Dec 242017
Western Digital's installation and description of their ESDI V series Hard disk floppy disk controller.
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Western Digital’s installation and description of their ESDI V series Hard disk floppy disk controller.
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Contents of the WD1007V.TXT file



Winchester/Floppy Disk Controller



Information furnished by Western Digital Corporation is believed to be accurate
and reliable. However, no responsibility is assumed by Western Digital
Corporation for its use; nor for any infringements of patents or other rights
of third parties which may result from its use. No license is granted by
implication or otherwise under any patent or patent rights of Western Digital
Corporation. Western Digital Corporation reserves the right to change
specifications at any time without notice.

Trademarks used in this text: IBM, AT, and Personal Computer AT are registered
trademarks of International Business Machines Corporation. Xenix and MS-DOS are
registered trademarks of Microsoft Corporation. NetWare and CompSurf are
registered trademarks of Novell Incorporated. SCO is a trademark of Santa Cruz
Operation, Incorporated.


The WD1007V-SE2 Winchester/Floppy Disk Controller interfaces two ESDI-
compatible hard disk drives and two floppy disk drives (5.25 or 3.5 inch) to a
PC-AT system processor. The WD1007V-SE1 is a hard drive only version of the
controller. The WD1007V BIOS ROM provides parameter tables, low-level
formatting, surface analysis and defect management routines to fully integrate
ESDI drive capabilities into your system.

This document describes installation of the WD1007V-SE1/SE2
Winchester/Floppy Disk Controller in the IBM Personal Computer AT or

The following is a summary of the steps you will take to configure
and install your controller board for use with your hard disk drive(s)
and floppy drive(s).

1. Gather together necessary equipment and software

2. Unpack and inspect controller board

3. Configure and install hardware

4. Run setup utilities

5. Format the hard drive

6. Check installation



This section describes steps you must take before installing the WD1007V
controller in your system.


Make sure you have all the necessary equipment and software for installation of
the WD1007V controller and configuration of your drive(s).

- screwdriver

- WD1007V-SE1 (Hard drive only controller) or WD1007V-SE2
(Hard drive and floppy controller)

- One 34-pin control cable (daisy-chained, if connecting two
hard drives)

- One 20-pin data cable (two cables, if you are connecting
two hard drives)

- One 34-pin floppy cable (daisy-chained, if you are connecting
two floppy drives)

- IBM PC-AT or compatible system with a maximum of two ESDI
hard drives or a maximum of two ESDI hard drives and two ANSI
standard floppy drives with a density sensor

- MS-DOS version 3.3 or higher, Xenix, NetWare or other operating
systems that provide disk partitioning

- If you are disabling the WD1007V BIOS ROM, then you will
also need Western Digital's WDFMT for the low-level formatting


Many system BIOS ROMs support only the older MFM/ST506 drives that have 17
sectors per track. The ESDI disk drive typically has 34 or more sectors per
track. Therefore, your system's BIOS ROM may not be adequate to support your
ESDI drive.

In terms of maximum flexibility and adaptability with different drives, Western
Digital recommends that you use the WD1007V BIOS ROM. ESDI drives have the
ability to present actual drive characteristics to the controller. The WD1007V
BIOS ROM reads the ESDI information and generates the appropriate drive table.

If you are installing a hard drive in your system and you want to use your
system's BIOS ROM to configure your drive, disable the WD1007V BIOS as
described in section 2, and refer to Appendix B for low-level formatting


You have the following controller board choices:

- Install the 1007V-SE1:

If you are installing a hard drive and your floppy controller is on the
motherboard or you currently have a separate floppy controller.

- Install the 1007V-SE2:

If you are installing a hard drive(s) and a floppy drive(s)
for the first time (there is no floppy controller on the motherboard)
or you wish to replace your current controller(s). You must remove
or disable any other controller in your system.


The 1007V-SE1/SE2 controller supports two ESDI drives, each having no more than
53 sectors per track, 16 heads and 2048 cylinders.

The 1007V-SE2 additionally supports two floppy disk drives (5.25 inch or 3.5
inch with single density, double density, and high density formats).


If you are installing a new hard drive along with the WD1007V controller board,
here are a few words about cables. Figure 1-1 shows both a twisted and a non-
twisted daisy chain cable for hard drives. Be careful not to confuse the
twisted hard disk cable with a floppy daisy chain cable. They are not
interchangeable. Floppy daisy chain cables also have 34-pin connectors and are
usually twisted. The only distinguishing mark may be that the floppy cable has
the twist located closer to pin 1 position. Also note that the twisted portion
of the hard drive cable must have exactly five wires.

