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Class (file Format)
A Java class file is a file (with the filename extension) containing Java bytecode that can be executed on the Java Virtual Machine (JVM). A Java class file is usually produced by a Java compiler from Java programming language source files ( files) containing Java classes (alternatively, other JVM languages can also be used to create class files). If a source file has more than one class, each class is compiled into a separate class file. JVMs are available for many platforms, and a class file compiled on one platform will execute on a JVM of another platform. This makes Java applications platform-independent. History On 11 December 2006, the class file format was modified under Java Specification Request (JSR) 202. File layout and structure Sections There are 10 basic sections to the Java class file structure: * Magic Number: 0xCAFEBABE * Version of Class File Format: the minor and major versions of the class file * Constant Pool: Pool of constants for the class * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Sun Microsystems
Sun Microsystems, Inc. (Sun for short) was an American technology company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, the Network File System (NFS), and SPARC microprocessors. Sun contributed significantly to the evolution of several key computing technologies, among them Unix, RISC processors, thin client computing, and virtualized computing. Notable Sun acquisitions include Cray Business Systems Division, Storagetek, and ''Innotek GmbH'', creators of VirtualBox. Sun was founded on February 24, 1982. At its height, the Sun headquarters were in Santa Clara, California (part of Silicon Valley), on the former west campus of the Agnews Developmental Center. Sun products included computer servers and workstations built on its own RISC-based SPARC processor architecture, as well as on x86-based AMD Opteron and Intel Xeon processors. Sun also dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Byte
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit of memory in many computer architectures. To disambiguate arbitrarily sized bytes from the common 8-bit definition, network protocol documents such as The Internet Protocol () refer to an 8-bit byte as an octet. Those bits in an octet are usually counted with numbering from 0 to 7 or 7 to 0 depending on the bit endianness. The first bit is number 0, making the eighth bit number 7. The size of the byte has historically been hardware-dependent and no definitive standards existed that mandated the size. Sizes from 1 to 48 bits have been used. The six-bit character code was an often-used implementation in early encoding systems, and computers using six-bit and nine-bit bytes were common in the 1960s. These systems often had memory wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Magic Number (programming)
In computer programming, a magic number is any of the following: * A unique value with unexplained meaning or multiple occurrences which could (preferably) be replaced with a named constant * A constant numerical or text value used to identify a file format or protocol; for files, see List of file signatures * A distinctive unique value that is unlikely to be mistaken for other meanings (e.g., Globally Unique Identifiers) Unnamed numerical constants The term ''magic number'' or ''magic constant'' refers to the anti-pattern of using numbers directly in source code. This has been referred to as breaking one of the oldest rules of programming, dating back to the COBOL, FORTRAN and PL/1 manuals of the 1960s. The use of unnamed magic numbers in code obscures the developers' intent in choosing that number, increases opportunities for subtle errors (e.g. is every digit correct in 3.14159265358979323846 and is this equal to 3.14159?) and makes it more difficult for the program to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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32-bit
In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32- bit units. Compared to smaller bit widths, 32-bit computers can perform large calculations more efficiently and process more data per clock cycle. Typical 32-bit personal computers also have a 32-bit address bus, permitting up to 4 GB of RAM to be accessed; far more than previous generations of system architecture allowed. 32-bit designs have been used since the earliest days of electronic computing, in experimental systems and then in large mainframe and minicomputer systems. The first hybrid 16/32-bit microprocessor, the Motorola 68000, was introduced in the late 1970s and used in systems such as the original Apple Macintosh. Fully 32-bit microprocessors such as the Motorola 68020 and Intel 80386 were launched in the early to mid 1980s and became dominant by the early 1990s. This generation of personal computers c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Endianness
In computing, endianness, also known as byte sex, is the order or sequence of bytes of a word of digital data in computer memory. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). A big-endian system stores the most significant byte of a word at the smallest memory address and the least significant byte at the largest. A little-endian system, in contrast, stores the least-significant byte at the smallest address. Bi-endianness is a feature supported by numerous computer architectures that feature switchable endianness in data fetches and stores or for instruction fetches. Other orderings are generically called middle-endian or mixed-endian. Endianness may also be used to describe the order in which the bits are transmitted over a communication channel, e.g., big-endian in a communications channel transmits the most significant bits first. Bit-endianness is seldom used in other contexts. Etymology Danny Cohen introduced the terms ''big-endian'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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16-bit
16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two most common representations, the range is 0 through 65,535 (216 − 1) for representation as an (unsigned) binary number, and −32,768 (−1 × 215) through 32,767 (215 − 1) for representation as two's complement. Since 216 is 65,536, a processor with 16-bit memory addresses can directly access 64 KB (65,536 bytes) of byte-addressable memory. If a system uses segmentation with 16-bit segment offsets, more can be accessed. 16-bit architecture The MIT Whirlwind ( 1951) was quite possibly the first-ever 16-bit computer. It was an unusual word size for the era; most systems used six-bit character code and used a word length of some multiple of 6-bits. This changed with the effort to introduce ASCII, which used a 7-bit code and naturally l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Octet (computing)
The octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term byte might be ambiguous, as the byte has historically been used for storage units of a variety of sizes. The term ''octad(e)'' for eight bits is no longer common. Definition The international standard IEC 60027-2, chapter 3.8.2, states that a byte is an octet of bits. However, the unit byte has historically been platform-dependent and has represented various storage sizes in the history of computing. Due to the influence of several major computer architectures and product lines, the byte became overwhelmingly associated with eight bits. This meaning of ''byte'' is codified in such standards as ISO/IEC 80000-13. While ''byte'' and ''octet'' are often used synonymously, those working with certain legacy systems are careful to avoid ambiguity. Octets can be represented using number systems of varying bases such as the hexadec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Java Remote Method Invocation
In computing, the Java Remote Method Invocation (Java RMI) is a Java API that performs remote method invocation, the object-oriented equivalent of remote procedure calls (RPC), with support for direct transfer of serialized Java classes and distributed garbage-collection. The original implementation depends on Java Virtual Machine (JVM) class-representation mechanisms and it thus only supports making calls from one JVM to another. The protocol underlying this Java-only implementation is known as Java Remote Method Protocol (JRMP). In order to support code running in a non-JVM context, programmers later developed a CORBA version. Usage of the term RMI may denote solely the programming interface or may signify both the API and JRMP, IIOP, or another implementation, whereas the term RMI-IIOP (read: RMI over IIOP) specifically denotes the RMI interface delegating most of the functionality to the supporting CORBA implementation. The basic idea of Java RMI, the distributed garbag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Grep
grep is a command-line utility for searching plain-text data sets for lines that match a regular expression. Its name comes from the ed command ''g/re/p'' (''globally search for a regular expression and print matching lines''), which has the same effect. grep was originally developed for the Unix operating system, but later available for all Unix-like systems and some others such as OS-9. History Before it was named, grep was a private utility written by Ken Thompson to search files for certain patterns. Doug McIlroy, unaware of its existence, asked Thompson to write such a program. Responding that he would think about such a utility overnight, Thompson actually corrected bugs and made improvements for about an hour on his own program called s (short for "search"). The next day he presented the program to McIlroy, who said it was exactly what he wanted. Thompson's account may explain the belief that grep was written overnight. Thompson wrote the first version in PDP-11 asse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Jerry Garcia
Jerome John Garcia (August 1, 1942 – August 9, 1995) was an American musician best known for being the principal songwriter, lead guitarist, and a vocalist with the rock band Grateful Dead, which he co-founded and which came to prominence during the counterculture of the 1960s. Although he disavowed the role, Garcia was viewed by many as the leader of the band. He was inducted into the Rock and Roll Hall of Fame in 1994 as a member of the Grateful Dead. As one of its founders, Garcia performed with the Grateful Dead for the band's entire 30-year career (1965–1995). Garcia also founded and participated in a variety of side projects, including the Saunders–Garcia Band (with longtime friend Merl Saunders), the Jerry Garcia Band, Old & In the Way, the Garcia/Grisman and Garcia/ Kahn acoustic duos, Legion of Mary, and New Riders of the Purple Sage (which he co-founded with John Dawson and David Nelson). He also released several solo albums, and contributed to a numbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Grateful Dead
The Grateful Dead was an American rock music, rock band formed in 1965 in Palo Alto, California. The band is known for its eclectic style, which fused elements of rock, Folk music, folk, country music, country, jazz, bluegrass music, bluegrass, blues, rock and roll, gospel music, gospel, reggae, world music, and psychedelic music, psychedelia; for Concert, live performances of lengthy jam session, instrumental jams that typically incorporated mode (music), modal and tonality, tonal musical improvisation, improvisation; and for its devoted fan base, known as "Deadheads". "Their music", writes Lenny Kaye, "touches on ground that most other groups don't even know exists." These various influences were distilled into a diverse and psychedelic whole that made the Grateful Dead "the pioneering Godfathers of the jam band world". The band was ranked 57th by ''Rolling Stone'' magazine in its "Rolling Stone's 100 Greatest Artists of All Time, The Greatest Artists of All Time" issue. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Palo Alto, California
Palo Alto (; Spanish for "tall stick") is a charter city in the northwestern corner of Santa Clara County, California, United States, in the San Francisco Bay Area, named after a coastal redwood tree known as El Palo Alto. The city was established in 1894 by the American industrialist Leland Stanford when he founded Stanford University in memory of his son, Leland Stanford Jr. Palo Alto includes portions of Stanford University and borders East Palo Alto, Mountain View, Los Altos, Los Altos Hills, Stanford, Portola Valley, and Menlo Park. At the 2020 census, the population was 68,572. Palo Alto is one of the most expensive cities in the United States in which to live, and its residents are among the most educated in the country. However, it also has a youth suicide rate four times higher than the national average, often attributed to academic pressure. As one of the principal cities of Silicon Valley, Palo Alto is headquarters to a number of high-tech companies, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |