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diff --git a/ext2ed/doc/user-guide.sgml b/ext2ed/doc/user-guide.sgml new file mode 100644 index 0000000..1e8f3cd --- /dev/null +++ b/ext2ed/doc/user-guide.sgml @@ -0,0 +1,2258 @@ +<!DOCTYPE Article PUBLIC "-//OASIS//DTD DocBook V4.1//EN"> + +<Article> + +<ArticleInfo> + +<Title>EXT2ED - The Extended-2 filesystem editor - User's guide</Title> +<AUTHOR> +<FirstName>Gadi Oxman, tgud@tochnapc2.technion.ac.il</FirstName> +</AUTHOR> +<PubDate>v0.1, August 3 1995</PubDate> + +<Abstract> + +<Para> +This is only the initial version of this document. It may be unclear at +some places. Please send me feedback with anything regarding to it. +</Para> + +</Abstract> + +</ArticleInfo> + +<Sect1> +<Title>About EXT2ED documentation</Title> + +<Para> +The EXT2ED documentation consists of three parts: + +<ItemizedList> +<ListItem> + +<Para> + The ext2 filesystem overview. +</Para> +</ListItem> +<ListItem> + +<Para> + The EXT2ED user's guide. +</Para> +</ListItem> +<ListItem> + +<Para> + The EXT2ED design and implementation. +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +<Para> +If you intend to used EXT2ED, I strongly suggest that you would be familiar +with the material presented in the <Literal remap="tt">ext2 filesystem overview</Literal> as well. +</Para> + +<Para> +If you also intend to browse and modify the source code, I suggest that you +will also read the article <Literal remap="tt">The EXT2ED design and implementation</Literal>, as it +provides a general overview of the structure of my source code. +</Para> + +</Sect1> + +<Sect1> +<Title>Introduction</Title> + +<Para> +EXT2ED is a "disk editor" for the ext2 filesystem. Its purpose is to show +you the internal structures of the ext2 filesystem in an rather intuitive +and logical way, so that it will be easier to "travel" between the various +internal filesystem structures. +</Para> + +</Sect1> + +<Sect1> +<Title>Basic concepts in EXT2ED</Title> + +<Para> +Two basic concepts in EXT2ED are <Literal remap="tt">commands</Literal> and <Literal remap="tt">types</Literal>. +</Para> + +<Para> +EXT2ED is object-oriented in the sense that it defines objects in the +filesystem, like a <Literal remap="tt">super-block</Literal> or a <Literal remap="tt">directory</Literal>. An object is +something which "knows" how to handle some aspect of the filesystem. +</Para> + +<Para> +Your interaction with EXT2ED is done through <Literal remap="tt">commands</Literal> which EXT2ED +accepts. There are three levels of commands: + +<ItemizedList> +<ListItem> + +<Para> + General Commands +</Para> +</ListItem> +<ListItem> + +<Para> + Extended-2 Filesystem general commands +</Para> +</ListItem> +<ListItem> + +<Para> + Type specific commands +</Para> +</ListItem> + +</ItemizedList> + +The General commands are always available. +</Para> + +<Para> +The ext2 general commands are available only when editing an ext2 filesystem. +</Para> + +<Para> +The Type specific commands are available when editing a specific object in the +filesystem. Each object typically comes with its own set of internal +variables, and its own set of commands, which are fine tuned handle the +corresponding structure in the filesystem. +</Para> + +</Sect1> + +<Sect1> +<Title>Running EXT2ED</Title> + +<Para> +Running EXT2ED is as simple as typing <Literal remap="tt">ext2ed</Literal> from the shell prompt. +There are no command line switches. +</Para> + +<Para> +When first run, EXT2ED parses its configuration file, <Literal remap="tt">ext2ed.conf</Literal>. +This file must exist. +</Para> + +<Para> +When the configuration file processing is done, EXT2ED screen should appear +on the screen, with the command prompt <Literal remap="tt">ext2ed></Literal> displayed. +</Para> + +</Sect1> + +<Sect1> +<Title>EXT2ED user interface</Title> + +<Para> +EXT2ED uses the <Emphasis>ncurses</Emphasis> library for screen management. Your screen +will be divided into four parts, from top to bottom: + +<ItemizedList> +<ListItem> + +<Para> + Title window +</Para> +</ListItem> +<ListItem> + +<Para> + Status window +</Para> +</ListItem> +<ListItem> + +<Para> + Main editing window +</Para> +</ListItem> +<ListItem> + +<Para> + Command window +</Para> +</ListItem> + +</ItemizedList> + +The title window just displays the current version of EXT2ED. +</Para> + +<Para> +The status window will display various information regarding the state of +the editing at this point. +</Para> + +<Para> +The main editing window is the place at which the actual data will be shown. +Almost every command will cause some display at this window. This window, as +opposed to the three others, is of variable length - You always look at one +page of it. The current page and the total numbers of pages at this moment +is displayed at the status window. Moving between pages is done by the use +of the <Command>pgdn</Command> and <Command>pgup</Command> commands. +</Para> + +<Para> +The command window is at the bottom of the screen. It always displays a +command prompt <Literal remap="tt">ext2ed></Literal> and allows you to type a command. Feedback +about the commands entered is displayed to this window also. +</Para> + +<Para> +EXT2ED uses the <Emphasis>readline</Emphasis> library while processing a command line. All +the usual editing keys are available. Each entered command is placed into a +history of commands, and can be recalled later. Command Completion is also +supported - Just start to type a command, and press the completion key. +</Para> + +<Para> +Pressing <Literal remap="tt">enter</Literal> at the command window, without entering a command, +recalls the last command. This is useful when moving between close entries, +in the <Command>next</Command> command, for example. +</Para> + +</Sect1> + +<Sect1> +<Title>Getting started</Title> + +<Sect2> +<Title>A few precautions</Title> + +<Para> +EXT2ED is a tool for filesystem <Literal remap="tt">editing</Literal>. As such, it can be +<Literal remap="tt">dangerous</Literal>. The summary to the subsections below is that +<Literal remap="tt">You must know what you are doing</Literal>. +</Para> + +<Sect3 id="mounted-ref"> +<Title>A mounted filesystem</Title> + +<Para> +EXT2ED is not designed to work on a mounted filesystem - It is complicated +enough as it is; I didn't even try to think of handling the various race +conditions. As such, please respect the following advice: +</Para> + +<Para> +<Literal remap="tt">Do not use EXT2ED on a mounted filesystem !