If you only have one hard drive in your system, then you will probably use a
standard two-connector, 34-pin cable (not shown).

Note that the cable or cable connectors have been "keyed" in some fashion, such
as a colored stripe on the cable identifying pin 1 position and/or a notch on
the connector. This is to ensure proper connection of the cables to the
drive(s) and controller card.


Non-twist Cable Twisted Cable



Hold the controller board by the ends. Static electrical discharge can
permanently damage components if the board is not carefully handled.

Remove the controller board from its antistatic pouch and inspect it for any
visible signs of damage (scratches, loose components, broken connectors).
Contact your dealer if there is damage.

Retain any packing materials for reuse if it becomes necessary to
return your controller.




Your hard disk drive has jumpers, switches, and/or termination resistors that
must be configured before you install the drive in your computer system. Before
proceeding with the installation of your controller card, make certain your
drive(s) is properly configured and physically installed according to the
manufacturer's instructions.

- Verify proper termination of the last hard disk drive. The
last drive (and only the last drive) in your system requires a termination

- Verify proper setting of drive select switches on your hard
drive, if necessary. Your hard drive must be configured to support
the hard sector mode. See Figure 2-1.

Figure 2-1 shows the proper drive selection settings and connections for your

hard drive, depending upon whether you are using a twisted or non-twisted daisy
chain cable. You may also have a standard two connector cable (not shown) for a
single hard disk drive. If you have such a cable, set your drive select as "1"
and do not remove the termination resistor.

34-Pin Twisted Cable

To Board Drive 1 (D:) Drive 0 (C:)
Last Drive


Jumper Drive 1 and Drive 0 as Drive Select 2

34-Pin Non Twisted Cable

To Board Drive 1 (D:) Drive 0 (C:)
Last Drive

Jumper Drive 1 as Drive Select 2
Jumper Drive 0 as Drive Select 1

Figure 2-1. Hard Disk Drive Select & Cables

Floppy drives are similarly selected and cabled. Be sure there is a termination
resistor on the last floppy drive. Refer to your Owner's Manual for your floppy
drive for proper selection and cabling information.


Before you install the WD1007V, verify that the controller's jumpers (small
shorting plugs) are properly set to reflect your configuration choices.
Modification of the standard factory settings on the controller is rarely

necessary. Modify the jumpers only under the direction of a qualified
individual, i.e., your dealer. Figure 2-2 illustrates the jumper locations on
the WD1007V-SE2 controller board. The WD1007V-SE1 board does not have jumpers
W5 and W6. Please read the jumper descriptions which follow.

J6 J3 J4 J5 J1

. .W5
2......12 .
1......11 .W3
. .W12
. .W6

WD1007V-SE2 1...3 W7 1...3 W8
P2 P1

FIGURE 2-2. WD1007V-SE2

Note: The WD1007V-SE1 version of this controller does not support floppy drives
and jumpers W5 and W6 are not used.

W1 Jumper Connections

Module jumper W1 selects the firmware options illustrated in Figure 2-2 when no
jumpers are installed. If you are merely replacing a WD1007A controller with a
WD1007V controller and you do not wish to reformat your currently installed
drive(s), you must install jumpers on W1 9-10 and W1 11-12.

W1 1-2: When a jumper is installed, no cacheing occurs.

When no jumper is installed, cacheing is enabled. Cacheing increases overall
system performance by reading ahead and buffering data sectors likely to be
requested by the host on subsequent read commands.

W1 3-4: When a jumper is installed, the host receives seven bytes of error
correction code (ECC) during Read Long and Write Long operations.

When no jumper is installed, four byte ECC mode is selected. This is the most
common selection. When using four byte ECC mode, three ECC bytes are
temporarily saved until the next command or data transfer occurs.

W1 5-6: When a jumper is installed, the controller assumes that the values
indicated by the Set Parameters command are the true physical values of the
drive. Install this jumper only if your system supports the true physical
parameters of your drive (number of heads, cylinders, SPT).

If you have a system which cannot support drives which have more than 17 SPT or
drives that have more than 1024 cylinders, you require the default selection
(no jumper). This provides a translation scheme to more fully utilize the
capacity of your drive. See "Translation" in Appendix A for further

W1 7-8: This is reserved. No jumper is installed.

W1 9-10: When a jumper is installed, it forces the drive to 35 SPT by issuing a
Set Unformatted Bytes per Sector command to the drive. This overrides the
drive's switches which select the SPT value. This jumper has no effect on
drives having data transfer rates of 15 Mbits per second.

Without a jumper, the controller uses the physical SPT value presented by the
drive ( as determined by the drive's jumper settings).

