Helpful Hints for
Installing Adaptec 2070A RLL (Run Length Limited) Hard Disk Controllers
CIS ID# 73107,1157
These notes are being written after several months of experimentation on
the setup and installation of various Hard Disks operated with the Adaptec
2070A RLL Controller card. I am an electronics specialist by trade, but not
a computer tech, so some of this may seem a little out-in-left-field, but it
This information is provided to hopefully be of some assistance to those
people trying to add an Adaptec 2070A controller card to their computer. I
am in no way involved with Adaptec Corp. or any of the hard disk manu-
facturers, and the information provided herein comes from my experimentation
with the 2070A card and several different hard drives (and has cost me a
fair sum of money and a couple of wiped-out disks!) I, Steve Sneed, am in
no way liable or responsible for the use of any information contained herein.
I believe it to be accurate, but you use it at your own risk.
CYA over with, let's get to what you came for...
The documentation that comes with the Adaptec 2070A varies depending on
who you aquire the card from. Many suppliers insert a single sheet or two of
basic information on running the in-BIOS low-level format program, and nothing
else. At least one supplier is including a nice 15-page manual which gives
much helpful information - but it's still not all you need. Do not blindly
believe the docs when they're only a page or two - I have seen 4 different
copies of documentation from 4 different wholesalers selling matched-set RLL
cards with Seagate ST238 drives - the format program instructions in each case
were different, and usually failed the first-time format. Information on
jumper settings has been missing or wrong. Worse, information received from
a couple of the supplier's tech-support departments has been wrong! It's
upsetting to say the least when the equipment seller doesn't know what he's
(*------------[ Hard Disk Setup Overview ]----------------*)
For those people unfamiliar with hard drive setup, I'll cover a few basics.
Unlike a floppy which requires only a single format operation to make it use-
able, a hard disk requires 3 separate formatting steps. Before the first 2
are performed, generally the system will not even acknowledge the existance
of the drive in the machine, returning a "Invalid Drive" error message if you
try to access the hard drive.
The first step is called "Low-level format." In this operation, the
totally blank hard disk has the cylinders defined and the sector markers
placed on each cylinder to "line out" the disk for later use. No actual data
area formatting occurs during this procedure - it is strictly to set up the
drive with the type of format used for later steps.
The second step is to place some information required by DOS on the very
first cylinder and sector. This information MUST be on the disk for DOS to
even know the drive exists! It tells DOS that the drive exists, how much
total space exists on the disk and where the system information can be found
on this particular drive. The program FDISK performs this operation, and must
be run on the low-level formatted disk before the last step is performed.
FDISK formats the first sector on the first track and installs the infor-
mation. Prior to running FDISK, if you call for the drive you will get an
"Invalid Drive" error message. After running FDISK, you will get a "Sector
Not Found" message (sometimes a "General Failure" error message with DOS
3.2.) This is a quick test of the proper operation of the low-level
formatting and FDISK procedures.
The last step is to high-level format the disk and usually copy the system
files onto the drive. This is done in most cases by running the FORMAT
program (just like a floppy) or in the case of some compatibles, a special
hard disk formatting program is included with the DOS or DOS Utilities disk.
FORMAT goes over the disk and formats the areas between the sector marks
placed by the low-level format procedure, and installs the system files if
the "/S" option is used. Once this step is finished, the drive is ready
to be used.
On the average, allow 1 to 1 and 1/2 hours to install and format the
drive. If you have no electronics experience or background installing
equipment in your computer, I strongly recomend you have a professional
computer technician or electronics tech install your drive and card. The
Adaptec 2070A controller card (and many other expansion cards) contains
static-electricity-sensitive devices which may be damaged or destroyed if
improperly handled. Never work on your computer while standing on a
(*---------[ Setting Up a Single-Drive System ]-----------*)
Adaptec recomends certain drives be used with the RLL card. Their Tech
Support department should be consulted prior to purchase of any drive, or
purchase of a card to update an existing drive - lists available from various
sources give conflicting information, and the card's manufacturer is the only
one who seems to really know what drives work. However, be aware that drives
which Adaptec says they "Do not recomend be used" with the 2070A card WILL
work in many cases - they just don't recomend these drives' use due to tech-
nical considerations (in most cases, these non-recomended drives' notch
filter networks do not exhibit a tight enough band-pass to correctly handle
the RLL encoding - meaning some of the drive's outer cylinders will not format
or will not stably retain data.) I have listed below the drives that I know
will work even though they are not recomended by Adaptec, and the best infor-
mation I have currently on the Adaptec-recomended drives.
