part 1 of the level 2 of the test (archive VFS implementation test).

Advanced features implemented.

• Archive VFS;
• Long file names support;
• Mouse click on name, size and time headers in the panel should change the sorting order to this attribute. Second mouse click on the same button reverses the sorting order;
• History for selection masks;
• Ctrl-Num-  / Ctrl-Num+ for selecting and deselecting all files irregarding the mask;
• There is a possibility to map a network drive;
• The possibility to create Windows associations.

WinCmd Contributions

• Drag and drop operations for directories and files (as in classical Windows-style file managers);
• The drive button bar and the button bar for frequent operations (also classical Windows-style managers feature);
• The possibility to create a favorite by dragging the directory to the toolbar (very useful and important enhancement that was implemented before Netscape and Explorer solutions to a similar problem in WEB-browsers context);
• When viewing the archive with the second panel in quick view mode WinCmd lists file README if it is available or binary representation if not (probably the listing of archive content would be more useful; also the name of the file, or better  list of files, should be made customizable);
• The possibility to hide the same files during the directory comparison (a very useful extension);
• Shift-Enter is used to execute "command /c <command>", so that DOS window will not be closed;
• Position of the windows on the screen can be saved;
• Creation of shortcuts for the selected files.

Incompatibilities

Ctrl-U does not switch panels is one panel contains the tree view.  Restore selection operation is absent. Directory favorites and folders in the start menu will be implemented in the v.3.5. Multiple file associations are supported in a limited way:   Wincmd uses the Win95 mechanism for associations. A right click or Shift-F10 opens the context menu, which can be extended and in a limited way supports multiple extensions.

Information window does not show the current file. Minor modification of this windows can increase the score and usability (I recommend to to change the information window to three line format used in FAR: the first line is info about group of selected files, if any, second is about the current file (it's name in actual case) and the third one - information about the current directory.

One minor, but important for long-time OFM users point: compare directories in not considered a command. It is considered a marking operation. Semantically this is correct, but classical key sequence F9-C-C for comparing the directories does not work. A key remapping mechanism is badly needed. 

NCW - Norton Commander for Windows95/NT

As I already pointed out NCW was essentially reanimation of discontinued product that was made by Symantec under pressers from European users (German users were especially vocal in this respect). The first impression after installing NCW was mixed. It is definitely the most expensive OFM implementation on the market ($120) and it is not directly available in USA (one needs to buy it from Great Britain) and it is not supported in By USA headquarters. But the functionality provided is very modest and from that point of view it seems to be overpriced. It looks like more or less diligent reproduction of NC5 in GUI -- more like a student project that advancement of the state of the art. It can be used as a OFM, but probably be recommended only for low level users.  For the power and long-time OFM users Windows Commander 3.5 is preferable (and much cheaper).

The main enhancement is a built-in scheduler.  I like it very much (BTW it can plays chime every hour). It  proved to be a really useful addition, that integrates well with OFM functionality. But file manipulation capabilities and support of command line are underpowered.

Despite the price NCW does not supply its own viewers and bundles basic Quick View Plus viewers. So to view HTML one need to get full version of Quick View Plus. If you try to use Navigator as a HTML viewer NCW try to display additional non existent empty file after loading the original one (looks like extra keystroke is transmitted to NCW).

Oleg Volochtchuck is listed in the development team. But recent rumors suggest that he moved to the USA and now works on other projects.

Advanced features implemented.

• NCW understand long file names and is NTFS compatible;
• Archive VFS support;
• Select file filter at last has history. No history or favorite list exists for directories;
• NCW can mount/unmount network drive.
•  

NCW Contributions

• Built-in scheduler. It's nice addition for Windows 95 or NT, but cron probably can be used instead.
• Compare operation for text files. That's really convenient addition to OFM set of file operations that was previously implemented via user menu. Advantage of integration are minimal - decent external program can do the job, but it's nice to have.
• In addition to file filters via "Gray +,-,*" it has operation filters that permit more flexible copying/moving of files. Advantages are connected with the ability to copy subtree using selection mask - a feature currently available only in DN via virtual subtree file system
• Split panel option permit viewing two files simultaneously. The value is uncertain
• Find option contains the possibility of finding files using size and date filters
• Shift-F2 provide NC Network neighborhood panel.

