Civil Rights
Movements, leaders, victories and the continuing fight for equality.
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Mansa Musa was the ruler of the Mali Empire in West Africa. Details recorded here should be sourced; unknown information is left blank.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
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| Computer architecture bit widths |
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| Binary floating-point precision |
| Decimal floating-point precision |
In computer architecture, 256-bit integers, memory addresses, or other data units are those that are 256 bits (32 octets) wide. Also, 256-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers, address buses, or data buses of that size. There are currently no mainstream general-purpose processors built to operate on 256-bit integers or addresses, though a number of processors do operate on 256-bit data.
A 256-bit quantity can store 2256 different values. The range of integer values that can be stored in 256 bits depends on the integer representation used.
The range of a signed 256-bit integer is from −57,896,044,618,658,097,711,785,492,504,343,953,926,634,992,332,820,282,019,728,792,003,956,564,819,968 to 57,896,044,618,658,097,711,785,492,504,343,953,926,634,992,332,820,282,019,728,792,003,956,564,819,967.
256-bit processors could be used for addressing directly up to 2256 bytes. Already 2128 (for 128-bit addressing) would greatly exceed the total data stored on Earth as of 2018, which has been estimated to be around 33.3 ZBs (over 274 bytes).[1]
Xbox 360 was the first high-definition gaming console to utilize the ATI Technologies 256-bit GPU Xenos[2] before the introduction of the current gaming consoles especially Nintendo Switch.
Some buses on the newer System on a chip (e.g. Tegra developed by Nvidia) utilize 64-bit, 128-bit, 256-bit, or higher.

CPUs feature SIMD instruction sets (Advanced Vector Extensions and the FMA instruction set etc.) where 256-bit vector registers are used to store several smaller numbers, such as eight 32-bit floating-point numbers, and a single instruction can operate on all these values in parallel. However, these processors do not operate on individual numbers that are 256 binary digits in length, only their registers have the size of 256-bits. Binary digits are found together in 128-bit collections.
Modern GPU chips may operate data across a 256-bit memory bus (or possibly a 512-bit bus with HBM3[3]).
The Efficeon processor was Transmeta's second-generation 256-bit VLIW design which employed a software engine to convert code written for x86 processors to the native instruction set of the chip.[4][5]
The DARPA funded Data-Intensive Architecture (DIVA) system incorporated processor-in-memory (PIM) 5-stage pipelined 256-bit datapath, complete with register file and ALU blocks in a "WideWord" processor in 2002.[6]
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In computer architecture, 256-bit integers, memory addresses, or other data units are those that are 256 bits (32 octets) wide. Also, 256-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers, address buses, or data buses of that size. There are currently no mainstream general-purpose processors built to operate on 256-bit integers or addresses, though a number of processors do operate on 256-bit data.
Bit-level parallelism is a form of parallel computing based on increasing processor word size. Increasing the word size reduces the number of instructions the processor must execute in order to perform an operation on variables whose sizes are greater than the length of the word. (For example, consider a case where an 8-bit processor must add two 16-bit integers. The processor must first add the 8 lower-order bits from each integer, then add the 8 higher-order bits, requiring two instructions to complete a single operation. A 16-bit processor would be able to complete the operation with single instruction.) Originally, all electronic computers were serial (single-bit) computers. The first electronic computer that was not a serial computer—the first bit-parallel computer—was the 16-bit Whirlwind from 1951. From the advent of very-large-scale integration (VLSI) computer chip fabrication technology in the 1970s until about 1986, advancements in computer architecture were done by increasing bit-level parallelism, as 4-bit microprocessors were replaced by 8-bit, then 16-bit, then 32-bit microprocessors. This trend generally came to an end with the introduction of 32-bit processors, which were a standard in general purpose computing for two decades. 64 bit architectures were introduced to the mainstream with the eponymous Nintendo 64 (1996), but beyond this introduction stayed uncommon until the advent of x86-64 architectures around the year 2003, and 2014 for mobile devices with the ARMv8-A instruction set. On 32-bit processors, external data bus width continues to increase. For example, DDR1 SDRAM transfers 128 bits per clock cycle. DDR2 SDRAM transfers a minimum of 256 bits per burst.
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 (RFC 791) 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 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 words of 12, 18, 24, 30, 36, 48, or 60 bits, corresponding to 2, 3, 4, 5, 6, 8, or 10 six-bit bytes, and persisted, in legacy systems, into the twenty-first century. In this era, bit groupings in the instruction stream were often referred to as syllables or slab, before the term byte became common. The modern de facto standard of eight bits, as documented in ISO/IEC 2382-1:1993, is a convenient power of two permitting the binary-encoded values 0 through 255 for one byte, as 2 to the power of 8 is 256. The international standard IEC 80000-13 codified this common meaning. Many types of applications use information representable in eight or fewer bits and processor designers commonly optimize for this usage. The popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the 8-bit byte. Modern architectures typically use 32- or 64-bit words, built of four or eight bytes, respectively. The unit symbol for the byte was designated as the upper-case letter B by the International Electrotechnical Commission (IEC) and Institute of Electrical and Electronics Engineers (IEEE). Internationally, the unit octet explicitly defines a sequence of eight bits, eliminating the potential ambiguity of the term "byte". The symbol for octet, 'o', also conveniently eliminates the ambiguity in the symbol 'B' between byte and bel.
In computing, octuple precision is a binary floating-point-based computer number format that occupies 32 bytes (256 bits) in computer memory. This 256-bit octuple precision is for applications requiring results in higher than quadruple precision. The range greatly exceeds what is needed to describe the size of the observable universe, precise to the Planck length. However, some problems in experimental mathematics do require octuple (or higher) precision.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
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