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Lately, a lot of questions and opinions about different file managers were raised on different forums. The questions mostly address the differences between standard asymmetric interface file managers (Konqueror, Windows Explorer, Nautilus) and symmetric interface file managers or commonly known as twin-panel FM's or commanders (Krusader, Total commander, Midnight Commander). This article describes basic differences and similarities between two classic types of managers for KDE: Konqueror as a member of asymmetric and Krusader as an orthodox twin panel file manager.

It can be stated that every single way of managing files can produce the same results. This can be applied to console, single-panel, or twin-panel file managers, or any other way one chooses it. The difference is in how many additional programs are required to achieve this goal and even more importantly, how fast or in how many steps some operation can be done. Very significant aspects that also need to be taken into consideration are the following:

* how intuitively an operation can be performed when required,
* how complex is the preparation before an action is carried out,
* how large a view port is required, and
* how verbose does the output of the operations need to be.

When considering these aspects, the console might be considered the perfect tool. It's extremely powerful and the most appropriate tool for file management, but it also requires a lot of knowledge and understanding of scripting, which fails the intuitive part. The console allows performing complicated tasks easily, if you already know how to use it. Output is as descriptive as one needs and it is the least view-space demanding.
However, this review will skip the console from comparison, since command-line interfaces can be easily accessed from any X file manager. The console is also considered the best choice for all of the more frequently repeated, complex actions which is why its strength is often incorporated and used by all file managers in the form of scripts or actions behind a simple click on an icon. It is usually common to describe a twin panel file manager as a file manager with advanced features, while single panel are marked as basic. The question is where do these advanced features come from? Since Krusader is built using the same KDE libraries as Konqueror that means that both can have similar functionality. This implies that everything advanced in Krusader is also advanced in Konqueror. So what is, then, the difference and where are the advantages?

The short version: Krusader is primarily a file manager, while Konqueror also handles other non file management specific tasks. This is a baseline that shifts the focus of using a different type of file manager. Let's start with the basics.

What's an asymmetric single panel file manager?
Single window file managers, such as Konqueror, usually have two panels, where the leftmost is a tree-view panel that is connected to a directory and an opposing file view which usually resides in the right side of the window. Left tree panel is strictly linked to file panel which shows the current selected folder. Actions are executed in stages where the first one is selecting the files, then setting the action and last execution of the action in another folder. These are three common steps, since the manager has no default predefined destination. The destination is set or selected before the execution itself. Setting destination means browsing to the new destination in current active window while selecting means executing another instance or activating another tab. This ensures the source and the destination, but still the two are not linked in a strict way. There is a good reason for this. The Konqueror is not only a file manager, but also file browser, a canvas for all the latest KDE technology, a web browser, a universal viewing application and much more. Check the Konqueror's features web page for more information and screenshots. It integrates wide palette of functions where most of them are click oriented, like browsing. This links the manager tightly to using a mouse. Konqueror also supports key bindings, but those are common keys used in every application, like Ctrl+a, to Select All Files, and similar keys. Konqueror can use a "split window" feature that gives an twin panel look, but it lacks it's panel dependent functionality.

What is then a twin panel file manager?
By definition all twin panel file managers, like Krusader, have a main window that is divided into three sub-windows called "panels". Two of them are usually identical in structure and are positioned horizontally or vertically side by side, while a third one sits on the bottom of the window. The third section is a command line which is expandable by nature and tries to mimic console functions. The structure of two side by side panels is linked and its functioning is strongly keyboard oriented, enabling the ability to perform all functions without a mouse. Two panels can be restructured to a single view, if one panel acts as a tree view to the opposite one. This holds the same characteristic functioning as the single panel file manager. Two panels, if set as equivalent, are defined as active or source and inactive or destination panel. Supported tabs allow the user to set many sources and many destinations, which can also be obligatorily connected. This means that executing and action from one source results in predefined destination. Krusader also comes with two pop up panels called third hand panels. Their function is selective to the panels. It can be a file viewer, searching panel, calculator of occupied space and more.

