Unusually, the Z80 CPU in the PCW 8256, 8512, 9512, 9256 and 9512+ had no directly connected ROM, which most computers used to start the boot process. Instead, at startup, the ASIC (customised circuit) at the heart of the PCW provided access to part of the 1k ROM within the Intel 8041 microcontroller used to drive the printer. The Z80 would copy 256 bytes via the ASIC into RAM, providing sufficient instructions to load the first sector from a floppy. The ROM-based code cannot display text, being too small to support character generation; instead, it displays a bright screen which is progressively filled by black stripes as the code is loaded from floppy.