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Dynamic Library
A dynamic library is a library that contains functions and data that can be consumed by a computer program at run-time as loaded from a file separate from the program executable. Dynamic linking or late binding allows for using a dynamic library by linking program library references with the associated objects in the library either at load-time or run-time. At program build-time, the linker records what library objects the program uses. When the program is run, a ''dynamic linker'' or ''linking loader'' associates program library references with the associated objects in the library. A dynamic library can be linked at build-time to a stub for each library resource that is resolved at run-time. Alternatively, a dynamic library can be loaded without linking to stubs. Most modern operating systems use the same format for both a dynamic library and an executableSome older systems, e.g., Burroughs MCP, Multics, also have a single format which affords two main advantages: it nec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Library (computing)
In computing, a library is a collection of System resource, resources that can be leveraged during software development to implement a computer program. Commonly, a library consists of executable code such as compiled function (computer science), functions and Class (computer programming), classes, or a library can be a collection of source code. A resource library may contain data such as images and Text string, text. A library can be used by multiple, independent consumers (programs and other libraries). This differs from resources defined in a program which can usually only be used by that program. When a consumer uses a library resource, it gains the value of the library without having to implement it itself. Libraries encourage software reuse in a Modular programming, modular fashion. Libraries can use other libraries resulting in a hierarchy of libraries in a program. When writing code that uses a library, a programmer only needs to know how to use it not its internal d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic-link Library
A dynamic-link library (DLL) is a shared library in the Microsoft Windows or OS/2 operating system. A DLL can contain executable code (functions), data, and resources. A DLL file often has file extension .dll even though this is not required. The extension is sometimes used to describe the content of the file. For example, .ocx is a common extension for an ActiveX control and .drv for a legacy (16-bit) device driver. A DLL that contains only resources can be called a ''resource DLL''. Examples include an icon library, with common extension .icl, and a font library with common extensions .fon and .fot. The file format of a DLL is the same as for an executable (a.k.a. EXE). The main difference between a DLL file and an EXE file is that a DLL cannot be run directly since the operating system requires an entry point to start execution. Windows provides a utility program (RUNDLL.EXE/RUNDLL32.EXE) to execute a function exposed by a DLL. Since they have the same format, an EXE can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Assembly Cache
The Global Assembly Cache (GAC) is a machine-wide CLI assembly cache for the Common Language Infrastructure (CLI) in Microsoft's .NET Framework. The approach of having a specially controlled central repository addresses the flaws in the shared library concept and helps to avoid pitfalls of other solutions that led to drawbacks like DLL hell. Requirements Assemblies residing in the GAC must adhere to a specific versioning scheme which allows for side-by-side execution of different code versions. Specifically, such assemblies must be strongly named. Usage There are two ways to interact with the GAC: the Global Assembly Cache Tool (gacutil.exe) and the Assembly Cache Viewer (shfusion.dll). Global Assembly Cache Tool gacutil.exe is an older command-line utility that shipped with .NET 1.1 and is still available with the .NET SDK. One can check the availability of a shared assembly in GAC by using the command: gacutil.exe /l One can register a shared assembly in the GAC by us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NET Framework
The .NET Framework (pronounced as "''dot net''") is a proprietary software framework developed by Microsoft that runs primarily on Microsoft Windows. It was the predominant implementation of the Common Language Infrastructure (CLI) until being superseded by the cross-platform .NET project. It includes a large class library called Framework Class Library (FCL) and provides language interoperability (each language can use code written in other languages) across several programming languages. Programs written for .NET Framework execute in a software environment (in contrast to a computer hardware, hardware environment) named the Common Language Runtime (CLR). The CLR is an process virtual machine, application virtual machine that provides services such as security, memory management, and exception handling. As such, computer code written using .NET Framework is called "managed code". FCL and CLR together constitute the .NET Framework. FCL provides the user interface, data access, d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environment Variable
An environment variable is a user-definable value that can affect the way running processes will behave on a computer. Environment variables are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process. They were introduced in their modern form in 1979 with Version 7 Unix, so are included in all Unix operating system flavors and variants from that point onward including Linux and macOS. From PC DOS 2.0 in 1982, all succeeding Microsoft operating systems, including Microsoft Windows, and OS/2 also have included them as a feature, although with somewhat different syntax, usage and standard variable names. Design In all Unix and Unix-like systems, as well as on Windows, each process has its own separate set of environment vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dependency Hell