</Literal> +</Para> + +<Para> +EXT2ED will not allow write access to a mounted filesystem. Although it is +fairly easy to change EXT2ED so that it will be allowed, I hereby request +again- EXT2ED is not designed for that action, and will most likely corrupt +data if used that way. Please don't do that. +</Para> + +<Para> +Concerning read access, I chose to leave the decision for the user through +the configuration file option <Literal remap="tt">AllowMountedRead</Literal>. Although read access +on a mounted partition will not do any damage to the filesystem, the data +displayed to you will not be reliable, and showing you incorrect information +may be as bad as corrupting the filesystem. However, you may still wish to +do that. +</Para> + +</Sect3> + +<Sect3> +<Title>Write access</Title> + +<Para> +Considering the obvious sensitivity of the subject, I took the following +actions: +</Para> + +<Para> + +<OrderedList> +<ListItem> + +<Para> + EXT2ED will always start with a read-only access. Write access mode +needs to be specifically entered by the <Command>enablewrite</Command> command. +Until this is done, no write will be allowed. Write access can be +disabled at any time with <Command>disablewrite</Command>. When +<Command>enablewrite</Command> is issued, the device is reopened in read-write +mode. Needless to say, the device permissions should allow that. +</Para> +</ListItem> +<ListItem> + +<Para> + As a second level of protection, you can disallow write access in +the configuration file by using the <Literal remap="tt">AllowChanges off</Literal> +configuration option. In this case, the <Command>enablewrite</Command> command +will be refused. +</Para> +</ListItem> +<ListItem> + +<Para> + When write access is enabled, the data will never change +immediately. Rather, a specific <Command>writedata</Command> command is needed +to update the object in the disk with the changed object in memory. +</Para> +</ListItem> +<ListItem> + +<Para> + In addition, A logging option is provided through the configuration +file options <Literal remap="tt">LogChanges</Literal> and <Literal remap="tt">LogFile</Literal>. With logging +enabled, each change to the disk will be logged at a very primitive +level - A hex dump of the original data and of the new written data. +The log file will be a text file which is easily readable, and you +can make use of it to undo any changes which you made (EXT2ED doesn't +make use of the log file for that purpose, it just logs the changes). +</Para> +</ListItem> + +</OrderedList> + +Please remember that this is only the initial release of EXT2ED, and it is +not very much tested - It is reasonable to assume that <Literal remap="tt">there are +bugs</Literal>. +However, the logging option above can offer protection even from this +unfortunate case. Therefor, I highly recommend that at least when first +working with EXT2ED, the logging option will be enabled, despite the disk +space which it consumes. +</Para> + +</Sect3> + +</Sect2> + +<Sect2 id="help-ref"> +<Title>The help command</Title> + +<Para> +When loaded, EXT2ED will show a short help screen. This help screen can +always be retrieved by the command <Command>help</Command>. The help screen displays a +list of all the commands which are available at this point. At startup, only +the <Literal remap="tt">General commands</Literal> are available. +This will change with time, since each object has its own commands. Thus, +commands which are available now may not be available later. +Using <Command>help</Command> <Emphasis>command</Emphasis> will display additional information about +the specific command <Emphasis>command</Emphasis>. +</Para> + +</Sect2> + +<Sect2 id="setdevice-ref"> +<Title>The setdevice command</Title> + +<Para> +The first command that is usually entered to EXT2ED is the <Command>setdevice</Command> +command. This command simply tells EXT2ED on which device the filesystem is +present. For example, suppose my ext2 filesystem is on the first partition +of my ide disk. The command will be: + +<Screen> +setdevice /dev/hda1 +</Screen> + +The following actions will take place in the following order: + +<OrderedList> +<ListItem> + +<Para> + EXT2ED will check if the partition is mounted. +If the partition is mounted (<Literal remap="tt">highly not recommended</Literal>), +the accept/reject behavior will be decided by the configuration +file. Cross reference section <XRef LinkEnd="mounted-ref">. +</Para> +</ListItem> +<ListItem> + +<Para> + The specified device will be opened in read-only mode. The +permissions of the device should be set in a way that allows +you to open the device for read access. +</Para> +</ListItem> +<ListItem> + +<Para> + Autodetection of an ext2 filesystem will be made by searching for +the ext2 magic number in the main superblock. +</Para> +</ListItem> +<ListItem> + +<Para> + In the case of a successful recognition of an ext2 filesystem, the +ext2 filesystem specific commands and the ext2 specific object +definitions will be registered. The object definitions will be read +at run time from a file specified by the configuration file. + +In case of a corrupted ext2 filesystem, it is quite possible that +the main superblock is damaged and autodetection will fail. In that +case, use the configuration option <Literal remap="tt">ForceExt2 on</Literal>. This is not +the default case since EXT2ED can be used at a lower level to edit a +non-ext2 filesystem. +</Para> +</ListItem> +<ListItem> + +<Para> + In a case of a successful autodetection, essential information about +the filesystem such as the block size will be read from the +superblock, unless the used overrides this behavior with an +configuration option (not recommended). In that case, the parameters +will be read from the configuration file. + +In a case of an autodetection failure, the essential parameters +will be read from the configuration file. +</Para> +</ListItem> + +</OrderedList> + +Assuming that you are editing an ext2 filesystem and that everything goes +well, you will notice that additional commands are now available in the help +screen, under the section <Literal remap="tt">ext2 filesystem general commands</Literal>. In +addition, EXT2ED now recognizes a few objects which are essential to the +editing of an ext2 filesystem. +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>Two levels of usage</Title> + +<Sect2> +<Title>Low level usage</Title> + +<Para> +This section explains what EXT2ED provides even when not editing an ext2 +filesystem. +</Para> + +<Para> +Even at this level, EXT2ED is more than just a hex editor. It still allows +definition of objects and variables in run time through a user file, +although of-course the objects will not have special fine tuned functions +connected to them. EXT2ED will allow you to move in the filesystem using +<Command>setoffset</Command>, and to apply an object definition on a specific place +using <Command>settype</Command> <Emphasis>type</Emphasis>. From this point and on, the object will +be shown <Literal remap="tt">in