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Editing
the SYSGEN Disk:
To install a
different drive into the Lt. Kernal system,
you'll first need to select a SCSI
embedded-controller drive and determine
the drives':
- Sectors/Track
- Number of Heads
- HIBYTE number of Cylinders
- LOBYTE number of Cylinders
In order for the
Lt. Kernal to understand what drive it is
connected to, you may need to edit the
SYSGEN floppy Disk and add hard drive parameter
data (Don't be an idiot, make a
working-copy of the SYSGEN disk and edit
the Copy :). After the SYSGEN Disk has been
modified, you'll need to install (or
reinstall) this modified SYSGEN disk onto
your new hard drive. Once you've reinstalled
SYSGEN, click Here to learn how to Configure
the drive.
Think about
This: In the section that described
how the Host Adapter works, we learned that
when power is first applied to the
system, the Host Adapter uses its BOOT
EPROM routines for Startup. One of the
very first things that happens during
startup is that some Data is fetched from
the Hard Drive. Besides the serial number
check, the system needs the drive
parameters so it'll know where to read and
write data! Didn't we forget something? If
we have Edited the SYSGEN disk, the New
parameters will still be on the floppy disk
and Not on the Hard Drive (yet)? If you caught
this, you win a prize! Yes, we are going to do
this in a couple of steps. The First of these
steps is that we need to EDIT the SYSGEN disk
with the New drive parameters.
There are two ways
to edit the SYSGEN disk:
- Manually edit the floppy
with a Sector editor program (Di-Sector,
Phlash, etc.)
- Use a C64 and 1541 drive
- Manually
edit and re-save to disk
- (See below to learn
What to edit)
- Use a Custom
editing program (EDITLTK2.SDA
written by Pete Bergeron)
- Allows you to easily
edit both Serial Number and drive
parameters
- Uses
default settings or predefined list
of Seagate or Quantum drives
- If your drive is
not on predefined list, you can edit
the list first,
or (preferably) write your own
new list containing all the drives
you may want to use.
- Pete's
program also allows for manual
entry of parameters (that's what
I use)
Using the
Custom program: If you're new to
sector editing, lazy (me) or just rusty,
Pete's program is Great! It's a menu-driven Basic
program that will Read your SYSGEN Disk, tell
you what's currently on it and allow you to make
changes. Pete also created two SEQ files
that contain a predefine list of drive
specifications. If your drive is on that
list, continue with editing. If not, you
could simply edit his SEQ file and add your
drive parameters. The program will then load that
SEQ file and make your new parameters available
for automatic insertion onto the disk. You also
have the option of directly entering the
parameters. I know that Pete was somewhat
surprised to hear that his program is
still being used, but if you have any
questions, you can email him at info@freeducky.org.
Pete's 'ltkedit2.sda' file contains
all programs, instructions and complete
Help files (see FILES page).
Manual
Editing: If you use Pete's program or
manually edit the SYSGEN disk, you'll be
editing TRACK 18, SECTOR 18 of Version 7.1
or v7.2 SYSGEN floppy disk. Earlier versions of
SYSGEN (e.g., v6.xx) are not discussed here, as
nobody seems to have that early version and Pete's
program is not compatible with DOS versions other
than v7.1 and v7.2 (these are the newest
software versions). The following
procedure assumes you already know how to
use a Sector editing program, so we will
only discuss which Bytes are edited and why. HOW
to edit is up to you.
The following list
describes Track 18, Sector 18, starting at
position ZERO (of the 256 byte string).
The only bytes listed are those related to
your Serial Number and drive parameters. Changing
any other byte values can render
your SYSGEN Disk inoperable, so it is
strongly suggested that no other position
values be changed. And, to keep things
consistent with a sector editor, all Track
and Sector position numbers are in HEX($).
So, load T18, S18 with your favorite
editor and look at the first $4D
positions. You'll see that the first 8 Bytes
are your Serial Number followed by Eight (8)
groups of 8-Byte drive table
cells:
- $00 - $07 is your Serial
Number
- MUST Match Serial Number
contained in Host Adapter EPROM!
- Remember
your Serial Number is in EPROM at
$A-$13 AND $100A-$1013
- ALL below
are Drive parameters
Only
- (note the gap from
$07 to $0E - Don't edit)
- $0E - $15
SCSI Drive Zero parameters (1st
drive)
- If you only install
ONE drive, this is the only area
that needs editing
- All other
cells should be:
128,0,0,0,0,0,0,0
- Manually
set the Drive to SCSI address
Zero
- $16 - $1D
Drive One parameters (2nd drive)
- If you add a second
drive here, set drive to SCSI
address One
- $1E - $25
Drive Two parameters (3rd drive)
- If you add a third
drive here, set drive to SCSI
address Two, etc.
- $26 - $2D
Drive three parameters (4th drive),
etc.
- $2E - $35
Drive four parameters (5th drive), etc.
- $36 - $3D
Drive five parameters (6th drive),
etc.
- $3E - $45
Drive six parameters (7th drive),
etc.
- $46 - $4D
Drive seven parameters (8th drive),
etc.
- (as above,
ALL unedited cells Must be
"128,0,0,0,0,0,0,0". During startup,
this 'string' is how LK DOS knows there
are No other drives attached)
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If, for some
reason, you want to use the Serial Number
on your current SYSGEN Disk, you may need
to change the Serial Number stored in the EPROM.
The S/N is stored in Two
locations on the EPROM; Addresses $A
to $13 and $100A to $1013 (for C64 and C128 modes). So, don't
forget the make all three S/Ns the same!
(NOTE: Locations $12,$13 and
$1012,$1013 of the EPROM are usually
"00" and your S/N ends at $11 and $1011).
Now that we know
Where to edit, let's look at what data
goes in these 8-byte drive table cells.
