partition counting for Alpha

[David van Leeuwen <david@tm.tno.nl>]

Hello,

I am somewhat conused about the various boot parts on an 164SX Alpha.
I had to carefully change from Redhat partitioning scheme to my own
while installing Debian/sid.  Therefore, the partitioning is not
ideal.  Currently, i have my only scsi disk partitioned

sda1: / ext2
sda2: /usr ext2
sda3: logical sda5, sda6
sda4: \ milo, loadlinux.exe msdos
sda5: swap
sda6: /home ext2

Everything works, so i am not complaining.  But i don't understand. 

1) the very-first scsi initialization (scsi bios) detects sda and
   calls it C:, no matter how many dos partitions there are (i had two
   when i moved milo to the physical end of sda). 
2) alpha-bios sees _three_ partitions, and calls sda4 the 3rd
   partition of disk 0
3) MILO (still the version from Redhat) sees only sda1 through sda3.
   Milo was compiled with linux-2.0.30, i think (disappears fast---it
   there a pause while milo is loaded?
4) Linux 2.0.35 sees the partitioning as describe above.  Physical
   order on sda is sda1 sda2 sda3 sda4.  

Q: why does alpha-bios see the dos partition as the _third_ and not
the fourth?  (I am afraid that at some point it wil call it the fourth
and i can't boot.  Not that i want to do that often, though.)

Q: Is there a maximum of 4 primary partitions, even for SCSI/Alpha (I
   thought that that limit was a MSDOS/Bios/IDE limit).  I believe SUN
   uses many partition on a singe SCSI disk. 

I used Debian's cfdisk to partition. 

---david