omniomni/omni-engineering huggingface dataset:
Memory debugger. A memory debugger is a debugger for finding software memory problems such as memory leaks and buffer overflows.  These are due to bugs related to the allocation and deallocation of dynamic memory. Programs written in languages that have garbage collection, such as managed code, might also need memory debuggers, e.g. for memory leaks due to "living" references in collections.

Overview
Memory debuggers work by monitoring memory access, allocations, and deallocation of memory. Many memory debuggers require applications to be recompiled with special dynamic memory allocation libraries, whose APIs are mostly compatible with conventional dynamic memory allocation libraries, or else use dynamic linking. Electric Fence is such a debugger which debugs memory allocation with malloc. Some memory debuggers (e.g. Valgrind) work by running the executable in a virtual machine-like environment, monitoring memory access, allocation and deallocation so that no recompilation with special memory allocation libraries is required.

Finding memory issues such as leaks can be extremely time consuming as they may not manifest themselves except under certain conditions. Using a tool to detect memory misuse makes the process much faster and easier.

As abnormally high memory utilization can be a contributing factor in software aging, memory debuggers can help programmers to avoid software anomalies that would exhaust the computer system memory, thus ensuring high reliability of the software even for long runtimes.

Comparison to static analyzer
Some static analysis tools can also help find memory errors. Memory debuggers operate as part of an application while it's running while static code analysis is performed by analyzing the code without executing it. These different techniques will typically find different instances of problems, and using them both together yields the best result.

List of memory debugging tools
This is a list of tools useful for memory debugging. A profiler can be used in conjunction with a memory debugger.

See also

Profiling (computer programming)
List of performance analysis tools
Debugger
Runtime error detection
Software testing
Software engineering
Computer programming
Core dump

References
Michael C. Daconta: C++ Pointers and Dynamic Memory Management, John Wiley & Sons, 
Andrew Koenig: C Traps and Pitfalls, Addison-Wesley,

External links
"Hunting Memory Bugs" by Ivan Skytte Jørgensen
"Comparison of Free Memory Checkers" by Jean-Philippe Martin 

Memory management software
Debugging
Splint (programming tool). Splint, short for Secure Programming Lint, is a programming tool for statically checking C programs for security vulnerabilities and coding mistakes. Formerly called LCLint, it is a modern version of the Unix lint tool.

Splint has the ability to interpret special annotations to the source code, which gives it stronger checking than is possible just by looking at the source alone. Splint is used by gpsd as part of an effort to design for zero defects.

Splint is free software released under the terms of the GNU General Public License.

Main development activity on Splint stopped in 2010. According to the CVS at SourceForge, as of September 2012 the most recent change in the repository was in November 2010. A Git repository at GitHub has more recent changes, starting in July 2019.

Example
#include <stdio.h>
int main()
{
    char c;
    while (c != 'x');
    {
        c = getchar();
        if (c = 'x')
            return 0;
        switch (c) {
        case '\n':
        case '\r':
            printf("Newline\n");
        default:
            printf("%c",c);
        }
    }
    return 0;
}

Splint's output:
<nowiki>
Variable c used before definition
Suspected infinite loop. No value used in loop test (c) is modified by test or loop body.
Assignment of int to char: c = getchar()
Test expression for if is assignment expression: c = 'x'
Test expression for if not boolean, type char: c = 'x'
Fall through case (no preceding break)
</nowiki>

Fixed source:
#include <stdio.h>
int main()
{
    int c = 0;  // Added an initial assignment definition.

    while (c != 'x') {
        c = getchar();  // Corrected type of c to int
        if (c == 'x') // Fixed the assignment error to make it a comparison operator.
            return 0;
        switch (c) {
        case '\n':
        case '\r':
            printf("Newline\n");
            break;  // Added break statement to prevent fall-through.
        default:
            printf("%c",c);
            break;  //Added break statement to default catch, out of good practice.
        }
    }
    return 0;
}

See also

Buffer overflow
Memory debugger
Software testing
List of tools for static code analysis

References

External links

Static program analysis tools
Free memory management software
Cross-platform software
Free software testing tools
Software using the GNU General Public License
Matthew Dillon. Matthew Dillon (born 1966) is an American software engineer known for Amiga software, contributions to FreeBSD and for starting and leading the DragonFly BSD project since 2003.