its native form</Literal> - You will see a list of the +variables rather than just a hex dump, and you will be able to change each +variable in the intuitive form <Command>set variable=value</Command>. +</Para> + +<Para> +To define objects, use the configuration option <Literal remap="tt">AlternateDescriptors</Literal>. +</Para> + +<Para> +There are now two forms of editing: + +<ItemizedList> +<ListItem> + +<Para> + Editing without a type. In this case, the disk block will be shown +as a text+hex dump, and you will be able to move along and change it. +</Para> +</ListItem> +<ListItem> + +<Para> + Editing with a type. In this case, the object's variables will be +shown, and you will be able to change each variable in its native form. +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +</Sect2> + +<Sect2> +<Title>High level usage</Title> + +<Para> +EXT2ED was designed for the editing of the ext2 filesystem. As such, it +"understands" the filesystem structure to some extent. Each object now has +special fine tuned 'C' functions connected to it, which knows how to display +it in an intuitive form, and how the object fits in the general design of +the ext2 filesystem. It is of-course much easier to use this type of +editing. For example: + +<Screen> +Issue <Emphasis>group 2</Emphasis> to look at the main copy of the third group block +descriptor. With <Emphasis>gocopy 1</Emphasis> you can move to its first backup copy, +and with <Emphasis>inode</Emphasis> you can start editing the inode table of the above +group block. From here, if the inode corresponds to a file, you can +use <Emphasis>file</Emphasis> to edit the file in a "continuous" way, using +<Emphasis>nextblock</Emphasis> to pass to its next block, letting EXT2ED following by +itself the direct blocks, indirect blocks, ..., while still preserving the +actual view of the exact block usage of the file. +</Screen> + +The point is that the "tour" of the filesystem will now be synchronous rather +than asynchronous - Each object has the "links" to pass between connected +logical structures, and special fine-tuned functions to deal with it. +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>General commands</Title> + +<Para> +I will now start with a systematic explanation of the general commands. +Please feel free to experiment, but take care when using the +<Literal remap="tt">enablewrite</Literal> command. +</Para> + +<Para> +Whenever a command syntax is specified, arguments which are optional are +enclosed with square brackets. +</Para> + +<Para> +Please note that in EXT2ED, each command can be overridden by a specific +object to provide special fine-tuned functionality. In general, I was +attempting to preserve the similarity between those functions, which are +accessible by the same name. +</Para> + +<Sect2 id="disablewrite-ref"> +<Title>disablewrite</Title> + +<Para> + +<Screen> +Syntax: disablewrite +</Screen> + +<Command>disablewrite</Command> is used to reopen the device with read-only access. When +first running EXT2ED, the device is opened in read-only mode, and an +explicit <Command>enablewrite</Command> is required for write access. When finishing +with changing, a <Command>disablewrite</Command> is recommended for safety. Cross +reference section <XRef LinkEnd="disablewrite-ref">. +</Para> + +</Sect2> + +<Sect2 id="enablewrite-ref"> +<Title>enablewrite</Title> + +<Para> + +<Screen> +Syntax: enablewrite +</Screen> + +<Command>enablewrite</Command> is used to reopen the device with read-write access. +When first running EXT2ED, the device is opened in read-only mode, and an +explicit <Command>enablewrite</Command> is required for write access. +<Command>enablewrite</Command> will fail if write access is disabled from the +configuration file by the <Literal remap="tt">AllowChanges off</Literal> configuration option. +Even after <Command>enablewrite</Command>, an explicit <Command>writedata</Command> +is required to actually write the new data to the disk. +When finishing with changing, a <Command>disablewrite</Command> is recommended for safety. +Cross reference section <XRef LinkEnd="enablewrite-ref">. +</Para> + +</Sect2> + +<Sect2> +<Title>help</Title> + +<Para> + +<Screen> +Syntax: help [command] +</Screen> + +The <Command>help</Command> command is described at section <XRef LinkEnd="help-ref">. +</Para> + +</Sect2> + +<Sect2 id="next-ref"> +<Title>next</Title> + +<Para> + +<Screen> +Syntax: next [number] +</Screen> + +This section describes the <Emphasis>general command</Emphasis> <Command>next</Command>. <Command>next</Command> +is overridden by several types in EXT2ED, to provide fine-tuned +functionality. +</Para> + +<Para> +The <Literal remap="tt">next general command</Literal> behavior is depended on whether you are editing a +specific object, or none. +</Para> + +<Para> + +<ItemizedList> +<ListItem> + +<Para> + In the case where Type is <Literal remap="tt">none</Literal> (The current type is showed +on the status window by the <Command>show</Command> command), <Literal remap="tt">next</Literal> +passes to the next <Emphasis>number</Emphasis> bytes in the current edited block. +If <Emphasis>number</Emphasis> is not specified, <Emphasis>number=1</Emphasis> is assumed. +</Para> +</ListItem> +<ListItem> + +<Para> + In the case where Type is defined, the <Command>next</Command> commands assumes +that you are editing an array of objects of that type, and the +<Command>next</Command> command will just pass to the next entry in the array. +If <Emphasis>number</Emphasis> is defined, it will pass <Emphasis>number</Emphasis> entries +ahead. +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +</Sect2> + +<Sect2 id="pgdn-ref"> +<Title>pgdn</Title> + +<Para> + +<Screen> +Syntax: pgdn +</Screen> + +Usually the edited data doesn't fit into the visible main window. In this +case, the status window will indicate that there is more to see "below" by +the message <Literal remap="tt">Page x of y</Literal>. This means that there are <Emphasis>y</Emphasis> pages +total, and you are currently viewing the <Emphasis>x</Emphasis> page. With the <Command>pgdn</Command> +command, you can pass to the next available page. +</Para> + +</Sect2> + +<Sect2> +<Title>pgup</Title> + +<Para> + +<Screen> +Syntax: pgup +</Screen> + +</Para> + +<Para> +<Command>pgup</Command> is the opposite of <Command>pgdn</Command> - It will pass to the previous +page. Cross reference section <XRef LinkEnd="pgdn-ref">. +</Para> + +</Sect2> + +<Sect2> +<Title>prev</Title> + +<Para> + +<Screen> +Syntax: prev [number] +</Screen> + +</Para> + +<Para> +<Command>prev</Command> is the opposite of <Command>next</Command>. Cross reference section +<XRef LinkEnd="next-ref">. +</Para> + +</Sect2> + +<Sect2 