developer their finest hour 
A disk operating system ( abbreviated DOS ) is a computer operating system that can use a disk storage device , such as a floppy disk , hard disk drive , or optical disc . A disk operating system must provide a file system for organizing , reading , and writing files on the storage disk . Strictly speaking , this definition does not apply to current generations operating systems , such as versions of ___MASK46___ Windows in use , while this definition is actually only used for older generations of operating systems . Hiroshima is perhaps best known as the first city in history to be targeted by a nuclear weapon when the ___MASK34___ Air Forces ( USAAF ) dropped an atomic bomb on the city ( and later on Nagasaki ) at 8 : 15 a . m . on August 6 , 1945 , near the end of World War II . Home computers were a class of microcomputers entering the market in 1977 , and becoming common during the 1980s . They were marketed to consumers as affordable and accessible computers that , for the first time , were intended for the use of a single nontechnical user . These computers were a distinct market segment that typically cost much less than business , scientific or engineering - oriented computers of the time such as the ___MASK26___ PC , and were generally less powerful in terms of memory and expandability . However , a home computer often had better graphics and sound than contemporaneous business computers . Their most common uses were playing video games , but they were also regularly used for word processing , doing homework , and programming . DR - DOS ( DR DOS , without hyphen up to and including version 6 . 0 ) is an operating system of the DOS family , written for ___MASK26___ PC - compatible personal computers . It was originally developed by Gary Kildall ' s Digital Research and derived from Concurrent PC DOS 6 . 0 , which was an advanced successor of CP / M - 86 . As ownership changed , various later versions were produced with names including Novell DOS and Caldera OpenDOS . Their Finest Hour : The Battle of Britain is a World War II combat flight simulator video game by Lawrence Holland , released in October 1989 for the Amiga , ___MASK69___ ST and DOS systems . It was the second game in the trilogy of World War II titles by LucasFilm Games , the others being Battlehawks 1942 ( 1988 ) and Secret Weapons of the Luftwaffe ( 1991 ) . The game was released with a 192 - page manual written by Victor Cross , that provided a detailed historical overview of the battle and pilots ' perspectives . A video game is an electronic game that involves human or animal interaction with a user interface to generate visual feedback on a video device such as a TV screen or computer monitor . The word " video " in " video game " traditionally referred to a raster display device , but as of the 2000s , it implies any type of display device that can ___MASK44___ two - or three - dimensional images . Some theorists categorize video games as an art form , but this designation is controversial . The Amiga is a family of personal computers sold by Commodore in the 1980s and 1990s . Based on the ___MASK86___ 68000 family of microprocessors , the machine has a custom chipset with graphics and sound capabilities that were unprecedented for the price , and a pre - emptive multitasking operating system called AmigaOS . The Amiga provided a significant upgrade from earlier 8 - bit home computers , including Commodore ' s own C64 . The ___MASK69___ 8 - bit family is a series of 8 - bit home computers introduced by ___MASK74___ in 1979 and manufactured until 1992 . All of the machines in the family are technically similar , and differ primarily in packaging . They are based on the MOS Technology 6502 CPU running at 1 . 79 MHz , and were the first home computers designed with custom co - processor chips . This architecture allowed the ___MASK69___ designs to offer graphics and sound capabilities that were more advanced than contemporary machines like the Apple II or Commodore PET , and gaming on the platform was a major draw . " Star Raiders " is widely considered the platform ' s killer app . The Luftwaffe was the aerial warfare branch of the combined German ___MASK7___ military forces during World War II . Germany ' s military air arms during the First World War , the " Luftstreitkräfte " of the Army and the " Marine - Fliegerabteilung " of the Navy , had been disbanded in May 1920 as a result of the terms of the Treaty of Versailles which stated that Germany was forbidden to have any air force . FreeDOS ( formerly Free - DOS and PD - DOS ) is a free operating system for ___MASK26___ PC compatible computers . It intends to provide a complete