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In 1968 Shirley Chisholm became the first Black woman elected to the United States Congress. In 1972 she launched a campaign for the Democratic presidential nomination, breaking another political barrier.
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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 The original Beowulf cluster built in 1994 by Thomas Sterling and Donald Becker at NASA. The cluster comprises 16 white box desktops each running a i486 DX4 processor clocked at 100 MHz, each containing a 500 MB hard disk drive, and each having 16 MB of RAM, leading to a total of roughly 8 GB of fixed disk storage and 256 MB of RAM shared within the cluster and a performance benchmark of 500 MFLOPS. |
A Beowulf cluster is a computer cluster of normally identical, commodity-grade computers networked into a small local area network with libraries and programs installed that allow processing to be shared among them. The result is a high-performance parallel computing cluster from inexpensive personal computer hardware.[1]
Beowulf originally referred to a specific computer built in 1994 by Thomas Sterling and Donald Becker at NASA.[2] They named it after the Old English epic poem, Beowulf.[3]
No particular piece of software defines a cluster as a Beowulf. Typically only free and open source software is used, both to save cost and to allow customization. Most Beowulf clusters run a Unix-like operating system, such as BSD, Linux, or Solaris. Commonly used parallel processing libraries include Message Passing Interface (MPI) and Parallel Virtual Machine (PVM). Both of these permit the programmer to divide a task among a group of networked computers, and collect the results of processing. Examples of MPI software include Open MPI or MPICH. There are additional MPI implementations available.
Beowulf systems operate worldwide, chiefly in support of scientific computing. Since 2017, every system on the Top500 list of the world's fastest supercomputers has used Beowulf software methods and a Linux operating system. At this level, however, most are by no means just assemblages of commodity hardware; custom design work is often required for the nodes (often blade servers), the networking, and the cooling systems.
A description of the Beowulf cluster, from the original "how-to", which was published by Jacek Radajewski and Douglas Eadline under the Linux Documentation Project in 1998:[4]
Beowulf is a multi-computer architecture which can be used for parallel computations. It is a system which usually consists of one server node, and one or more client nodes connected via Ethernet or some other network. It is a system built using commodity hardware components, like any PC capable of running a Unix-like operating system, with standard Ethernet adapters, and switches. It does not contain any custom hardware components and is trivially reproducible. Beowulf also uses commodity software like the FreeBSD, Linux or Solaris operating system, Parallel Virtual Machine (PVM) and Message Passing Interface (MPI). The server node controls the whole cluster and serves files to the client nodes. It is also the cluster's console and gateway to the outside world. Large Beowulf machines might have more than one server node, and possibly other nodes dedicated to particular tasks, for example consoles or monitoring stations. In most cases, client nodes in a Beowulf system are dumb, the dumber the better. Nodes are configured and controlled by the server node, and do only what they are told to do. In a disk-less client configuration, a client node doesn't even know its IP address or name until the server tells it.
One of the main differences between Beowulf and a Cluster of Workstations (COW) is that Beowulf behaves more like a single machine rather than many workstations. In most cases client nodes do not have keyboards or monitors, and are accessed only via remote login or possibly serial terminal. Beowulf nodes can be thought of as a CPU + memory package which can be plugged into the cluster, just like a CPU or memory module can be plugged into a motherboard.
Beowulf is not a special software package, new network topology, or the latest kernel hack. Beowulf is a technology of clustering computers to form a parallel, virtual supercomputer. Although there are many software packages such as kernel modifications, PVM and MPI libraries, and configuration tools which make the Beowulf architecture faster, easier to configure, and much more usable, one can build a Beowulf class machine using a standard Linux distribution without any additional software. If you have two networked computers which share at least the
/homefile system via NFS, and trust each other to execute remote shells (rsh), then it could be argued that you have a simple, two node Beowulf machine.
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As of 2014[update] a number of Linux distributions, and at least one BSD, are designed for building Beowulf clusters. These include:
The following are no longer maintained:
A cluster can be set up by using Knoppix bootable CDs in combination with OpenMosix. The computers will automatically link together, without need for complex configurations, to form a Beowulf cluster using all CPUs and RAM in the cluster. A Beowulf cluster is scalable to a nearly unlimited number of computers, limited only by the overhead of the network.
