From: dnichols@ceilidh.beartrack.com (Don Nichols (DoN.))
Newsgroups: comp.sys.3b1
Subject: Re: Help formatting a Seagate ST251-1
Date: 31 Jul 92 00:13:17 GMT
Organization: D and D Data, Vienna Virginia

In article <1992Jul30.025939.7323@cc.gatech.edu> gregh@cc.gatech.edu writes:
>I was in the process of installing a Seagate ST251-1 drive in my att7300,
>when I noticed that I can only get it formatted to about 30 MB.  The specs
>from Seagate claim that it has a capacity of 42.8 MB.  The specs I used to 
>format it were: 820 cyl, 6 tracks per cyl and 17 tracks per sect.  Has anyone 
>else has this problem?  Any advice on this would be very much appriciated!

	You've got two things working against you here.  The system uses
only 16 of the 17 sectors/track for data, reserving the extra in each track
for replacing bad blocks.  The other thing that you may be missing here is
that a certain portion of the disk is set aside for swap space, even if
you're using it as a second drive on a modified system.  It won't let you
get the swap space below a certain minimum, and you shouldn't attempt to if
this is the only drive on your system, since without swap space, the system
gets rather sick :-) 

	If it is a second drive, you can do something like what I do, which
is to make a filesystem on the swap partition on the second drive, and mount
that as /tmp, so you don't ever have to worry about a program building
enough files in /tmp to wedge the system with no space left in the root
partition.

	There is also a small amount of disk space used for the VHB (Volume
Home Block) which tells the system how it is partitioned, what bad-block
replacement to do, and also provides room in there for the bootstrap loader,
to keep it out of the way of the working parts of the disk.  That way, it
can't be trashed by a runaway program (or programmer. :-)

	If you want to see what has happened with the formatted drive, once
you are up and running, you can type iv -t /dev/rfp000.  (You must be root
to do this.)  Use /dev/rfp010 for the second drive, if that is what this
is.  Here are the results on my system:

ceilidh:csu 19:55#  iv -t /dev/rfp000
Winchester disk
Volume Name: WINCHE
1224 Cylinders. 15 Heads per Cylinder.
There are 17 Physical Sectors (of 512 bytes) per Track.
        255 Physical Sectors per Cylinder, 312120 Physical Sectors per Disk.
There are 8 Logical Blocks (of 1024 bytes) per Track.
        120 Logical Blocks per Cylinder, 146880 Logical Blocks per Disk.
The Step Rate supplied to the Controller is 0.
Partition 0: start Track=0, size (in Blocks)=120
Partition 1: start Track=15, size (in Blocks)=15000
Partition 2: start Track=1890, size (in Blocks)=45000
Partition 3: start Track=7515, size (in Blocks)=86760
Loader starts at Block 2 (size=24 Blocks).
Bad Block Table starts at Block 1 (size=1 Blocks).
The Bad Block Table contains 54 entries.

ceilidh:csu 19:55#  iv -t /dev/rfp010
Second winchester disk
Volume Name: WINCHE
1170 Cylinders. 7 Heads per Cylinder.
There are 17 Physical Sectors (of 512 bytes) per Track.
        119 Physical Sectors per Cylinder, 139230 Physical Sectors per Disk.
There are 8 Logical Blocks (of 1024 bytes) per Track.
        56 Logical Blocks per Cylinder, 65520 Logical Blocks per Disk.
The Step Rate supplied to the Controller is 0.
Partition 0: start Track=0, size (in Blocks)=56
Partition 1: start Track=7, size (in Blocks)=15000
Partition 2: start Track=1882, size (in Blocks)=50464
Bad Block Table starts at Block 1 (size=1 Blocks).
The Bad Block Table contains 22 entries.

'csu' is an alternate login for root which gets me tcsh for a shell.  This
way, I don't risk breaking shell scripts run as root.  The first disk is a
Miniscribe 3085, the second is a Priam 190.  Each logical block listed above
is two physical blocks, to add to the confusion.  I should have given them
more imaginative names than "WINCHE", but that was done by the diagonstics
disk, rather than the alternate formattng by use of iv.

	Good Luck
		DoN.
-- 
Donald Nichols (DoN.)     | Voice (Days): (703) 704-2280 (Eves): (703) 938-4564
D&D Data                  |  Email: <dnichols@ceilidh.beartrack.com>
I said it - no one else   |         <nichols@nvl.army.mil>
	--- Black Holes are where God is dividing by zero ---
Newsgroups: comp.sys.3b1