Flint

Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white or brown in colour, and often has a glassy or waxy appearance. A thin layer on the outside of the nodules is usually different in colour, typically white and rough in texture. From a petrological point of view, "flint" refers specifically to the form of chert which occurs in chalk or marly limestone. Similarly, "common chert" (sometimes referred to simply as "chert") occurs in limestone.

Origin

The exact mode of formation of flint is not yet clear but it is thought that it occurs as a result of chemical changes in compressed sedimentary rock formations, during the process of diagenesis. One hypothesis is that a gelatinous material fills cavities in the sediment, such as holes bored by crustaceans or molluscs and that this becomes silicified. This hypothesis certainly explains the complex shapes of flint nodules that are found. The source of dissolved silica in the porous media could be the spicules of silicious sponges. Certain types of flint, such as that from the south coast of England, contain trapped fossilised marine flora. Pieces of coral and vegetation have been found preserved like amber inside the flint. Thin slices of the stone often reveal this effect.

Computer

A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.

Conventionally, a computer consists of at least one processing element, typically a central processing unit (CPU), and some form of memory. The processing element carries out arithmetic and logic operations, and a sequencing and control unit can change the order of operations in response to stored information. Peripheral devices allow information to be retrieved from an external source, and the result of operations saved and retrieved.

Mechanical analog computers started appearing in the first century and were later used in the medieval era for astronomical calculations. In World War II, mechanical analog computers were used for specialized military applications such as calculating torpedo aiming. During this time the first electronic digital computers were developed. Originally they were the size of a large room, consuming as much power as several hundred modern personal computers (PCs).

Computer repair technician

A computer repair technician is a person who repairs and maintains computers and servers. The technician's responsibilities may extend to include building or configuring new hardware, installing and updating software packages, and creating and maintaining computer networks.

Overview

Computer repair technicians work in a variety of settings, encompassing both the public and private sectors. Because of the relatively brief existence of the profession, institutions offer certificate and degree programs designed to prepare new technicians, but computer repairs are frequently performed by experienced and certified technicians who have little formal training in the field like private sectors

A repair technician might work in a corporate information technology department, a central service center, or a retail computer sales environment. A public sector technician might work in the military, national security or law enforcement communities, health or public safety field, or an educational institution. Despite the vast variety of work environments, all computer technicians perform similar physical and investigative processes, including technical support. Experienced technicians might specialize in fields such as data recovery, system administration, or information systems. Some technicians are self-employed or own a firm that provides services in a regional area. Some are subcontracted as freelancers or consultants. This type of technician ranges from hobbyists and enthusiasts that volunteer or make a little side money, to those who work professionally in the field.

Flint, Michigan

Flint is the largest city and county seat of Genesee County, Michigan. Located along the Flint River, 66 miles (106 km) northwest of Detroit, it is the largest city in the Flint/Tri-Cities region of Michigan. According to the 2010 census, Flint has a population of 102,434, making it the seventh largest city in Michigan. The Flint metropolitan area is located entirely within Genesee County. It is the fourth largest metropolitan area in Michigan with a population of 425,790 in 2010.

Founded as a village by fur trader Jacob Smith in 1819, Flint became a major lumbering area on the historic Saginaw Trail during the 19th century, and incorporated as a city in 1855. It later became a leading manufacturer of carriages and other vehicles earning it the nickname "Vehicle City".

In 1908, William Crapo Durant formed General Motors in Flint, and it was later the home of the Flint Sit-Down Strike of 1936–37 that played a vital role in the formation of the United Auto Workers. After World War II, Flint became an automobile manufacturing powerhouse for GM's Buick and Chevrolet divisions, both of which were founded in Flint. However, by the late 1980s the city sank into a deep economic depression after GM closed and demolished several factories in the area, the effects of which remain today.