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.bss
In computer programming, the block starting symbol (abbreviated to .bss or bss) is the portion of an object file, executable, or assembly language code that contains statically allocated variables that are declared but have not been assigned a value yet. It is often referred to as the "bss section" or "bss segment". Typically only the length of the bss section, but no data, is stored in the object file. The program loader allocates memory for the bss section when it loads the program. By placing variables with no value in the .bss section, instead of the .data or .rodata section which require initial value data, the size of the object file is reduced. On some platforms, some or all of the bss section is initialized to zeroes. Unix-like systems and Windows initialize the bss section to zero, allowing C and C++ statically allocated variables initialized to values represented with all bits zero to be put in the bss segment. Operating systems may use a technique called zero-fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code Segment
In computing, a code segment, also known as a text segment or simply as text, is a portion of an object file or the corresponding section of the program's virtual address space that contains executable instructions. Segment The term "segment" comes from the memory segment, which is a historical approach to memory management that has been succeeded by paging. When a program is stored in an object file, the code segment is a part of this file; when the loader places a program into memory so that it may be executed, various memory regions are allocated (in particular, as pages), corresponding to both the segments in the object files and to segments only needed at run time. For example, the code segment of an object file is loaded into a corresponding code segment in memory. The code segment in memory is typically read-only and has a fixed size, so on embedded systems it can usually be placed in read-only memory (ROM), without the need for loading. If the code segment is n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Segment
In computing, a data segment (often denoted .data) is a portion of an object file or the corresponding address space of a program that contains initialized static variables, that is, global variables and static local variables. The size of this segment is determined by the size of the values in the program's source code, and does not change at run time. The data segment is read/write, since the values of variables can be altered at run time. This is in contrast to the ''read-only data segment'' ('' segment'' or ''.rodata''), which contains static constants rather than variables; it also contrasts to the code segment, also known as the text segment, which is read-only on many architectures. Uninitialized data, both variables and constants, is instead in the BSS segment. Historically, to be able to support memory address spaces larger than the native size of the internal address register would allow, early CPUs implemented a system of segmentation whereby they would store a small se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 700/7000 Series
The IBM 700/7000 series is a series of large-scale (mainframe) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s use vacuum-tube logic and were made obsolete by the introduction of the transistorized 7000s. The 7000s, in turn, were eventually replaced with System/360, which was announced in 1964. However the 360/65, the first 360 powerful enough to replace 7000s, did not become available until November 1965. Early problems with OS/360 and the high cost of converting software kept many 7000s in service for years afterward. Architectures The IBM 700/7000 series has six completely different ways of storing data and instructions: *First scientific (36/18-bit words): 701 (Defense Calculator) *Later scientific (36-bit words, hardware floating-point): 704, 709, 7040, 7044, 7090, 7094 *Commercial (variable-length character strings): 702, 705, 7080 * 1400 series (variab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Aircraft
The United Aircraft Corporation was an American aircraft manufacturer formed by the break-up of United Aircraft and Transport Corporation in 1934. In 1975, the company became United Technologies. History Pre-1930s 1930s The Air Mail scandal of the early 1930s resulted in a rebuilt air mail system, under the Air Mail Act of 1934, in which carriers and their equipment manufacturers (e.g., of airframes and engines) could no longer be owned by the same company.. The United Aircraft and Transport Corporation was broken up on September 26, 1934, as a result of this new law. The corporation's airline interests went on to become United Airlines. Its manufacturing interests east of the Mississippi River—Pratt & Whitney, Chance Vought, and Sikorsky—remained together as the new United Aircraft Corporation, headquartered in Hartford with Frederick Rentschler, founder of Pratt & Whitney, as president. All manufacturing interests west of the Mississippi became part of a revived Boeing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linker (computing)
In computing, a linker or link editor is a computer system program that takes one or more object files (generated by a compiler or an assembler) and combines them into a single executable file, library file, or another "object" file. A simpler version that writes its output directly to memory is called the ''loader'', though loading is typically considered a separate process. Overview Computer programs typically are composed of several parts or modules; these parts/modules do not need to be contained within a single object file, and in such cases refer to each other by means of symbols as addresses into other modules, which are mapped into memory addresses when linked for execution. While the process of linking is meant to ultimately combine these independent parts, there are many good reasons to develop those separately at the source-level. Among these reasons are the ease of organizing several smaller pieces over a monolithic whole and the ability to better define t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
64-bit Computing
In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A computer that uses such a processor is a 64-bit computer. From the software perspective, 64-bit computing means the use of machine code with 64-bit virtual memory addresses. However, not all 64-bit instruction sets support full 64-bit virtual memory addresses; x86-64 and ARMv8, for example, support only 48 bits of virtual address, with the remaining 16 bits of the virtual address required to be all 0's or all 1's, and several 64-bit instruction sets support fewer than 64 bits of physical memory address. The term ''64-bit'' also describes a generation of computers in which 64-bit processors are the norm. 64 bits is a word size that defines certain classes of computer architecture, buses, memory, and CPUs and, by extension, the software th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Van Der Linden
Peter van der Linden (born 1963) is an American technologist and author. (in Dutch) He has worked for companies such as and , and has written books on , C, |
Keyword (computer Programming)
Keyword may refer to: Computing * Keyword (Internet search), a word or phrase typically used by bloggers or online content creator to rank a web page on a particular topic * Index term In information retrieval, an index term (also known as subject term, subject heading, descriptor, or keyword) is a term that captures the essence of the topic of a document. Index terms make up a controlled vocabulary for use in bibliographic record ..., a term used as a keyword to documents in an information system such as a catalog or a search engine * Keyword advertising, a form of online advertising * Keyword clustering, a search engine optimization technique * A reserved word in a programming language Other * Keyword (linguistics), word which occurs in a text more often than we would expect to occur by chance alone * Keyword (rhetoric), a word that academics use to reveal the internal structure of an author's reasoning * '' Keywords: A Vocabulary of Culture and Society'', 1973 non-fiction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Static (keyword)
In some programming languages such as C (and its close descendants like C++, Objective-C, and Java), static is a reserved word controlling both lifetime (as a static variable) and visibility (depending on '' linkage''). The effect of the keyword varies depending on the details of the specific programming language. Common C/C++ behavior In C and C++, the effect of the static keyword in C depends on where the declaration occurs. static may act as a storage class (not to be confused with classes in object-oriented programming), as can extern, auto and register (which are also reserved words). Every variable and function has one of these storage classes; if a declaration does not specify the storage class, a context-dependent default is used: *extern for all top-level declarations in a source file, *auto for variables declared in function bodies. In these languages, the term "static variable" has two meanings which are easy to confuse: # A variable with the same lifetime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
