MegaRamHD is an IDE controller and fast RAM expansion connects to the side expansion slot of A500/A500+. It can be expanded with up to 8MB of 16-bit fast ram using standard 30-pin SIMM modules. It also allow you to connect one IDE hard drive (low profile, 1 inch height max). Elsat.device is installed in the MRHD's ROM and doesn't allow you to connect more than one IDE device. This limitation can be fixed with a special patch, probably available on Aminet. Hard drives formated with the MegaRamHD CAN'T be read with standard amiga scsi.device & vice versa because it doesn't use the standard RDB format.
The MegaRAM has a pass through for other units
Jumpers
JP2 JP1 JP2 JP1 JP2 JP1 JP2 JP1
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2 MB 4 MB 8 MB AMNESIA
2 MB = one pair of 1MB SIMM's
4 MB = two pairs of 1MB SIMM's
8 MB = one pair of 4MB SIMM's
AMNESIA = memory switched off