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Movements, leaders, victories and the continuing fight for equality.
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Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
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
ESMexpress is a computer-on-module (COM) standard. It is a complete processor module that currently supports several low-power Intel and PowerPC platforms. Every module has a CPU, as well as memory and a range of serial communication interfaces such as PCI Express, Gigabit Ethernet, USB, SATA, SDVO, LVDS and HD audio. These interfaces are defined in the form factor's specification, and signals are assigned to two 120-pin connectors. This fixed pin mapping ensures that different ESMexpress modules can be exchanged more easily. Consequently, ESMexpress typically does not have an onboard FPGA. The idea behind this is to implement very specialized functions in an FPGA on the COM's carrier board to ease upgrades of the system CPU through exchange of the ESMexpress module. The ESMexpress standard includes only one form factor: 95 x 125 mm. The most important specialty of this computer-on-module is its surrounding mechanical concept, which was designed for especially severe environmental conditions, for example in railway or avionics, or in the automation industry. The large temperature ranges prevalent in such fields of use are met by the modules through a cooling concept that does not need a fan for the CPU: the computer board is embedded into an aluminum frame and cover that can lead the heat off the processor by conduction cooling. At the same time this mechanical set-up provides stability to withstand vibration, but also electromagnetic compatibility (EMC).
A computer-on-module (COM) is a type of single-board computer (SBC), a subtype of an embedded computer system. An extension of the concept of system on chip (SoC) and system in package (SiP), COM lies between a full-up computer and a microcontroller in nature. It is very similar to a system on module (SOM).
Embedded System Module, or ESM, is a compact computer-on-module (COM) standard. An ESM module typically includes a CPU processor, memory, module-specific I/O interfaces and a number of basic front I/O connectors. They can be plugged on a carrier board or be used as a stand-alone processor card. If the ESM module is plugged on a carrier, it relies on the standard PCI bus as a board-to-board interface. In this case two connectors create a link to the carrier. While the "J1" connector provides a specified PCI connection, the "J2" connector brings I/O signals from the ESM module to the carrier, which then includes all necessary connectors. The signal assignment of J2 is not fixed but can be completely customized, although there are reserved pins for a 64-bit PCI bus interface. A third connector, "J3", is used for additional I/O signals if the ESM module has no front I/O. The signal assignment of this connector is fixed to support a special set of I/O functions. A large part of the I/O functions on ESMs are often controlled by an onboard FPGA component (field-programmable gate array) so that every module can easily be tailored to a specialized application through user-defined functions. Such functions are loaded into the FPGA as IP cores. Using FPGAs also reduces dependence on special controller chips which may become obsolete, thus extending the card's serviceability. ESMs are typically used on boards for CompactPCI and VMEbus as well as single-board computers for embedded applications. A company standard by MEN Micro, a manufacturer of embedded computers, specifies the ESM concept and the different types of modules. The ESM specification defines one form factor for the printed circuit board: 149 × 71 mm (5.9 × 2.8 in). Depending on the processor type, most ESM modules have heat sinks and can be operated in wide temperature ranges up to -40 to +85 °C. A mechanical specialty of ESM modules is that their connectors are compatible with the PCI-104 module standard. These modules can be "stacked" onto ESM modules, e. g., for additional peripheral interfaces.
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 →Shirley Chisholm, elected in 1968.
