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Western Digital Technical Support
Disk Manager FAQ Sheet
This document was last modified on Wednesday, 20-Nov-96 09:01:46 PDT
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 1: Do I need to use Disk Manager to support large Enhanced IDE hard drives 
under Windows 95? 
 2: What version of Disk Manager will work properly with Windows 95? 
 3: I have Disk Manager 6.0x and Windows 95 reports DOS Compatibility mode. 
How can I get utilize the Windows 95 built in 32 bit drivers? 
 4: Are there any issues involving Disk Manager and Windows 95 version of 
DoubleSpace? 
 5: Will Windows 95 Scandisk and Defrag utilities work on my Disk Manager-
installed hard drive(s)? 
 6: What is Dynamic Drive Overlay (DDO)? 
 7: How do I recover from "DDO Integrity error" message? 
 8: Why do I need Disk Manager? 
 9: How does Disk Manager impact 32 bit disk access (32bda)? 
 10: How do I install OS/2, NT, Novell NetWare on my DM-installed drive? 
 11: Disk Manager says my hard drive is not a Western Digital, but it is? 
 12: How do I remove Disk Manager? 
 13: How does Disk Manager use memory? 
 14: I installed my Caviar drives with Disk Manager and when I tried to 
install DOS 6.2 I ended up with a 504 meg drive. Why? 
 15: Everything was working fine after I installed Disk Manager, but this 
morning I got a "DDO Integrity Error" and I can't access the hard drive. 
 16: I can only get 16 bit file access in WGFW on the slave drive I 
formatted with Disk Manager. How can I change this? 
 17: Why are my drive letters all switched around? 
 18: How do I create a Disk Manager boot disk? 
 19: Can caching controllers cause problems with Disk Manager? 
 20: I am trying to recover a Disk Manager read/write partition, but have 
had no luck. What am I doing wrong? 
 21: I used the Alt-T, CTRL-F10 keyboard combination to remove Disk Manager, 
but it did not seem to work. What could be the problem? 
 22: I am experiencing data corruption on my drive that was installed with 
Disk Manager running OS/2 Warp. My motherboard uses the RZ1000 PCI-EIDE 
controller chip. Are there any known problems? 
 23: While installing Windows 95, Disk Manager was not able to complete the 
installation of DDO 6.03d. In the manual mode (DM/M v6.03a) i found out the 
problem was caused when the system file "IO.SYS" was copied to hard disk. 
What should be done? 

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1: Do I need to use Disk Manager to support large Enhanced IDE hard drives 
under Windows 95?

To get the full capacity of your hard drive under Windows 95, you must have 
either hardware support (a translating system BIOS or an EIDE controller card), 
or software support such as Disk Manager. Windows 95 does support and 
recognize Disk Manager version 6.0x. The Disk Manager driver, when loaded 
from the Master Boot Record (MBR, when drive is in the master position) or in 
the Config.sys (as a device driver, when drive is in the slave position), will be 
properly recognized by Windows 95, hence Windows 95 will install properly 
along with your other software packages. 

2: What version(s) of Disk Manager function properly with Windows 95?

Disk Manager versions 6.03 or higher will function properly with Windows 95. 
If you have version 6.03 thru 6.03c, Western Digital recommends downloading 
Dmpatch.exe from our Online Services and updating the Dynamic Drive 
Overlay to 6.03d. 

3: I have Disk Manager 6.0x and Windows 95 reports DOS Compatibility mode. 
How can I get utilize the Windows 95 built in 32-Bit Protected-mode IDE 
driver?

Disk Manager version 6.0x is supported by Windows 95. However, there are a 
few things you must keep in mind: 

CMOS setting for your hard drive should display a number equal or less than 
1,024 for cylinders. 32-Bit Disk Access driver ( WDCDRV.386, *WDCTRL, 
etc.) loaded from the System.ini file must be disabled prior to Windows 95 
installation. Be sure to set the value of the cylinder count in your CMOS to less than 1024. 
Disk Manager does not require that these values match the actual cylinders for 
your drive to function properly. Additionally, edit your SYSTEM.INI and under 
the [386 Enh] section and disable 32-Bit Disk Access by placing a semi colon 
";" at the beginning of the line: 

;32Bit DiskAccess=On 

or simply change On to Off on this line. WDCDRV.386 is not required since 
Windows 95 provides its own 32-bit protected mode Port drivers for support of 
your IDE drives. 