W1 11-12: When a jumper is installed, an alternate sector per track is
provided. The alternate sector is useful when deallocating media defects.
Mapping out media defects is important if you have an operating system which
can accommodate only a certain number of errors. If you choose to format an
alternate SPT for deallocation of media defects, you will lose some of your
drive's storage capacity.

This feature is explained further in Appendix A.

W3 thru W12 Jumper Connections

W3 Jumper Connection

To disable the installed WD1007V BIOS ROM, place a jumper on W3 1-2. Use the
system BIOS for low level formatting. See Appendix B.

W5 Jumper Connection

Without a jumper on W5 1-2, the WD1007V supports single-speed floppy drives.
When jumpered, dual-speed floppy drives are supported.

W6 and W12 Jumper Connection

To select the module's secondary address ranges, install jumpers on W6 1-2
(floppy drives ) and W12 1-2 (fixed drives). The primary address ranges of 1F0-
1F7 and 3F2-3F7 are selected when jumpers are not installed. Secondary address
ranges are selected only when using a second controller or as a means of
disabling a device.

W7 Jumper Connection

The 1007V-SE1/SE2 controller offers the default interrupt request, IRQ14.
Jumper W7 1-2 is factory installed. Note that MS-DOS, OS/2, and most other
operating systems work with IRQ14. Some operating systems may work with IRQ15
if custom drivers are installed. If your particular application requires IRQ15,
install the jumper on W7 2-3.

W8 Jumper Connection

W8 2-3 is jumpered to select the BIOS address range CC000 through CFFFF or, if
expressed as a "segment:offset" address, CC00:0000 to CC00:3FFF (CF00:0FFF).

By removing the jumper from W8 2-3 and placing it on jumper W8 1-2, the BIOS
address range can be changed to C8000 through CBFFF or, if expressed as a
segment:offset address, C800:0000 to C800:3FFF (CB00:0FFF). You only need to do
this when there is a conflict between the BIOS address range and another
device's address.



To avoid electrical shock, make sure that all power
to your computer is off and the power cord is disconnected from the
electrical source.

1. Remove the power cord from the computer. If you remove any
cables, note their location (for easy reassembly).

2. Remove the cover of the computer according to the instructions
in your Owner's Manual.

3. Install your hard drive(s) and floppy drive(s) according
to the manufacturer's instructions. Refer to your Owner's Manual for
information about proper drive termination and select switches. Be
certain there is a termination resistor on the last hard drive and
last floppy drive in your system. Be sure you use the right
kind of cables for each device. (See Chapter 1, "Identifying Cables".

4. Remove or disable any other disk controller in your system
if you are installing the WD1007V-SE2. If you have a controller on
your motherboard, disable it according to the manufacturer's instructions.

5. Select any 16-bit expansion slot and remove the expansion
slot cover. It is best to locate the controller in the closest available
expansion slot relative to the drive. Put the expansion slot cover
away and save it for possible future use. Retain the screw to hold
the controller board in place.

6. Connect the hard drive(s) to the controller board by following
these steps:


When routing the cables, be careful not to pinch them.
Cables must not get caught between the cover and the boards
nor should they obstruct any air flow path from fans or vents.

Do not confuse a daisy chain cable for a hard drive with a floppy dasiy chain
cable. They are not interchangeable.

a. Connect the 34-pin control cable from the drive(s) to J5
connector on the controller. (See Figure 2-6.) Match the keyed connectors.
Keyed connectors prevent accidental reversal of the cables which can
cause severe damage to the drive and the controller.

The daisy chain control cable has three connectors. If you
have a second drive, plug the middle connector into the back of the
second drive. The shorter length of the cable connects the drives:
the longer length connects the drives to the controller card.

b. Attach the 20-pin data cable to J4 connector on the controller.

c. If you have a second hard disk drive, attach the second
20-pin data cable to J3 connector on the controller.

J4's cable connects to Drive 0: J3's cable connects to
Drive 1.

Note (DOS only)

Your system will identify Drive 0 as Drive C: Subsequent drives or partitions
are identified as D:, E:, F:, etc.

7. Connect the floppy drive(s) to the controller board by following
these steps:

a. Attach the 34-pin floppy cable to J1 connector.

A daisy chain cable has three connectors. If you have a
second drive, plug the middle connector into the back of the second
drive. The shorter length of the cable connects the drives: the longer
length connects the drives to the controller card.

8. If your system provides an activity LED indicator for the
drive, plug it into J6 on the controller.

9. Carefully slide the controller board into the expansion
slot. Ensure that the board is seated properly by pressing down evenly
on both ends of the board. Secure the board with the expansion cover

10. Replace computer cover.

11. Reattach all cables and power cords to the back panel of
the system.

The hardware installation is now complete.