id="recall-ref"> +<Title>recall</Title> + +<Para> + +<Screen> +Syntax: recall object +</Screen> + +<Command>recall</Command> is the opposite of <Command>remember</Command>. It will place you at the +place you where when saving the object position and type information. Cross +reference section <XRef LinkEnd="remember-ref">. +</Para> + +</Sect2> + +<Sect2> +<Title>redraw</Title> + +<Para> + +<Screen> +Syntax: redraw +</Screen> + +Sometimes the screen display gets corrupted. I still have problems with +this. The <Command>redraw</Command> command simply redraws the entire display screen. +</Para> + +</Sect2> + +<Sect2 id="remember-ref"> +<Title>remember</Title> + +<Para> + +<Screen> +Syntax: remember object +</Screen> + +EXT2ED provides you <Literal remap="tt">memory</Literal> of objects; While editing, you may reach an +object which you will like to return to later. The <Command>remember</Command> command +will store in memory the current place and type of the object. You can +return to the object by using the <Command>recall</Command> command. Cross reference +section <XRef LinkEnd="recall-ref">. +</Para> + +<Para> +<Literal remap="tt">Note:</Literal> + +<ItemizedList> +<ListItem> + +<Para> + When remembering a <Literal remap="tt">file</Literal> or a <Literal remap="tt">directory</Literal>, the +corresponding inode will be saved in memory. The basic reason is that +the inode is essential for finding the blocks of the file or the +directory. +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +</Sect2> + +<Sect2> +<Title>set</Title> + +<Para> + +<Screen> +Syntax: set [text || hex] arg1 [arg2 arg3 ...] + +or + +Syntax: set variable=value +</Screen> + +The <Command>set</Command> command is used to modify the current data. +The <Command>set general command</Command> behavior is depended on whether you are editing a +specific object, or none. +</Para> + +<Para> + +<ItemizedList> +<ListItem> + +<Para> + In the case where Type is <Command>none</Command>, the first syntax should be +used. The set command affects the data starting at the current +highlighted position in the edited block. + +<ItemizedList> +<ListItem> + +<Para> + When using the <Command>set hex</Command> command, a list of +hexadecimal bytes should follow. +</Para> +</ListItem> +<ListItem> + +<Para> + When using the <Command>set text</Command> command, it should be followed +by a text string. +</Para> +</ListItem> + +</ItemizedList> + +Examples: + +<Screen> + set hex 09 0a 0b 0c 0d 0e 0f + set text Linux is just great ! + +</Screen> + +</Para> +</ListItem> +<ListItem> + +<Para> + In the case where Type is defined, the second syntax should be used. +The set commands just sets the variable <Emphasis>variable</Emphasis> with the +value <Emphasis>value</Emphasis>. +</Para> +</ListItem> + +</ItemizedList> + +In any case, the data is only changed in memory. For an actual update to the +disk, use the <Command>writedata</Command> command. +</Para> + +</Sect2> + +<Sect2> +<Title>setdevice</Title> + +<Para> + +<Screen> +Syntax: setdevice device +</Screen> + +The <Command>setdevice</Command> command is described at section <XRef LinkEnd="setdevice-ref">. +</Para> + +</Sect2> + +<Sect2> +<Title>setoffset</Title> + +<Para> + +<Screen> +Syntax: setoffset [block || type] [+|-]offset +</Screen> + +The <Command>setoffset</Command> command is used to move asynchronously inside the file +system. It is considered a low level command, and usually should not be used +when editing an ext2 filesystem, simply because movement is better +utilized through the specific ext2 commands. +</Para> + +<Para> +The <Command>offset</Command> is in bytes, and meanwhile should be positive and smaller +than 2GB. +</Para> + +<Para> +Use of the <Command>block</Command> modifier changes the counting unit to block. +</Para> + +<Para> +Use of the <Literal remap="tt">+ or -</Literal> modifiers signals that the offset is relative to +the current position. +</Para> + +<Para> +use of the <Literal remap="tt">type</Literal> modifier is allowed only with relative offset. This +modifier will multiply the offset by the size of the current type. +</Para> + +</Sect2> + +<Sect2> +<Title>settype</Title> + +<Para> + +<Screen> +Syntax: settype type || [none | hex] +</Screen> + +The <Command>settype</Command> command is used to move apply the object definitions of +the type <Emphasis>type</Emphasis> on the current position. It is considered a low level +command and usually should not be used when editing an ext2 filesystem since +EXT2ED provides better tools. It is of-course very useful when editing a +non-ext2 filesystem and using user-defined objects. +</Para> + +<Para> +When <Emphasis>type</Emphasis> is <Emphasis>hex</Emphasis> or <Emphasis>none</Emphasis>, the data will be displayed as +a hex and text dump. +</Para> + +</Sect2> + +<Sect2> +<Title>show</Title> + +<Para> + +<Screen> +Syntax: show +</Screen> + +The <Command>show</Command> command will show the data of the current object at the +current position on the main display window. It will also update the status +window with type specific information. It may be necessary to use +<Command>pgdn</Command> and <Command>pgup</Command> to view the entire data. +</Para> + +</Sect2> + +<Sect2> +<Title>writedata</Title> + +<Para> + +<Screen> +Syntax: writedata +</Screen> + +The <Command>writedata</Command> command will update the disk with the object data that +is currently in memory. This is the point at which actual change is made to +the filesystem. Without this command, the edited data will not have any +effect. Write access should be allowed for a successful update. +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>Editing an ext2 filesystem</Title> + +<Para> +In order to edit an ext2 filesystem, you should, of course, know the structure +of the ext2 filesystem. If you feel that you lack some knowledge in this +area, I suggest that you do some of the following: + +<ItemizedList> +<ListItem> + +<Para> + Read the supplied ext2 technical information. I tried to summarize +the basic information which is needed to get you started. +</Para> +</ListItem> +<ListItem> + +<Para> + Get the slides that Remy Card (The author of the ext2 filesystem) +prepared concerning the ext2 filesystem. +</Para> +</ListItem> +<ListItem> + +<Para> + Read the kernel sources. +</Para> +</ListItem> + +</ItemizedList> + +At this point, you should be familiar with the following terms: +<Literal remap="tt">block, inode, superblock, block groups, block allocation bitmap, inode +allocation bitmap, group descriptors, file, directory.