Installing Adaptec 2070A RLL Hard Disk Controllers

By: Steve Sneed 1987

Installing Adaptec 2070A RLL (Run Length Limited) Hard Disk Controllers

JUMPERS:
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):

 M-N
 O-P
 Q-R
 S-T
 

These are further divided 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 connected to.
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 format process!

The following table is the best I have seen for jumper configuration:

Remember, these are the DEFAULT parameters settings! Example for the tables above:
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 )

CABLING:
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.

FORMATTING:
From the DOS prompt, run
DEBUG.

When you see the "-" prompt, enter: G=C800:CCC This calls and runs 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 . The 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 program 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

     (*---------[  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
"0".

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.

DRIVES:

Seagate ST-225:
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.

MicroScience HH-725A
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.