You can also download a file named Dmpatch.exe from Western Digital Online 
Services to update your Disk Manager 6.0x drivers for additional Windows 95 
support. 

Western Digital Online Services can be reached as follows: 

 Worldwide Web, www.wdc.com
 FTP site, ftp.wdc.com
 Western Digital's forum on America On-line, Keyword: WDC
 BBS, (714) 753-1234

4: Are there any issues involving Disk Manager and Windows 95 version of 
DoubleSpace?

Windows 95 supports all previous versions of Microsoft compression utility, 
including DoubleSpace and DriveSpace. In addition, there are new compression 
options for a hard drive available with the Windows 95 Plus Pack. All the above 
compression utilities will function with your Disk Manager-installed hard drive. 
For third party compression packages, please contact the manufacturer for 
compatibility issues with Windows 95. 

5: Will Windows 95 Scandisk and Defrag utilities work on my Disk Manager-
installed hard drive(s)?

Yes, you can use the Windows 95 version of Scandisk and Defrag programs on 
any drive installed with Disk Manager. However, we recommend that you use 
our Wddiag.exe utility to scan your drive as it is better prepared to recognize 
and report any issue with the drive. 

6: What is Dynamic Drive Overlay (DDO)?

Disk Manager 6.03 employs technology called Dynamic Drive Overlay (DDO). 
Unlike previous versions which loaded a driver via config.sys, DDO is a pre-
boot loader. This means that all the necessary code is loaded during the boot 
sequence rather than through driver files. As always, our drivers exist to provide 
solutions to BIOS or DOS limitations. In the case of DDO, this driver allows 
access to the full capacity of the new large IDE drives. Please note that Dynamic 
Drive Overlay is not the same as Overlay.exe which prevents data loss on your 
Caviar drives. 

7: How do I recover from "DDO Integrity error" message?

When facing the the DDO Integrity error, follow the step of the these main 4 
categories of possible recovery techniques. Be sure to follow these steps in the 
order they appear and only move on to the next method only and only if the 
previous method did not succeed: 

 Method 1: Run Dmcfig /y and follow the prompts to reconstruct your DDO. 
 Method 2: Manual Mode (Single Partition) 

1.Boot from a bootable DOS floppy. 2.Insert the Disk Manager diskette in A:. 
3.Type DM /m to start Disk Manager in Manual mode. 4.At Disk Manager 
Status screen press ALT-C. 5.At Disk Manager Main Menu choose (H)ard Disk 
Installation. 6.Select Disk 1. 7.At Hard Disk Installation Menu choose 
(P)artition Setup and Configuration. 8.On line 1, underneath TYPE, confirm that 
it says *DOS. The * is important. 

 If it does not show *DOS, try Method 3. 
 If it shows *DOS, then continue with this procedure. 

9.With the highlighted bar on line 1 (the line showing *DOS), press the W key. 
(There is no option for "W" on the screen. You will not see anything happen.) 
The "W" rewrites the boot information. 10.The highlight bar should now be on 
the line that says "Save Partition Table and Continue." Press (enter), then choose 
(Y) to save. 11.Hit ESC until you get back to the "Disk Manager Main Menu." 
12.Hit ESC again and select (Yes) to exit Disk Manager. 13.Remove the floppy 
and reboot the system. The DDO should come up and the system will boot to C: 

 Method 3: Manual Mode (Single Partition) 

