|
Slab Allocation
Slab allocation is a memory management mechanism intended for the efficient memory allocation of objects. In comparison with earlier mechanisms, it reduces fragmentation caused by allocations and deallocations. This technique is used for retaining allocated memory containing a data object of a certain type for reuse upon subsequent allocations of objects of the same type. It is analogous to an object pool, but only applies to memory, not other resources. Slab allocation was first introduced in the Solaris 2.4 kernel by Jeff Bonwick. It is now widely used by many Unix and Unix-like operating systems including FreeBSD and Linux.M. Tim JonesAnatomy of the Linux slab allocator Basis Slab allocation renders infrequent the very costly practice (in CPU time) of initialization and destruction of kernel data-objects, which can outweigh the cost of allocating memory for them. Jeff Bonwickbr>The Slab Allocator: An Object-Caching Kernel Memory Allocator (1994)/ref> When the kernel cre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Management
Memory management is a form of resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single process might be underway at any time. Several methods have been devised that increase the effectiveness of memory management. Virtual memory systems separate the memory addresses used by a process from actual physical addresses, allowing separation of processes and increasing the size of the virtual address space beyond the available amount of RAM using paging or swapping to secondary storage. The quality of the virtual memory manager can have an extensive effect on overall system performance. In some operating systems, e.g. OS/360 and successors, memory is managed by the operating system. In other operating systems, e.g. Unix-like operating sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DragonFly BSD
DragonFly BSD is a free and open-source Unix-like operating system forked from FreeBSD 4.8. Matthew Dillon, an Amiga developer in the late 1980s and early 1990s and FreeBSD developer between 1994 and 2003, began working on DragonFly BSD in June 2003 and announced it on the FreeBSD mailing lists on 16 July 2003. Dillon started DragonFly in the belief that the techniques adopted for threading and symmetric multiprocessing in FreeBSD 5 would lead to poor performance and maintenance problems. He sought to correct these anticipated problems within the FreeBSD project. Due to conflicts with other FreeBSD developers over the implementation of his ideas, his ability to directly change the codebase was eventually revoked. Despite this, the DragonFly BSD and FreeBSD projects still work together, sharing bug fixes, driver updates, and other improvements. Intended as the logical continuation of the FreeBSD 4.x series, DragonFly has diverged significantly from FreeBSD, implementing lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Pool
Memory pools, also called fixed-size blocks allocation, is the use of pools for memory management that allows dynamic memory allocation comparable to malloc or C++'s operator new. As those implementations suffer from fragmentation because of variable block sizes, it is not recommendable to use them in a real time system due to performance. A more efficient solution is preallocating a number of memory blocks with the same size called the memory pool. The application can allocate, access, and free blocks represented by handles at run time. Many real-time operating systems use memory pools, such as the Transaction Processing Facility. Some systems, like the web server Nginx, use the term ''memory pool'' to refer to a group of variable-size allocations which can be later deallocated all at once. This is also known as a ''region''; see region-based memory management. Simple memory pool implementation A simple memory pool module can allocate, for example, three pools at compile t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed-size Blocks Allocation
Memory management is a form of resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single process might be underway at any time. Several methods have been devised that increase the effectiveness of memory management. Virtual memory systems separate the memory addresses used by a process from actual physical addresses, allowing separation of processes and increasing the size of the virtual address space beyond the available amount of RAM using paging or swapping to secondary storage. The quality of the virtual memory manager can have an extensive effect on overall system performance. In some operating systems, e.g. OS/360 and successors, memory is managed by the operating system. In other operating systems, e.g. Unix-like operating syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illumos
Illumos (stylized as illumos) is a partly free and open-source Unix operating system. It is based on OpenSolaris, which was based on System V Release 4 (SVR4) and the Berkeley Software Distribution (BSD). Illumos comprises a kernel, device drivers, system libraries, and utility software for system administration. This core is now the base for many different open-sourced illumos distributions, in a similar way in which the Linux kernel is used in different Linux distributions. The maintainers write ''illumos'' in lowercase since some computer fonts do not clearly distinguish a lowercase ''L'' from an uppercase ''i'': ''Il'' (see homoglyph). The project name is a combination of words ''illuminare'' from Latin for ''to light'' and ''OS'' for ''Operating System''. Overview Illumos was announced via webinar on Thursday, 3 August 2010, as a community effort of some core Solaris engineers to create a truly open source Solaris by swapping closed source bits of OpenSolaris wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memcached