</Literal>Most of the above +are objects in EXT2ED. +</Para> + +<Para> +When editing an ext2 filesystem it is recommended that you use the ext2 +specific commands, rather then the general commands <Command>setoffset</Command> and +<Command>settype</Command>, mainly because: + +<OrderedList> +<ListItem> + +<Para> + In most cases it will be unreliable, and will display incorrect +information. + +Sometimes in order to edit an object, EXT2ED needs the information +of some other related objects. For example, when editing a +directory, EXT2ED needs access to the inode of the edited directory. +Simply setting the type to a directory <Literal remap="tt">will be unreliable</Literal>, +since the object assumes that you passed through its inode to reach +it, and expects this information, which isn't initialized if you +directly set the type to a directory. +</Para> +</ListItem> +<ListItem> + +<Para> + EXT2ED offers far better tools for handling the ext2 filesystem +using the ext2 specific commands. +</Para> +</ListItem> + +</OrderedList> + +</Para> + +</Sect1> + +<Sect1> +<Title>ext2 general commands</Title> + +<Para> +The <Literal remap="tt">ext2 general commands</Literal> are available only when you are editing an +ext2 filesystem. They are <Literal remap="tt">general</Literal> in the sense that they are not +specific to some object, and can be invoked anytime. +</Para> + +<Sect2 id="general-superblock"> +<Title>super</Title> + +<Para> + +<Screen> +Syntax: super +</Screen> + +The <Command>super</Command> command will "bring you" to the main superblock copy. It +will automatically set the object type to <Literal remap="tt">ext2_super_block</Literal>. Then you +will be able to view and edit the superblock. When you are in the +superblock, other commands will be available. +</Para> + +</Sect2> + +<Sect2> +<Title>group</Title> + +<Para> + +<Screen> +Syntax: group [number] +</Screen> + +The <Command>group</Command> command will "bring you" to the main copy of the +<Emphasis>number</Emphasis> group descriptor. It will automatically set the object type to +<Literal remap="tt">ext2_group_desc</Literal>. Then you will be able to view and edit the group +descriptor entry. When you are there, other commands will be available. +</Para> + +</Sect2> + +<Sect2> +<Title>cd</Title> + +<Para> + +<Screen> +Syntax: cd path +</Screen> + +The <Command>cd</Command> command will let you travel in the filesystem in the nice way +that the mounted filesystem would have let you. +</Para> + +<Para> +The <Command>cd</Command> command is a complicated command. Although it may sound +simple at first, an implementation of a typical cd requires passing through +the group descriptors, inodes, directory entries, etc. For example: +</Para> + +<Para> +The innocent cd /usr command can be done by using more primitive +EXT2ED commands in the following way (It is implemented exactly this way): + +<OrderedList> +<ListItem> + +<Para> + Using <Command>group 0</Command> to go to the first group descriptor. +</Para> +</ListItem> +<ListItem> + +<Para> + Using <Command>inode</Command> to get to the Bad blocks inode. +</Para> +</ListItem> +<ListItem> + +<Para> + Using <Command>next</Command> to pass to the root directory inode. +</Para> +</ListItem> +<ListItem> + +<Para> + Using <Command>dir</Command> to see the directory. +</Para> +</ListItem> +<ListItem> + +<Para> + Using <Command>next</Command> until we find the directory usr. +</Para> +</ListItem> +<ListItem> + +<Para> + Using <Command>followinode</Command> to pass to the inode corresponding to usr. +</Para> +</ListItem> +<ListItem> + +<Para> + Using <Command>dir</Command> to see the directory of /usr. +</Para> +</ListItem> + +</OrderedList> + +And those commands aren't that primitive; For example, the tracing of the +blocks which belong to the root directory is done automatically by the dir +command behind the scenes, and the followinode command will automatically +"run" to the correct group descriptor in order to find the required inode. +</Para> + +<Para> +The path to the <Command>general cd</Command> command needs to be a full pathname - +Starting from <Filename>/</Filename>. The <Command>cd</Command> command stops at the last reachable +point, which can be a directory entry, in which case the type will be set to +<Literal remap="tt">dir</Literal>, or an inode, in which case the type will be set to +<Literal remap="tt">ext2_inode</Literal>. Symbolic links (Only fast symbolic links, meanwhile) are +automatically followed (if they are not across filesystems, of-course). If +the type is set to <Literal remap="tt">dir</Literal>, you can use a path relative to the +"current directory". +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>The superblock</Title> + +<Para> +The superblock can always be reached by the ext2 general command +<Command>super</Command>. Cross reference section <XRef LinkEnd="general-superblock">. +</Para> + +<Para> +The status window will show you which copy of the superblock copies you are +currently editing. +</Para> + +<Para> +The main data window will show you the values of the various superblock +variables, along with some interpretation of the values. +</Para> + +<Para> +Data can be changed with the <Command>set</Command> and <Command>writedata</Command> commands. + +<Screen> +For example, set s_r_blocks_count=1400 will reserve 1400 blocks for root. +</Screen> + +</Para> + +<Sect2> +<Title>gocopy</Title> + +<Para> + +<Screen> +Syntax: gocopy number +</Screen> + +The <Command>gocopy</Command> command will "bring you" to the backup copy <Emphasis>number</Emphasis> +of the superblock copies. <Command>gocopy 0</Command>, for example, will bring you to +the main copy. +</Para> + +</Sect2> + +<Sect2> +<Title>setactivecopy</Title> + +<Para> + +<Screen> +Syntax: setactivecopy +</Screen> + +The <Command>setactivecopy</Command> command will copy the contents of the current +superblock copy onto the contents of the main copy. It will also switch to +editing of the main copy. No actual data is written to disk, of-course, +until you issue the <Command>writedata</Command> command. +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>The group descriptors</Title> + +<Para> +The group descriptors can be edited by the <Command>group</Command> command. +</Para> + +<Para> +The status window will indicate the current group descriptor, the total +number of group descriptors (and hence of group blocks), and the backup copy +number. +</Para> + +<Para> +The main data window will just show you the values of the various variables. +</Para> + +<Para> +Basically, you can use the <Command>next</Command> and <Command>prev</Command> commands, along with the +<Command>set</Command> command, to modify the group descriptors. +</Para> + +<Para> +The group descriptors object is a junction, from which you can reach: + +<ItemizedList> +<ListItem> + +<Para> + The inode table of the corresponding block group (the <Literal remap="tt">inode</Literal> +command) +</Para> +</ListItem> +<ListItem> + +<Para> + The