The single panel actually has two and the twin panel usually at least three panels! Is someone putting me on?
The names single and twin denote the number of simultaneously usable panels. There are file managers that have four or more panels, but still function as a twin panel, since the pairs of panels are not directly connected. The main difference between the two types of file manager is ideology behind operations. It's predicted, that the more complex the operation gets, the less appropriate it is for a simplistic mouse action. Since most mouse actions consist of drag and drop, it makes all actions limited by three main traits; first holding, then doing something and at last releasing the mouse button. Some single panel file managers are also introducing mouse gestures, which can drastically improve the mouse usability, especially of "doing something", but are still limited in functioning and less appropriate for users with accessibility problems. Mice with many buttons can drastically improve the speed of performance, but usually those buttons are not set. Using a mouse can be very operational in some cases and one big panel is more appropriate for mouse oriented usages, while on the other hand two panels are more strictly confined to source - destination operations like managing files. Since both types of application use similar add-on technologies like profiles, bookmarks, tabs, file associations and other, the real and the most important differences remain how fast or in how many steps an action can be completed, how the actions can be prepared, how much a big view port is needed and how verbose the operations need to be.

The function shapes the form.
This statement might be taken from Darwin's evolution, but still can also be useful in describing file managers. For fast operations, preparation is one big difference between Krusader and the Konqueror. Krusader sorts and searches for files in every possible way. To make the statement lighter, I need to add, that if some way was not implemented yet, it's surely on the to-do list or was never asked for. Functions like "show only this file type", "feed to virtual folder", "predefined masks", "profiles", and "search for something in everything" that can be executed through a single shortcut are really features only needed by a more demanding audience. After widening the preparation idea to synchronization, comparing and multi renaming, even though the last two usually call external apps, this ideology is mind blowing. For example, to compare two files, one needs to fulfill one of four possibilities: select two files in one directory, select two in different directories in different panels, select any two from virtual folder or select one in one panel, if second file has the same name in other panel. Only the first one can be done in Konqueror, because its one panel is never aware of another tab or another window. Every file operation denotes one of the tree basic actions. First action is an execution of file as an application or as a document. If an "odt" file is executed, we don't expect it to do something, but rather expect some other app to handle this type. In this case this document is handled by OpenOffice.org. Same goes for "pdf" or "mp3", but using different applications. In case we deal with executables, then those files usually do not have extensions, but do some specific tasks. This action is executed with single or double mouse click or by hitting "enter" on the high-lighted file, in every type of file manager.

Second action is changing the document file itself in primary position. This functionality differs from two compared file managers. The "odt" format might be best handled by OpenOffice.org, and "html" by Firefox, but how does an application know what I need to do with it, or if another action is more suitable? For this single panel, which is build for usage, there really is no standard solution. On the other hand twin panel file managers try to specify every possible application for their type of function to be more productivity and less usability specific oriented. Every twin panel file manager has two buttons for view and edit. First one shows the contents behind the file type and second allows editing this content. In this case, a "html" is not only linked to a browser that shows the webpage, but also the build-in editor, that allows to change the contents or build-in viewer for different views. One application for the job is an ideology behind big single panel file managers. You have files, which are associated with some app that handles the format. You also have some other app that does something else with the file behind the designated type. Konqueror's right click shows the "open with" entry in the menu, while Krusader holds different shortcut keys for different actions. For example a "html" file can be executed in Firefox with enter or double-click, it is also linked to classic F3 for text view and F4 for text edit mode and third these two keys can be combined with some metakey, for viewing and editing respectively in special application. For example shift+F4 executes loading in predefined editor. Whether the applications should be all-in-one or one-for-specific task is debated about a lot, but usually users prefer the first, while specialists prefer second, due to the fact that shorter apps execute faster and it's easier to control. The viewing and editing is a very important feature in twin panels. The built-in editor and viewer are usually bundled with different enhancements like color-coding of the tags in specific programming languages, the two support multiple encodings and have the ability to change it with save command among other. All these can be assigned to Konqueror, but searching for specialized app is a bit more complicated, since it is selected through a selection dialog. The real problem starts when the app is not listed among predefined. But same operations can also be easily executed in Konqueror using drag and drop. The difference is, that in this case both windows must be opened. The difference, as shown, is not in whether the action can be done, but rather how it's done.