Biography
Dillon studied electronic engineering and computer science at the University of California, Berkeley, where he first became involved with BSD in 1985. He also became known for his Amiga programming, his C compiler DICE and his work on the Linux kernel. He founded and worked at Best Internet from 1994 until 1997, contributing to FreeBSD in that time. His "Diablo" internet news transit program was very popular with many ISPs.

In 1997, Dillon gained commit access to the FreeBSD code and heavily contributed to the virtual memory subsystem, amongst other contributions.

Concerned with problems he saw in the direction FreeBSD 5.x was headed in regards to concurrency, and coupled with the fact that Dillon's access to the FreeBSD source code repository was revoked due to a falling-out with other FreeBSD developers, he started the DragonFly BSD project in 2003, implementing the SMP model using light-weight kernel threads. The DragonFly project also led to the development of a new userspace kernel virtualisation technique in 2006, called Virtual Kernel, originally to ease the development and testing of subsequent kernel-level features; a new file system, called HAMMER, which he created using B-trees; HAMMER was declared production-ready with DragonFly 2.2 in 2009; and, subsequently, HAMMER2, declared stable in 2018 with DragonFly 5.2.

Most recently, Dillon has gotten a number of headlines around CPU errata.  In 2007, this was after Theo de Raadt of OpenBSD raised the alarm around the seriousness of some of the errata for Intel Core 2 family of CPUs.  Dillon has independently evaluated Intel's errata, and did an overview of Intel Core errata as well, suggesting that several of them were so serious as to warrant avoiding any processor where the issues remain unfixed.  Dillon has since been a fan of AMD processors, and, subsequently in 2012, he has discovered a brand-new deficiency in some AMD processors for which no existing erratum existed at the time.  Dillon continued his work around CPU issues as late as 2018, presenting solutions to tackle the latest security vulnerabilities like Meltdown, some of which have been subsequently adopted by OpenBSD as well.

Dillon was a frequent guest on bsdtalk during the runtime of the show, and was interviewed several times for KernelTrap.

References

External links
 Matt Dillon home page
 Matt Dillon IRC interview from SlashNet
 OSNews interview (March 13, 2004)

1966 births
Living people
Engineers from San Francisco
University of California, Berkeley alumni
American computer programmers
Amiga people
BSD people
DragonFly BSD
FreeBSD people
Free software programmers
Kernel programmers
Alginite. Alginite is a component of some types of kerogen alongside amorphous organic matter.  Alginite consists of organic-walled marine microfossils, distinct from inorganic (silica)-walled microfossils that comprise diatomaceous earth.

Alginite is a complex soil aggregate of algae based biomass fossil, clay, volcanic ash and calcium carbonate. This material contains a complete spectrum of minerals, biological, macro- and micro-organisms helping to turn lands fertile again in regions where soil has been severely degraded in the past.
 
At least two forms of alginite are distinguishable, "alginite A" (telalginite) and "alginite B" (lamalginite).  The "A" form contains morphologically distinguishable microfossils while the "B" form is more amorphous and film-like.

References

External links
 
 

Sedimentology
Organic minerals
Petrology
Elcat Electric Vehicles. Elcat was a battery electric vehicle manufacturer and an electric vehicle importer based in Järvenpää, Finland.

Elcat Automotive was owned by an electricity producer called Fortum until the production decreases in the early 21st century. Elcat began working in 1974 to design electric cars for Nordic climate. The first prototypes for Elcat's automotive industry were made in 1985 with a joint venture plan with Subaru's Sambar, Dias, and Domingo vans, while the first commercial product was released in 1990. The users of Elcat vehicles were Finnish post office (Posti) and Stockholm-based delivery service.

Elcat ceased car production in 2002 and pivoted to importing electric vehicles. The company imported and sold electric quadricycles, golf carts, and maintenance vehicles as well as electric mopeds and bicycles.

