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General Hard Drive FAQ Sheet
Western Digital Technical Support (http://www.wdc.com/support)
This document was last modified on Saturday, 01-Mar-97 14:06:56 PDT
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1: Will a Caviar drive work in my system? 
2: Do I have to do anything with my original drive when adding a new drive to my 
system? 
3: I installed my new Caviar drive and entered the drive parameters in the CMOS, 
but the drive will not boot or it displays the message "HDD controller failure." 
Why? 
4: What are the master/slave jumper settings on Western Digital drives? 
5: What is the drive type and the drive parameters in the CMOS, for Western Digital 
drives? 
6: CHKDSK or SCANDISK report a few bad sectors. How do I go about fixing the 
problem? 
7: Drive will not partition when I run FDISK. It hangs the system or it displays the 
message: "Runtime error." What does this mean? 
8: I want to add a hard drive to my new system which includes a partitioned 2.5GB 
drive (C and D). When I installed the drive in my system my drive letters are changed. 
The D partition on the new drive becomes E. Can I change drive letters or can I install 
without this problem?
9: My Caviar drive will work as a slave but not as a master (or vice versa). Why? 
10: I have two Western Digital hard drives on my computer. When I turn on the 
computer, only the first hard drive shows up.  If I soft boot (ctrl/alt/del.), then 
both show up.  How do I get both to show up the first time?
11: CMOS, FDISK and File Manager in Windows report less than the capacity of my new 
drive, but CHKDSK reports the right number of bytes. Which is correct? 
12: Can a hard drive and a CD ROM be installed on the same EDE data cable? Also will 
this arrangement degrade the  performance of the hard drive in any way? 
13: How can I use the full capacity of my Caviar AC31600 drive? 
14: What are the differences between overlays 1 and 2? When should you use 1 or 2??
15: What is EIDE (Enhanced IDE), and what are the current features of EIDE?
16: What is the difference between AC 31600 and AC 21600?
17: What is the difference between EIDE and Fast-ATA? 
18: I had to use EZ Drive of which partitioned the new drive using drive letters (D) 
and (E). My CD ROM used to be (D). I changed the LASTDRIVE (D) to read last drive 
(F) but it still does not let me use my CD ROM.
19: What is LBA (Logical Block Addressing)? 
20: Is there anything that might cause my hard drive electrical problems? 
21: How come I'm getting "out of disk space" message after loading in 800 MB of data 
on my 1 GB drive? 

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1: Will a Caviar  drive work in my system?

If your computer is 100% IBM AT compatible and it has a 40-pin IDE interface 
connector on the motherboard or an IDE host adapter, a Caviar drive should work 
in your system. 

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2: Do I have to put a jumper on my original drive when adding a 
new drive to my system?

Most likely, yes. One hard drive must be designated as the master drive 
(preferably the new Caviar drive) and the other as the slave drive. For the 
non Caviar hard drive please contact the appropriate manufacturer from the list 
below: 

IBM	 914) 765-1900
Maxtor	 408) 432-1700
Quantum	 408) 894-4000
Seagate	 408) 438-8222

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3: I installed my new Caviar drive and entered the drive parameters 
in the CMOS, but the drive will not boot or it displays the message 
"HDD controller failure." Why?

First , you must partition and format the drive. Boot off of a bootable diskette, 
run Fdisk to partition your drive and then format it using Format.com.

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4: What are the master/slave jumper settings on Western Digital 
drives?

All Western Digital Caviar drives are configured the same. Jumper pins 5 to 6 for 
master. Jumper pins 3 to 4 for slave. 

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5: What is the drive type and the drive parameters in the CMOS, 
for Western Digital drives?

Drive parameters (cylinders, heads and sectors per track) are printed on the 
drive label for your convenience. Precompensation (Precomp) and Landing zone 
(L-Zone) should be set equal to the drive's cylinders + 1. Select user type or 
custom type for your drive since this is the type which will allow you to enter 
your own parameters. Older systems that do not offer user type can either upgrade 
the BIOS or set the drive to drive type 1 (which perhaps is a small drive) and run 
Disk Manager or EZ-Drive from A drive to get the full capacity of the drive. 
Otherwise you would be limited to the biggest size drive your BIOS would allow. 
Here is a complete list of drive parameters for all hard disks manufactured by 
Western Digital.

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6: CHKDSK or SCANDISK report a few bad sectors. How do I go about fixing the 
problem?

You can use the Western Digital defect management utility. The utility is 
Wdatide.exe. One of the options is the comprehensive surface analysis. It will 
mark all grown defects bad (if needed) and it will compensate for the lost 
capacity by utilizing the spare tracks. 

NOTE: This utility is data destructive. Back up data before use. Due to the 
sensitive operation, Wdatide.exe could take quite a bit of time depending on 
the capacity of your drive. 

