SherbyNet - /page/wikibook/entry.mu

Micron Document

<!DOCTYPE html>

<title>Linear Executable</title>

</head>

<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Linear Executable</span></span>

</h1>

</header>

<div id="mw-content-text" class="mw-body-content mw-content-ltr" lang="en" dir="ltr"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><p><b>Linear Executable (LE)</b> is <a href="File_format" title="File format">file format</a> for <a href="Executable_code" class="mw-redirect" title="Executable code">executable code</a> designed for 32-bit protected mode operating systems. Originally used by the <a href="OS/2" title="OS/2">OS/2</a> operating system and adopted by various <a href="DOS_extender" title="DOS extender">DOS extenders</a>, it also served as the file format for <a href="VxD" title="VxD">Virtual Device Drivers (VxD)</a> in early versions of Windows, including <a href="Windows_3.x" title="Windows 3.x">Windows 3.x</a> and the <a href="Windows_3.x" title="Windows 3.x">Windows 9x</a> series.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The malleability of LE files attracted interest in using them for <a href="Steganography" title="Steganography">steganography</a>.<sup id="cite_ref-FOOTNOTEZaidanOthmanZaidanRaji2009_2-0" class="reference"><a href="#cite_note-FOOTNOTEZaidanOthmanZaidanRaji2009-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="History">History</h2></div>

<p>The LE format was first introduced in the early 1990s during a period of transition from <a href="16-bit_computing" title="16-bit computing">16-bit</a> to <a href="32-bit_computing" title="32-bit computing">32-bit computing</a>. It was developed as an extension of the older <a href="New_Executable" title="New Executable">New Executable (NE)</a> format, which was used for 16-bit applications. Limitations in memory management and addressing led to the development of LE as a 32-bit replacement. LE expanded on NE's functionality by allowing the system to operate in protected mode.

</p><p>An extended version of the format, called LX, was developed specifically for OS/2 Warp and supported further extensions over the LE format.

</p>

<div class="mw-heading mw-heading2"><h2 id="Structure">Structure</h2></div>

<p>Files in the LE format begin with an MZ header (the standard DOS executable header) for backward compatibility with DOS systems. Within the MZ header, at offset <code>0x3C</code>, there is a 32-bit value referred to as the <code>e_lfanew</code>field, which contains a pointer to the extended header (the LE header). The LE header starts with the <a href="ASCII" title="ASCII">ASCII</a> characters <code>LE</code> (or <code>LX</code> in <a href="OS/2" title="OS/2">OS/2 Warp</a>). In Linear Executables, file offsets and structures are typically defined relative to the start of the LE header or as absolute offsets within the file.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="Usage">Usage</h2></div>

<ul><li><a href="OS/2" title="OS/2">OS/2</a>: IBM's OS/2 operating system used the LE format for its executables and <a href="Dynamic-link_library" title="Dynamic-link library">DLLs</a> in its 32-bit variants.</li>

<li><a href="DOS_extender" title="DOS extender">DOS Extenders</a>: The format was popular among DOS extenders, such as <a href="DOS/4G" title="DOS/4G">DOS/4GW</a>, which allowed DOS applications to operate in protected mode, bypassing the limitations of real-mode memory constraints.</li>

<li><a href="VxD" title="VxD">Windows VxD Drivers</a>: Windows 3.x and the Windows 9x series used the LE format for Virtual Device Drivers (VxD).</li></ul>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

/* start https://en.wikipedia.org/ */

.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}

/* end https://en.wikipedia.org/ */

</style><div class="reflist">

/* start https://en.wikipedia.org/ */

.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}

/* end https://en.wikipedia.org/ */

</style><cite id="CITEREFSklyarov2004" class="citation book cs1">Sklyarov, Dmitry (2004). <i>Hidden Keys to Software Break-Ins and Unauthorized</i>. A-LIST. p. 125. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>9781931769303</bdi>.</cite></span>

</li>

<li id="cite_note-FOOTNOTEZaidanOthmanZaidanRaji2009-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEZaidanOthmanZaidanRaji2009_2-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFZaidanOthmanZaidanRaji2009">Zaidan et al. 2009</a>.</span>

</li>

<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://archive.org/details/IBMOS2Warp4ToolkitDocuments2/32-bit%20Linear%20eXecutable%20Module%20Format%20%28LX%29%20Specification/">"IBM OS/2 Warp 4 Toolkit Documents 2"</a>. <i><a href="IBM" title="IBM">IBM</a></i>.</cite></span>

</li>

</ol></div></div>

<div class="mw-heading mw-heading2"><h2 id="Sources">Sources</h2></div>

<ul><li><cite id="CITEREFDavisWallace1997" class="citation book cs1">Davis, P.; Wallace, M. (1997). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=eTsXKHqU158C&pg=PA251">"LE File Format"</a>. <i>Windows Undocumented File Formats</i>. File Secrets Revealed. Taylor & Francis. pp. <span class="nowrap">251–</span>274. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-87930-437-9</bdi><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-12-17</span></span>.</cite></li>

<li><cite id="CITEREFZaidanOthmanZaidanRaji2009" class="citation book cs1">Zaidan, A.A.; Othman, Fazidah; Zaidan, B.B.; Raji, R.Z.; Hasan, Ahmed.K.; Naji, A.W. (2009). <a rel="nofollow" class="external text" href="https://www.iaeng.org/publication/WCE2009/WCE2009_pp259-265.pdf">"Securing Cover-File Without Limitation of Hidden Data Size Using Computation Between Cryptography and Steganography"</a> <span class="cs1-format">(PDF)</span>. <i>Proceedings of the World Congress on Engineering</i>. Vol. 1. London, U.K. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-988-17012-5-1</bdi>.</cite><span class="cs1-maint citation-comment"><code class="cs1-code">{{cite book}}</code>: CS1 maint: location missing publisher (link)</span></li></ul>

<p><br>

</p>

/* start https://en.wikipedia.org/ */

.mw-parser-output .asbox{position:relative;overflow:hidden}.mw-parser-output .asbox table{background:transparent}.mw-parser-output .asbox p{margin:0}.mw-parser-output .asbox p+p{margin-top:0.25em}.mw-parser-output .asbox-body{font-style:italic}.mw-parser-output .asbox-note{font-size:smaller}.mw-parser-output .asbox .navbar{position:absolute;top:-0.75em;right:1em;display:none}.mw-parser-output :not(p):not(.asbox)+style+.asbox,.mw-parser-output :not(p):not(.asbox)+link+.asbox{margin-top:3em}

/* end https://en.wikipedia.org/ */

</style></div><div><div class="zim-footer">

This article is issued from <a class="external text" title="Last edited on 2025-07-30" href="https://en.wikipedia.org/wiki/?title=Linear_Executable&oldid=1303397805">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.

</div>

</div></div>

</div>

</main>

</div>

</body></html>