Tru64 UNIX, formerly known as Digital UNIX, which is in turn formerly known as OSF/1, uses the partitioning scheme similar to the BSD disk label, which allows for up to eight partitions per disk drive. The partitions are numbered 1 through to 8 in Linux and lettered a through to h in UNIX. Linux kernels 2.2 and higher always correspond 1 to a, 2 to b and so on. For example, rz0e in Tru64 UNIX would most likely be called sda5 in Linux. Partitions in a Tru64 disk label may overlap. Moreover, if this disk will be used from Tru64, the c partition is required to span the entire disk (thus overlapping all other non-empty partitions). Under Linux this makes sda3 identical to sda (sdb3 to sdb, if present, and so on). However, the partman partitioning tool used by &d-i; cannot handle overlapping partitions at present. As a result, it is currently not recommended to share disks between Tru64 and Debian. Partitions on Tru64 disks can be mounted under Debian after installation has been completed. Another conventional requirement is for the a partition to start from the beginning of the disk, so that it always includes the boot block with the disk label. If you intend to boot Debian from that disk, you need to size it at least 2MB to fit aboot and perhaps a kernel. Note that this partition is only required for compatibility; you must not put a file system onto it, or you'll destroy data. It is possible, and indeed quite reasonable, to share a swap partition between UNIX and Linux. In this case it will be needed to do a mkswap on that partition every time the system is rebooted from UNIX into Linux, as UNIX will damage the swap signature. You may want to run mkswap from the Linux start-up scripts before adding swap space with swapon -a. If you want to mount UNIX partitions under Linux, note that Digital UNIX can use two different file system types, UFS and AdvFS, of which Linux only understands the former. Windows NT uses the PC-style partition table. If you are manipulating existing FAT or NTFS partitions, it is recommended that you use the native Windows NT tools (or, more conveniently, you can also repartition your disk from the AlphaBIOS setup menu). Otherwise, it is not really necessary to partition from Windows; the Linux partitioning tools will generally do a better job. Note that when you run NT, the Disk Administrator may offer you to write a harmless signature on non-Windows disks if you have any. Never let it do that, as this signature will destroy the partition information. If you plan to boot Linux from an ARC/AlphaBIOS/ARCSBIOS console, you will need a (small) FAT partition for MILO. 5 MB is quite sufficient. If Windows NT is installed, its 6 MB bootstrap partition can be employed for this purpose. Debian &releasename; does not support installing MILO. If you already have MILO installed on your system, or install MILO from other media, Debian can still be booted from ARC.