1.Boot from a bootable DOS floppy. 2.Insert the Disk Manager diskette in A:. 
3.Type DM /m to start Disk Manager in Manual mode. 4.At Disk Manager 
Status screen press ALT-C. 5.At Disk Manager Main Menu choose (H)ard Disk 
Installation. 6.Select Disk 1. 7.AT Hard Disk Installation Menu choose 
(P)artition Setup and Configuration. 8.Choose (N) for New Table. 9.Choose 
(Yes) in response to "Allow drive to be installed with a single DOS partition?" 
10.At "Partition Types" choose DOS. 11.At "Partition Entry Modes" choose 
(M)Bytes. 12.In response to "Enter size of partition in Mbytes" press (enter). 
Scroll up to Line 1. Underneath TYPE confirm that it says *DOS. The * is 
important. 

 If it does not show *DOS, see the note below.
 If it shows *DOS, then continue with the procedure. 

13.Scroll back down to "Save Partition Table and Continue" and press (enter). 
Then choose (Y) to save. 14.Hit ESC until you get back to the "Disk Manager 
Main Menu." 15.Hit ESC again and select (Yes) to exit Disk Manager. 
16.Remove the floppy and reboot the system. The DDO should come up and the 
system will boot to C: 

 Method 4: Manual Mode (Multiple Partitions) 

1.Boot from a bootable DOS floppy. 2.Insert the Disk Manager diskette in A:. 
3.Type DM /m to start Disk Manager in Manual mode. 4.At Disk Manager 
Status screen press ALT-C. 5.At Disk Manager Main Menu choose (H)ard Disk 
Installation. 6.Select Disk 1. 7.At Hard Disk Installation Menu choose 
(P)artition Setup and Configuration. 8.On line 1, underneath TYPE, confirm that 
it says *DOS. On line 2 confirm that it says *DOS-Extended. The * is 
important. 

 If it does not show *DOS and *DOS-Extended, see the note below. 
 If it shows *DOS and *DOS-Extended, then continue with this procedure. 

9.With the highlighted bar on line 1 (the line showing *DOS), press the W key. 
(There is no option for "W" on the screen. You will not see anything happen.) 
The "W" rewrites the boot information. 10.The highlight bar should now be on 
the line that says "Save Partition Table and Continue." Press (enter), then choose 
(Y) to save. 11.At Hard Disk Installation Menu choose (P)artition Setup and 
Configuration again. 12.Place the highlighted bar on line 2 (the line showing 
*DOS-Extended) and press the W key. 13.The highlight bar should now be on 
the line that says "Save Partition Table and Continue." Press (enter), then choose 
(Y) to save. 14.Hit ESC until you get back to the "Disk Manager Main Menu." 
15.Hit ESC again and select (Yes) to exit Disk Manager. 16.Remove the floppy 
and reboot the system. The DDO should come up and the system will boot to C: 

NOTE: If *DOS or *DOS Extended do not appear under TYPE (it will only say 
DOS or DOS-Extended), the DDO has been corrupted to the extent that the 
DDO cannot be reliably restored to the drive. You can continue on with the 
procedure, however, you may or may not be able to access the data. If the 
system boots and you can access data, then you should back up important data 
and Disk Manager should be re-installed on the hard drive. 

8: Why do I need Disk Manager?

The basic issue is that while current versions of DOS can create a partition up to 
2.1 GB in size, it can only do this if the geometry of the drive (cyl x hd x spt) 
has less than 1024 cylinders. The maximum geometry that the BIOS (pre-LBA) 
can work with is 1024 x 16 x 63. (This works out to 504 megabytes). DOS, 
basically knowing that BIOS won't exceed 1024 cylinders, doesn't feel it should 
have to either. However, DOS doesn't care about the head or sector per track 
(SPT) count. Unless you have some type of technology which can perform track 
mapping to translate the geometry so that it appears to have less than 1024 
cylinders, this is the most capacity you will be able to partition. Ontrack's Disk 
Manager software performs this translation from a software perspective for IDE 
drives. There are controller cards which can perform the translation from a 
hardware perspective and newer BIOSes which have the LBA (logical block 
addressing) function can perform the translation from a firmware perspective. 
There is also another issue which serves to further complicate the situation. In 
the early days of hard drives; capacity depended on whether the drive was 
formatted or non-formatted. The capacity of new drives was determined in 
millions of bytes - when formatted, the capacity was determined in megabytes. 
The megabyte capacity was a smaller number as you were dividing by 1024 
instead of by 1000 (as you did with millions of bytes). All drive manufacturers 
calculate drive capacity in millions of bytes. 