DOS - compatible environment for running legacy software and supporting embedded systems . ___MASK14___ , Inc . ( also known as DR or DRI ; originally Intergalactic ___MASK14___ ) was the company created by Dr . Gary Kildall to market and develop his CP / M operating system and related products . It was the first large software company in the microcomputer world . ___MASK14___ was based in Pacific Grove , California . World War II ( often abbreviated to WWII or WW2 ), also known as the Second World War , was a global war that lasted from 1939 to 1945 , although related conflicts began earlier . It involved the vast majority of the world ' s nations  including all of the great powers  eventually forming two opposing military alliances : the Allies and the Axis . It was the most widespread war in history , and directly involved more than 100 million people from over 30 countries . In a state of " total war ", the major participants threw their entire economic , industrial , and scientific capabilities behind the war effort , erasing the distinction between civilian and military resources . Marked by mass deaths of civilians , including the Holocaust ( in which approximately 11 million people were killed ) and the strategic bombing of industrial and population centres ( in which approximately one million were killed , and which included the atomic bombings of Hiroshima and Nagasaki ), it resulted in an estimated 50 million to 85 million fatalities . These made World War II the deadliest conflict in human history . ___MASK86___ , Inc . is an American multinational telecommunications company based in Schaumburg , Illinois , United States . After having lost $ 4 . 3 billion from 2007 to 2009 , the company was divided into two independent public companies , ___MASK86___ Mobility and ___MASK86___ Solutions on January 4 , 2011 . ___MASK86___ Solutions is generally considered to be the direct successor to ___MASK86___ , Inc ., as the reorganization was structured with ___MASK86___ Mobility being spun off . ___MASK86___ Mobility was acquired by Lenovo in 2014 . x86 is a family of backward compatible instruction set architectures based on the ___MASK28___ 8086 CPU and its ___MASK28___ 8088 variant . The 8086 was introduced in 1978 as a fully 16 - bit extension of ___MASK28___ ' s 8 - bit based 8080 microprocessor , with memory segmentation as a solution for addressing more memory than can be covered by a plain 16 - bit address . The term " x86 " came into being because the names of several successors to ___MASK28___ ' s 8086 processor end in " 86 ", including the 80186 , 80286 , 80386 and 80486 processors . The ___MASK7___ ( lit . " defence force ") was the unified armed forces of Nazi Germany from 1935 to 1946 . It consisted of the " Heer " ( army ), the " Kriegsmarine " ( navy ) and the " Luftwaffe " ( air force ). The designation " ___MASK7___ " for Nazi Germany ' s military replaced the previously used term , " Reichswehr " ( 1919  35 ), and was the manifestation of Nazi Germany ' s efforts to rearm the nation to a greater extent than the Treaty of Versailles permitted . Simulation is the imitation of the operation of a real - world process or system over time . The act of simulating something first requires that a model be developed ; this model represents the ___MASK48___ characteristics or behaviors / functions of the selected physical or abstract system or process . The model represents the system itself , whereas the simulation represents the operation of the system over time . DOS , short for " disk operating system ", is an acronym used to describe the family of several very similar command - line computer operating systems for x86 - based computers : primarily MS - DOS and PC DOS , but also DR - DOS , FreeDOS , ROM - DOS , and PTS - DOS . None of these systems were officially named " DOS ", and indeed " DOS " is a general term for disk operating system . Lawrence Holland is an American game designer , and president of the now defunct ___MASK41___ . He is most famous for the published by ___MASK31___ . Combat flight simulators are simulation video games ( similar to amateur flight simulation software ) used to simulate military aircraft and their operations . These are distinct from dedicated flight simulators used for professional pilot and military flight training which consist of realistic physical recreations of the actual aircraft cockpit , often with full - motion platform . ___MASK42___ was an American manufacturer of computers and video game consoles from 1984 to 1996 . Atari Corp . was founded in July 1984 when Warner Communications sold the home computing and game console divisions of Atari , Inc . to Jack Tramiel . Its chief