12. Follow the instructions for system setup.


Your setup utility performs numerous tasks that are essential to the definition
of your system. Whether this is an initial setup or a change to your existing
system, you need to run the setup utility to tell the system what types of
hardware are installed.

Follow the instructions in your operating system manual, system BIOS manual or
use whatever means your particular system provides to perform an initial setup.
If later you experience problems with any hardware device, be sure to check
your system setup. You may have incorrectly defined a device or not identified
it at all.


Before you can use your ESDI drive, you need to perform these three steps:

1. Perform low-level formatting using the WD1007V BIOS utility
or, if you are not using the WD1007V BIOS, use WDFMT. (See Appendix
B for WDFMT instructions.)

2. Partition your drive using MS-DOS 3.3 or higher (FDISK utility)
or use other operating systems that allow partitioning, such as Xenix
and NetWare.

3. Perform high-level formatting using the operating system's
normal formatting program. For MS-DOS use the "Format C: (or D:)/S"
command which formats the drive to accept MS-DOS files and copies
the operating system to the drive.


If you decided to disable the WD1007V BIOS ROM (W3 has pins 1 and 2 jumpered),
skip the following instructions and instead go to Appendix B for low level
formatting instructions.


If you are using the WD1007V BIOS to configure your drive, there must be no
jumper installed on jumper connector W3. Proceed with the following steps.

1. Place your DOS system diskette in Drive A and turn on your
system. At the A:\>> prompt type:

debug and press the ENTER key

2. At the program prompt "-", type:

G=CC00:5 (Use C800:5 if W8 1-2 is jumpered)

This causes the system to execute program code stored at location
CC005 (or C8005, if W8 1-2 is jumpered) in ROM. The BIOS then tries
to read the parameter tables from the drive and store them in the
shadow RAM. You will see the screen shown in Figure 3-1.

To execute a function, simply enter the number of the desired routine.
The BIOS executes that routine and then prompts you to press a key
to return to the main menu. Note that after you have finished formatting
and running the various routines, you must make a proper exit through
function 7 to set the drive type.


Selection of any of the menu choices will cause permanent loss of any data
files that may exist on the drive. If you have not backed up your files and you
wish to exit, press CONTROL-C or CONTROL-BREAK. Perform a power-up reboot to
clear the shadow RAM.

Following is a brief description of the formatting routines performed by the
WD1007V BIOS utility. We recommend that you select and perform the routines in
this order:

- Low Level Format

- Mark Defect List Automatically

- Verify Drive

- Surface Analysis

- Change Drive Type and Exit

The WD1007V BIOS offers these features:

1. On-screen HELP menu

2. Low-level format - Formatting routines are present
to do the low-level initialization of the disk surface. The drive
is formatted according to the number of physical sectors per track.
You may also format an alternate track if you have placed a jumper
on W1 11-12. (See "Alternate Sector", Appendix A.

Transparent to the user, this routine formats with a sector
skew. The sector skew, which is fixed at two, allows the controller
to maintain a 1:1 interleave across head boundaries on most drives.
Sector skewing is a method of formatting in which the sector numbers
are rotated in the interleave table for each track. (See "Format "
in Appendix A for further information.) If a sector skew other than
2 is needed, use WDFMT to do a low level format, but use WD1007V BIOS
for the rest of the options.


When performing a low-level format of an ESDI drive,
use the drive's physical parameters.

3. Mark Defect List Automatically - This routine automatically
reads the manufacturer's defect list for each head and identifies
and marks bad sectors. If an alternate sector is available, a bad
sector can be deallocated without having to mark a sector as bad.
This routine allows you to present an error-free drive to the system.

4. Mark Defect List by Hand - This routine is the same
as the previous one, except that it allows the user to enter the list
of media defects provided by the manufacturer. Use this routine if
you are unable to enter the defects automatically.

5. Verify Drive routine - This routine performs a quick
media verification. If a bad spot is discovered and an alternate sector
is available, the bad sector is deallocated. If an alternate sector
is not available, the sector is marked as bad.

6. Surface Analysis routine - This routine performs
a long-term test on the entire drive. It identifies bad tracks on
the drive and, in the event that there is only one bad sector on the
track (and it is NOT sector zero), it uses the alternate sector when
reformatting the track. This prevents the controller from identifying
the sector as "bad".

7. Change Drive Type and Exit routine - There are five
possible options available for defining drive type. The drive type
can be changed by using the "+" and "-" keys.