Elcat went bankrupt in 2017.

Models
Cityvan, speed , distance 
Cityvan 200, speed , distance 
Cityvan 202, speed , distance 
Citywagon 202, speed , distance

References

External links

Elcat's website

Electric trucks
Car manufacturers of Finland
Defunct motor vehicle manufacturers of Finland
Defunct manufacturing companies of Finland
John Frederic Daniell. John Frederic Daniell  (12 March 1790 – 13 March 1845) was an English chemist and physicist.

Biography
Daniell was born in London. In 1831 he became the first professor of chemistry at the newly founded King's College London; and in 1835 he was appointed to the equivalent post at the East India Company's Military Seminary at Addiscombe, Surrey. His name is best known for his invention of the Daniell cell, an element of an electric battery much better than voltaic cells. He also invented the dew-point hygrometer known by his name, and a register pyrometer; and in 1830 he erected in the hall of the Royal Society a water-barometer, with which he carried out a large number of observations. A process devised by him for the manufacture of illuminating gas from turpentine and resin was in use in New York City for a time.

In 1842 he was awarded an honorary Doctorate of Civil Law by the University of Oxford.

Publications
Daniell's publications included Meteorological Essays (1823), an Essay on Artificial Climate considered in its Applications to Horticulture (1824), which showed the necessity of a humid atmosphere in hothouses devoted to tropical plants, and an Introduction to the Study of Chemical Philosophy (1839).

Lectures
In 1840 he was invited to deliver the Royal Institution Christmas Lecture on The First Principles of Franklinic Electricity.

Death and commemoration
Daniell died suddenly of apoplexy in London in March 1845, while attending a meeting of the council of the Royal Society, of which he had become a fellow in 1813 and Foreign Secretary in 1839.

The lunar crater Daniell is named after him.

See also
Timeline of hydrogen technologies

References

Bibliography
 
 

1790 births
1845 deaths
English physicists
English inventors
English chemists
Academics of King's College London
Fellows of the Royal Society
People of the Industrial Revolution
Recipients of the Copley Medal
Royal Medal winners
Battery inventors
People associated with electricity
Committee members of the Society for the Diffusion of Useful Knowledge
Alumni of the University of Oxford
Ford Köln. The Ford Köln is an automobile that was produced by Ford Germany from 1933 until 1936 at its Cologne plant.

Origins
The English Ford company had developed the car and introduced it in 1932 as the Ford Model Y. The German-built version, renamed Ford Köln to stress the vehicle's German provenance, was first seen at the 1933 Berlin Motor Show.   The name came from the German name for the city of Cologne.   The early cars were built with components and other support from the company's English associate, but during the first year of production componentry was increasingly sourced locally.

Evolution
Subsequently, the German company offered alternative bodied cars of its own design, including notably, for 1934/35, a cheap open topped "Cabrio-Limousine" that used timber-frame construction with synthetic leather covering after the manner of some of the smaller DKWs and Adlers.  This bargain basement special was promoted as a "car for everyman" ("Wagen für Jedermann") and priced in 1935 at 1,850 Marks, which was 360 Marks less than the manufacturer's advertised price for the normally bodied two-door sedan/saloon.

Technical specification
The Köln had a four-cylinder, four-stroke engine  of 933 cc giving 21 hp (16 kW) at 3400 rpm. The top speed was . It had a three-speed gearbox (plus reverse) with synchromesh on second and third gear. It was a small car weighing, in bare chassis form, only : an empty car with a body fitted weighed between  and .

Commercial
Public response to the car was lukewarm due to a rigid axle based front suspension and a perpendicular body style which was by now perceived as old fashioned.  In its class the car faced heavy competition, mainly from Opel, DKW and Adler: commercially the Ford Köln, with 11,121 cars produced between 1933 and 1936, was not a great success. Adler produced 24,013 of their similarly sized Trumpf Juniors in less than two years between 1934 and 1935.  Ford Köln volumes were also disappointing when compared with the 153,117 produced by Ford of Britain of the equivalent model.

In 1935 the Ford Köln was replaced by the Ford Eifel which was a larger car (based on the British Model C).