If you are reading this prior to purchasing a hard drive, I *STRONGLY*
recomend that you purchase one of the matched-set Seagate ST238/2070A packages
available from many suppliers. The ST238 is the drive the 2070A was made for,
and the ST238 was especially designed for the RLL format's requirements. This
combination give a 31 Meg (formatted) drive, about as big as you can go with
DOS and an 8088 processor. I don't work for either of these companies, but I
do run several of their drives on several different machines and I know the
combination works - and works RIGHT!
There are 4 sets of jumper pins located on the lower middle of the com-
ponent side of the card. These are the only jumpers you will need to worry
about in most instances. The other jumpers in the upper corner of the card
are for high-performance drive capabilities and self-test.
The lower jumpers are marked (from the top set down):
These are further devided into groups of two, with the M-N and O-P pins being
used to configure drive 0 and the two lower sets used for drive 1. Note that
the 2070A can support 2 drives of mixed size and manufacturer, and these
drives can be located anywhere above B: in the system - the drive #s 0 and 1
reference only the first and second drive related to the 2070A they are
These jumper settings are used *ONLY* if you intend to format your drive
to one of the parameters tables built into the 2070A's BIOS - they are IGNORED
by the card if you input drive parameters at the start of the format. This
is an important thing to note, as most of the documentation I have seen has
worried the purchaser with jumper settings, only to bypass them during the
The following table is the best I have seen for jumper configuration:
Jumper Table | 0 1 2 3
Drives | Sysquest (most 10Meg Tandon MicroScience
Supported | SQ319R drives) TM 755 HH-725 (not "A")
| Lapine Vertex Seagate
| Titan V150 ST-238
Size: MFM | 20 Meg 10 Meg 40 Meg 20 Meg
RLL | 31 Meg 15.5 Meg 62 Meg 31 Meg
# of Heads | 4 2 5 4
# of Cyls. | 615 612 981 612
Jumper Table | Pins Jumpered Pins NOT Jumpered
Drive 0: |
Table 0 | M-N & O-P ----
1 | M-N O-P
2 | O-P M-N
3 | ---- M-N & O-P
Drive 1: |
Table 0 | Q-R & S-T ----
1 | Q-R S-T
2 | S-T Q-R
3 | ---- Q-R & S-T
Remember, these are the DEFAULT parameters settings! Example for the tables
When installing a Seagate ST-238 as drive 0:
Pins jumpered: none Pins NOT jumpered: M-N & O-P
( pins Q-R and S-T have no effect on drive 0 )
The cables required to connect the 2070A are usually not provided with the
card when purchased by itself. You will need 2 ribbon cables:
1 ea. 20-conductor 22 awg ribbon w/ 1- Female 20pin dual header plug
and 1- Female Card-Edge (Molex-Type) connector
1 ea. 34-conductor 22 awg ribbon w/ 1- Female 34pin dual header plug
and 1- Female Card-Edge connector (all these connectors should be
the clamshell, self-stripping type.)
The 2070A cable connectors are labeled J0, J1 and J2. On a one-drive in-
stallation, only dual header pin connectors J0 and J2 are used. Connect the
cables to J0 and J2 prior to installing the card in the machine - you're too
likely to bend a pin trying to install them after the card is down in the
motherboard. Install the drive according to the Mfgrs. directions, connect
the power plug (it's keyed - don't force it the wrong way!) and the con-
troller card cables, close the machine back up and apply power. If the drive
light comes on and stays on all the time, you have the controller cables back-
wards. Turn the power off, turn the connectors over (at the drive end), and
try it again. Note that the cable comming out of the connectors should point
the same direction on both cables at both ends.
With power off, verify again that all cables are routed safely and con-
nected correctly (make sure that the HD cables don't come in contact with
exposed head assemblies on the floppy drives!) Close the machine back up,
place a DOS disk in A: and boot the computer. From the DOS prompt, run
When you see the "-" prompt, enter: G=C800:CCC
the built-in low-level format program that's in ROM on the controller card.
