During the epic console war of the early '90s, Sega and Nintendo used every weapon in their arsenal to gain the upper hand on each other. Any feature or technique that was seen as an advantage was quickly turned into a marketing point, and when Sonic the Hedgehog arrived on the scene, Sega was quick to focus on the fact that its console was capable of doing things faster than the competition.
Some of this is based on solid fact; the Motorola 68000 CPU inside the Mega Drive / Genesis is clocked at 7.6 MHz, which means it's more than twice as fast as the Ricoh 5A22 which powers the SNES, which runs at 3.58 MHz.
However, consoles are sold on buzz words and not geeky specifications, so when Sega of America's Marty Franz discovered a trick which allowed developers to push data onto the graphics chip while a scanline was being drawn on-screen, his colleague Scott Bayliss christened it 'Blast Processing' – something he's not terribly proud of, it should be noted – and Sega's marketing department had another stick to beat Nintendo with. It even made the slogan part of its advertising campaign, proudly stating that the Genesis had it, but the SNES didn't.
However, former Sculptured Software developer Jeff Peters – who worked on numerous games for the console, including the SNES port of Mortal Kombat – says that his studio discovered a similar technical trick on the SNES before Sega started mouthing off about blast processing on its console, but it was focused on audio rather than graphics.
When porting Mortal Kombat to Nintendo's console, Sculptured Software hit a massive problem – the amount of graphics data being put onto the cart meant that sound had to be cut back drastically. To overcome this problem, Peters and his team used a homegrown system which allowed them to read sounds from the cartridge one at a time and blast them directly to a buffer in the sound memory. Internally, it was called (you guessed it) blast processing.
Speaking to David L. Craddock for his book Arcade Perfect, Peters said:
That was before Sega adopted the slogan. We could just blast sound from the cartridge onto the game scene. That allowed us to keep the resolution and sample rate of the VO higher, as well as be able to have more sound samples to use in a given fight, or on a given level.
While the two tricks were achieving different things, it's interesting to note that both were possible on either console – despite Sega's insistence that only its console could do such a thing. These days, you're more likely to find companies comparing TFLOPs and SDD access speed, but the '90s were a more innocent time, when little marketing gimmicks like blast processing could make all of the difference.