Mega Drive

The Sega Mega Drive was Sega's third console. It was a 16 bit console released in Japan in 1988 and in America in 1989. It was released in the rest of the world in 1990. It had the name Genesis in North America, because Sega was unable to secure the rights to the Mega Drive name. It was the competitor of the SNES, but is was released 2 years earlier.

Development
Although the Sega Master System had proved a success in Brazil and Europe, it failed to ignite much interest in the North American or Japanese markets, which by the mid-to-late 1980s were both dominated by Nintendo with 95% and 92% market shares respectively. Hoping to dramatically increase their share, Sega set about creating a new machine that would be at least as powerful as the then most impressive hardware on the market - the 16-bit Commodore Amiga,Atari ST, and the Macintosh II home computers.

Since the Sega System 16 was very popular, Hayao Nakayama, Sega's CEO at the time, decided to make their new home system utilize a 16-bit architecture. The final design was ported to the arcade, and eventually used in the Mega-Tech, Mega-Play and System-C arcade machines. Any game made for the Mega Drive hardware could easily be ported to these systems.

The first name Sega considered for their console was the MK-1601, but they ultimately decided to call it the "Sega Mega Drive". "Mega" had the connotation of superiority, and "Drive" had the connotation of speed and power. Sega used the name Mega Drive for the Japanese, European, Asian, Australian and Brazilian versions of the console. The North American version went by the name "Genesis" due to a trademark dispute, while the South Korean versions were called Super Gam*Boy (수퍼겜보이) and Super Aladdin Boy (transliterated from 수퍼알라딘보이; this was the Korean version of Mega Drive 2). The Korean-market consoles were licensed and distributed by Samsung Electronics.

Japanese release
The Mega Drive was released in Japan in October 29 1988 for ¥21,000, almost exactly a year after the first of the fourth generation consoles - NEC PC Engine. Although this initially caused slow sales, the Mega Drive soon eclipsed the earlier machine in popularity. However, after the release of the PC-Engine CD add-on and the Nintendo Super Famicom, the Mega Drive soon lost ground. The Mega Drive was not as popular as the two aforementioned systems in Japan.

North American release
In 1987, Sega announced a North American release date for the system of January 9 1989, making it the second console to feature a 16-bit CPU (the first one being the Mattel Intellivision) and the first to feature single-instruction 32-bit arithmetic. Sega was not able to meet the initial release date and U.S. sales began on August 14, 1989 in New York City and Los Angeles with a suggested retail price of USD$200 at launch. The Genesis was released in the rest of North America on September 15 of the same year with the price reduced slightly to $190.

The Genesis initially competed against the 8-bit NES, over which it had superior graphics and sound. Nonetheless, it had a hard time overcoming Nintendo's ubiquitous presence in the consumer's home and the huge catalogue of popular games already available for it. In an attempt to build themselves a significant consumer base, Sega decided to focus on slightly older buyers, especially young men in their late teens and early 20s who would have more disposable income and who were anxious for more "grown-up" titles with more mature content and/or more in-depth game play. As such, Sega released titles such as Altered Beast and the Phantasy Star series. Although the NES and Nintendo's impending SNES were still threats to Sega's market share, they had forced the theoretically competitive TurboGrafx-16 system into relative obscurity, thanks in part to NEC's poor North American marketing campaign.

European release
The European release was on November 30, 1990. In the United Kingdom and Republic of Ireland it was priced at £189.99. The first UK shipment of 30,000 units was sold at retailers Comet, Dixons, Rumbelows and Toys "R" Us

Brazilian release
The Mega Drive was released by Tec Toy in 1990, only a year after the Brazilian release of the Sega Master System. Tec Toy also released the internet service Mega Net, and made exclusive games including a port of Duke Nukem 3D. The Mega Drive is still manufactured in Brazil, with many games built into the console.

Competition
Eventually, the main competition for the Mega Drive became Nintendo's 16-bit SNES, over which it had a head start in terms of user base and number of games, reversing the problem Sega had faced against the NES. The Mega Drive continued to hold on to a healthy fan base composed significantly of RPG and sports games fans. The release of Sonic the Hedgehog in 1991 began to threaten Nintendo's up-to-then stranglehold on the number one console position in the USA. Sonic was released to replace former mascot Alex Kidd, and to provide the "killer app" that Sega needed. This sparked what was arguably the greatest console war in video gaming history.