Incompatibilities

Ctrl-E, Ctrl-R and Ctrl-O do not work at all. Generally command line support leave much to be desired. Renaming of directories is clumsy. 

Sectant implementations

JC line - an example of sectant implementation

JC Commander made its first official English-language release in early 1996 - the same year as FAR and IMHO was influenced by MC and DN. V2.0 released in early 1996 supported long file names under WIN95. The current version is 2.2 and exists for  OS/2, Dos and Windows95. It can be considered as advanced sectant implementation.

Among advanced features supported by JC:

• Macrorecoder (JC permits to record a key sequence and replay it once or multiple times)
• Archive VFS ( ZIP, ARJ, ZOO, LHA and LZH are supported)
• The long file names support in Win95, OS/2 and network drives.
• Directory favorite list (in limited fashion - I see no ability to add the current directory to favorites)
• Unix style regular expression in selections e.g. *.[c-h].
• Commands can be applied to the list of selected files
• Attrib command works with date and time
• Customizable file highlighting scheme
• Binary directory difference operation (line in DN)
• Rudimental selection mask language similar to DN but with support of regular expressions and inversion symbol. For example it is possible to specify   *.c; *.h  directory in the selection menu. In PC world is is easier than *.[c h]. More complex example is much difficult to convert to a regular expression (*.txt;*.bat; *.inf;*.doc) and they are more natural to construct.   Interestingly enough this enhancements were probably dictated by deviations from the orthodoxy in treating selections (see below).
• Multiple file edit is possible with the integrated file editor. Functions to copy text from one file to another are implemented. The integrated fileviewer has syntax highlighting option (but not for HTML).
• The macrofunctions of JetCommander can be used in editor too.

JC deviations

Although a strong product,  the value of JC is greatly undermined by serious deviations from the orthodox doctrine in more ways that other implementations discussed above. It does not pass Part 1 of the orthodoxness test and can be classified as a sectant implementation. 

A lot of keystrokes that are engraved in motor skills of long time OFM users behave differently. For example, such a basic for OFM users keystroke as Alt-F1 does not provide list of drives for left panel. Alt-F10 does not show Tree search panel, but just changes the second panel to the tree view, Alt-U does not exchange panels. 

Selections are not persistent. That mean that selection of *.exe and then *.com will not lead to selection of files with extensions EXE and .COM.  Even worse the deselection key (Gray "-") does not accept any regular expression at all.

Although the level of implementation is pretty impressive, I do not recommend JC to long time OFM users, unless the author implements key assignment scheme in the Setup in future versions.

Comparative table

* Feature set is 100%, but key compatibility is 90%

About the author

The author start working with NC 2.0 in late 1989 and used all major orthodox implementations since including NC 3.0, 4.0, 5.0,  VC 4.0, FC, VC5.0beta, FAR 1.50b and several other OFMs. My main OFM for the last 4 years was VC, but now I use FAR more often. I also have some experience with  GUI-based OFMs including Windows Commander and Norton Commander for Windows 95.

Author would appreciate comments of the technical issues raised in the paper. Please sent you comments to nnb@bellatlantic.net.  The latest copy of the paper is available from the www.softpanorama.org.

Acknowledgments

The author would like to thank  Finn Ekberg Christiansen (the maintainer of the Unofficial Volkov Commander Page) for his feedback on the v.1.01 of the article and to Eugene Roshal, who point out a lot of errors and inconsistencies in the v.1.02 and 1.03  of the paper.

Supplement 1.

The Orthodoxness Test (version 0.6).

The Orthodoxness Test is a five stage test, results of which are depicted in a way similar to TCP/IP addresses i.e. 100.45.0.0 means that particular OFM has a score 100% on part 1 (basic NC compatibility), score 46% out  on the part 2 (Virtual File Systems) and zeroes on the part three and four of the test (see below).

