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Name: Yet Another Enhanced IDE/Fast-ATA/ATA-2 FAQ
Version: 1.92
Archive-name: pc-hardware-faq/enhanced-IDE/part1
Posting-Frequency: Monthly (the 24th)
Last-modified: 1998/01/23
URL: http://come.to/eide
Maintained-by: Peter den Haan <pieterh@sci.kun.nl>
The Enhanced IDE/Fast-ATA FAQ
John Wehman (jwehman@got.net) and Peter den Haan
(pieterh@sci.kun.nl)
v1.92, 1998/01/23
This FAQ addresses issues surrounding Enhanced IDE, ATA-2, ATAPI and
Enhanced BIOSes. It includes practical questions, background informa-
tion and lists of net resources.
1. First off...
2. Introduction
2.1. EIDE and Fast-ATA
2.2. IDE and ATA
2.3. ATA-2
2.4. ATA-3
2.5. ATA Packet Interface
2.6. Ultra-ATA
2.7. ATA-4
2.8. The Enhanced BIOS
2.9. The secondary port and beyond
3. General questions
3.1. What are the main features of EIDE and Fast-ATA?
! 3.2. What are the main features of Ultra-ATA?
! 3.3. Are those rumors about buggy interfaces true?
! 3.4. What is a megabyte?
4. Before buying...
4.1. What should I look for in an ATA-2 (Fast-ATA, EIDE) interface?
4.2. Is my BIOS Enhanced? How can I recognize this?
4.3. Is my 50MHz VL bus system compatible with ATA-2 interfaces?
! 4.4. Are old IDE drives compatible with EIDE and U-ATA interfaces?
! 4.5. Can I use EIDE and U-ATA drives with my old (E)IDE interface?