block allocation bitmap (the <Literal remap="tt">blockbitmap</Literal> command) +</Para> +</ListItem> +<ListItem> + +<Para> + The inode allocation bitmap (the <Literal remap="tt">inodebitmap</Literal> command) +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +<Sect2> +<Title>blockbitmap</Title> + +<Para> + +<Screen> +Syntax: blockbitmap +</Screen> + +The <Command>blockbitmap</Command> command will let you edit the block bitmap allocation +block of the current group block. +</Para> + +</Sect2> + +<Sect2> +<Title>entry</Title> + +<Para> + +<Screen> +Syntax: entry number +</Screen> + +The <Command>entry</Command> command will move you to the <Emphasis>number</Emphasis> group descriptor in the +group descriptors table. +</Para> + +</Sect2> + +<Sect2> +<Title>inode</Title> + +<Para> + +<Screen> +Syntax: inode +</Screen> + +The <Command>inode</Command> command will pass you to the first inode in the current +group block. +</Para> + +</Sect2> + +<Sect2> +<Title>inodebitmap</Title> + +<Para> + +<Screen> +Syntax: inodebitmap +</Screen> + +The <Command>inodebitmap</Command> command will let you edit the inode bitmap allocation +block of the current group block. +</Para> + +</Sect2> + +<Sect2> +<Title>next</Title> + +<Para> + +<Screen> +Syntax: next [number] +</Screen> + +The <Command>next</Command> command will pass to the next <Emphasis>number</Emphasis> group +descriptor. If <Emphasis>number</Emphasis> is omitted, <Emphasis>number=1</Emphasis> is assumed. +</Para> + +</Sect2> + +<Sect2> +<Title>prev</Title> + +<Para> + +<Screen> +Syntax: prev [number] +</Screen> + +The <Command>prev</Command> command will pass to the previous <Emphasis>number</Emphasis> group +descriptor. If <Emphasis>number</Emphasis> is omitted, <Emphasis>number=1</Emphasis> is assumed. +</Para> + +</Sect2> + +<Sect2> +<Title>setactivecopy</Title> + +<Para> + +<Screen> +Syntax: setactivecopy +</Screen> + +The <Command>setactivecopy</Command> command copies the contents of the current group +descriptor, to its main copy. The updated main copy will then be shown. No +actual change is made to the disk until you issue the <Command>writedata</Command> +command. +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>The inode</Title> + +<Para> +An inode can be reached by the following two ways: + +<ItemizedList> +<ListItem> + +<Para> + Using <Command>inode</Command> from the corresponding group descriptor. +</Para> +</ListItem> +<ListItem> + +<Para> + Using <Command>followinode</Command> from a directory entry. +</Para> +</ListItem> +<ListItem> + +<Para> + Using the <Command>cd</Command> command with the pathname to the file. + +For example, <Command>cd /usr/src/ext2ed/ext2ed.h</Command> +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +<Para> +The status window will indicate: + +<ItemizedList> +<ListItem> + +<Para> + The current global inode number. +</Para> +</ListItem> +<ListItem> + +<Para> + The total total number of inodes. +</Para> +</ListItem> +<ListItem> + +<Para> + On which block group the inode is allocated. +</Para> +</ListItem> +<ListItem> + +<Para> + The total number of inodes in this group block. +</Para> +</ListItem> +<ListItem> + +<Para> + The index of the current inode in the current group block. +</Para> +</ListItem> +<ListItem> + +<Para> + The type of the inode (file, directory, special, etc). +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +<Para> +The main data window, in addition to the list of variables, will contain +some interpretations on the right side. +</Para> + +<Para> +If the inode corresponds to a file, you can use the <Command>file</Command> command to +edit the file. +</Para> + +<Para> +If the inode is an inode of a directory, you can use the <Command>dir</Command> command +to edit the directory. +</Para> + +<Sect2> +<Title>dir</Title> + +<Para> + +<Screen> +Syntax: dir +</Screen> + +If the inode mode corresponds to a directory (shown on the status window), +you can enter directory mode editing by using <Literal remap="tt">dir</Literal>. +</Para> + +</Sect2> + +<Sect2> +<Title>entry</Title> + +<Para> + +<Screen> +Syntax: entry number +</Screen> + +The <Command>entry</Command> command will move you to the <Emphasis>number</Emphasis> inode in the +current inode table. +</Para> + +</Sect2> + +<Sect2> +<Title>file</Title> + +<Para> + +<Screen> +Syntax: file +</Screen> + +If the inode mode corresponds to a file (shown on the status window), +you can enter file mode editing by using <Command>file</Command>. +</Para> + +</Sect2> + +<Sect2> +<Title>group</Title> + +<Para> + +<Screen> +Syntax: group +</Screen> + +The <Command>group</Command> command is used to go to the group descriptor of the +current group block. +</Para> + +</Sect2> + +<Sect2> +<Title>next</Title> + +<Para> + +<Screen> +Syntax: next [number] +</Screen> + +The <Command>next</Command> command will pass to the next <Emphasis>number</Emphasis> inode. +If <Emphasis>number</Emphasis> is omitted, <Emphasis>number=1</Emphasis> is assumed. +</Para> + +</Sect2> + +<Sect2> +<Title>prev</Title> + +<Para> + +<Screen> +Syntax: prev [number] +</Screen> + +The <Command>prev</Command> command will pass to the previous <Emphasis>number</Emphasis> inode. +If <Emphasis>number</Emphasis> is omitted, <Emphasis>number=1</Emphasis> is assumed. +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>The file</Title> + +<Para> +When editing a file, EXT2ED offers you a both a continuous and a true +fragmented view of the file - The file is still shown block by block with +the true block number at each stage and EXT2ED offers you commands which +allow you to move between the <Literal remap="tt">file blocks</Literal>, while finding the +allocated blocks by using the inode information behind the scenes. +</Para> + +<Para> +Aside from this, the editing is just a <Literal remap="tt">hex editing</Literal> - You move the +cursor in the current block of the file by using <Command>next</Command> and +<Command>prev</Command>, move between blocks by <Command>nextblock</Command> and <Command>prevblock</Command>, +and make changes by the <Command>set</Command> command. Note that the set command is +overridden here - There are no variables. The <Command>writedata</Command> command will +update the current block to the disk. +</Para> + +<Para> +Reaching a file can be done by using the <Command>file</Command> command from its inode. +The inode can be reached by any other means, for example, by the +<Command>cd</Command> command, if you know the file name. +</Para> + +<Para> +The status window will indicate: + +<ItemizedList> +<ListItem> + +<Para> + The global block number. +</Para> +</ListItem> +<ListItem> + +<Para> + The internal file block number. +</Para> +</ListItem> +<ListItem> + +<Para> + The file