On older kernels (2.2 and earlier) the ISA bus could be read or written with these functions and without ioremap being used. This is no longer true in Linux 2.4. A set of equivalent functions exist for easy legacy driver porting. The functions available are prefixed with 'isa_' and are isa_readb, isa_writeb, isa_readw, isa_writew, isa_readl, isa_writel, isa_memcpy_fromio and isa_memcpy_toio

These functions should not be used in new drivers, and will eventually be going away.