The core of the OS needs 64 KB ROM. On the CPC6128 it needs a ROM expansion or similar. Compatible products are EPROM-cards, the [[X-MEM]], [[MegaFlash]], [[Inicron ROM-RAM-Box|ROM-RAM-BOX]], [[SYMBiFACE II|SYMBiFACE II]], [[Ramcard 128|RAMcard]], Jareks [[CPC.Flash|Flash-ROM]], [[MegaROM]] or similar products. If you don't own such a card, you can take a look at '''FutureOS''' by using a compatible CPC Emulator ([[JavaCPC|JavaCPC]], [[WinCPC|WinCPC]], [[CaPriCe|Caprice]], [[WinApe|WinApe]], [[!CPCemu|CPCEmu]], [[Arnold]], [[Sugarbox]]) or others.
The core of the OS itself is executed directly in (PseudoFlash-)ROM or [[Dobbertin EPROM 224|EPROM]] (in four 16 KB blocks). It jumps between the ROMs with the help of a little common area. Therefore the numbers of the four 16 KB ROMs are hardcoded and the jumps are very quick. Applications like ROManager can change all that numbers.
'''FutureOS''' uses 2 KB (&B800...&BFFF) of the first 64 KB; the remaining RAM is available to applications. Additional RAM can be reserved for DIRectory buffering. Furthermore the OS uses memory management (up to 4 MB), file-handling and specialized Low/Mid/High-level routines to access the hardware.