The score is determined separately for each section. For example if section weight is 10% and a given OFM comply with 80% of subsections of this section, then the total score for the section will be 10%*80%=8%.  If weights of subsections are not given then equal weight of each subsection is assumed (i.e. the weight of each subsection is equal to 100/number_of_subsections).

Important notes:

• The Orthodoxness Test does not require key assignments correspond to NC as long as there is a possibility to change them.
• The structure of main menu is not defined in the test.

Part 1. Basic compatibility

1. Compatibility with NC 5.0 semantics in basic key movement (the key assignments listed below can different, if remapping capability exists) on the left to right panels including, but not limited to the following (10% with equal weight of each subsection) :

• The Tab key should change active panel to passive and passive to active;

• "Ctrl-\" key should move to the root directory;

• Ctrl-PgDn and Ctrl-PgUp  move to the upper(current) and lower level(parent i.e. cd ..) directories;

• "Ctrl-R" - should reread the directory;

• "Ctrl-U" - should swap panels;

• Alt-F1 and Alt-F2 should produce list of disks for left and right panels;

• Insert should select the file;

• Gray+ and Gray- should select and deselect file using a regular expression or mask;

• Crtl-Q should switch to quick view;

• Ctrl-O should hide panels (for classical OFM only, n/a to GUI-based);

• Ctrl-L should switch to the information panel. 

2. Compatibility of  F1..F8 operations with NC 3.0 semantics:

• F1 - should envoke help;

• F2 - user menu or equivalent (start menu)

• F3 - should envoke built-in viewer or default viewer (GOFM);

• F4 - should envoke built-in editor or default editor (GOFM);

• Alt-F3 and Alt-F4 should select alternative viewer and editor. there should be a possibility to switch Alt-F3/F3 Alt-F4/F4 assignment so that alternative viewer/editor would be selection of F3/f4;

• F8 operation should perform deletion of subtrees is it is applied to the directory with non-empty subdirectories;

• F5/F6 should copy/move subtrees if applied to directories. Movement of directories within the same logical drive does not result in copy operation; Both copy and should provide the possibility to select the target from tree view panel (F10).

• File attribute command should permit change single file or group of files attributed and or timestamps for file, selected group of files or subtree (if applied to the directory);

• F8 should delete files of groups of files or directory subtree if applied to the directory.


3. Tree view compatibility:

• Ability to copy files from a panel with regular representation to arbitrary directory in the passive panel tree.

• Ability to use F10 key from the copy menu (F5) and move menu (F6) to select target on the tree representation.

• Movement of the cursor on the panel with tree representation should not lead to change of the directory on the current panel.

• Quick view tree navigation: navigating the tree in one panel will make current(highlighted) directory current on the second(passive) panel.


4. Selection/deselection compatibility:

• Gray + and Gray - as a file selection keys;

• Selection and deselection operations are persistent (second selection operation add to existing selection);

• Gray "*" as Invert Selection operation; 

• Restore Selection operation (no standard key exist). It should restore highlighting of   files selected for last copying operation.

• Compare directories operation selects newer files on each panel.


5. Tree search panel compatibility:

• Alt-F10 or other hot key should produce tree view of the current panel with the ability to select new current directory on this representation.

• Pressing Alt-F10 should NOT produce rescanning of the disk without reason.

• Quick search option should be available in this panel.

• Ctrl-Enter should  jump to the next directory with the same name of prefix

6. Quick view compatibility:

• For text file content should be should in text mode

• For archive content of the archive should be should

• For other file binary view should be shown

• Pressing F3 or alt-F3 in quick view should lead to regular viewer selection


7. Quick search compatibility:

• Alt-letter (or Ctrl-Alt for GUI-based versions) quick search option should be available for both regular and tree representations of the panel.

• Ctrl-Enter during quick search should move to the next item with given initial letters.