4.6. Will an ATAPI (EIDE) CD-ROM work with an IDE interface?
4.7. Do I need a BIOS update to connect an ATAPI CD-ROM?
4.8. Can large drives be used with my old BIOS?
4.9. I need an Enhanced BIOS to access >504MB. How do I get one?
4.10. Can I use a large harddisk with OSs other than DOS/Windows?
4.11. I heard that Win95 provides support for large IDE disks.
4.12. Can I use more than 2 or 4 hard drives?
4.13. Does <insert operating system> support ATAPI (IDE) CD-ROMs?
4.14. I need a PCI ATA-2 interface that uses only one slot.
4.15. Will adding an Ultra-ATA interface help my drives' performance?
5. Installation
5.1. Which drive/device should be Slave?
5.2. Does it matter how I connect the devices to the cable?
5.3. Does an old HD or CDROM slow down a new drive?
5.4. I need a longer IDE cable; how long can I make it?
5.5. Can I safely move my harddisk between computers?
6. Configuration
6.1. Should I use my interface's device drivers?
6.2. What should I use: Normal, LBA or Large?
6.3. Can I safely change the BIOS' xlation mode (None, LBA, Large)?
6.4. Should I enable EIDE busmastering in my BIOS?
6.5. FDISK sees only 504MB of my disk!
6.6. FDISK will partition only 2GB.
6.7. I have no fancy EBIOS, but I have an 1GB partition and it works.
6.8. I have software to break the 504MB barrier. Should I use it?
6.9. Can I keep my Disk Manager/EZDrive partition with a new BIOS?
6.10. I need to remove Disk Manager/EZDrive.
6.11. I can enable write caching on my harddisk. Should I?
6.12. My drive letters have changed!
7. Performance
7.1. Why isn't my drive as fast as it's advertised to be?
7.2. Why is my new EIDE, U-ATA interface no faster than my old one?
7.3. I benchmarked my drive and it's getting slower!
7.4. A guy on the net has the same drive and he gets 33MB/s!
7.5. Busmastering drivers don't do much...
8. Troubleshooting
8.1. Why do I get NO ROM BASIC, SYSTEM HALTED?
8.2. I have problems with my Award 4.50G BIOS and large drives.
8.3. My 2GB+ drive is not recognized or crashes.
8.4. My 4GB+ drive has problems in MSDOS 6.22 or below.
8.5. Help! I have OnTrack Disk Manager installed and now...
8.6. My mode 3-4-5-6 drive has data corruption problems.
8.7. Are there supposed to be bad sectors on the drive?
8.8. I keep getting CRC errors and serial overruns.
8.9. Can my drive do 32-bit access?
8.10. Help! Windows 3.x 32-bit disk access doesn't work anymore!
8.11. Help! Windows for Workgroups' 32-bit file access fails!
8.12. Help! Win95 indicates my drive uses compatibility mode!
8.13. My partitions become a mess in MS-DOS mode.
8.14. Win95 sees my partitions, but DOS doesn't.
8.15. Win95 keeps losing my second IDE channel!
8.16. The Win95 busmastering drivers won't work.
8.17. My ATAPI (IDE) CD-ROM driver won't recognize the CD-ROM.
9. The user's net.resource guide
9.1. The user's net.resource guide: I/O card drivers
9.2. The user's net.resource guide: hardware manufacturers
9.3. The user's net.resource guide: software and BIOS houses
10. ATA: harddisks
10.1. How does ATA(-2) work?
10.2. What are PIO modes?
10.3. What are DMA modes?
10.4. How are the ATA(-2,PI) I/O ports assigned?
10.5. What does an ATA-2 interface do?
10.6. What is Block mode?
10.7. What is LBA?
10.8. How does security work?
10.9. What is S.M.A.R.T.?
10.10. What is PRML?
10.11. What are MR heads?
11. ATAPI: CD-ROMs and tapes
11.1. How does ATAPI differ from, and coexist with, ATA(-2)?
11.2. What's so special about the secondary port?
12. The EBIOS: translation
12.1. Why translation?
12.2. How does translation work?
12.3. I'd like to know how translation works in detail.
12.4. What is in the Enhanced Disk Parameter Table?
12.5. How many types of translating/Enhanced BIOSes are there?
13. Software details
13.1. Details on OnTrack Disk Manager
13.2. How does Windows' 32-bit disk access work?
14. Hacker's resource guides
14.1. The hacker's documentation guide
14.2. The hacker's net.resource guide
1. First off...
This FAQ is the work of John Wehman (jwehman@got.net) and Peter den
Haan (pieterh@sci.kun.nl). The homepage of the FAQ is
o <http://come.to/eide>
The HTML version should also be online on
o <http://www.wi.leidenuniv.nl/ata/>
and the text version is available by FTP from
o <ftp://ftp.netcom.com/pub/cl/clau/ide_ata/>
o <ftp://ftp.rahul.net/pub/lps/hard-disk/ya-ata.faq>
o <ftp://ftp.wi.leidenuniv.nl/pub/faqs/>
o <ftp://rtfm.mit.edu/pub/usenet/news.answers/pc-hardware-
faq/enhanced-IDE/>
You can also get it by e-mail from pieterh@sci.kun.nl by sending a
message with "EIDE FAQ text" in the Subject: header. The body of
the message will be ignored. You can replace "text" by "PostScript"
or "html" if you want something more fancy than plain text.
Anything else will probably break the mail server and cause it to
send you an uuencoded coredump :-)
DISCLAIMER.
The information in this FAQ comes without any warranty. The
authors or distributor will not accept responsibility for any
damage incurred directly or indirectly through use of the
information contained in this FAQ.
COPYRIGHT.
This document is copyright (c) John Wehman and Peter den Haan.
You are free to distribute it by electronic means and make as
many copies as you want on electronic or magnetic media, convert
it to a different format, and embed control sequences, as long
as the text of this document remains unmodified, with copyright
notices intact. Splitting up this document is allowed on the
condition that the resultant parts are presented as a
recognizable whole that makes up the full, unmodified text. You
are allowed to make paper copies of this document for personal
use; however, distribution of printed copies for profit is
prohibited without the authors' prior permission.
THANKS.
To everyone on comp.sys.ibm.pc.hardware.storage for
encouragement and feedback, especially those who took the time
to communicate their comments in some detail. To Hale Landis
without whom the FAQ would have been considerably less accurate
on a number of key points; to Stephanie Brady from OnTrack for
extensive Disk Manager related information; to Aron Eisenpress
for critically reading the FAQ time and again; and many, many
others.
TODO.
o Drop the definition of megabyte as 1048576 bytes, which is
nonstandard in this context, and use 1000000 byte MBs instead.
o Reorganize the FAQ, with a complete overhaul of the text.
o Write howto type documents walking through specific tasks.
o Tweak the HTML output more. Perhaps find another translator.
NOTE.
The text, PostScript and HTML versions of the FAQ are all
produced from a common linuxdoc-SGML source. This solution is
not perfect and all versions do contain some infelicities.
Apologies. Suggestions for improvement are most welcome, as are
complimentary copies of more professional multi-format authoring
tools.
2. Introduction
The aim of this introduction is to make you familiar with the most
important buzzwords used in this FAQ and to provide a concise overview
of the issues involved. To get the most out of the information in the
FAQ proper, start here.
2.1. EIDE and Fast-ATA
! The IDE field has seen a great number of changes since a few years
! ago. These novelties are commonly known under the names Enhanced IDE
! (EIDE) and Ultra-ATA. EIDE has caused a lot of confusion since it is
! merely a marketing program from Western Digital which, in turn, builds
! on a couple of real standards: ATA-2 and ATAPI. Fast-ATA, launched by
Seagate and endorsed by Quantum in response to WD's marketing is
! similar. It builds on ATA-2 only. Ultra-ATA is a widely supported
! extension of ATA-2 (and ATA-3) adding high speed DMA modes.