- No Drive Present. The BIOS automatically selects
a drive type 0 if there is no drive present. You will see the message
"*** NONE SELECTED OR NO DRIVE PRESENT !***" next to the drive number.

- Non-translation. This option uses the drive's actual
physical parameters (number of cylinders, heads, and SPT). The maximum
number of cylinders is 1023.

- Translation - 17 SPT. Select this option when the
drive is being used in a system that does not support drives with
SPT values greater than 17 SPT. The low-level format uses the actual
physical SPT, while the parameter tables created will show 17 SPT.

- Translation - 63 SPT. Select this option if the drive
has more than 1024 cylinders, and it is being used in a system which
can only recognize a maximum of 1024 cylinders. Translation must always
be enabled when such a condition exists. Translation provides greater
use of the drive capacity even though most types of AT BIOS recognize
only a maximum of 1024 cylinders.

- Special non-translation. Select this option only
if your drive has more than 1023 cylinders and you are using a custom
device driver or operating system to obtain full usage of your ESDI
drive. If you choose this option and don't have a custom driver or
a special operating system, you will greatly reduce your storage capacity.


After you have completed the low-level formatting of your drive using the
WD1007V BIOS utility, you will need to partition your drive and perform a high-
level format. The three main operating systems (MS-DOS, NetWare, and Xenix) all
handle disk usage differently.


After you have completed the low-level formatting of each hard drive in your
system, use the FDISK and FORMAT utilities to prepare your drive for the MS-DOS
operating system. Refer to your operating system manual for complete

1. Use FDISK to partition your drive. If your version of MS-DOS
does not support the creation of multiple logical drives, disk enhancement
software drivers can be used to obtain full usage of your high capacity
drive or you may wish to upgrade your operating system.

2. Use the "Format C:(D:)/S" command to perform high-level
formatting of the drive. This utility formats the drive to accept
your operating system's files and allows you to copy the operating
system to the drive. You must format all logical drives (partitions).

SCO Xenix

The SCO Xenix operating system does not limit the size of the disk partition.
During the installation of the Xenix operating system, the user is prompted for
information on how to partition the disk. The entire disk may be used for Xenix
or separate partitions can be created for both Xenix or MS-DOS. (Note: Create
the MS-DOS partition first using MS-DOS FDISK.) The Xenix installation performs
all tasks comparable to the DOS FDISK and FORMAT utilities.

SCO Xenix 2.1 can create a parameter table for the drive outside of the system
BIOS. The user is prompted at installation time to supply the drive parameters.
Previous versions of the SCO Xenix operating system assumed 17 sectors per
track, regardless of the information contained in the parameter table. If you
have an older version, use the 17 sector translation option provided by the
WD1007V BIOS utility.

Novell NetWare

Novell NetWare is a local area network (LAN) operating system. If you are using
NetWare 2.0a, you must select the 17 SPT drive type offered by the WD1007V BIOS
utility. If you are using NetWare 2.1 or later, any number of sectors per track
is permissible. If you are running NetWare in a non-dedicated mode or if you
are using the standard AT hard disk driver that comes with NetWare, we
recommend that you select these parameters: 63 SPT and 16 heads. This will
accommodate a drive size of 512 Mbytes.

NetWare requires you to run a program called CompSurf to prepare the disk
drive. When running CompSurf, do not format your drive. Answer "NO" when asked
"Format the disk?" or you will lose all the BIOS information and defect
information on your drive. When asked if you wish to maintain the defect map,
respond "Yes" if you use the WD1007V BIOS utility.



After you have completed the hardware installation and properly formatted your
drive, you are ready to use your system.


With your operating system installed on your hard drive, you can now boot your
system from your active MS-DOS (or other operating system) partition. Remember
to remove any diskettes from Drive A or your system will default to Drive A
when you reboot.

Simultaneously press the CTRL ALT DEL keys to reboot the system.

The system should respond and your monitor should finally display the C prompt
(C>>). Your installation is complete.


If you have a problem with your system, first re-read the instructions to be
sure you followed them correctly. It is important to type information exactly
as instructed.

Repeat the procedures a second time. If you obtain the same results, then check
the next section "If You Have a Problem".

If You Have a Problem

First check your physical installation. Check for reversed cables, an
overloaded system power supply, incorrect drive selection, etc.

The following section lists some common problems and possible solutions to try.

PROBLEM: No response.

SOLUTION: Change cables. Do NOT interchange floppy disk drive cables
with hard drive cables. Check your system setup configuration.

PROBLEM: Winchester activity LED always on.

SOLUTION: Check cable connections. Replace cables. Verify that drive
is not malfunctioning.