8. Shell execution compatibility (the ability to specify the shell and its parameters required for GUI-based implementations)

• The ability to view results of shell command execution (hide panels option)

• Cursor movement keys work like in DOS shell when panels are hidden

• History of commands should be available (Alt-F8) and selection of prev. and next command from the history should be possible with hotkeys (Ctrl-E, Ctrl-X or Alt-Ctrl-E, Alt-Ctrl-X in GOFMs)

9. Sorting directories compatibility:

• The ability to view files(but not directories) sorted by name, time, size, and unsorted order.

• The ability to reverse the sorting order

• Ctrl-F3...Ctrl-F8 for "NETSU" (resorting by Name, Extension, Time, Size, Unsorted).


10. . User menu script invocation compatibility (GUI implementations can provide alternative methods to run custom scripts with parameters taken from the panel):

• The ability to specify hotkey and label for each script

• Multiple commands can be written without need to create a separate batch file


11. . Association management compatibility:

• The ability to specify one or several associations for the same extension

• In case several associations specified for a particular extension there should be a possibility to select a suitable one from the menu or run the first "no questions asked".

Part 2.Virtual file systems support

Support of  two VFS - archive and FTP is now required for leading OFMs.   Currently only FAR and MC support both.

1. Archive virtual file system(25%):

• Compress and extract commands that permit compress subtree into archive with optional deletion of subtree. Extract command should permit creation of a folder for extraction.  Shift-F1..Shift-F2 operations should probably be reserved for extraction and compression correspondingly( FAR, DN):

• Navigation compatibility:
• pressing of the Enter key on the archive file should produce the listing of archive content in the panel;
• Any operation for leaving the folder should work as closing the archive view.
• Quick search (alt-<letter>) should work on archive VFS panel.

• Reasonable subset of file operations implemented: 
• View, quick view  and edit should be supported
• Files can be selected, deselected as in regular folder
• File or groups can copied (copying to regular folder result in extraction; copying to archived folder results in compression; copied, moved, viewed and so on.
• Files can be deleted and renamed
• Support of View(including "Quick View" and Edit operations)
• Support of directory based operations with archive as a target(compressing directory with all subdirectories to the archive)
• Support of compare directories operation between archive and regular folder and between two archives.

• Support of at least ZIP, ARJ, RAR and LHA;

• Ability to view self-extracting archives via Ctrl-PgDn;

• Support of additional commands (integrity check, repair, etc.) via special menu item(for example Shift-F3);


2. FTP virtual file system (25%). 

• Panel navigation and representation:
• Uppercase file names should not be converted to lowercase on the FTP VFS panel
• Quick search (alt-<letter>) should work on archive VFS panel.

• Operations on files, selected files and directories:
  • copy (with option of changing of case of the files)
  • move
  • delete
  • MKDIR
  • Option of changing case to the lowercase of all files in copy and move operations
  • rename (including changing of the case of files
  • compare directories

3. Flat tree VFS --  the ability to view all files in a given directory and its subdirectories as a plain list (like in Xtree) .  This is a very important feature for system administration  (20%). 
   • Ability to view the directory and all its subdirectory as a single virtual directory
   • Ability to perform basic operation that use this virtual directory as a source
   • Ability to use filters to view files only with given extensions

4. Briefcase VFS. All operations that use this panel as a source and as a target should be allowed (15%). 
   • Ability to copy directories and files to the briefcase drive;
   • Ability to use a briefcase drive as a source for all relevant file and selection based operations;
   • Ability to discard the briefcase drive.

5. FindFile/List  VFS -- the ability to view file search results as a regular panel with all file operations available as well as the capability of multiple searches using a text-file list (as in DN). All operations that use this panel as a source should be allowed (15%)

Part 3. Modern extensions

To get to this section a feature need to be implemented in at least one major OFM implementation and prove its usefulness. Features for which no reference implementation exists are listed in section 4 of the text.

1. Navigation enhancements (favorites and history for visited directories): 10%

• The history of visited directories, so that the user can switch from one to the other like in Netscape or other WEB browser (currently implemented in MC, DN and FAR);

• The ability to add the current directory to the favorites list;

• The ability to edit the favorite's list;

• The ability to create named groups of favorites;

• The ability to jump back to prev. visited directory with a single hot-key.