You are shown a program header, then prompted for some information as below:
Enter Sector Interleave:
You should always enter "3" at this prompt.
Enter Drive ID (0/1):
Since this is the only drive on this card, enter "0".
Should We Use Default Drive Parameters (Y/N)?
This is the catch point I mentioned earlier. If you have one of the drives
listed it the above table (or the probably-compatable list below) and have
set the jumpers to match, enter "Y". If you do not, or are trying an unknown
drive type, enter "N". The following four prompts are issued *ONLY* if you
answer "N" to this prompt!
Number Of Logical Units for This Drive (1 to 8):
If your drive will have 32 Meg or less after formatting (such as the Sea-
gate ST-238), enter "1". If the drive will have more than this after
formatting, it must be segmented in logical units of no more than 32 Meg.
If this is the case, figure how many logical units the drive will have and
enter that number.
Step Pulse Rate (0 to 7):
Generally, use "3". If you know the step pulse spec for your drive, and
you're lucky enough to have documentation which shows the chart for step
pulse rates, use that figure.
Number of Heads (1 to 16):
Enter the number of read/write heads your drive has. Generally, most 20
Meg HDs have 4, most 10 Meg HDs have 2.
Number of Cylinders:
Enter the number of cylinders (tracks) your drive has. See the jumper
table above for examples of cylinder counts for average drives.
At this point, the program will hesitate a second or two while it examines
your drive to see if it in fact matches (or comes reasonably close to) the
information you have just entered. If not, an error code is displayed and
you are prompted to run the program again. If you hang up at this point, it
means that 1 or more of your entered parameters doesn't match what the card
sees for the drive - re-examine your parameter information and try again. If
it shows you the next prompt, you're in good shape. This is the prompt you
are shown if you answered "Y" to the default drive parameters prompt above.
Specify the Defect Byte Offset Encoding: MFM or RLL (M/R)?
Whether or not you specified default drive parameters, answer "M".
Enter Defect List as "Cyl/Head/Byte" or "Head/Cyl/Byte" (C or H)?
Some drives will require entry of the defect map information for the drive,
usually a tag glued to the drive. Most drives do not. Generally, enter "C".
Type defect File Name, or Press "Enter":
Enter Defect Locations as Cyl/Head/Byte
(A Blank Line Ends the List)
Unless you have tried everything else to no avail, just press
2070A card will automatically try to correct media defects, and those that
it can't correct will be locked out during high-level format.
If you have a format failure after checking and correcting all your other
entries, you will need to enter here the defect information listed with your
drive. Most defect charts I've seen were in "Cyl/Head/Byte Offset" format,
and since you've already chosen that format with the prompt above, enter the
chart information in that form. This will almost never be required if you
are formatting your drive by jumper table instead of by entered information.
Are the Above Parameters Correct (Y/N)?
Review your entries. If they are correct, enter "Y".
The formatting will now begin. The procedure formats the disk, then goes
back and checks it. The initial formatting portion takes about 4 minutes on
a ST-238 or other 20 Meg HD. The recheck takes far longer - about 12 to 14
minutes on a ST-238. Any errors detected will be reported.
Once the format is complete, you are informed and prompted to run the pro-
gram again - answer "N". At this point, run FDISK to partition the disk and
then FORMAT C:/S to high-level format the disk and make it bootable. You
now have a RLLed hard disk! Enjoy!
(*---------[ Installation with 2 Drives ]----------*)
Addition of a second drive to the existing installation, or installing 2
drives at the same time, requires nothing more than the single-drive setup
other than 1 different and 1 extra cable, and the fact that you must run
the format procedure a second time for the second drive. Jumper settings
for the second drive are covered above, and the formatting procedure is
exactly the same except for the second prompt - enter "1" here instead of
CABLING (2nd DRIVE):
You will need a duplicate of the cable used from the 2070A's J0 connector,
and you will need a longer version of the cable from J2 to the drive. The
smaller cable goes from J1 on the 2070A to the second drive.
** VERY IMPORTANT!! ** Do NOT, repeat do *NOT* use a standard floppy drive
cable for the larger cable!!! Look at your cable for your floppy drive(s).