References

Bibliography

Koln
Cars introduced in 1932
NICE (disambiguation). NICE  may refer to:

Educational institutions
 National Institute for Health and Care Excellence in the UK
 Noorul Islam College of Engineering, a former name of Noorul Islam Centre for Higher Education (NICHE), Kumarakoil, India
 North Idaho College of Education, a former name of Lewis–Clark State College in Lewiston, Idaho

Other organizations and companies
 International (Nice) Classification of Goods and Services
 Nassau Inter-County Express, a bus system in Nassau County, New York
 National Independent Cadres and Elites, in Iraq
 National Information & Credit Evaluation, a Korean comprehensive credit information provider
 National Institute for Coordinated Experiments, a fictional organisation in C.S. Lewis' novel That Hideous Strength
 NICE Car Company, a distributor of electric vehicles in London
 NICE Ltd., an Israeli surveillance and data analytics company

Other
 Neutral Ion Coupling Explorer, a candidate Small Explorer program spacecraft
 NICE classification of colorectal polyps
 NICE Corridor, also known as the Bangalore–Mysore Infrastructure Corridor

See also
Nice (disambiguation)
Max Knoll. Max Knoll (17 July 1897 – 6 November 1969) was a German electrical engineer and co-inventor of the electron microscope.
Knoll was born in Wiesbaden and studied at the University of Munich and at the Technischen Hochschulen in Munich and Berlin-Charlottenburg, where he obtained his doctorate in the Institute for High Voltage Technology. In 1927 he became the leader of the electron research group there, where he and his co-worker, Ernst Ruska, invented the electron microscope in 1931. In April 1932, Knoll joined Telefunken in Berlin to do developmental work in the field of television design. He was also a private lecturer in Berlin.

After World War II, Knoll joined the University of Munich as an extraordinary professor and director of the Institute for Electromedicine. He moved to the USA in 1948, to work at the Department of Electrical Engineering at Princeton University.

In 1956 he returned to Munich and engaged in a series of experiments at the Technische Hochschule, involving the generation of phosphenes by electrically stimulating the brains of himself and other subjects. He retired in 1966.

See also
Scanning electron microscope
Transmission electron microscopy

References

1897 births
1969 deaths
Engineering educators
German electrical engineers
Knoll, Max
Academic staff of the Ludwig Maximilian University of Munich
Microscopists
Princeton University faculty
Technical University of Munich alumni
Academic staff of the Technical University of Munich
Technische Universität Berlin alumni
Scientists from Wiesbaden
Engineers from Hesse
Aventurine. Aventurine is a form of quartzite, characterised by its translucency and the presence of platy mineral inclusions that give it a shimmering or glistening effect termed aventurescence.

Background
The most common color of aventurine is green, but it can also be orange, brown, yellow, blue, or grey. Chrome-bearing fuchsite (a variety of muscovite mica) is the classic inclusion and gives a silvery green or blue sheen. Oranges and browns are attributed to hematite or goethite. Because aventurine is a rock, its physical properties vary: its specific gravity may lie between 2.64–2.69 and its hardness is somewhat lower than single-crystal quartz at around 6.5.

Aventurine feldspar or sunstone can be confused with orange and red aventurine quartzite, although the former is generally of a higher transparency. Aventurine is often banded and an overabundance of fuchsite may render it opaque, in which case it may be mistaken for malachite at first glance.

The name aventurine derives from the Italian "a ventura" meaning "by chance". This is an allusion to the lucky discovery of aventurine glass or goldstone at some point in the 18th century. One story is that this kind of glass was originally made accidentally at Murano by a workman, who let some copper filings fall into the molten "metal", whence the product was called avventurino. From the Murano glass the name passed to the mineral, which displayed a rather similar appearance. Although it was known first, goldstone is now a common imitation of aventurine and sunstone. Goldstone is distinguished visually from the latter two minerals by its coarse flecks of copper, dispersed within the glass in an unnaturally uniform manner. It is usually a golden brown, but may also be found in blue or green.