PROBLEM: "Error Reading Fixed Disk" message after booting the system.

SOLUTION: DOS partition not active. See FDISK instructions in your
DOS manual.

PROBLEM: "Hard Disk Drive Not Ready" or "01" Error Code.

SOLUTION: You may have an overloaded power supply. Update system power
supply. read your system/drive manufacturers' manuals to see if the
power supply can handle the drive.

PROBLEM: You can't get full capacity from your drive.

SOLUTION: This probem has several possible causes and several solutions.
These are listed below:

1. You have a drive with more than 1024 cylinders and you selected a drive type
with more than 1023 cylinders. Most operating systems cannot handle this.
Repeat the low level format and this time select a drive type with less than
1024 cylinders.

2. You are using physical mode and you have a drive with more than 1024
cylinders. You selected a drive with 1023 cylinders and a specific number of
physcial heads and a specific number of SPT. Try using translation mode and
select a drive type with 16 heads and 63 SPT. (Jumper W1 5-6 removed, and use
the WD1007V BIOS).

3. You are using alternate sectors. This option will improve performance, but
decreases capacity by one sector per track. For example, if you have a drive
with 35 SPT then 1/35th of your drive capacity is lost.

4. Your current operating system may only recognize a maximum capacity of 512
Mbytes. To gain access to the full capacity of your hard drive, you will need
to change your operating system or possibly obtain a special driver. Contact
the dealer that sold you your drive. He should be able to recommend a solution
so that you can fully utilize your drive's capacity.

PROBLEM: You have a dual density floppy drive, but you can format/read
only one density of diskettes (either 720KB or 1.44MB).

SOLUTION: You do not have an ANSI standard floppy drive with a density
sensor. Therefore your drive will only read one media density.
Contact your drive manufacturer.

PROBLEM: You need to use WDFMT, but don't have a copy of it.

SOLUTION: Contact the Western Digital Bulletin Board. Appendix C
has the instructions for obtaining software from the Bulletin Board.

If you are unable to resolve a problem, contact your dealer.



In order to utilize the maximum storage capacity of ESDI drives, the WD1007V-
SE2 controller resolves two types of problems associated with the
implementation of ESDI drives in an AT environment:

1. An older BIOS or some operating systems may only recognize
17 SPT, whereas ESDI drives have 34 or more SPT.

The WD1007V BIOS provides translation schemes to more fully
utilize the capacity of the ESDI drive, even though the system can
only recognize 17 SPT.

2. Most personal computers address disk space via the INT 13
BIOS software interface.This software interface provides only four
bits to specify head number, six bits for a sector number and ten
bits for a cylinder number. Thus, the ideal drive for the INT 13 software
interface could have 16 heads, 63 sectors per track, and 1023 cylinders.

The WD1007V BIOS provides translation schemes to maximize
the disk space that can be addressed by INT 13. The standard 63 SPT
translation creates a logical drive with 16 heads and 63 sectors per
track. It maps the drive's physical characteristics into these logical
parameters by converting the logical disk address parameters supplied
by the host into a logical sequential sector number. These logical
sector numbers are then translated into actual physical parameters
so that all physical sectors on the drive are utilized.

When disk address translation is disabled (jumper on W1
5-6), mapping is one-to-one. Each physical sector maps directly to
a logical sector.


Formatting routines perform the low-level initialization of the disk surface.
The drive is formatted with the physical characteristics read from the drive.
Formatting is done at a 1:1 interleave ratio which makes it possible to read or
write an entire track in one rotation of a disk. The format routine formats
with the selected sector skew (a skew of 2 is recommended for optimal
performance) and also may format an optional spare sector on each track. This
spare sector is used to deallocate a bad sector on a track.

The sector skew, when fixed at two, allows the controller to maintain a 1:1
interleave across all head boundaries. Sector skewing is a method of formatting
by which the sector numbers are rotated in the interleave table each time a new

head on a cylinder is formatted. Selecting a skew of 2 causes the first sector
after index on Head 0 to be identified as Sector 1. The sector identified as
Sector 1 on Head 1 is the third physical sector from index as shown in
Figure A-1.

Head Sector Numbers
0 1 2 3 4 5 6 7 8 9 10
1 9 10 1 2 3 4 5 6 7 8
2 7 8 9 10 1 2 3 4 5 6

Interleave: 1:1
Sector skew: 2


This formatting procedure allows the controller to maintain 1:1 interleave when
reading across the head boundary. This becomes critical when the number of
sectors per track increases and the time allowed for completion of overhead
functions decreases. By changing the sector numbers the controller has enough
time to complete needed tasks and be ready to read the ID field of the
first sector on the next head.


