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From: Troy Wollenslegel (
Date: Wed Feb 19 1997 - 12:14:11 CST

Troy Wollenslegel <> wrote:
> I am trying to install a SEAGATE ST11200N drive on a Sparc 10. I know
> that the old SUN 1.05G drives used to be ST11200N drives with a bios
> change.( or so I thought) I installed the drive in the system and when I
> formatted it it said
> 2. sd2 at esp0 slave 16
> sd2: <SUN1.05 cyl 2036 alt 2 hd 14 sec 72>
> When I went to Seagate's web site to get more information I found that
> Seagate lists the ST1200N as having 1872 Cyl/15 heads/74 sec.
> Are these the same drives? Should I use what Seagate's disk parameters?
> or should I trust what Sun says about the drives?

David H. Brierley <>
Bismark Espinoza <bismark@alta.Jpl.Nasa.Gov>
Russ Poffenberger

Basically Sun used several drives the parameters for the SUN 1.05G drive
will work with any of the. If you want the max space you should use the
specs from the drive itself.

Russ Poffenberger Engineering Specialist
From: "David H. Brierley" <>

On Wed, 19 Feb 1997, Troy Wollenslegel wrote:

Yes, the "SUN1.05" drive is a Seagate ST11200N. You can use the SUN1.05
parameters or you can use the Segate parameters. The thing to remember is
that cylinders, head and tracks don't really mean that much to a SCSI disk,
the only really important parameter is the total number of blocks.

If you want another set of options to try, stick the following in your
/etc/format.dat file and then you can select "Seagate St11200N" when you
format the drive.

# From (Sam Horrocks)
disk_type = "Seagate ST11200N" \
        : ctlr = SCSI : fmt_time = 4 \
        : trks_zone = 15 : asect = 12 : atrks = 30 \
        : ncyl = 1714 : acyl = 1 : pcyl = 1715 : nhead = 15 : nsect = 80 \
        : rpm = 5411 : bpt = 40960
partition = "Seagate ST11200N" \
        : disk = "Seagate ST11200N" : ctlr = SCSI \
        : a = 0, 2056800 : b = 0, 0 : c = 0, 2056800 : g = 0, 0

# This file is available for anonymous ftp from in
# /sun-managers/format.dat.


>From Wed Feb 19 12:58:44 1997

SCSI could care less about head sectors and cylinders When you access a SCSI drive you request block number N. Unix was written Before SCSI at a time when the disk drivers had to worry about the physical layout of the disk drive. The format util was written to handle this type of drive. The head/cyl addresses are converted to block number for a SCSI drive.

You can use the Seagate layout if you want to. Remember that your partition parameters need to be adjusted to allocate the correct number of blocks. Check that the number of blocks is the same. If it is then you can select the drive type with the type command and use the SUN1.05G type. Otherwise you can enter a new type and specify the Seagate config. Sun was lying about the actual layout of the disk. The Seagate label is telling the truth. Sun used several vendors to ship the SUN1.05G disk but modified the label so that they all format and partition the same.

type # select drive type extract manufactures table format disk partition disk label disk newfs.

The exact commands vary with the version of Sunos or Solaris that you are running. The newer versions of Solaris even have an auto type selection. The auto type selection will do a mode sense to determine the drive layout and then generate a label for that drive.

Remember that the number_of_blocks_per_cyl = hd x sec number_of_blocks_per_partition = number_of_blocks_per_cyl x number_of_cyl.

From: bismark@alta.Jpl.Nasa.Gov (Bismark Espinoza)

The disktab entry from Sun will work. The disktab entry from Sun is applicable to several 1.05 GB disks from different vendors. You can play with the parameters from Seagate and get a little more disk space.

Yuo can also try this one to get more space:

disk_type = "SEAGATE ST31200" \ : ctlr = SCSI : fmt_time = 3 \ : trks_zone = 9 : atrks = 18 : asect = 9 \ : ncyl = 2692 : acyl = 2 : pcyl = 2700 : nhead = 9 : nsect = 85 \ : rpm = 5411 : bpt = 49980


SCSI disk devices really don't care about specifics like heads, cylinders, etc. What is important are the total number of blocks, which you can get by multiplying out all the above numbers.

What you get in your examples are 2052288 blocks for the Sun format, and 2077920 for Seagates, just a hair more.

Typically, Sun uses drives from several manufacturers. Since not all manufacturers have the exact same specs, Sun picks a set of parameters that will work for any of the qualified drives, which may be less than maximum for some.

You should be able to use either format, go with Seagates if you want a little more space. Stick with Suns to be 100% compatible. If you get errors when you try and run "newfs" or "fsck" about illegal seek, then you have exceeded the drive capacity.

-- Russ Poffenberger Engineering Specialist

-- Troy Wollenslegel - - My life has a superb cast, but I can't figure out the plot.

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