Since &debian; Squeeze, support for booting in ESA/390 mode was dropped. Your machine needs to support the z/Architecture, 64-bit support is mandatory. The userland of the s390 port is still compiled for ESA/390, though. All zSeries and System z hardware is fully supported. &arch-title; support software is included from the kernel 3.1 development stream. The most current information about IBM's Linux support can be found at the Linux on System z page on developerWorks. PAV and HyperPAV are supported transparently, multipathing is not needed to take advantage of these storage system features. Be sure to configure the devices during DASD device selection. The alias devices will not be offered neither for formatting, partitioning nor direct use.