products were the Atari ST , , Atari 7800 , Atari Lynx , and Atari Jaguar . The company reverse merged with JTS Inc . in 1996 , becoming a small division , which itself closed when JTS liquidated the IP to Hasbro Interactive in 1998 . Secret Weapons of the Luftwaffe ( SWOTL ) is a World War II air - combat flight simulation video game released in August and expanded in 1992 by LucasFilm Games . It is a MS - DOS game for ___MASK26___ PC compatibles . The ___MASK86___ 68000 ("' sixty - eight - thousand '"; also called the m68k or ___MASK86___ 68k , "" sixty - eight - kay "") is a 32 - bit CISC microprocessor with a 16 - bit external data bus , designed and marketed by ___MASK86___ Semiconductor Products Sector ( later Freescale Semiconductor , now NXP ). Introduced in 1979 with HMOS technology as the first member of the successful 32 - bit m68k family of microprocessors , it is generally software forward compatible with the rest of the line despite being limited to a 16 - bit wide external bus . After 37 years in production , the 68000 architecture is still in use . AmigaOS is the proprietary native operating system of the Amiga and AmigaOne personal computers . It was developed first by ___MASK90___ and introduced with the launch of the first Amiga , the Amiga 1000 , in 1985 . Early versions of AmigaOS required the ___MASK86___ 68000 series of 16 - bit and 32 - bit microprocessors . Later versions were developed by Haage & Partner ( AmigaOS 3 . 5 and 3 . 9 ) and then Hyperion Entertainment ( AmigaOS 4 . 0 - 4 . 1 ). A PowerPC microprocessor is required for the most recent release , AmigaOS 4 . Strategic bombing is a military strategy used in a total war with the goal of defeating the enemy by destroying its morale or its economic ability to ___MASK44___ and transport materiel to the theatres of military operations , or both . It is a systematically organized and executed attack from the air which can utilize strategic bombers , long - or medium - range missiles , or nuclear - armed fighter - bomber aircraft to attack targets deemed vital to the enemy ' s war - making capability . MS - DOS (; acronym for " ___MASK46___ Disk Operating System ") is a discontinued operating system for x86 - based personal computers mostly developed by ___MASK46___ . It was the most commonly used member of the DOS family of operating systems , and was the main operating system for ___MASK26___ PC compatible personal computers during the 1980s and the early 1990s , when it was gradually superseded by operating systems offering a graphical user interface ( GUI ), in various generations of the graphical ___MASK46___ Windows operating system by ___MASK46___ Corporation . ___MASK69___ is a corporate and brand name owned by several entities since its inception in 1972 , currently by ___MASK69___ Interactive , a subsidiary of the ___MASK99___ publisher ___MASK69___ , SA ( ASA ). The original ___MASK74___ founded in 1972 by Nolan Bushnell and Ted Dabney was a pioneer in arcade games , home video game consoles , and home computers . The company ' s products , such as " Pong " and the ___MASK69___ 2600 , helped define the electronic entertainment industry from the 1970s to the mid - 1980s . ___MASK31___ Entertainment Company , LLC is an American video game publisher and licensor . Until 2013 , it was also a video game developer . ___MASK31___ is best known for its graphic adventure games , as well as games based on the " Star Wars " and " Indiana Jones " franchises . Its headquarters are located in San Francisco , California . The ___MASK69___ ST is a line of home computers from ___MASK42___ and the successor to the ___MASK69___ 8 - bit family . The initial ST model , the 520ST , saw limited release in the spring of 1985 and was widely available in July . The ___MASK69___ ST is the first personal computer to come with a bit - mapped color GUI , using a version of Digital Research ' s GEM released in February 1985 . The 1040ST , released in 1986 , is the first personal computer to ship with a megabyte of RAM in the base configuration and also the first with a cost - per - kilobyte of less than US $ 1 . The ___MASK26___ System / 360 introduced byte - addressable memory with 8 - bit bytes , as opposed to bit - addressable or decimal digit - addressable or word - addressable memory , although its general purpose registers were 32 bits wide , and addresses were contained in the lower 24 bits of those addresses . Different models of System / 360 had different internal data path widths ; the ___MASK26___ System / 360 Model 30 ( 1965 ) implemented the 32 - bit System / 360 architecture , but had an 8 bit native path width , and performed 32 - bit arithmetic 8 bits at a time .