Before the Z-Mem by TotO, there were the X-Mem and the Y-Mem : the difference is the addressing of RAM and ROM. While the X-MEM addresses the lower ROM, ROMs 0-6 and 8-31, the Y-MEM addresses the ROMs from 32 to 63. The X-MEM allows to access 512 Kb RAM using the port &7Fxx. And the Y-MEM addresses another 512 Kb using the port &7Exx.
Using the X-MEM and the Y-MEM together you get 1 Mb of expansion RAM and 1 MB of Flash-ROM for the CPC or Plus computers.
And so the new Amstrad CPC expansion card Z-Mem get 1 Mb of RAM already (but without ROMs), useful for SymbOS users or to run the demo Bad Apple which needs as such RAM as 1 Mb ! So see this demo running with a Z-Mem and a PlayCity below.
The Z-Mem manages all PAL modes for the 464/664 and 464+ users. A switch "RAM 64K/SET" let you run like a basic 6128 ou to state the quantity of memory to use up to 1024 Kb. The Z-MEM will be sold for 29.90 € for 2x512K SRAM (other configurations to be defined later).
The D-ROM (dual rom) is a 2x 256Kb flash board for 19.90 €) that allows you to handle two independants sets of ROM, boot, firmware or DOS (ROM7 compatible). The principle is the same than the ROM part of the X-Mem. The card let you boot on either of them with its own firmware and basic. A switch "ROM7 YES/NO" let users with CPC without AMSDOS (or which cant be desactivated) to install their own DOS.