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In August 1908, a white mob attacked Springfield, Illinois’s Black community, destroying homes and businesses and lynching two Black men. National outrage over the violence helped spur the movement that created the NAACP the following year.
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
The Intel 80387SX (387SX or i387SX) is the coprocessor, also called a FPU, for the Intel 80386SX microprocessor. Introduced in 1987,[1] it was used to perform floating-point arithmetic operations directly in hardware. The coprocessor was designed only to work with the 386SX, rather than the standard 386DX. This was because the original 80387 could not communicate with the altered 16 bit data bus of the 386SX, which was modified from the original 386DX's 32 bit data bus. The 387SX uses a 68-pin PLCC socket, just like some variants of the 80286 and the less common 80186 CPU, and was made in speeds ranging from 16 MHz to 33 MHz, matching the clock speed range of the Intel manufactured 386SX. Some chips like the IIT 3C87SX could get up to 40 MHz, matching the clock speeds of the fastest 386SX CPUs.
With the 386SX/387SX combination, it provides three to five times the floating-point performance compared to the 80286/80287 combination.[2]
The initial 16-MHz version of 387SX initially retailed for US$506.[3] A low-power version of 387SX to go along with low-power version of 386SX was also available.[4] In 1991, a 25-MHz model was made available for US$189,[5] followed by a 33-MHz model in 1993 with listed price of US$109.[6]
The 80C187 co-processor, designed to pair with the CMOS-based based Intel 80C186 CPU, was also introduced in the same year as the 387SX and uses its core as well, while using a 8087-like interface.[7]
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
The Intel 80387SX (387SX or i387SX) is the coprocessor, also called a FPU, for the Intel 80386SX microprocessor. Introduced in 1987, it was used to perform floating-point arithmetic operations directly in hardware. The coprocessor was designed only to work with the 386SX, rather than the standard 386DX. This was because the original 80387 could not communicate with the altered 16 bit data bus of the 386SX, which was modified from the original 386DX's 32 bit data bus. The 387SX uses a 68-pin PLCC socket, just like some variants of the 80286 and the less common 80186 CPU, and was made in speeds ranging from 16 MHz to 33 MHz, matching the clock speed range of the Intel manufactured 386SX. Some chips like the IIT 3C87SX could get up to 40 MHz, matching the clock speeds of the fastest 386SX CPUs. With the 386SX/387SX combination, it provides three to five times the floating-point performance compared to the 80286/80287 combination. The initial 16-MHz version of 387SX initially retailed for US$506. A low-power version of 387SX to go along with low-power version of 386SX was also available. In 1991, a 25-MHz model was made available for US$189, followed by a 33-MHz model in 1993 with listed price of US$109. The 80C187 co-processor, designed to pair with the CMOS-based based Intel 80C186 CPU, was also introduced in the same year as the 387SX and uses its core as well, while using a 8087-like interface.
The Intel 80186, also known as the iAPX 186, or just 186, is a microprocessor and microcontroller introduced in 1982. It is based on the Intel 8086 and, like it, has a 16-bit external data bus multiplexed with a 20-bit address bus. The 80188 is a variant with an 8-bit external data bus.
A microprocessor is a computer processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit (CPU). The microprocessor is capable of interpreting and executing machine code and performing arithmetic operations. The microprocessor is a multipurpose, clock-driven, register-based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory, and provides results (also in binary form) as output. Microprocessors contain both combinational logic and sequential digital logic, and operate on numbers and symbols represented in the binary number system. The integration of a whole CPU onto a single or a few integrated circuits using very-large-scale integration (VLSI) greatly reduced the cost of computing. Integrated circuit processors are produced in large numbers by highly automated metal–oxide–semiconductor (MOS) fabrication processes, resulting in a relatively low unit price. Single-chip processors increase reliability because there are fewer electrical connections that can fail. As microprocessor designs improve, the cost of manufacturing a chip (with smaller components built on a semiconductor chip the same size) generally stays the same, according to Rock's law. Continued increases in microprocessor capacity have since rendered other forms of computers almost completely obsolete (see history of computing hardware), with one or more microprocessors used in everything from the smallest embedded systems and handheld devices to the largest mainframes and supercomputers. Before microprocessors, small computers had been built using racks of circuit boards with many medium- and small-scale integrated circuits. These were typically of the TTL type. Microprocessors combined this into one or a few large-scale ICs. While there is disagreement over who deserves credit for the invention of the microprocessor, the first commercially available microprocessor was the Intel 4004, designed by Federico Faggin and introduced in 1971. A microprocessor is distinct from a microcontroller, a type of system on a chip. A microprocessor is related but distinct from a digital signal processor, a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing.
x87 is a floating-point-related subset of the x86 architecture instruction set. It originated as an extension of the 8086 instruction set in the form of optional floating-point coprocessors (FPU) that work in tandem with corresponding x86 CPUs. These microchips have names ending in "87". This is also known as the NPX (numeric processor extension). Like other extensions to the basic instruction set, x87 instructions are not strictly needed to construct working programs, but provide hardware and microcode implementations of common numerical tasks, allowing these tasks to be performed much faster than corresponding machine code routines can. The x87 instruction set includes instructions for basic floating-point operations such as addition, subtraction and comparison, but also for more complex numerical operations, such as the computation of the tangent function and its inverse, for example. Most x86 processors since the Intel 80486 have had these x87 instructions implemented in the main CPU, but the term is sometimes still used to refer to that part of the instruction set. Before x87 instructions were standard in PCs, compilers or programmers had to use rather slow library calls to perform floating-point operations, a method that is still common in (low-cost) embedded systems.
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.
MORE →Madam C.J. Walker