2.2. IDE and ATA
IDE (Integrated Drive Electronics--or numerous other interpretations)
and ATA (AT Attachment) are one and the same thing: a disk drive
implementation designed to integrate the controller onto the drive
itself, thereby reducing interface costs, and making firmware
implementations easier. This low cost/easy integration created a boom
in the disk drive industry, as PC integrators readily ate up the low-
cost alternative. Since the late 80's, ATA (as it is properly called)
has become the drive of choice for the cost inhibited buyer.
2.3. ATA-2
When it became clear that improvements in harddrive technology and the
increasing demands made by software would eventually strain the
capacity of the ATA interface, the drive industry, in the form of the
Small Form Factor (SFF) Committee, created a compatible extension of
ATA called ATA-2. This standard not only adds faster PIO modes and DMA
modes, but also improves upon Plug'n'Play and compatibility with
future revisions of the standard.
While there is also a new way of addressing sectors on the harddisk
(LBA), this is merely a simplification. Contrary to common myth LBA
proper has nothing to do with breaking the famous 504MB (528 million
bytes) barrier. In fact, even in the old ATA/IDE standard the capacity
limit is well over 100GB.
2.4. ATA-3
The latest revision of the standard is ATA-3. Key features include:
improved reliability, especially of PIO mode 4; a simple password-
based security scheme; more sophisticated power management; and Self
Monitoring Analysis and Report Technology (S.M.A.R.T.), allowing the
drive to warn you about certain types of impending failure.
ATA-3 does not define any faster modes. Even though some manufacturers
! were once marketing "mode 5" equipment, there will never be a PIO mode
! beyond ATA-2 PIO mode 4.
2.5. ATA Packet Interface
One of the disadvantages of ATA is that it was designed for harddisks
only. That was fine back when a high end PC shipped with just a floppy
drive and a 40MB harddisk, but today CD-ROM and tape drives are
commonplace devices that should preferably run off a single low-cost
interface. The ATA Packet Interface (ATAPI) is a standard designed for
devices such as CD-ROMs and tape drives that plug into an ordinary ATA
(IDE) port.
The principal advantage of ATAPI hardware is that it's cheap and works
on on every PC with an IDE or 'EIDE' adapter. ATAPI tape drives can
enjoy superior performance and reliability compared to the popular
QIC117 'floppy' tape devices.
Beware that although ATAPI devices plug into the IDE interface, they
differ considerably from an IDE harddisk. Caching controllers and
other intelligent interfaces will not work unless they're ATAPI aware.
Booting from an ATAPI CD-ROM is only possible with the latest BIOSes.
2.6. Ultra-ATA
Ultra-ATA is somewhat similar to Ultra-SCSI in the sense that it
! bridges the gap between the current standard (ATA-3) and ATA-4, which
! isn't quite finished yet. Ultra-ATA adds a new, high performance mode:
! DMA/33 with 33MB/s bandwidth, twice that of DMA mode 2. It is
! supported by Intel's Pentium II chipset, the TX Pentium chipset, the
! latest Intel competitors and a few add-on (PCI) cards.
2.7. ATA-4
Work on the next standard, predictably called ATA-4, has already
started. First and foremost it is a much-needed attempt to merge ATA-3
and ATAPI into one. Faster transfer modes are also on the agenda, of
course: it will incorporate Ultra-ATA's DMA/33, at least.
Regarding other features, the future for strong command overlap looks
rather bleak: the current proposal is a hideous animal and important
players like Microsoft do not plan on supporting it in its present
form. More limited forms of overlap stand a somewhat better chance of
surviving.
2.8. The Enhanced BIOS
A rather different issue was the 504MB (or, equivalently, 528 million
bytes) capacity limit that becomes apparent when accessing IDE drives
through the BIOS. It is caused by the disk geometry (cylinders, heads,
sectors) supported by the combination of an IDE drive and the BIOS'
software interface ('int13'). Both IDE/ATA and the BIOS are capable
of supporting huge disks, but their combined limitations conspire to
restrict the useful capacity of the drive to 504MB. Since only MSDOS
still uses the BIOS for harddisk access, this is sometimes erroneously
thought to be an MSDOS limitation; other operating systems experience
the same restrictions at boot time though.
An Enhanced BIOS works around this problem by representing the drive
to the software using a different geometry than the native geometry of
the drive itself. This juggling act is called 'translation'. For
example, if your drive has 1500 cylinders and 16 heads, a translating
BIOS will make software programs think that the drive has 750
cylinders and 32 heads.
You do not need an "EIDE" adapter to use harddisks greater than 504MB.