Memcached (pronounced variously ''mem-cash-dee'' or ''mem-cashed'') is a general-purpose distributed memory-caching system. It is often used to speed up dynamic database-driven websites by caching data and objects in RAM to reduce the number of times an external data source (such as a database or API) must be read. Memcached is free and open-source software, licensed under the Revised BSD license. Memcached runs on Unix-like operating systems (Linux and macOS) and on Microsoft Windows. It depends on the libevent library. Memcached's APIs provide a very large hash table distributed across multiple machines. When the table is full, subsequent inserts cause older data to be purged in least recently used (LRU) order. Applications using Memcached typically layer requests and additions into RAM before falling back on a slower backing store, such as a database. Memcached has no internal mechanism to track misses which may happen. However, some third party utilities provide this functi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perl
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was officially changed to Raku in October 2019. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. Raku, which began as a redesign of Perl 5 in 2000, eventually evolved into a separate language. Both languages continue to be developed independently by different development teams and liberally borrow ideas from each other. The Perl languages borrow features from other programming languages including C, sh, AWK, and sed; They provide text processing facilities without the arbitrary data-le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NetBSD
NetBSD is a free and open-source Unix operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was forked. It continues to be actively developed and is available for many platforms, including servers, desktops, handheld devices, and embedded systems. The NetBSD project focuses on code clarity, careful design, and portability across many computer architectures. Its source code is publicly available and permissively licensed. History NetBSD was originally derived from the 4.3BSD-Reno release of the Berkeley Software Distribution from the Computer Systems Research Group of the University of California, Berkeley, via their Net/2 source code release and the 386BSD project. The NetBSD project began as a result of frustration within the 386BSD developer community with the pace and direction of the operating system's development. The four founders of the NetBSD project, Chris Demetriou, Theo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buddy Allocation
The buddy memory allocation technique is a memory allocation algorithm that divides memory into partitions to try to satisfy a memory request as suitably as possible. This system makes use of splitting memory into halves to try to give a best fit. According to Donald Knuth, the buddy system was invented in 1963 by Harry Markowitz, and was first described by Kenneth C. Knowlton (published 1965). The Buddy memory allocation is relatively easy to implement. It supports limited but efficient splitting and coalescing of memory blocks. Algorithm There are various forms of the buddy system; those in which each block is subdivided into two smaller blocks are the simplest and most common variety. Every memory block in this system has an ''order'', where the order is an integer ranging from 0 to a specified upper limit. The size of a block of order n is proportional to 2n, so that the blocks are exactly twice the size of blocks that are one order lower. Power-of-two block sizes make addr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SLUB (software)
SLUB (''the unqueued slab allocator'') is a memory management mechanism intended for the efficient memory allocation of kernel objects which displays the desirable property of eliminating fragmentation caused by allocations and deallocations. The technique is used to retain allocated memory that contains a data object of a certain type for reuse upon subsequent allocations of objects of the same type. It is used in Linux and became the default allocator since 2.6.23. See also * Slab allocation (SLAB) * SLOB Slob or SLOB may refer to: * Slob, United States Virgin Islands, a settlement * Arie Slob (born 1961), Dutch politician * Jan Janz Slop or Jan Slob (1643–1727), Dutch Golden Age painter * '' S.L.O.B.'', debut full-length album by American death ... Notes External links The SLUB allocatorSLUB: The unqueued slab allocator V6 Memory management algorithms Linux kernel {{Linux-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SLOB
{{Disambiguation ...
Slob or SLOB may refer to: * Slob, United States Virgin Islands, a settlement * Arie Slob (born 1961), Dutch politician * Jan Janz Slop or Jan Slob (1643–1727), Dutch Golden Age painter * '' S.L.O.B.'', debut full-length album by American deathcore band Dr. Acula * "Slob", a song on the album ''Maladroit'' by Weezer * "Slob", derogatory slang term for a member of a Bloods gang * "Slob", "slobland", a dialect term for mudflats, mostly Irish In computing: * slob (KDF9), syllabic octal notation as used in conjunction with the English Electric KDF9 computer * SLOB (Linux), a memory allocation mechanism in Linux Kernel See also * Slobodan Slobodan ( sr-Cyrl, Слободан) is a Serbo-Croatian masculine given name which means "free" (''sloboda'' / meaning "freedom, liberty") used among other South Slavs as well. It was coined by Serbian liberal politician Vladimir Jovanović w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP-UX
HP-UX (from "Hewlett Packard Unix") is Hewlett Packard Enterprise's proprietary implementation of the Unix operating system, based on Unix System V (initially System III) and first released in 1984. Current versions support HPE Integrity Servers, based on Intel's Itanium architecture. Earlier versions of HP-UX supported the HP Integral PC and HP 9000 Series 200, 300, and 400 computer systems based on the Motorola 68000 series of processors, the HP 9000 Series 500 computers based on HP's proprietary FOCUS architecture, and later HP 9000 Series models based on HP's PA-RISC instruction set architecture. HP-UX was the first Unix to offer access control lists for file access permissions as an alternative to the standard Unix permissions system. HP-UX was also among the first Unix systems to include a built-in logical volume manager. HP has had a long partnership with Veritas Software, and uses VxFS as the primary file system. It is one of four commercial operating systems that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