Provisioning of operating systems and other software for a Beowulf Cluster can be automated using software, such as Open Source Cluster Application Resources. OSCAR installs on top of a standard installation of a supported Linux distribution on a cluster's head node.
{{cite book}}: ISBN / Date incompatibility (help)[dead link]
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Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
A Beowulf cluster is a computer cluster of normally identical, commodity-grade computers networked into a small local area network with libraries and programs installed that allow processing to be shared among them. The result is a high-performance parallel computing cluster from inexpensive personal computer hardware.
A computer port is a hardware piece on a computer where an electrical connector can be plugged to link the device to external devices, such as another computer, a peripheral device or network equipment. This is a non-standard term. Electronically, the several conductors where the port and cable contacts connect, provide a method to transfer data signals between devices. Bent pins are easier to replace on a cable than on a connector attached to a computer, so it was common to use female connectors for the fixed side of an interface. Computer ports in common use cover a wide variety of shapes such as round (PS/2, etc.), rectangular (FireWire, etc.), square (Telephone plug), trapezoidal (D-Sub — the old printer port was a DB-25), etc. There is some standardization to physical properties and function. For instance, most computers have a keyboard port (currently a Universal Serial Bus USB-like outlet referred to as USB Port), into which the keyboard is connected. Physically identical connectors may be used for widely different standards, especially on older personal computer systems, or systems not generally designed according to the current Microsoft Windows compatibility guides. For example, a 9-pin D-subminiature connector on the original IBM PC could have been used for monochrome video, color analog video (in two incompatible standards), a joystick interface, or a MIDI musical instrument digital control interface. The original IBM PC also had two identical 5 pin DIN connectors, one used for the keyboard, the second for a cassette recorder interface; the two were not interchangeable. The smaller mini-DIN connector has been variously used for the keyboard and two different kinds of mouse; older Macintosh family computers used the mini-DIN for a serial port or for a keyboard connector with different standards than the IBM-descended systems.
A personal computer (PC), or simply computer, is a computer designed for personal use. It is typically used for tasks such as word processing, web browsing, email, file management, spreadsheets, and video calling. Unlike large, costly minicomputers and mainframes, time-sharing by many people at the same time is not used with personal computers. Personal computers are designed to be operated directly by an end user, instead of a computer expert, administrator, company or technician. The term "home computer" has also been used, primarily in the late 1970s and 1980s. The advent of personal computers and the concurrent Digital Revolution have significantly affected the lives of people. In 1981, the IBM Personal Computer was released, and IBM PC compatibles soon followed; the term PC came to be used historically to refer exclusively to these computers. Other personal computers introduced at around the same time, such as the Apple II, TRS-80, and Commodore 64, tended to be called home computers. Since the early 1990s, computers running the "Wintel" software–hardware platform stack (a Microsoft operating system, initially MS-DOS and later Windows, on a CPU based on Intel's x86 architecture) came to dominate the personal computer market, and the term "PC" most often refers to the Wintel platform, or to Windows PCs in general (regardless of processor architecture). Alternatives to Windows, which tend to be referred to as "personal computers" but not "PCs", occupy a minority share of the market; they are predominantly Unix-based or Unix-like operating systems, such as macOS on Apple's Mac platform, and Linux, including the Linux-derived ChromeOS, though most distributions are free and open-source. Other notable platforms until the 1990s were the Amiga, Atari ST, and the PC-98 line.
Code: The Hidden Language of Computer Hardware and Software (1999) is a book by Charles Petzold that seeks to teach how personal computers work at a hardware and software level. In the preface to the 2000 softcover edition, Petzold wrote that his goal was for readers to understand how computers work at a concrete level that "just might even rival that of electrical engineers and programmers" and that he "went as far back" as he could go in regard to the history of technological development. Petzold describes Code as being structured as moving "up each level in the hierarchy" in which computers are constructed. On June 10, 2022, Petzold announced that an expanded second edition would be published later that year. The second edition was released on July 28, 2022, along with an interactive companion website (www.codehiddenlanguage.com) developed by Petzold. The idea of writing the book came to him in 1987 while writing a column called "PC Tutor" for PC Magazine.
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 →The Greenwood District.