We recommend using Wddiag.exe as your day-to-day utility. You can still use 
Scandisk or any other disk utility, however, Wddiag.exe and other Western Digital 
software alike, are engineered to work with your Caviar drives. Hence we recommend 
using our Allstar utilities rather than your off the shelf software. 

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7: My drive will not partition when I run Fdisk. It hangs the system 
or it displays the message: "Runtime error." What does this mean?

This is usually caused by corruption or damage to track zero. Use the utility 
Wdclear.exe to format drive. If that does not help, call Western Digital 
Technical support at 1(800) ASK-4-WDC for further instructions. 

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8: I want to add a hard drive to my new system which includes a 
partitioned 2.5GB drive (C and D). When I installed the drive in 
my system my drive letters are changed. The D partition on the 
new drive becomes E. Can I change drive letters or can I install 
without this problem.

Hard drives are BIOS supported. Also, all DOS based operating systems 
(including Windows) assign drive letters to the Primary  DOS partitions first, 
then the Extended and Logical partitions are assigned drive letters. DOS will not 
allow you to change drive letters. The only way to get the drives to read in order 
is to create only Extended with Logical partitions on the slave drive. 

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9: My Caviar drive will work as a slave but not as a master (or vice 
versa). Why?

Check master/slave jumpers. Also, some drive's speed and timing differ drastically 
as to the initial spin up sequence. This might confuse the system where one of the 
drives may not be recognized. The best solution for this situation is to make either 
drive the master or the slave until there is a combination the system will accept. 

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10: I have two Western Digital hard drives on my computer. When I turn on the 
computer, only the first hard drive shows up.  If I soft boot (Ctrl/Alt/Del), 
then both show up.  How do I get both to show up the first time?

If the hard drive boots on a warm boot but not on a cold boot that would imply 
to a BIOS timing problem. The hard drive is accessing its signals too fast for 
the BIOS to recognize it. Check the BIOS setup screen for any of the following 
options and set them as designated:

Quick Power on Self Test ( disable )
Fast Boot Option ( disable )
Hard Disk Initialization time out (set this to 30 )
Above 1 MB or any Ram Count option ( enable )

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11: CMOS, Fdisk and File Manager in Windows report less than 
the capacity of my new drive, but Chkdsk reports the right number 
of bytes. Which is correct?

Setup (CMOS) and FDISK use 1,048,256 bytes per megabyte (sometimes referred to 
as a "binary meg"). Hard disk manufactures and CHKDSK define 1,000,000 bytes to 
be a decimal megabyte. This is why some utilities show 515 MB for a 540 MB
drive and some show the actual number as the table below demonstrates:

Model		Capacity (MB)	CMOS (MB)	CHKDSK (MB)
===========================================================
AC2850		853.6		814.1		853.6
AC21200		1281.9		1222.3		1281.9
AC32100		2111.8		2035.6		2111.8

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12: Can a hard drive and a CD-ROM be installed on the same 
EIDE data cable ? Also will this arrangement degrade the  
performance of the hard drive in any way? 

Yes, a EIDE hard drive and a EIDE CD-ROM can be connected on the same cable. 
The drive should be  jumpered as Master and jumper the CD-ROM as Slave. Installing 
a CD-ROM on the same cable as the hard drive can sometimes cause a reduction of 
performance in the hard drive.

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13: How can I use the full capacity of my Caviar AC2540 drive?

You can use Disk Manager to obtain full capacity if your system does not support 
LBA mode. If your system does support LBA mode, you can enable LBA in your CMOS 
setup utility. 

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14: What are the differences between Western Digitals overlays 1 
and overlay 2 programs? When should each one be used?

Overlay1.exe and overlay2.exe are firmware updates for specific drive model 
numbers.

Overlay1.exe covers the following drive models: 

    AC32500H  CCC:F1
    AC32100H  CCC:F1
    AC31600H  CCC:A1, A2, B0, B1, B2, B3
    AC21600H  CCC:F1
    AC21200H  CCC:E0, E1
    AC21000H  CCC:A1, A2, B0, B1, B2, E0, 

Overlay2.exe covers the following drives models:

    AC11000 
    AC22100
    AC32500
    AC33100

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15: What is EIDE (Enhanced IDE), and what are the current features of EIDE?

Based on extensive experience with IDE, in 1993 Western Digital introduced a 
proposal for a new, but compatible, extension to the standard. Because this 
extension was an enhancement of the existing IDE standard and fully backward 
compatible, it was termed Enhanced IDE (EIDE). The new standard includes an 
expanded drive command and register set. The new command and register set ensures 
that the older systems (without EIDE) will work with the new EIDE drives. When 
systems are upgraded with only a new hard disk drive, they must contend with the 
well-known limitations of the standard IDE connection. These limitations can be 
overcome by upgrading other system components such as the IDE controller and system 
BIOS. Whenever an EIDE hard disk drive is used to upgrade a system it makes sense 
to choose only system components that support EIDE. 