The following CELL chart shows each position,
its purpose and the values of our ST1201N example
(note the number of Heads, Sectors/Track and HiByte/LoByte
Cylinders) If you wanted to add
an additional ST1201N drive, you would use
the same values at T18/S18, position $16 -
$1D:
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Position
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T/S/Pos
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ST1201N
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Byte
Function
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0
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$0E
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128
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BIT
7="N" embedded controller, BIT
0-6= Pulse Width for
3100
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1
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$0F
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0
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Step
Period
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2
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$10
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36
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Sectors/Track
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3
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$11
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9
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Number
of Heads
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4
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$12
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4
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Number
of Cylinders - High
Byte
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5
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$13
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44
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Number
of Cylinders - Low
Byte
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6
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$14
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0
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Write
precomp Cylinders
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7
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$15
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0
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unknown,
but is ZERO on all
(spare?)
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8-Byte Drive Table Cell
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Looking at the
above chart, there are a couple of areas
of special interest. First, I haven't found
a drive where a Step Value other
than Zero is required. Secondly, the
'Write Precomp Cylinders' is only a factor
if you're trying to use an old
non-embedded drive like a PCST225 where
this number would be 128. Finally, position
'0' will always be '128' with the odd exception
of original Xetec 20MB drive, my favorite, the Miniscribe
8425S where this number would be 192
(slow).
Remember that if you edit the
SYSGEN Disk to use one or more hard drives, you also need to physically
set each hard drive to the proper SCSI address (via jumpers).
Once you have
edited the correct drive-table cell(s),
save your changes to the disk. This completes
the SYSGEN Disk editing requirements.
And, if you used Pete's program,
you actually made the same changes
to the same locations on Track 18,
Sector 18. So, by either editing method,
you have made a New Master SYSGEN disk,
so making a copy of This disk would
be wise.
NOTE:
When making copies of the SYSGEN Disk,
I suggest you use a whole-disk copy program
and Not a 'file copier' program. The reason
is that a whole-disk copier will copy the Disk Name, ID and
all the files in the same order as the
original SYSGEN, which will make is easier
to compare the two disks.
Let's assume that
you have added a new drive as the Only
Hard Drive on your system. Before you perform
a new SYSGEN, which is
the next step, you may need or want
to Format this drive. IF you already
formatted the drive on your PC or Mac to
better verify the drives' condition,
that's fine and you can disregard the
'formatting' section below and go straight to the
SYSGEN - Install page.
Technically, there
is no reason to format a working drive!
When you install LK DOS software onto the
drive, the process will first erase the portion
of the drive where LtK DOS will be
written. Also, the area of the drive where
your files will be stored has its own
file-directory written during drive
Configuration and Activation. The real
purpose of formatting the drive is to
remap any bad media.
I prefer to format
LTK drives on a PC or Mac because I can
better determine the condition of the
drive as well as verify mapping out of bad media.
Once you have performed a Low Level
format with verification, it doesn't
matter if you then partition the drive
as a scratch disk or
install other drivers (bootable, mountable,
etc.). Just set the drive to a single
partition (one logical drive), set the
desired SCSI ID# (usually Jumpers on the Drive) and leave it at that.
(No, you can't 'password' the
drive!). However, ... there is one reason I use the 'frm-clr.prg'
program...
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Formatting
your New Drive:
Formatting a drive
on the Lt. Kernal is done differently from
the way it's done on a PC or Mac. If you
are using a 20 Meg Miniscribe (the drive
which was originally supplied by Xetec), you
can use the included LTK-format program (frm-clr.prg).
Note:
There is one reason to use the 'frm-clr.prg' program
on Drives other than on the MiniScribe 8425S 20MB! First,
this Format & Clear program works on many other
drives. In fact, if you use this program on a drive you have never
tried before, and it works, it means you will Not have any problems using
this drive with the Lt. Kernal! The reason is that the first part
of the program sends a regular SCSI FORMAT Command to the drive, which works
on most drives. However, the second part of the program 'Clears' the
area on the drives that will later store LtK DOS. It is in this second
part that fewer drives will properly respond, indicating that you won't
get past the very first part of a SYSGEN! So, you might think of running
this program as a diagnostic on un-tried drives.
If you use this
program, you'll need to use the following
procedure:
- Ensure that the Commodore
and external drive enclosure are turned
off
- Connect the
Host Adapter to the Commodore and make
sure
- HIRAM & CAEC are
properly connected if using a
C64, or
- Daughterboard
is installed properly and HIRAM is
connected if using a
C128
- (see Host
Adapter installation
article)
- Disconnect the
SCSI Data cable between the Host
Adapter and External Drive
enclosure
- Power up the
Commodore. Wait for time-out
- With a Host Adapter
attached to the Commodore and
no hard drive connected, the system
will look for the drive. After about
60 seconds, the system times-out and
the Commodore will bootup to its normal
startup screen.
- Once the
Commodore is at the startup screen,
re-connect the SCSI Data cable between
the Host Adapter and the hard drive and
apply power to the drive
enclosure.
- NOW, load and
run the LTK Format program
("frm-clr.prg")
- Run the program by entering
SYS 8192
- Gee, I wonder what this program could do if it
were modified? Hmm? :)
- When
formatting is completed, the Drive
is ready for SYSGEN installation.
- If
you are wondering, yes, the above procedure is the same for doing a SYSGEN
but without running 'frm-clr.prg'.
Remember that
doing a low-level format on ANY drive is
easier to perform on your PC or Mac even
if you use a Miniscribe. When the format operation
is complete, refer to the SYSGEN
sections for DOS installation and
information about the DOS commands.
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Top
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Lt.
Kernal Data Archive 2003-2008
/ Contact Author for Inquires
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