By 1992, Sega was enjoying a strong hold on the market, holding a 55% market share in North America. Faced with a slight recession in sales and a brief loss of market share to the SNES, Sega again looked to Sonic to rejuvenate sales. The release of the highly anticipated Sonic the Hedgehog 2, coinciding with an aggressive ad campaign that took shots at Nintendo, fuelled Genesis sales a while longer and boosted Sega's market share percentage back up, to an astounding 65%.

Less than a year later, in 1993, Sega released a redesigned version of the console at a newly reduced price. By consolidating the internal chipset onto a smaller, unified motherboard, Sega was able to both physically reduce the system's size and bring down production costs by simplifying the assembly procedure and reducing the number of integrated circuits required for each unit.

Aside from the release of the Sega CD and 32X add-ons for the Mega Drive, Sega's last big announcement came in the form of a partnership with Time Warner in the U.S. to offer a subscription-based service called Sega Channel, which would allow subscribers to "download" games on a month-by-month basis.

The failures of the Sega CD and 32X, a lack of effective advertising, and disputes between Sega of America and Sega of Japan had taken their toll on the company. By mid 1994, Sega's market share had dropped from 65% to 46%, and the official announcements of newer, more powerful consoles, such as the Saturn, Sony Playstation, and Nintendo 64 signalled that the 16-bit era was drawing to a close. Interest in the Genesis suffered greatly as a result, compounding its already falling sales. In 1996, less than a year after the debut of their Saturn console, Sega quickly brought their participation in the 16-bit era to an end by discontinuing production of the Mega Drive and its associated accessories. This obviously angered consumers around the world who had bought the Sega CD and 32X attachments only to see Sega abandon all support. This can, at least in slight, be seen as a contributing factor to the downfall of Sega as a console manufacturer.

Resurgent popularity
In recent years, there has been something of a revival of interest in the Mega Drive/Genesis, led largely by the grey market trade in both unlicensed cartridges and dumped ROMs, which are played through emulators such as Kega Fusion, GENS, or Genecyst. There is also a trend towards home programming, using the PC-based SGCC.

In the 2000s, there came a trend toward plug-and-play TV games, and Radica has released licensed, self-contained versions of the Sega Mega Drive in both North America (as the Play TV Legends Sega Genesis) which contain six popular games in a small box and control pad. It does not have a cartridge slot, and thus is a dedicated console. However, Benjamin Heckendorn, of Atari portablizing fame, has proven that it is possible to connect a cartridge slot with some soldering.

The GameTap subscription gaming service includes a Genesis emulator, and has several dozen licensed Genesis games in its catalogue.

On March 23 2006, it was announced at the Game Developers Conference in San Jose, California that Nintendo will offer Sega Mega Drive games to be emulated on the Wii home console. These games will be available along with other systems' titles under the Wii's Virtual Console. The 16-bit Sega selections available on the Virtual Console at launch are Altered Beast, Columns, Dr. Robotnik's Mean Bean Machine, Ecco the Dolphin, Golden Axe, Gunstar Heroes, Ristar, and Sonic the Hedgehog. Each title costs 800 Wii Points ($8US) except in Japan, where they are 600 Points (¥600).

On May 22 2006 Super Fighter Team released Beggar Prince, a game translated from a 1996 Chinese original. It is the first commercial Sega Megadrive game since 1998. It was released worldwide.

At Tokyo Game Show on September 21 2006, Ken Kutaragi, President and CEO of Sony Computer Entertainment, announced that Sega Mega Drive game ports will be available on the PlayStation Network Platform (network service for the Playstation 3). No specific titles or price points have been confirmed as of yet, with Kutagari simply stating that these specifics will be discussed with individual publishers. This, however, was later contradicted by SEGA Japan when a short statement was issued stating "that such claims are not correct at this point".

Variations
During its lifespan, the Mega Drive and Genesis quite possibly received more officially licensed variations than any other console. While only one major design revision of the console was created during its lifespan, each region has its own peculiarities and unique items, while other variations were exercises in reducing costs (such as the removal of the little-used 9-pin EXT. port) or expanding the capabilities of the Mega Drive/Genesis.

Technical specifications
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Graphics
The Mega Drive has a dedicated VDP (Video Display Processor) for playfield and sprite control. This is an improved version of the Sega Master System VDP, which in turn is derived from the Texas Instruments TMS9918. It contains both mode 4 (for Master System compatibility) and mode 5 (for native Genesis games). However, Master System programs can switch the VDP into mode 5 and make use of advanced VDP features. This page only discusses mode 5 capabilities.

