A patch is a piece of software designed to fix problems with, or update a computer program or its supporting data. This includes fixing security vulnerabilities and other bugs, and improving the usability or performance. Though meant to fix problems, poorly designed patches can sometimes introduce new problems (see software regressions).

Patch management is the process of using a strategy and plan of what patches should be applied to which systems at a specified time.

Types

Programmers publish and apply patches in various forms. Because propietary authors withhold their source code, their patches are distributed as binary executables instead of source. This type of patch modifies the program executable—the program the user actually runs—either by modifying the binary file to include the fixes or by completely replacing it.

Patches can also circulate in the form of source code modifications. In these cases, the patches consist of textual differences between two source code files. These types of patches commonly come out of open source projects. In these cases, developers expect users to compile the new or changed files themselves.

Because the word "patch" carries the connotation of a small fix, large fixes may use different nomenclature. Bulky patches or patches that significantly change a program may circulate as "service packs" or as "software updates".Microsoft Windows NT and its successors (including Windows 2000, Windows XP, and later versions) use the "service pack" terminology.

In several Unix-like systems, particularly Linux, updates between releases are delivered as new software packages. These updates are in the same format as the original installation so they can be used either to update an existing package in-place (effectively patching) or be used directly for new installations.

History

Historically, software suppliers distributed patches on paper tape or on punched cards, expecting the recipient to cut out the indicated part of the original tape (or deck), and patch in (hence the name) the replacement segment. Later patch distributions used magnetic tape. Then, after the invention of removable disk drives, patches came from the software developer via a disk or, later, CD_ROOM via mail. Today, with almost universal Internet access, end-users must download most patches from the developer's website.

Today, computer programs can often coordinate patches to update a target program. Automation simplifies the end-users' task -- they need only to execute an update program, whereupon that program makes sure that updating the target takes place completely and correctly. Service packs for Microsoft Windows NT and its successors and for many commercial software products adopt such automated strategies.

Some programs can update themselves via the Internet with very little or no intervention on the part of users. The maintenance of server software and of operating systems often takes place in this manner. In situations where system administrators control a number of computers, this sort of automation helps to maintain consistency. The application of security patches commonly occurs in this manner.

Application

The size of patches may vary from a few kilobytes to hundreds of megabytes — mostly more significant changes imply a larger size, though this also depends on whether the patch includes entire files or only the changed portion(s) of files. In particular, patches can become quite large when the changes add or replace non-program data, such as graphics and sounds files. Such situations commonly occur in the patching of computer games. Compared with the initial installation of software, patches usually do not take long to apply.

In the case of operating systems and computer server software, patches have the particularly important role of fixing security holes. To facilitate updates, operating systems often provide automatic or semi-automatic update facilities.

Completely automatic updates have not succeeded in gaining widespread popularity in corporate computing environments, partly because of the aforementioned glitches, but also because administrators fear that software companies may gain unlimited control over their computers.Package management systems can offer various degrees of patch automation.

Usage of completely automatic updates is far more widespread in the consumer market, due largely to the fact that Microsoft Windows added support for them, and Service Pack 2 of Windows XP enabled them by default.

Cautious users, particularly system administrators, tend to put off applying patches until they can verify the stability of the fixes. Microsoft (W)SUS support this. In the cases of large patches or of significant changes, distributors often limit availability of patches to qualified developers as a beta test.

Applying patches to firmware poses special challenges: re-embedding typically small code sets on hardware devices often involves the provision of totally new program code, rather than simply of differences from the previous version. Often the patch consists of bare binary data and a special program that replacesthe previous version with the new version is provided. Amotherboards update is an example of a common firmware patch. Any unexpected error or interruption during the update, such as a power outage, may render the motherboard unusable. It is possible for motherboard manufacturers to put safeguards in place to prevent serious damage. An example safeguard is to keep a backup of the firmware to use in case the primary copy is determined to be corrupt (usually through the use of achecksum, such as a CRC).

Computer games

Computer games receive patches to fix compatibility problems after their initial release just like any other software, but they can also be applied to change game rules or algorithems. These patches may be prompted by the discovery of exploits in the multyplayer game experience that can be used to gain unfair advantages over other players. Extra features and game play tweaks can often be added. These kinds of patches are common in firts person shooter with multiplayer capability, and in  MMORPGs, which are typically very complex with large amounts of content, almost always rely heavily on patches following the initial release, where patches sometimes add new content and abilities available to players. Because the balance and fairness for all players of an MMORPG can be severely corrupted within a short amount of time by an exploit, servers of an MMORPG are sometimes taken down with short notice in order to apply a critical patch with a fix.