The average 540 (+/-) drive is actually 540 millions of bytes, which works out 
to about 515 megabytes. This is using the full geometry of the drive, which is 
1048 x 16 x 63. If you are looking at the amount of drive that DOS can work 
with, you are using a geometry of 1024 x 16 x 63 which works out to 528 
millions of bytes or 504 megabytes. You can expect to see any of these four 
capacities, depending on which geometry your utility (such as chkdsk) is using. 

Disk Manager also provides the solution to not having the correct type in the 
CMOS drive type table to describe a particular drive. Most BIOSes these days 
have auto-configure options and User Definable Types (UDTs). If however, 
these options are not available to you, then Disk Manager can allow you to get 
full access to a drive that is not described in CMOS. 

Finally, Disk Manager can be a handy utility for resolving specific problems. 
Below are just two ways in which Disk Manager can be a life-saver: 

While one typically does not want to low level an IDE drive, there are times 
when you will need a tool to do this correctly (especially when someone has 
already messed things up with the wrong tool - like the system BIOS!). Low 
leveling IDE drives is tricky because of the way they translate themselves - 
physical parameters are needed for a low level. Disk Manager is able to get the 
correct parameters from the drive itself as well as any other pertinent 
information. Another very good use for Disk Manager involves CMOS. Say that 
you lose CMOS and can't remember how to re-set your UDT. You can use Disk 
Manager to view the partition table and gather the information you need for re-
setting CMOS. 

9: How does Disk Manager impact 32 bit disk access (32bda)?

Microsoft followed the WD 1003 standard when developing their 32bda driver 
(WDCTRL). This standard follows the traditional BIOS limitations, including 
the inability to recognize a drive over 1024 cylinders, 16 heads and 63 sectors 
per track. These parameters add up to 504 megabytes or 528 millions of bytes. 
Because WDCTRL follows the WD 1003 standard, it can't address above 504 
megabytes either. Disk Manager provides access to drives that are larger than 
504 - WDCTRL cannot work with these drives. We wrote our own 32bda driver 
(WDCDRV.386) which performs the same function, but also knows how to 
work with our larger drives. 

10: How do I install Windows 95, OS/2 WARP, Windows NT or Novell 
NetWare on my Caviar drive which has been installed using Disk Manager?

If you have Disk Manager version 6.03, 6.03a or 6.03b, download a file named 
Dmpatch.exe from Western Digital Online Services: 

 Worldwide Web, www.wdc.com
 FTP site, ftp.wdc.com
 Western Digital's forum on America On-line, Keyword: WDC
 BBS, (714) 753-1234

For Novell Netware installations, you must acquire IDE.DSK (dated after 
September 1994) for translating or non translating BIOS support of large EIDE 
drives. 

This file has the latest Disk Manager drivers which allow you to install OS/2 
version 2.1x, OS/2 WARP, Windows NT 3.5x or Windows 95 on your hard 
drive. Please view the readme file packed within DMPATCH.EXE for further 
details. 

11: Disk Manager says my hard drive is not a Western Digital, but it is?

Western Digital's version of Disk Manager checks for the presence of a Western 
Digital hard drive. Disk Manager starts by sending a "who are you and how big 
are you" query to your drive. If the response is anything but Western Digital, 
Disk Manager will produce an error message. Some sophisticated IDE cards will 
intercept queries and commands sent to the drive. For example, a controller card 
might respond "the drive is XXX MB and I'm Brand XYZ Card". This will 
cause Disk Manager to believe there is no Western Digital drive even if there is. 
You should try to disable the BIOS on your controller, or format the drive using 
another controller card to avoid this problem. 

