In computing, rebasing is the process of modifying data based on one reference to another. It can be one of the following:

Shared libraries

Rebasing is the process of creating a

shared library In computer science, a library is a collection of non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, pre-written code and subr ...

image in such a way that it is guaranteed to use

virtual memory In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very l ...

without conflicting with any other

shared libraries In computer science, a library is a collection of non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, pre-written code and subro ...

loadable in the system. IBM

VM/370 VM (often: VM/CMS) is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The following versions ...

''discontinuous saved segments'' (DCSS) were an early example of this technique, though not called ''rebasing''. The technique is used extensively on

Win32 The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems. The name Windows API collectively refers to several different platform implementations th ...

platforms to avoid the overhead of address relocation of system DLLs by the loader. Some security extensions to

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whic ...

x86 x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was int ...

use rebasing to force the use of code addresses below 0x00ffffff in order to introduce a 0x00 byte into all code pointers; this eliminates a certain class of

buffer overflow In information security and programming, a buffer overflow, or buffer overrun, is an anomaly whereby a program, while writing data to a buffer, overruns the buffer's boundary and overwrites adjacent memory locations. Buffers are areas of memor ...

security problems related to improper checking of

null-terminated string In computer programming, a null-terminated string is a character string stored as an array containing the characters and terminated with a null character (a character with a value of zero, called NUL in this article). Alternative names are C str ...

s, common in the C

programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming ...

Other uses

* Rebasing is the act of moving

changeset In version control software, a changeset (also known as commit and revision) is a set of alterations packaged together, along with meta-information about the alterations. A changeset describes the exact differences between two successive versio ...

s to a different

branch A branch, sometimes called a ramus in botany, is a woody structural member connected to the central trunk of a tree (or sometimes a shrub). Large branches are known as boughs and small branches are known as twigs. The term ''twig'' usually ...

when using a

revision control In software engineering, version control (also known as revision control, source control, or source code management) is a class of systems responsible for managing changes to computer programs, documents, large web sites, or other collections o ...

system, or, in some systems, by synchronizing a branch with the originating branch by merging all new changes in the latter to the former. For example,

Git Git () is a distributed version control system: tracking changes in any set of files, usually used for coordinating work among programmers collaboratively developing source code during software development. Its goals include speed, data inte ...

and

Darcs Darcs is a distributed version control system created by David Roundy. Key features include the ability to choose which changes to accept from other repositories, interaction with either other local (on-disk) repositories or remote repositories vi ...

do this (but Darcs extends the concept and calls it "patch commutation"). * The mechanism that the Microsoft Exchange or

Outlook Outlook or The Outlook may refer to: Computing * Microsoft Outlook, an e-mail and personal information management software product from Microsoft * Outlook.com, a web mail service from Microsoft * Outlook on the web, a suite of web applications ...

daylight saving time Daylight saving time (DST), also referred to as daylight savings time or simply daylight time (United States, Canada, and Australia), and summer time (United Kingdom, European Union, and others), is the practice of advancing clocks (typical ...

(DST) rebasing tool TZMOVE.EXE uses to recalculate and reschedule appointment dates that are affected by DST.

Shared libraries

Other uses

See also

Further reading