offset. +</Para> +</ListItem> +<ListItem> + +<Para> + The file size. +</Para> +</ListItem> +<ListItem> + +<Para> + The file inode number. +</Para> +</ListItem> +<ListItem> + +<Para> + The indirection level - Whether it is a direct block (0), indirect +(1), etc. +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +<Para> +The main data window will display the file either in hex mode or in text +mode, select-able by the <Command>display</Command> command. +</Para> + +<Para> +In hex mode, EXT2ED will display offsets in the current block, along with a +text and hex dump of the current block. +</Para> + +<Para> +In either case the <Literal remap="tt">current place</Literal> will be highlighted. In the hex mode +it will be always highlighted, while in the text mode it will be highlighted +if the character is display-able. +</Para> + +<Sect2> +<Title>block</Title> + +<Para> + +<Screen> +Syntax: block block_num +</Screen> + +The <Command>block</Command> command is used to move inside the file. The +<Emphasis>block_num</Emphasis> argument is the requested internal file block number. A +value of 0 will reach the beginning of the file. +</Para> + +</Sect2> + +<Sect2> +<Title>display</Title> + +<Para> + +<Screen> +Syntax: display [text || hex] +</Screen> + +The <Command>display</Command> command changes the display mode of the file. +<Command>display +hex</Command> will switch to <Command>hex mode</Command>, while <Command>display text</Command> will switch +to text mode. The default mode when no <Command>display</Command> command is issued is +<Command>hex mode</Command>. +</Para> + +</Sect2> + +<Sect2> +<Title>inode</Title> + +<Para> + +<Screen> +Syntax: inode +</Screen> + +The <Command>inode</Command> command will return to the inode of the current file. +</Para> + +</Sect2> + +<Sect2> +<Title>next</Title> + +<Para> + +<Screen> +Syntax: next [num] +</Screen> + +The <Command>next</Command> command will pass to the next byte in the file. If +<Emphasis>num</Emphasis> is supplied, it will pass to the next <Emphasis>num</Emphasis> bytes. +</Para> + +</Sect2> + +<Sect2> +<Title>nextblock</Title> + +<Para> + +<Screen> +Syntax: nextblock [num] +</Screen> + +The <Command>nextblock</Command> command will pass to the next block in the file. If +<Emphasis>num</Emphasis> is supplied, it will pass to the next <Emphasis>num</Emphasis> blocks. +</Para> + +</Sect2> + +<Sect2> +<Title>prev</Title> + +<Para> + +<Screen> +Syntax: prev [num] +</Screen> + +The <Command>prev</Command> command will pass to the previous byte in the file. If +<Emphasis>num</Emphasis> is supplied, it will pass to the previous <Emphasis>num</Emphasis> bytes. +</Para> + +</Sect2> + +<Sect2> +<Title>prevblock</Title> + +<Para> + +<Screen> +Syntax: prevblock [num] +</Screen> + +The <Command>nextblock</Command> command will pass to the previous block in the file. If +<Emphasis>num</Emphasis> is supplied, it will pass to the previous <Emphasis>num</Emphasis> blocks. +</Para> + +</Sect2> + +<Sect2> +<Title>offset</Title> + +<Para> + +<Screen> +Syntax: offset file_offset +</Screen> + +The <Command>offset</Command> command will move to the specified offset in the file. +</Para> + +</Sect2> + +<Sect2> +<Title>set</Title> + +<Para> + +<Screen> +Syntax: set [text || hex] arg1 [arg2 arg3 ...] +</Screen> + +The <Command>file set</Command> command is working like the <Literal remap="tt">general set command</Literal>, +with <Literal remap="tt">type=none</Literal>. There are no variables. +</Para> + +</Sect2> + +<Sect2> +<Title>writedata</Title> + +<Para> + +<Screen> +Syntax: writedata +</Screen> + +The <Command>writedata</Command> command will update the current file block in the disk. +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>The directory</Title> + +<Para> +When editing a file, EXT2ED analyzes for you both the allocation blocks of +the directory entries, and the directory entries. +</Para> + +<Para> +Each directory entry is displayed on one row. You can move the highlighted +entry with the usual <Command>next</Command> and <Command>prev</Command> commands, and "dive in" +with the <Command>followinode</Command> command. +</Para> + +<Para> +The status window will indicate: + +<ItemizedList> +<ListItem> + +<Para> + The directory entry number. +</Para> +</ListItem> +<ListItem> + +<Para> + The total number of directory entries in this directory. +</Para> +</ListItem> +<ListItem> + +<Para> + The current global block number. +</Para> +</ListItem> +<ListItem> + +<Para> + The current offset in the entire directory - When viewing the +directory as a continuous file. +</Para> +</ListItem> +<ListItem> + +<Para> + The inode number of the directory itself. +</Para> +</ListItem> +<ListItem> + +<Para> + The indirection level - Whether it is a direct block (0), indirect +(1), etc. +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +<Sect2> +<Title>cd</Title> + +<Para> + +<Screen> +Syntax: cd [path] +</Screen> + +The <Command>cd</Command> command is used in the usual meaning, like the global cd +command. + +<ItemizedList> +<ListItem> + +<Para> + If <Emphasis>path</Emphasis> is not specified, the current directory entry is +followed. +</Para> +</ListItem> +<ListItem> + +<Para> + <Emphasis>path</Emphasis> can be relative to the current directory. +</Para> +</ListItem> +<ListItem> + +<Para> + <Emphasis>path</Emphasis> can also end up in a file, in which case the file inode +will be reached. +</Para> +</ListItem> +<ListItem> + +<Para> + Symbolic link (fast only, meanwhile) is automatically followed. +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +</Sect2> + +<Sect2> +<Title>entry</Title> + +<Para> + +<Screen> +Syntax: entry [entry_num] +</Screen> + +The <Command>entry</Command> command sets <Emphasis>entry_num</Emphasis> as the current directory +entry. +</Para> + +</Sect2> + +<Sect2> +<Title>followinode</Title> + +<Para> + +<Screen> +Syntax: followinode +</Screen> + +The <Command>followinode</Command> command will move you to the inode pointed by the +current directory entry. +</Para> + +</Sect2> + +<Sect2> +<Title>inode</Title> + +<Para> + +<Screen> +Syntax: inode +</Screen> + +The <Command>inode</Command> command will return you to the parent inode of the whole +directory listing. +</Para> + +</Sect2> + +<Sect2> +<Title>next</Title> + +<Para> + +<Screen> +Syntax: next [num] +</Screen> + +The <Command>next</Command> command will pass to the next directory entry. +If <Emphasis>num</Emphasis> is supplied, it will pass to the next <Emphasis>num</Emphasis> entries. +</Para> + +</Sect2> + +<Sect2> +<Title>prev</Title> + +<Para> + +<Screen> +Syntax: prev [num] +</Screen> + +The <Command>prev</Command> command will pass to the previous directory entry. +If <Emphasis>num</Emphasis> is supplied, it will pass to the previous <Emphasis>num</Emphasis> entries. +</Para> + +</Sect2> + +<Sect2> +<Title>writedata</Title> + +<Para> + +<Screen> +Syntax: writedata +</Screen> + +The <Command>writedata</Command> command will write the current directory entry to the +disk. +</Para> + +</Sect2> + +</Sect1> + +<Sect1 id="block-bitmap"> +<Title>The block allocation bitmap</Title> + +<Para> +The <Literal remap="tt">block allocation bitmap</Literal> of any block group can be reached from +the corresponding group descriptor. +</Para> + +<Para> +You will be offered a bit listing of the entire blocks in the group. The +current block will be highlighted and its number will be displayed in the +status window. +</Para> + +<Para> +A value of "1" means that the block is allocated, while a value of "0" +signals that it is free. The value is also interpreted in the status +window. You can use the usual <Command>next/prev</Command> commands, along with the +<Command>allocate/deallocate</Command> commands. +</Para> + +<Sect2> +<Title>allocate</Title> + +<Para> + +<Screen> +Syntax: allocate [num] +</Screen> + +The <Command>allocate</Command> command allocates <Emphasis>num</Emphasis> blocks, starting from the +highlighted position. If <Emphasis>num</Emphasis> is not specified, <Emphasis>num=1</Emphasis> is assumed. +Of-course, no actual change is made until you issue a <Command>writedata</Command> command. +</Para> + +</Sect2> + +<Sect2> +<Title>deallocate</Title> + +<Para> + +<Screen> +Syntax: deallocate [num] +</Screen> + +The <Command>deallocate</Command> command deallocates <Emphasis>num</Emphasis> blocks, starting from the +highlighted position. If <Emphasis>num</Emphasis> is not specified, <Emphasis>num=1</Emphasis> is assumed. +Of-course, no actual change is made until you issue a <Command>writedata</Command> command. +</Para> + +</Sect2> + +<Sect2> +<Title>entry</Title> + +<Para> + +<Screen> +Syntax: entry [entry_num] +</Screen> + +The <Command>entry</Command> command sets the current highlighted block to +<Emphasis>entry_num</Emphasis>. +</Para> + +</Sect2> + +<Sect2> +<Title>next</Title> + +<Para> + +<Screen> +Syntax: next [num] +</Screen> + +The <Command>next</Command> command will pass to the next bit, which corresponds to the +next block. If <Emphasis>num</Emphasis> is supplied, it will pass to the next <Emphasis>num</Emphasis> +bits. +</Para> + +</Sect2> + +<Sect2> +<Title>prev</Title> + +<Para> + +<Screen> +Syntax: prev [num] +</Screen> + +The <Command>prev</Command> command will pass to the previous bit, which corresponds to the +previous block. If <Emphasis>num</Emphasis> is supplied, it will pass to the previous +<Emphasis>num</Emphasis> bits. +</Para> + +</Sect2> + +</Sect1> + +<Sect1> +<Title>The inode allocation bitmap</Title> + +<Para> +The <Literal remap="tt">inode allocation bitmap</Literal> is very similar to the block allocation +bitmap explained above. It is also reached from the corresponding group +descriptor. Please refer to section <XRef LinkEnd="block-bitmap">. +</Para> + +</Sect1> + +<Sect1> +<Title>Filesystem size limitation</Title> + +<Para> +While an ext2 filesystem has a size limit of <Literal remap="tt">4 TB</Literal>, EXT2ED currently +<Literal remap="tt">can't</Literal> handle filesystems which are <Literal remap="tt">bigger than 2 GB</Literal>. +</Para> + +<Para> +I am sorry for the inconvenience. This will hopefully be fixed in future +releases. +</Para> + +</Sect1> + +<Sect1> +<Title>Copyright</Title> + +<Para> +EXT2ED is Copyright (C) 1995 Gadi Oxman. +</Para> + +<Para> +EXT2ED is hereby placed under the GPL - Gnu Public License. You are free and +welcome to copy, view and modify the sources. My only wish is that my +copyright presented above will be left and that a list of the bug fixes, +added features, etc, will be provided. +</Para> + +<Para> +The entire EXT2ED project is based, of-course, on the kernel sources. The +<Literal remap="tt">ext2.descriptors</Literal> distributed with EXT2ED is a slightly modified +version of the main ext2 include file, /usr/include/linux/ext2_fs.h. Follows +the original copyright: +</Para> + +<Para> + +<Screen> +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +</Screen> + +</Para> + +</Sect1> + +<Sect1> +<Title>Acknowledgments</Title> + +<Para> +EXT2ED was constructed as a student project in the software +laboratory of the faculty of electrical-engineering in the +<Literal remap="tt">Technion - Israel's institute of technology</Literal>. +</Para> + +<Para> +At first, I would like to thank <PersonName><FirstName>Avner</FirstName> <SurName>Lottem</SurName></PersonName> and <PersonName><Honorific>Doctor</Honorific> <FirstName>Ilana</FirstName> <SurName>David</Surname></PersonName> for their interest and assistance in this project. +</Para> + +<Para> +I would also like to thank the following people, who were involved in the +design and implementation of the ext2 filesystem kernel code and support +utilities: + +<ItemizedList> +<ListItem> + +<Para> +<PersonName><FirstName>Remy</FirstName> <SurName>Card</SurName></PersonName> + +Who designed, implemented and maintains the ext2 filesystem kernel +code, and some of the ext2 utilities. Remy Card is also the author +of several helpful slides concerning the ext2 filesystem. +Specifically, he is the author of <Literal remap="tt">File Management in the Linux +Kernel</Literal> and of <Literal remap="tt">The Second Extended File System - Current State, +Future Development</Literal>. + +</Para> +</ListItem> +<ListItem> + +<Para> +<PersonName><FirstName>Wayne</FirstName> <SurName>Davison</SurName></PersonName> + +Who designed the ext2 filesystem. +</Para> +</ListItem> +<ListItem> + +<Para> +<PersonName><FirstName>Stephen</FirstName> <Surname>Tweedie</SurName></PersonName> + +Who helped designing the ext2 filesystem kernel code and wrote the +slides <Literal remap="tt">Optimizations in File Systems</Literal>. +</Para> +</ListItem> +<ListItem> + +<Para> +<PersonName><FirstName>Theodore</FirstName> <SurName>Ts'o</SurName></PersonName> + +Who is the author of several ext2 utilities and of the ext2 library +<Literal remap="tt">libext2fs</Literal> (which I didn't use, simply because I didn't know +it exists when I started to work on my project). +</Para> +</ListItem> + +</ItemizedList> + +</Para> + +<Para> +Lastly, I would like to thank, of-course, <PersonName><FirstName>Linus</FirstName> <SurName>Torvalds</SurName></PersonName> and the +Linux community for providing all of us with such a great operating +system. +</Para> + +<Para> +Please contact me in a case of bug report, suggestions, or just about +anything concerning EXT2ED. +</Para> + +<Para> +Enjoy, +</Para> + +<Para> +Gadi Oxman <tgud@tochnapc2.technion.ac.il> +</Para> + +<Para> +Haifa, August 95 +</Para> + +</Sect1> + +</Article> |