12: How do I remove Disk Manager?

To remove Disk Manager from your drive, boot clean from a floppy (no 
Config.sys). Run Fdisk command and delete the Non-Dos partition. Then run 
the DOS Format command. DDO will be completely removed. 

NOTE: Removing the Dynamic Drive Overlay (DDO) is data destructive. You 
must backup your data before commencing. 

13: How does Disk Manager use memory?

Ontrack's DDO (Dynamic Drive Overlay - the utility which allows access to 
>504 mb) starts by loading into conventional memory, where it consumes 6k . It 
then moves to take 4k of upper memory, leaving behind a 62 byte "footprint" at 
the top end of conventional. This can sometimes conflict with other programs. 
You can change how Disk Manager loads into memory in the following manner: 

During the boot process, when you see the message which tells you to press the 
space bar to boot from floppy, press the "S" key instead, and then answer "Y" to 
the next question. This will cause Disk Manager to stay in conventional 
memory, rather than moving to high memory and may resolve the conflict you 
are experiencing. 

If this does resolve the problem; there is a special version of Disk Manager 
drivers which will prevent you from having to hit the "S" key every time you 
boot. The file is called Loadlow.zip and can be found on Ontrack BBS at (612) 
937-0860. 

14: I installed my Caviar drives with Disk Manager and when I tried to install 
DOS 6.2 I ended up with a 504 meg drive. Why?

After you format the drive with Disk Manager, it is critical that you load 
Dynamic Drive Overlay (DDO) into memory before booting from a floppy. It is 
required, for instance, to boot from floppy to install DOS 6.2. The procedure 
would be as follows: 

Boot from the hard drive. When you see the "press spacebar to boot from 
diskette" message, press the spacebar, insert the diskette and "press any key to 
continue" 

The boot will proceed from the floppy, but DDO will have had a chance to load 
into memory and the partitions will now make sense (so the DOS install will not 
re-format). 

15: Everything was working fine after I installed Disk Manager, but this 
morning I got a "DDO Integrity Error" and I can't access the hard drive. Why?

This message indicates that the sector containing the DDO (dynamic drive 
overlay) information (at the front end of the drive) has become corrupted. This 
should be considered as being the symptom of a greater problem, rather than as 
a problem in itself. This can be caused by: 
 infection by a boot or partition sector virus (most common). Boot from a clean 
DOS diskette and run a virus scan software. 
 power surge 
 hardware failure (usually the controller card) 
 shutting the computer down in the middle of a write 

Related topics: Recovery procedure 

16: I can only get 16 bit file access in Windows for Workgroups on the slave 
drive I formatted with Disk Manager. How can I change this?

When Disk Manager is used to format the Master drive, the DDO (dynamic 
drive overlay) is loaded during the boot process, from the front end (non data 
area) of the drive. In this situation, there is no device=dmdrvr.bin line in the 
Config.sys file. 

However, if Disk Manager is used to format the slave drive and the Master was 
formatted straight DOS, there will be that line in the config.sys and the DDO is 
loaded differently. It is this difference in how DDO is loaded that is causing the 
16 bit file access on the second drive. The only resolution would be to back up 
all the data on the Master drive and format it also with Disk Manager. This 
would cause the DDO to be loaded during the boot process and allow 32 file 
access on both drives. 

17: Why are my drive letters all switched around?

DOS allocates drive letters every time you boot. It starts first on spindle 1, then 
goes to spindle 2 (3, 4 and so on) looking first for primary DOS partitions and 
then for DOS extended partitions. When it has done this, it then allocates drive 
letters as requested by drivers loaded in config.sys (CD-ROMs, hardcards, etc). 

When you boot from the hard drive, DDO (dynamic drive overlay) is loaded 
before DOS. This means that when DOS looks at spindle 1, it can "see" that 
primary DOS partition and gives it C. It then goes to the second drive and 
allocates D. 

