Relocatable Object Module Format (OMF) Specification

Tool Interface Standards
OMF: Relocatable Object Module Format, Version 1.1
The Relocatable Object Module Format Specification, Version 1.1, is the result of the work of
the Tool Interface Standards (TIS) Committee--an association of members of the microcomputer
industry formed to work toward standardization of the software interfaces visible to development
tools for 32-bit Intel Architecture operating environments. Such interfaces include object
module formats, executable file formats, and debug record information and formats.
The goal of the committee is to help streamline the software development process throughout the
microcomputer industry, currently concentrating on 32-bit operating environments. To that end,
the committee has developed specifications--some for file formats that are portable across
leading industry operating systems, and others describing formats for 32-bit Windows operating
systems. Originally distributed collectively as the TIS Portable Formats Specifications, Version
1.1, these specifications are now separated and distributed individually.
TIS Committee members include representatives from Absoft Corporation, Autodesk
Corporation, Borland International Corporation, IBM Corporation, Intel Corporation, Lahey
Corporation, Lotus Corporation, MetaWare Corporation, Microtec Research, Microsoft
Corporation, Novell Corporation, The Santa Cruz Operation, and WATCOM International
Corporation. PharLap Software Incorporated and Symantec Corporation also participated in the
specification definition efforts.
The Relocatable Object Module Format Specification, Version 1.1, is the latest deliverable of
the TIS Committee. It is based on existing, proven formats in keeping with the TIS Committee's
goal to adopt, and when necessary, extend existing standards rather than invent new ones.
Relocatable Object Module Format Specification (OMF)
This document represents the TIS OMF specification, the 32-bit Relocatable Object Module
Format standard. OMF is the official definition for the standard relocatable object module
format (OMF) for 32-bit applications and tools for Intel Architectures. This document presents
the heritage of the format with a focus on its current 32-bit aspects. It is published and
controlled by the Tool Interface Standards (TIS) Committee, an open industry standards body,
and will be revised as clarifications and technical information become available to the TIS
Committee.
This OMF represents the consolidation of different OMFs in use today into a single industry
standard specification. The information included within this document has been compiled from
the following documents: The MS-DOS Encyclopedia by Microsoft Press, the PharLap 386/Link
Reference Manual, the Intel 8086 object module specification (Intel Technical Specification
121748-001), the IBM OS/2 16/32-bit Object Module Format (OMF) and Linear eXecutable
Module Format (LX), Revision 7 (dated April 24, 1993), and internal Microsoft documents.