The third aspect is changing the location of files. This change can be something like copying, moving, uploading, packing or something. Konqueror needs right click and copy and then right click and paste after the new destination is selected, or drag and drop if two instances are opened. In twin panels these are linked from source panel to destination with a single key combination, F5, F6, alt+P respectively.
For example, packing selected files is really no more that hitting alt+P and enter, if the default compression utility is "tar.gz". If you prefer other, you can change the default or simply selecting different tool among many for the job. Konqueror users usually don't deal much with packing and, thus is this action handled by some outside all in one application that can also be called from the right-click menu. The Konqueror's ideology for operations implies that packing is primarily done to source directory; while for twin panel it's whatever the destination offers. I need to mention, that packing and copying can also be performed in Konqueror using a single action, if you select different output location, but you need to select one which is by default more than one mouse click away.

Another big difference is how verbose is the manager when comes to showing information about the files. Basic info about files is in Konqueror when files are viewed in list view. Same info is shown in Krusader, but it has a special line under every panel for additional file or directory info. Even more information can be found in special filelight module that is integrated into panels as a third hand popup. Krusader is extremely descriptive and informative, while Konqueror usually hides this info since users don't need it. In the latest version Krusader introduced short number codes for permission assigned to every file, while also allows them to be shown in other ways. This info is file specific, but it's still shown in the panel. Konqueror shows this information in Properties section of the right click menu in single, most descriptive, way.

Big viewport does not need to be specifically mentioned. Everyone trying to browse the web using one fourth of the fifteen inch screen or viewing an online media file knows that some things are better big than small, while some are just the reverse. Konqueror has a big window which is suitable for many operations that Krusader can never be used for. You can view a webpage in Krusader, but I don't think that many people are using it for that task.

What are the real advantages of OFM and Krusader?
There are five major advantages that come with twin panel file managers:
* the first real advantage of OFM's for file management lie in the paradigm, that one panel is always aware of the other, the opposite one. This simplifies basic file operations as moving, packing and copying and also other more specific tasks like comparing directories, synchronizing them and gathering information about the system.
* secondly it's strongly keyboard oriented. Key bindings are usually selected in a way to facilitate usage whether the keys are executed single handedly or with both hands. Keyboard operations are the fastest way to execute commands.
* third advantage is a built-in viewer and editor with specialized functions for programming languages and multiple encodings.
* fourth is a strong incorporation of scripting support like User-action system. This extends the functionality and also simplifies the common frequently repeating tasks.
* fifth is extremely descriptive and verbose outputs of actions and system information.

This makes no sense.
Well this might make no sense for the user who has never used twin-panel file managers. If you look at the documentation on the Krusader's webpage you see, that it's not expected that everyone know all the functions available. This also happens to long time users of Krusader. Many users in forums like to tell, it's the "fullness" of the manager that gets them confused. On the other hand users that did spend some time with it really have trouble living without it. This can not be said to be reversed. I've yet to meet a person, that after some time using twin panel, changes to single panel one. Forums are full of users asking for a replacement for MS Windows twin panel file managers. Anyway, using one or another to manage files is for users to decide and falls straight to the needs that users have. Although Krusader is considered an advanced file manager with many features on board, it is also very easy to use and very intuitive for new users. The advanced features can be used if needed, but can also be ignored. This makes Krusader unique and can be appropriate for both new and advanced users. Most Linux distributions only provide single-window file manager, which might be the reason, why penetration of twin panel managers is so very slow.

For more information about both KDE file managers, please visit:
Krusader - twin panel file manager;
Konqueror - multi purpose manager for KDE.
Softpanorama - home of the
orthodox file management paradigm.

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