If you have two floppy drives, you will notice that in one of the connectors
that plugs onto the floppy, there are 4 lines that are "flipped over" in the
connector (usually the last one.) This "flipping over" of these control
lines is called "Radial Drive Selection." This is required for floppies, but
CAN NOT BE USED with the 2070A. The larger cable must carry all lines
straight thru all connectors, and of course the cable connectors must all
face the same way. Another important note: The last connector on the cable
must go on the drive specified as Drive 0... not drive 1 as seems more
logical. Don't ask me why, I've never seen a schematic for the card. But
that's the way it has to be. The cable from J0 goes to drive 0, the cable
from J1 goes to drive 1, and the larger cable goes from J2 to drive 1 and
then to drive 0.
FORMATTING (2nd DRIVE):
If the first drive is not already formatted, perform the format procedures
on it FIRST, then low-level format the second drive. In some cases, depending
on your machine and version of DOS and FDISK, you will have to completely
disconnect drive 0 and connect drive 1 as if it were drive 0 for FDISK to
find the second drive. If this is the case, reconnect the drives in their
normal order before running FORMAT on the second drive.
(*----------[ Special Drive Information ]------------*)
"Not Recomended" drives that work:
Adaptec's Tech Support department will tell you if your drive is "not
recomended" to be used with their controller... and if it is not, they will
give you NO further help! This is understandable; they do not want the
liability involved with helping you set up a drive that they themselves have
had problems with or know will not function properly or reliably with their
card. However, several drives that they say are "not recomended" will
work with their card. See my disclamer at the beginning of this document
concerning this information.
I also recomend that you get a copy of the On-Track Hard Disk Manager
program or other HD manager, especially if you are setting up one of these
"not recomended" drives. Also recomended is a good disk organizer program.
An exellent shareware organizer is DOG101A.
This is an older version of the ST-238. It is the drive most often
supplied with clones, and also comes in the Kaypro PC 20Meg machine.
Plentiful, reliable and reasonably priced, it can be formatted RLL using
the same specs and jumper settings as the 238. However, due to the fact
that the 225 has Oxide-coated media instead of plated media and the
notch filters' band-pass is wider than the 238, you may find that you have
problems with initial low-level format or that the outer cylinders will
not format. I currently have 1 ST-225 in a clone running RLL with it's
full 31 Meg available, and 1 running in a Kaypro 16 which has the last
50 or so cylinders unavailable, giving about 28 Meg total space. This
second drive required 2 low-level format runs before it formatted, but
has been in heavy use for about 6 months with no problems.
Several of the documents supplied with 2070A cards listed this drive
as usable, but Adaptec calls it "not recomended." The one I have set up
was an older 725A originally supplied with a clone and a Western Digital
controller, and has 10 DIP switches on the rear of the unit between the
cable connectors. The switch settings used on this drive were:
1 2 3 4 5 6 7 8 9 10
UP DN UP UP DN DN DN DN DN UP
If you have a 725A with only 9 switches, set them as if switch 4 did not
exist. If you have a 725A with no switches (to my knowledge originally
supplied with the XEBEC controller) you're on your own - I have not set
one of these up and have no knowledge of whether it will work. I have
heard that MicroScience no longer exists (although I do not know if this
is true), so you may be on your own as far as service is concerned; the
drive overhaul facility we use for hard disks will not work on these
drives because MicroScience will not release documentation on the drive.
Use the same jumper settings as the Seagate ST-238 on this drive, and use
the in-BIOS parameter set.
(*------------[ Card Layout ]--------------*)
| M O Q S |
| . . . . |
| . . . . |
| N P R T |
| . . . . . . |
| . . . . . . |
| High-Performance jumpers |
| .......... |
| J1 .......... |
| ................. .......... |
| J2 ................. J0 .......... |
(*-------[ In Finis... ]--------*)
I hope you find this information useful. I am trying to compile a known-
good list of drives that will work under RLL format with the 2070A card. If
you have installed a drive with the 2070A that is not listed here, please
leave me a message at either of the following locations describing your
experiences and whether or not the drive performs to your expectations.
CompuServe EasyPlex ID# 73107,1157
The C2G PCBoard BBS
300/1200/2400 8/N/1 24 hrs./day - 7 days a week
I will update this information from time to time so that hopefully the
latest information will be available to those who need it. Thanks!