When you boot from the floppy, the driver line in config.sys (dmdrvr.bin) kicks 
off DDO - but this doesn't happen until *after* DOS has already gone looking 
for primary DOS partitions and assigned drive letters. Because DDO wasn't in 
memory when it looked at spindle 1, it did not see that partition. It did see the 
partition on the non-Disk Manager spindle and that became C. Config.sys 
loaded our driver, which kicked off DDO and asked for drive letters - DOS saw 
the partition on spindle 1 and gave it the next drive letter, D.  An easy way to avoid this is to start the boot 
from the hard drive. When you see 
the press spacebar to boot from diskette message, press the spacebar to halt the 
boot process and insert your boot floppy. The boot will continue on the floppy, 
but DDO will have loaded and the drive letters will be allocated as usual. 

18: How do I create the floppy so that I can boot from floppy and still have 
DDO load?

Follow the directions in the Disk Manager help section for creating an 
Emergency boot floppy, or use Dmcfig.exe follows: 
DMCFIG /d=a:
follow the prompts and answer (Y)es to the appropriate questions. 

19: Can caching controllers cause problems with Disk Manager?

Some caching controllers interfere with Disk Manager's ability to auto-identify 
the hard drive. In this case, a list of model numbers will appear. Simply select 
your drive from the list and continue as usual. Alternately, you could disable the 
cache temporarily. 

20: I am trying to recover a Disk Manager read/write partition, but have had no 
luck. What tips can you give me?

A read/write partition can be recovered with the "n" option in Disk Manager. 
Treat this the same way you would a DOS partition except you answer "NO" to 
dynamic configuration. Although it is possible to create a read/write with 
dynamic configuration, however, it is highly unlikely. If the re-creation is 
correct, a "*" is displayed in front of the read/write, otherwise do not save the 
partition because it does not match the original. This will work with 1 partition 
or multiple partitions, just as it would with a DOS or Extended DOS partition. 

21: I used the Alt-T, CTRL-F10 keyboard combination to remove Disk 
Manager, but it did not seem to work. What could be the problem?

It is possible that Alt-T did not remove Disk Manager as well as the first track 
(63 sectors) because there was a boot sector virus or write protect option 
enabled in the system BIOS. Either case, we suggest you use Wd_clear.exe to 
low-level format your drive in removing Disk Manager. 

NOTE: All of the actions above are data destructive. Obtain a backup of your 
drive before commencing. 

22: I am experiencing data corruption on a drive that was installed with Disk 
Manager running OS/2 Warp. My motherboard uses the RZ1000 PCI-EIDE 
controller chip. Are there any known problems?

Yes, theRZ1000 PCI-EIDE controller chip (common in older Intel Boards) has 
issues dealing with read and write operations from floppy-to-hard disk when 
using OS/2 Warp, resulting in lost data, and corrupted files. IBM has made 
available a software fix for this issue called PJ19409.ZIP, which will replace the 
existing IBMIS506.ADD file. The issue, is how it would affect drive with Disk 
Manager (with the update from DMPATCH.EXE) that had already replaced the 
IBMIS506.ADD file. Since PJ19409.ZIP came out after January 15th, the 
replacement ADD file should be compatible with the Disk Manager, so that you 
should not experience any problems when using the PJ19409.ZIP (or newer 
revs) on a OS/2 WARP system using Disk Manager. 

23: While installing Windows 95, Disk Manager was not able to complete the 
installation of DDO 6.03d. In the manual mode (DM/M v6.03a) i found out the 
problem was caused when the system file "IO.SYS" was copied to hard disk. 
What should be done?

Windows 95 version of IO.SYS is too large for Disk Manager 6.03d to handle. 
Therefore, use a DOS boot disk when Disk Manager prompts for a systems disk. 
Then, to install Window 95, reboot, let the dynamic drive overlay load, hit the 
spacebar to freeze it, then insert the Windows 95 disk #1 in the A: drive and 
proceed to install the rest of Windows 95.