Master System compatibility
One of the key design features of the console was its backwards compatibility with Sega's previous console, the Sega Master System (SMS). The 16-bit design was based upon the 8-bit design, albeit enhanced and extended in many areas. In order to achieve backwards compatibility, the original SMS central processor and sound chip (the Z80 and SN76489) were included in the Mega Drive and the Mega Drive's Video Display Processor (VDP) was capable of the SMS VDP's mode 4 (though it cannot run in modes 0, 1, 2, or 3).

As the cartridge slot was of a different shape, Sega released the Power Base Converter, a separate device that sat between an SMS cartridge and the Mega Drive's cartridge slot. The Power Base Converter did not contain any SMS components, instead functioning as a pass-through device. The converter contained a top slot for cartridge based games along with a front slot for card based games. Once an 8-bit game was inserted, the system put the Z80 in control, leaving the 68000 idle.

Both 2-button SMS pads and standard Mega Drive pads could be used to play SMS games, although due to slight differences in how the pads operate, some SMS games inadvertently cause the wrong set of inputs to be selected in a Mega Drive pad, preventing input from working properly and necessitating the use of an SMS controller. As with the SMS, the PAUSE button was not part of the gamepad connector and instead was implemented as a push-button switch on the device.

In Japan the device was known as the Mega Adaptor. The PAL variant was called the Master System Converter in mainland Europe.

The Power Base Converter was not fully compatible with the redesigned Mega Drive 2, requiring the removal or modification of the device's casing to fit correctly due to the console's new shape. A second version, the Master System Converter II, was released to address this problem. This second version adapter, however, was produced in far fewer quantities and is much tougher to find (and more expensive) than the original Power Base Convertor.

Trivia

 * Majesco's Genesis 3 (single-chip and dual-chip versions) retains the Mode 4 support but has the Master System compatibility removed from the bus controller logic. This renders the Power Base Converter or any other adapter useless. 68000 software can still enable and use Mode 4, however.
 * One of the 68000's instructions, TAS, is intended for semaphore communication in multiprocessor machines and locks the 68000 bus during memory access. The Sega hardware did not support this unusual bus cycle and ignored the write-back phase. Two games, Gargoyles from Buena Vista Interactive, and Ex-Mutants from Sega make use of the TAS instructions and expect it not to write to memory. As a result, these games work on original Sega machines but not the Majesco Genesis 3, which has correct support for TAS.
 * It is possible to overclock the Motorola 68000 CPU in some cases in excess of 300% (the current known world record is 25.4 MHz), though it may not be completely stable beyond a certain point on each console. The result of overclocking the CPU doesn't speed up the games any, but actually eliminates slowdown that some games are plagued by.
 * Another possible modification is to replace the stock 68000 processor with a 68010. Since the CPU isn't socketed, this requires the removal of the old CPU, and soldering in of the new. The 68010 is a pin-compatible enhanced version of the 68000, which is a bit more efficient internally and offers some new features. Also, the DAC's digital audio output may sound cleaner and less distorted because the 68010 has a "loop mode" to run small loops faster, which may allow the Z80 to receive PCM data faster. However, the 68010 is not 100% object code-compatible with the 68000, so machines modified with a 68010 processor are not able to run certain games properly, such as Sonic 3, Sonic and Knuckles, Street Fighter II, Red Zone, and a few others.
 * Contrary to popular belief, Model MK-1631 (Mega Drive 2) does have a Z80 CPU. Depending on the board revision, the system has either a Zilog Z84C00 or a Custom Sega 315-5676 or similar. Because the Z80 is used for sound production by many games it is a necessary component. The idea that the redesigned machine has no Z80 came from reports of incompatibility between those models and the Power Base Converter, which provides Sega Master System compatibility, but the true prohibiting factor is the shape of the device. The redesigned cartridge port is too far forward on the system to connect a Power Base Converter without first removing its plastic housing.
 * One of Sega's most famous advertisements in North American media was its slogan "Genesis does what Nintendon't", which showcased the graphics that the Mega Drive had against the aging NES.
 * By the time the SNES was released and Sonic the Hedgehog 2 as well, Sega promoted the console with Blast Processing, which was a term that Sega coined because the Mega Drive/Genesis's 68000 processor had a higher clock speed than the SNES's 65c816.
 * A later slogan flashed text on the screen:
 * WELCO
 * METOT
 * HENEX
 * TLEVEL
 * It's a fractured way of saying "WELCOME TO THE NEXT LEVEL".