• The ability to  move favorites to the toolbar (WinCmd)  or unused part of main menu.


2. Selection extensions:

• Special keys (for example "Ctrl-Gray+" and "Ctrl-Gray-") for selecting deselecting all files regardless of current selection;

• Click on current file in the panel information line(bottom line of the panel) should input file extension to the selection list and select all files with that extension in the panel (mentioned in VC documentation).

• Hotkey for selection of all files with extension equal to the extension of the current file (can be also performed by clicking on the file in the information window of the the current panel, especially in GOFMs) .

• UNIX-style regular expressions support  in selections (expression *a*.* should select files like my_bak.tmp and my_bat.txt, not all files) (MC, FAR).

• Ability to list several masks, separated by semicolon and use negation symbol with mask (JC). 


3. Command line extensions:

• Persistent command history (possibly via an option to save command history) (FAR 1.50b);

• Ability to edit the command history (DN);

• Command completion feature: Ctrl-End at the end of the command line complete the command starting with these symbols from the command history. It should be possible to press Ctrl-enter several times to find the nest command in the history that has the same prefix;

• The operation for inserting current path from left and right panels (Ctrl-[ and Ctrl-]);

• Esc is to equivalent Ctrl-O and hide both panel, so that the DOS screen is visible (VC);

• The operation for inserting selected files into command line(Ctrl-I) or equivalent (like if FAR).

• Multiple commands with semicolon as a separator

• ability to invoke different command shell or command shell with predefined parameters (for example COMMAND /E:2048)


4. Commands enhancements: 

• Support of persistent history for copy, move and create directory operations (FAR 1.50b)

• Keyboard macros (FAR, JC). Several typical file operations in OFM can be generalized as macros. The most typical example is "synchronize directories" operation which is essentially a sequence of compare directories and copy files operations. Another one is operation of creating a subdirectory in the current directory and then copying selected files to this directory. It's not possible to perform this frequent operation with one keystroke in most OFMs known to the author(NC5 does have a synchronize operation as a separate command). One need to use key macro utility like KM by E.Yutsis to achieve this. It would be nice to have that mechanism built-in.

• Options menu should have an item that gives possibility to specify  option to command.com required  to run a command (for example /e:2048). Currently implemented in VC

• File attribute command should have an additional functionality to change filestamps of one or selected files and work for the current directory (in this case the whole tree should be affected like in
  Attrib *.* /s ), file or selected files.

• Ability to execute arbitrary command or script for selected files (FAR, DN)

• Find file (Alt-F7) operation should permit finding file using date, time and size as selectors (NCW)

• Case conversion command for files via special menu (implemented in FC, FAR, DN and VC)

• Option of changing case to the lowercase of all files in copy and move operations (FAR)


5. Panel view enhancements:

• Mouse click on name, size and time headers in the panel should change the sorting order to this attribute. Second mouse click on the same button reverses the sorting order (Windows Commander 3.03; NCW 1.0);

• Additional video modes  (at least support of 30-line screen mode for COFMs line in DN) or ability to change font (GOFM only; like in WinCmd)

• Uniform treatment Ctrl-0..Ctrl-9 key sequences as a selectors of 10 predefined panel templates (with the ability to customize panels via special extension file) (FAR 1.50b)

• Descript.ion file processing  (4DOS compatibility feature) (DN, FAR, VC);

• Alt key activated top menu (you need to press F9 in other OFMs, but it is not convenient as one can press the Alt key without removing hands from the keys) (VC);

• Usage of the panel bottom border as the second line of the information windows (for displaying the number of files in the current directory) and upper delimiter of the information line for showing the number of selected files (FAR 1.50b). 

• Compact UNIX like timestamp column (time only for the recent files) (currently implemented in Win95 version of MC)

• Multiple panel windows (DN). It is a very nice feature, but does the benefits outweigh the costs is unclear. Directory favorite list can provide 50% of the functionality with much less implementation cost.