The WDFMT 2.10 utility and the WD1007V BIOS utility both provide the ability to
format an alternate sector on the track. This spare sector is identified as
Sector 0, making it invisible to the system BIOS which expects sector numbers
starting at 1. This sector is always formatted as the last physical sector on
the track. WDFMT and the WD1007V BIOS use the spare sector if an error is
encountered with any sector on a track. The program reformats the track,
numbering the bad sector as zero and shifting the following sectors one to the
right. If more than one sector is bad, the entire track is marked as bad when

The alternate sector feature provides the ability to map out defects so that an
error-free drive can be presented to the operating system. This may be
important to you if your operating system can handle only a certain number of
media defects. Note that formatting an alternate sector will somewhat reduce
the available storage space on your drive.



Before you disable the WD1007V BIOS ROM and use the system BIOS, you need to
determine if your system BIOS provides the appropriate drive tables for
integration of your ESDI drive into your AT system. If it does not, you require
the WD1007V BIOS. In order to properly install your ESDI drive, your system
must have drive tables whose parameters match those of your drive. The drive

tables specify the number of cylinders, heads, and sectors per track (SPT). It
is often difficult to match the drive and the drive table exactly. When
integrating an ESDI hard disk drive into your system, you must match sectors
per track and number of heads exactly.

If you are installing a hard drive in your system and you plan to disable the
WD1007V BIOS, you then need to examine your system BIOS. Use one of the
following two methods to examine your system BIOS:

1. Use your system's set-up program

2. Use the debug utility to examine the AT BIOS


If you are unable to determine whether your system BIOS is adequate, then
use the WD1007V BIOS ROM.

Using your system's setup program

To determine if a system BIOS has the physical drive parameters required for
your ESDI drive, refer to the appropriate manual for information about your
setup utility, i.e., MS-DOS Users Guide, Advanced Diagnostics Guide, system
BIOS guide, or user guide for other operating system. This utility can provide
you with information about the drive types your system supports. If your drive
tables do not support more than 17 sectors per track, we recommend that you use
the WD1007V BIOS. The WD1007V BIOS provides translation schemes to fully
utilize the capacity of your drive within the limits of the operating system.

Using the DOS Debug Utility to examine the AT BIOS

Use the DOS Debug Utility to examine the system parameter tables to see if the
drive is listed in the AT BIOS.

1. Place your DOS system diskette in Drive A and boot your system.

2. At the prompt (A:\>) type:

debug and press the ENTER key

Although some systems locate drive parameters in other locations, the standard
location in the AT BIOS is F000:E401. The proper command at the Debug prompt
(-) is as follows:

DF000:E401 and press the ENTER key

This displays eight lines of data from the BIOS ROM corresponding to drive
types 1 through 8. By entering another "D" at the debug prompt, another eight
lines of data will be displayed, corresponding to drive types 9 through 16.
Continue this procedure until all drive parameter information for all drive
types is displayed. If your drive's parameters are encountered in this process,
the system BIOS supports your particular drive.

Each parameter table has 16 bytes of data. Data from the BIOS ROM is displayed
in hexadecimal, least significant byte first. This data breaks down as follows:

Bytes 1 and 2 Number of Cylinders

Byte 3 Number of Heads

Bytes 4 & 5 Not Used

Bytes 6 & 7 Write Precompensation Cylinder

Byte 8 Not Used

Byte 9 Control Byte (=08H for 8 heads)

Bytes 10-12 Not Used

Bytes 13 & 14 Landing Zone 3

Byte 15 Sectors per Track

Byte 16 Not Used


If you are using the drive tables provided by your system BIOS, then use WDFMT
to low-level format your drive. If you do not already have it, you can obtain
WDMFT from the Western Digital Bulletin Board. See Appendix C.


When low-level formatting an ESDI drive, use the drive's physical
parameters, i.e., 8 heads and 34 or more sectors per track. If a format
for 17 sectors per track is attempted, only the data fields will be

The WDFMT utility performs low-level formatting, bad track entry, disk verify,
and surface analysis and defect management. Use a 1:1 interleave, a skew of 2,
and format the drive using the physical parameters of the drive. If Jumper W1
11-12 is installed, also format an alternate sector.

To use WDFMT follow these instructions:


Back up any valuable files that may exist on your drive. Use of WDFMT will
cause permanent loss of any existing data files.

1. Insert the WDFMT utility diskette in Drive A and type:

WDFMT and press the ENTER key

2. When the utility screen appears on your monitor, you will
be prompted to supply the following information. For each prompt for
information, type in your response and press ENTER.

- Drive 0 or 1 (Select drive to be formatted.)

