There are at least two rz25's, rz25e and rz25l.  The rz25e is around
400 meg and the rz25l is about 500 meg.  Run rzdisk on the drive to
get it's parameters:
   rzdisk -g current /dev/rrz1c
The numbers that you are interested in are:
  Sectors per track                     62
  Maximum number of cylinders           1476
  Maximum number of heads               9

In the readme it says the number of blocks per partition doesn't matter
but I found that it was necessary to make sure the partitions end
on cylinder bounderies.  The size of the C partition has to be
sectors/track * tracks/cylinder * cylinders.  Here is my rz25 disklabel
based on the above information, it has a larger than necessary root
partition.

type: SCSI
disk: rs25
label: 
flags:
bytes/sector: 512
sectors/track: 62
tracks/cylinder: 9
sectors/cylinder: 558
cylinders: 1476
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # milliseconds
track-to-track seek: 0  # milliseconds
drivedata: 0 

4 partitions:
#        size   offset    fstype   [fsize bsize   cpg]
  a:    55800        0    4.2BSD     1024  8192    16   # (Cyl.    0 - 99)
  b:   111600    55800      swap                        # (Cyl.  100 - 299)
  c:   823608        0    unused     1024  8192         # (Cyl.    0 - 1475)
  d:   656208   167400    4.2BSD     1024  8192    16   # (Cyl.  300 - 1475)



On Tue, 29 Oct 1996, H. Jared Agnew wrote:

>   Evening,
> 
>   I'm having a bit of trouble labeling my rz25.  The disktab that comes with
> netbsd doesn't seem to work.  I have my pmax booting diskless of of a FreeBSD
> box, but I can not get the pmax to disklabel the rz25.  This is what
> I've dont so far, any sudgestions would be greatly apreciated.
> 
> Disklabel from when drive was Ultrix,
> 
> root:obi-wan:/home/jagnew >disklabel rz2
> # /dev/rrz2c:
> type: SCSI
> disk: 
> label: 
> flags:
> bytes/sector: 512
> sectors/track: 0
> tracks/cylinder: 0
> sectors/cylinder: 1
> cylinders: 0
> total sectors: 832527
> rpm: 0
> interleave: 0
> trackskew: 0
> cylinderskew: 0
> headswitch: 0           # milliseconds
> track-to-track seek: 0  # milliseconds
> drivedata: 0 
> 
> 8 partitions:
> #        size   offset    fstype   [fsize bsize   cpg]
>   a:    16384        0    unused        0     0         # (Cyl.    0 - 16383)
>   b:    65536    16384    unused        0     0         # (Cyl. 16384 - 81919)
>   c:   832527        0    unused        0     0         # (Cyl.    0 - 832526)
> disklabel: sectors/track 0
> 
> The machine functioned fine when it had ultrix on it so I'm guessing this
> was not a bad disklabel, but my guess is not so good usualy. ;)
> 
> Here is waht I'm trying and then my errors
> 
> /etc/disktab for rz25
> 
> rz25|RZ25|DEC RZ25 Winchester:\
>         :dt=SCSI:ty=winchester:ns#62:nt#9:nc#1476:\
>         :pa#32768:oa#0:ba#8192:fa#1024:\
>         :pb#131072:ob#32768:bb#8192:fb#1024:tb=swap:\
>         :pc#832527:oc#0:bc#8192:fc#1024:\
>         :pd#222896:od#163840:bd#8192:fd#1024:\
>         :pe#222896:oe#386736:be#8192:fe#1024:\
>         :pf#222895:of#609632:bf#8192:ff#1024:\
>         :pg#668687:og#163840:bg#8192:fg#1024:
> 
> my commands to try and disklabel
> 
> disklabel -w -B -b /usr/mdec/rzboot -s /usr/mdec/bootrz rz2 rz25 "newlabel"
> 
> and here are the errors.
> 
> disklabel: partition c: partition extends past end of unit
> disklabel: partition f: partition extends past end of unit
> disklabel: partition g: partition extends past end of unit
> 
> Anyhelp would be very nice.
> 
> ---  Jared
> --jared@vt.edu
> 
>