Dependency hell is a colloquial term for the frustration of some software users who have installed software packages which have dependencies on specific versions of other software packages. The dependency issue arises when several packages have dependencies on the same ''shared'' packages or libraries, but they depend on different and incompatible versions of the shared packages. If the shared package or library can only be installed in a single version, the user may need to address the problem by obtaining newer or older versions of the dependent packages. This, in turn, may break other dependencies and push the problem to another set of packages. Problems Dependency hell takes several forms: ; Many dependencies : An application depends on many libraries, requiring lengthy downloads, large amounts of disk space, and being very portable (all libraries are already ported enabling the application itself to be ported easily). It can also be difficult to locate all the depende ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
POSIX
The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with command line shells and utility interfaces, for software compatibility (portability) with variants of Unix and other operating systems. POSIX is also a trademark of the IEEE. POSIX is intended to be used by both application and system developers. As of POSIX 2024, the standard is aligned with the C17 language standard. Name Originally, the name "POSIX" referred to IEEE Std 1003.1-1988, released in 1988. The family of POSIX standards is formally designated as IEEE 1003 and the ISO/IEC standard number is ISO/ IEC 9945. The standards emerged from a project that began in 1984 building on work from related activity in the ''/usr/group'' association. Richard Stallman suggested the name ''POSIX'' to the IEEE instead of the former ''IEEE-IX''. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Loading
Dynamic loading is a mechanism by which a computer program can, at run time, load a library (or other binary) into memory, retrieve the addresses of functions and variables contained in the library, execute those functions or access those variables, and unload the library from memory. It is one of the three mechanisms by which a computer program can use some other software within the program; the others are static linking and dynamic linking. Unlike static linking and dynamic linking, dynamic loading allows a computer program to start up in the absence of these libraries, to discover available libraries, and to potentially gain additional functionality. History Dynamic loading was a common technique for IBM's operating systems for System/360 such as OS/360, particularly for I/O subroutines, and for COBOL and PL/I runtime libraries, and continues to be used in IBM's operating systems for z/Architecture, such as z/OS. As far as the application programmer is concerned, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Static Library
A static library or statically linked library contains functions and data that can be included in a consuming computer program at build-time such that the library does not need to be accessible in a separate file at run-time. If all libraries are statically linked, then the resulting executable will be stand-alone, a.k.a. a static build. A static library is either merged with other static libraries and object files at build-time to form a single executable or loaded at run-time into the address space of their corresponding executable at a static memory offset determined at compile-time/link-time. Comparison to dynamic linking Historically, all library linking was static, but today dynamic linking is an alternative and entails inherent trade-offs. An advantage of static over dynamic is that the application is guaranteed to have the library routines it requires available at run-time, as the code to those routines is embedded in the executable file. With dynamic linking, no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenVMS
OpenVMS, often referred to as just VMS, is a multi-user, multiprocessing and virtual memory-based operating system. It is designed to support time-sharing, batch processing, transaction processing and workstation applications. Customers using OpenVMS include banks and financial services, hospitals and healthcare, telecommunications operators, network information services, and industrial manufacturers. During the 1990s and 2000s, there were approximately half a million VMS systems in operation worldwide. It was first announced by Digital Equipment Corporation (DEC) as VAX/VMS (''Virtual Address eXtension/Virtual Memory System'') alongside the VAX-11/780 minicomputer in 1977. OpenVMS has subsequently been ported to run on DEC Alpha systems, the Itanium-based HPE Integrity Servers, and select x86-64 hardware and hypervisors. Since 2014, OpenVMS is developed and supported by VMS Software Inc. (VSI). OpenVMS offers high availability through computer cluster, clustering—the ability t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loadable Kernel Module
A loadable kernel module (LKM) is an executable library that extends the capabilities of a running kernel, or so-called ''base kernel'', of an operating system. LKMs are typically used to add support for new hardware (as device drivers) and/or filesystems, or for adding system calls. When the functionality provided by an LKM is no longer required, it can be unloaded in order to free memory and other resources. Most current Unix-like systems and Windows support loadable kernel modules but with different names, such as kernel loadable module (kld) in FreeBSD, kernel extension (kext) in macOS (although support for third-party modules is being dropped), kernel extension module in AIX, dynamically loadable kernel module in HP-UX, kernel-mode driver in Windows NT and downloadable kernel module (DKM) in VxWorks. They are also known as kernel loadable module (KLM), or simply as kernel module (KMOD). Advantages Without loadable kernel modules, an operating system would have to inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