- The number of cylinders...

- The number of heads ...

- The number of sectors per track...

- The interleave value (Select an interleave value of 1.)

- The precompensation value (Enter the number of cylinders
plus one.)

- The sector skew (Enter 2)

- Alternate sector (Enter "yes" only if Jumper W1 11-12 is

3. When you have completed your entries, the utility program will advance to
the following screen.

***Western Digital Corporation***
AT Disk Format Utility
Rev. 2.10
Current drive parameters are:

Drive (0/1) : 0
Cylinders : 1023
Heads : 8
Sectors : 35
Interleave : 1
Precomp : 1024
Skew : 2
Alt Sector : No


Format disk CAUTION this will destroy
all data on drive!

Verify disk
Bad sector entry
Surface test CAUTION this will destroy
all data on drive!


You have four menu choices: format disk, verify disk, bad sector entry, and
surface test.

Following is a brief description of the formatting routines offered by WDFMT:

Format Disk - This routine performs a low-level format of the drive. It formats
the drive according to the information which you previously entered.

Verify Disk - This routine is a short-term test of the surface that identifies
bad tracks on the drive and lists them by head and cylinder number. If an
alternate sector is available, a bad sector can be deallocated without having
to mark an entire track as "bad".

Bad Sector Entry - This routine allows you to enter the list of bad tracks. The
bad track information is marked on the label on top of the drive. Entering the
manufacturer's list of bad tracks ensures the safety of your data by
identifying all bad tracks or marginally defective tracks on your drive. Once
these defective tracks have been marked, they will not be used to store data.

Surface Test - This routine is a long-term test of the surface that identifies
bad tracks.

4. From the menu select the routine you wish to perform.,

We recommend you follow these steps:

a. Select "Format disk" and press the ENTER key to begin low-level

b. When you have finished formatting, return to the main menu
and select Verify Disk or Surface Test.

c. When the verify and/or surface test is finished, select
"Bad sector entry" and press the ENTER key. Locate the bad track
information marked on the label on top of the drive. Type in the bad
track list as follows:

ccc and press ENTER
h and press ENTER

where ccc = bad track cylinder number (1-4 digits) and

h = bad track head number (1-2 digits)

Type in the cylinder number and press ENTER. Type in the
head number and press ENTER. Continue until all bad track
information has been entered.

d. When you have finished, select Quit to exit the WDFMT utility.

Return to Chapter 3 for the high level formatting instructions.



Western Digital has a low-level formatting utility called WDFMT which is
available on Western Digital's Technical Support Bulletin Board. If you decide
to disable the WD1007V BIOS ROM, then you need to use the WDFMT utility. You
can execute this program by entering "WDFMT" and following the directions
provided by the On-line Help.


You may download Western Digital's diagnostic utility, WDFMT, and other
product information from the Bulletin Board if you have a modem.

To access the bulletin board you require:

- A Hayes compatible modem

- 1200 or 2400 Baud rate

- Format: 8 data bits, 1 stop bit, no parity

The Bulletin Board number is (714) 756-8176. The Bulletin Board will ask you
some preliminary questions about your modem setup and the type of system you
are calling from before sending you to the main menu. Refer to your modem
manual for instructions on proper modem setup.

Once you gain access to the main menu, follow these general steps:

- Select for software

- Select "Storage"

- Select "Utilities"

- Specify WDFMT

To receive the software program, select and then the transfer protocol.
Respond to the prompts for transfer protocol, file name, etc.

On screen Help (H) is available if you have any problems. If you need
additional assistance, contact Technical Support at (800) 832-4778.

Radio Frequency Interference Statement

This Western Digital product has been verified to comply with the limits for a
Class B computing device pursuant to subpart J of Part 15 of FCC rules. This
does not guarantee that interference will not occur in individual
installations. Western Digital is not responsible for any television, radio, or
other interference caused by unauthorized modifications of this product.

If interference problems do occur, please consult the system equipment owner's
manual for suggestions. Some of these suggestions include relocation of the
computer system away from the television or radio or placing the computer AC
power connection on a different circuit or outlet.

This digital apparatus does not exceed the Class B limits for radio noise for
digital apparatus set out in the Radio Interference Regulations of the Canadian
Department of Communications.

Western Digital
2445 McCabe Way
Irvine, CA 92714
(800) 847-6181 (714) 863-0102
FAX (714) 863-1656 TLX 910-595-1139
Technical Support: (800) 832-4778
Bulletin Board Support(714) 756-8176

Part No. 79-000367-000

WD0027S 8/89

If you require further information or other technical support, please contact
your authorized dealer:

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