Tools

There are several tools to aid in the patch application process, such as RTPatch, Jupdater,stable update or Visual Patch.Win Zip Extraktor can launch a program that can apply a patch

In software development

Patches sometimes become mandatory to fix problems with libraries or with portions of source code for programs in frequent use or in maintenance. This commonly occurs on very large-scale software projects, but rarely in small-scale development.

In open source projects, the authors commonly receive patches or many people publish patches that fix particular problems or add certain functionality, like support for local languages outside the project's locale. In an example from the early development of the Linux operating system (noted for publishing its complete source code), linus trovalds, the original author, received hundreds of thousands of patches from many programmers to apply against his original version.

The Apache Http Se originally evolved as a number of patches that Briant Behlendorf collated to improve NCSA HTTPd, hence a name that implies that it is a collection of patches (a patchy server). The FAQ on the project's official site states that the name 'Apache' was chosen from respect for the Native American Indian tribe of Apache. However, the 'a patchy server' explanation was initially given on the project's website.

Security patches

A security patch is a change applied to an asset to correct the weakness described by a vulnerability. This corrective action will prevent successful exploitation and remove or mitigate a threat’s capability to exploit a specific vulnerability in an asset.

Security patches are the primary method of fixing security vulnerabilities in software. Currently Microsoft releases its security patches once a month, and other operating systems and software projects have security teams dedicated to releasing the most reliable software patches as soon after a vulnerability announcement as possible. Security patches are closely tied to responsible disclosure.

Hot patching

Hot patching is the application of patches without shutting down and restarting the system or the program concerned. This addresses problems related to unavailability of service provided by the system or the program.A patch that can be applied in this way is called a hot.

Management IQ Consumers Still Going Green

Posted by: Jena McGregor on February 7, 2009

Looking for new ways to grow? In this environment, many companies are trying to find some kind of new way to grab the interest of spending-wary consumers. Boston Consulting Group believes that move might be going green.
In a survey of 9,000 consumers in North America, Europe, China, and Japan, the consulting firm found that despite the slumping economy, more shoppers sought out green products in 2008 than in 2007. Some 34 percent of Europeans (up 2 percent from 2007) said they would continue to systematically look for green products. And in a similar study of 1,040 consumers in the United States in January, some 32 percent said they still seek out and often purchase green products.
There’s no telling whether that trend will hold as the economy worsens and more consumers lose jobs, making that organic, fair-trade, recycled product potentially a little more difficult to buy. (While not always more expensive, the economics of eco-merchandise often tends to drive prices up.)
If you’re going to make a bet on such products, make sure consumers can find them. BCG reports that one big complaint from consumers in the survey regarded how organic supermarket goods are placed in what they call the “green ghetto.” Rather than place a limited assortment of organic products in a low-traffic location, the consumers complained, mix them in with other products and make them easy to find.

Do you know that this is the most frequently searched Google phrase that drives people to my site (and I’m sure very many other sites in this space as well)? Ah, this is easy enough to answer and so I posed the question to myself : What exactly is the Supply Chain?
I must confess that I really couldn’t come up with an answer that didn’t suffer from some rebuttal or the other. So I pose it to you as well – What is the Supply Chain?
Now some may hearken to the introduction that most have of the supply chain that usually have the neat diagrams that connect material flow from neat boxes of producers, intermediaries etc and information flow in the reverse direction. But is that what it is? In the sense, does the activity of material and information flow define Supply Chain Management? In other words, is Supply Chain Management just an activity descriptor?
Well, if it is not just an activity descriptor – then you can safely put away transportation, warehouse and all sorts of other management. Inventory Management?
So let’s move up that chain to see whether it is about the customer? Forecasting? S&OP? In other words, is it about getting an analytical feel for the way demand is going to be or a structured process about marshalling a firm’s resources and fulfilling that demand whatever that might be? Again, how is this different from some definite activity?
Alright, maybe it is not one activity but a rhythm of many activities that must be more or less in harmony. So how is that different from just Operations Management with a new focus on getting all the links functioning together?
You see where I’m going…
Perhaps we take the easy route and point to an activity (or activities) or point to a piece of software (ERP, MRP, SCM, TMS, WMS etc)?
If someone came to you and asked you – “What is Supply Chain Management?” , what would you say?
Now, that’s a proper way to start the year off!!