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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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