The majority of green and blue-green aventurine originates in India (particularly in the vicinity of Mysore and Chennai) where it is employed by prolific artisans. Creamy white, gray and orange material is found in Chile, Spain and Russia. Most material is carved into beads and figurines with only the finer examples fashioned into cabochons, later being set into jewelry.

See also 
Dioptase
Optical phenomena
List of minerals
Malachite
Jade

References

External links

Aventurine at Mindat.org

Quartz gemstones
Pratt & Whitney JT9D. The Pratt & Whitney JT9D engine was the first high bypass ratio jet engine to power a wide-body airliner. Its initial application was the Boeing 747-100, the original "Jumbo Jet". It was Pratt & Whitney's first high-bypass-ratio turbofan.

Development

The JT9D program was launched in September 1965 and the first engine was tested in December 1966.
It received its FAA certification in May 1969 and entered service in January 1970 on the Boeing 747.
It subsequently powered the Boeing 767, Airbus A300 and Airbus A310, and McDonnell Douglas DC-10.
The enhanced JT9D-7R4 was introduced in September 1982 and was approved for 180-minute ETOPS for twinjets in June 1985. By 2020, the JT9D had flown more than 169 million hours.
Production ceased in 1990, to be replaced by the new PW4000.

The JT9D was developed from the STF200/JTF14 demonstrator engines. The JTF14 engine had been proposed for the C-5 Galaxy program but the production contract was awarded to the General Electric TF39. The engine's first test run took place in a test rig at East Hartford, Connecticut, with the engine's first flight in June 1968 mounted on a Boeing B-52E which served as a JT9D flying testbed.
In 1968, its unit cost was $800,000, $ million today.

Design

The JT9D introduced advanced technologies in structures, aerodynamics, and materials, which included titanium alloys and nickel alloys, to improve fuel efficiency and reliability compared to the Pratt & Whitney JT3D earlier turbofan.
The engine featured a single-stage fan, a three-stage low-pressure compressor, and an eleven-stage high-pressure compressor coupled to a two-stage high-pressure turbine and four-stage low-pressure turbine. The JT9D-3, the earliest certified version of the engine, weighed  and produced  thrust.

Pratt & Whitney faced difficulties with the JT9D design during the Boeing 747 test program. Engine failures during the flight test program resulted in thirty aircraft being parked outside the factory with concrete blocks hanging from the pylons, awaiting redesigned engines.
Boeing and Pratt & Whitney worked together in 1969 to solve the problem. The trouble was traced to ovalization, in which stresses during takeoff caused the engine casing to deform into an oval shape resulting in rubbing of high-pressure turbine blade tips. This was solved by strengthening the engine casing and adding yoke-shaped thrust links.

JT9D engines powering USAF Boeing E-4A airborne command posts were designated F105.

Variants
All variants have the same number of compressor and turbine stages.

Applications
 Airbus A300
 Airbus A310
 Boeing 747-100/200/300/SP
 Boeing 767 (early models)
 Boeing RC-1
 McDonnell Douglas DC-10-40

Specifications (JT9D-7R4)

See also

References

External links

 

High-bypass turbofan engines
JT9D
1960s turbofan engines
Progressive shifting. Progressive shifting is a technique for changing gears commonly practiced by drivers of semi-trailer trucks. It is meant to reduce fuel consumption — something very important for drivers who travel several hundred miles each day.

Progressive shifting is accomplished by changing gears upward as early as possible when accelerating while staying within the flat torque range. Each shift will go a little higher into the RPM until the vehicle is in its top gear at cruising speed. After each shift is completed, the engine and transmission should be operating at or near the lowest rpm speeds recommended by the manufacturers of those parts.

The fastest acceleration is achieved when the truck is receiving as close as possible to maximum power throughout the entire time it is accelerating. E.g. in a truck with a Caterpillar C15 engine, it is achieved by going all the way up to 1950RPM, then shifting to a gear that will put the engine at 1500RPM.

In contrast, using progressive shifting, i.e. maintaining maximum torque, the overall acceleration is slower but there is increased fuel efficiency and lower wear of the engine due to lower RPM.

External links

Trucks