View source for Otten & Fecht 1 MB RAM-Disc

Not much known.

Reportedly, the RAM is accessed in 128-byte sectors.

The RAM is accessed using I/O ports. It can not be banked in like common RAM expansions do. So it's a real RAM disc, not an RAM expansion.
There was support for FutureOS for a while. That support was abandoned later due to the very high price of the RAM disc (more than 1000 DM) corresponding to a very small number of units sold.

== I/O Ports ==

#F9FC - #F9FE Otten & Fecht 1 MB RAM-Disc (R/W)
#FBF0 - #FBFF Otten & Fecht 1 MB RAM-Disc (R/W)

(Data taken from the FutureOS manual).