One of the great things about the MB02+ disc system is/was the DMA. Using the device’s built-in Zilog DMA chip you could throw data around at very high rates, meaning some nice FX (such as Multitech and other lovely graphics effects) were possible. Over on the WOS forum Velesoft, the Czech hardware guru has mentioned the Data-Gear, an internal mod that provides the same DMA functionality as the MB02+, without needing an actual MB02+. Nice, huh? In fact, here’s an example of what you can achieve - the green area is the time spent doing DMA. Yep, entire screen scrolling in about half a frame.”
Have a look at:
http://www.worldofspectrum.org/forums/showthread.php?t=15109
Also as mentioned on raww.org:
“Data Gear DMA Interface
Posted By: icabod, Friday, March 16, 2007 - 01:29 PM
One of the great things about the MB02+ disc system is/was the DMA. Using the device’s built-in Zilog DMA chip you could throw data around at very high rates, meaning some nice FX (such as Multitech and other lovely graphics effects) were possible. Over on the WOS forum Velesoft, the Czech hardware guru has mentioned the Data-Gear, an internal mod that provides the same DMA functionality as the MB02+, without needing an actual MB02+. Nice, huh? In fact, here’s an example of what you can achieve - the green area is the time spent doing DMA. Yep, entire screen scrolling in about half a frame.”