EIDE consists of a more powerful feature set and extension to the existing 
IDE standard: 

Higher capacities for hard disk drives; 

up to 8.4 GB per device 
BIOS translation 
IDE Logical Block Addressing 

Up to 4 devices per system 

including CD-ROM and tape drives 

Faster host data transfer rates 

Mode 3 and Mode 4 PIO (flow control)

Easier set-up and auto-detection of hard disk drive features less expensive and 
more compatible way to connect other peripherals such as CD-ROM and tape drives 
maintain "Plug and Play" compatibility, first achieved by IDE. 

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16: What is the difference between AC 31600 and AC 21600?

The AC 31600 and the AC 21600 are the same as far as performance is concerned. 
The AC 21600 is a newer drive that incorporates the latest drive electronics 
and a higher media density. 

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17: What is the difference between EIDE and Fast-ATA?

Fast-ATA (faster transfer modes, like PIO mode 4) is a subset of Enhanced IDE 
which indicates the ability to run at higher transfer rates. Fast-ATA does not 
include all of the features of EIDE and primarily focuses on faster host data 
transfer rates (which is only one of the Enhanced IDE components). 

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18: I had to use EZ Drive which partitioned the new drive using drive letters 
(D) and (E). My CD ROM used to be assigned a drive letter (D). I changed the 
LASTDRIVE=D to read LASTDRIVE=F in the System.ini file, but the system  still 
does not let me use my CD ROM. What should I do?

Most likely you will have to re install your CD-ROM installation software. Try 
adding a switch at the end of your MSCDEX statement in your Autoexec.bat file. 
/L:x The x represents the drive letter for the CD-ROM.  

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19: What is LBA (Logical Block Addressing)?

LBA (logical block addressing) is an addressing scheme to get past the 528 megabyte 
limit imposed on the current addressing standard of an IDE disk drive. There are other 
addressing schemes in the market seen usually in recent BIOS manufactures extended 
CMOS setup. Examples of others are: 

ECHS (Extended Cylinder, Head, Sector addressing scheme and sometimes seen as just 
"CHS" listed in the CMOS setup) 
Large 
Big IDE 

All of which achieve the same end results as LBA but are not as widely used. 

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20: Is there anything that might cause my hard drive electrical 
problems?

Yes, recently there have been a number of Y power adapters on the market that are 
incorrectly wired. Y power adapters are used to expand a computer systems power 
availability. They consist of a clear plastic plug with 4 metal prongs on one end 
(this end attaches to an existing power connector within your computer) and 2 sets 
of wires leading to 2 plugs with female connections on the other ends (these ends 
are attached to internal devices such as hard drives, CD-ROM drives etc.). The 
problem with some of these newer connectors are that the wires are attached 
incorrectly on one of the female connectors, and using this connector can cause 
severe damage to any device attached to it. 

To check the Y power adapter for incorrect wiring, examine both female connectors. 
Make certain that both of the female connectors are lined up with the 2 chamfered 
(rounded) corners facing up and both of the squared corners facing down. The 4 wires 
attached to the female connectors should now be in the following order from left to 
right:

Yellow (12 V), Black (ground), Black (ground), Red (5 V)

If this order is reversed on one of the connectors, then your Y power adapter is 
faulty and should not be used. Properly manufactured Y power connectors can be 
purchased your local computer dealer or Western Digital Technical Support 
department. 

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21: How come I'm getting "out of disk space" message after 
loading in 800 MB of data on my 1 GB drive?

In DOS, every file that is stored gets at least one allocation unit (called a 
"cluster") no matter what the size of the file is. The size of the cluster grows 
incrementally with the size of the partition. If you have a 1.08 gig partition, 
the cluster size will be 32k. This means that even a 62 byte batch file is going 
to consume 32k of storage space (the difference between the 32k of the cluster 
and the 22 bytes that the file really needs is called "slack space"). The only 
feasible way to reduce the cluster size is to reduce the partition size. The 
break down for DOS 4 and above is as follows: 

Partition Size		Sector per Cluster	Cluster Size
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   0 -   15 MB			8		 4 KB
  16 -  127 MB			4		 2 KB
 128 -  255 MB			8		 4 KB
 256 -  511 MB		       16		 8 KB
 512 - 1023 MB		       32		16 KB
1024 - 2145 MB		       64		32 KB

NOTE: There is no listing for cluster size for partitions greater than 2.1 GB 
since the 2.1 GB partition limit is imposed by the maximum number of clusters 
and the largest cluster size supported by the FAT16 file system. To utilize 
drives larger than 2.1GB under FAT16 file system, you need to create additional 
partitions. 
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