6. Tree view panel enhancements:

• Directory tree should has expand/collapse options:
• + : Expands/reads the tree starting at the current directory for one subdirectory level
• - : Collapse the subdirectory tree below the current
  directory.
• * : Expands/reads all subdirectories starting at the
  current directory.

• Presence of "Quick View" Tree operation when moving in the tree representation of the left panel change current directory on the right panel.

• Add to archive operation on the directory(Shift-F1) should create archive of that directory and optionally delete the directory and all files in it.

• Complete archive extraction to the directory operation(Shift-F2) on the archive should create directory with the name of the archive by default and unarchive all files into this directory.

• Ability to change attributes of directories.

• Better navigation on the tree view.
• Ability to return to the immediate parent of the directory(for example by Ctrl-. or backspace);
• Ability to jump from one directory to the directory with the same name but on a different branch(Ctrl-Enter);
• Gray+  move to the next directory on the same level, Gray- to the next directory on the prev. level (UFO).
• For tree view in the information windows directory level should be visible (UFO, but not it displays the directory level in the upper line instead of the panel information window);


7. Built-in viewer enhancements:

• Entering any letter or digit in viewer should activate search for this letter (FAR) (25%)

• The ability to switch from the built-in viewer to the panels view and back (DN, FAR, any Windows OFM); Ability to jump to the selected directory from the viewer (25%)

• Ability to select string and search the selected string without entering it (25%);

• Ability to switch to the panel view of the file path which is highlighted in viewer (25%).

• Symbol filter (ASCII only/Full set as in UFO)

8. Built-in editor enhancements:
• Search for any selected string.
• The ability to switch from the built-in editor to the panels view and back (DN, FAR, any GOFM).
• The ability to open several editor windows and switch between them (DN, any GORM).
• An option  "Open file under cursor" and "Go to the directory under cursor" option in built-in editor.


9. User menu and extension macro substitution symbol extensions:

• The include files capability in both user menu and extensions associations (VC)

• Additional macro variables (VC, FAR; see the table)
  
                                                                                                                       Table  

	Type of macrovarible	Active Panel	Passive Panel	Comment	Midnight Commander
1	File name without extension	!	%	VC, FAR	Standard unix feature (basename)
2	File name	!.!	%.%	VC, FAR	%f, %F
3	Path	!\	%\	VC, FAR	%d, %D
4	Drive	!:	%:	VC, FAR	Not applicable to unix
5	Selected files list	!@	%@	VC,FAR	%t, %T
6	Short file name	!~	%~`	FAR, VC	Not applicable to unix
7	Short file name with extension	!~.!	%~.%	VC, !-! in FAR	Not applicable to unix
8	List of short names of selected files	!~@	%~@	FAR, VC	Not applicable to unix

Part 4. Recommended extensions/Wish list

1. A separate from the macrorecoder key assignment mechanism similar to QEdit (via Setup) of MultiEdit (via run-time menu) editors. That can lessen the problem of incompatible key assignment for the same  functions in different OFMs.

2. Context dependent dynamic associations (it is easy to distinguish the type of the file by reading the first sector or block of the file. For example classic problem of guessing content of the document with extension  .DOC (is it in the  ASCII, RTF of MS Word format) can be solved this way.

3. Additional capabilities of working with favorites (like in Netscape)

4. Deletion of duplicates and automatic sorting of visited directories list by frequency (favorites lists).

5. Implementation of @ not as a separate macro variable, but as a modifier to any existing macro variable (for example @!.! with the following semantics: it should have a value of current file if no files are selected and value of the list of selected files otherwise.

6. Mkdir button should be dimmed if the active panel view archive content.

7. The bottom menu should show F1..F12, nor F1-F10 (IMHO now to find an XT keyboard is rather difficult :-).
8.  

9. . The title tag in HTML documents should be considered as a description and viewed in the appropriate field on the panel.

10. . Integration of  HTML-related navigation (see discussion above)

11. . Integration of TCL or REXX as a macro language

12. . Integration of a simple HTML viewer with ability to jump from hyperlink to the panel view of the appropriate directory.