The de facto standard is described in the Microsoft/IBM "INT 13
Extensions" document. Phoenix has presented a superset in their
"Phoenix Enhanced BIOS" specification. Phoenix, AMI, Award and MR
BIOSes are based on the Microsoft/IBM specification.
2.9. The secondary port and beyond
Last but not least, the usual limit of two devices was far too
restrictive if CD-ROMs and tape drives were to be connected to the IDE
interface in addition to the harddisk(s). Fortunately the solution was
already known in the form of a so-called secondary harddisk interface.
The possibility of such an interface has been there for a long time,
but support was lacking.
There is nothing special about a secondary channel; it is an ordinary
(E)IDE port that uses a different interrupt and I/O addresses to avoid
clashes with the ordinary (primary) one. A secondary interface allows
you to connect another ribbon cable with two more ATA devices
(harddisk, ATAPI CD-ROM or ATAPI tape). Today, many interfaces
combine both primary and secondary port on a single board to make a
dual-ported interface that handles up to four devices.
To use harddisks on the secondary port with DOS and Windows 3.x, you
will need BIOS (either system BIOS or adapter BIOS) or driver support.
You can recognize a BIOS with four drive support by the fact that it
allows for four sets of drive parameter in the BIOS setup.
There are two further (semi-)standard channels beyond the secondary
port: the tertiary and quaternary ones. Some soundcard IDE interfaces
can be configured as tertiary or quaternary. See section 10.4 for the
I/O and IRQ assignments. Software support for these is still rare.
3. General questions
3.1. What are the main features of EIDE and Fast-ATA?
The fast transfer modes (PIO modes 3 and 4, multiword DMA modes 1 and
2) are the cornerstones of Fast-ATA and EIDE. These are marketing
terms contrived by disk drive manufacturers. Enhanced IDE is a
Western Digital trademark; Fast-ATA is a term coined by Seagate, and
endorsed by Seagate and Quantum.
EIDE consists of:
o Fast transfer modes: PIO mode 3 or better, multiword DMA mode 1 or
better,
o LBA mode (explained in section 10.7),
o Four devices on the ATA interface: secondary port,
o No 504MB limit with DOS: WD Enhanced BIOS,
o tape backup and CD-ROM devices on the ATA interface: ATAPI.
Fast-ATA and Fast-ATA-2 embrace:
o PIO mode 3 (and 4 for Fast-ATA-2), multiword DMA mode 1 (and 2 for
Fast-ATA-2),
o Read/Write multiple commands (also known as block mode; see Q10.6),
o LBA mode.
The difference between the two schemes is mainly in the scope of EIDE.
Hardware can be tagged 'EIDE' even if only part of the EIDE feature
set has been implemented, which can lead to some confusion. This FAQ
will avoid the term EIDE whenever possible, discussing its component
parts (ATA-2, ATAPI, etc) instead. This allows you to see exactly what
'EIDE' features you need in your specific situation.
! 3.2. What are the main features of Ultra-ATA?
!
! To everything EIDE has on offer, Ultra-ATA adds the following:
!
! o Even faster transfer modes, most importantly DMA/33 with double the
! bandwidth of DMA mode 2 and PIO mode 4. There are no new PIO modes.
!
! o Improved reliability using DMA/16 and DMA/33. A checksum is added
! to the data sent over the ATA interface. That way, data corruption
! can be detected and the data retransmitted. On an ordinary EIDE
! interface you wouldn't notice the corruption until it was too late.
!
! Ultra-ATA was first proposed by Quantum and is widely accepted now.
!
!
! 3.3. Are those rumors about buggy interfaces true?
Very true, unfortunately.
This FAQ doesn't really deal with specific interfaces, but two very
popular interface chips have been shown to contain bugs too serious to
ignore:
o the CMD640x, a dual-channel PCI to EIDE interface used on many
mainboards (Intel!) and interface boards, has a number of dangerous
bugs you need to be aware of.
o The PC-Tech RZ-1000, used on AT&T, Dell, Gateway and Intel boards,
also has two data-corrupting bugs. See also
<http://www.intel.com/procs/support/rz1000/index.htm>.
In both cases, the corruption occurs only in specific software
environments and is very subtle; you can go on working for months
without suspecting anything more than buggy software. The damage can
be immense. For all the details, look at Roedy Green's (roedy@bix.com)
"PCI EIDE controller flaws" FAQ included with his EIDE test
<ftp://garbo.uwasa.fi/pc/diskutil/eidete19.zip> program which will
test your system for the bugs.
BE WARNED that you're playing Russian roulette with your data if you
continue working on an affected machine without taking notice of this
problem.
3.4. What is a megabyte?
The word "mega" is an ISO prefix designating a factor 1,000,000. A
proper megabyte is 1,000,000 bytes. Because computers use binary
technology and like working with powers of two, 2^20 bytes, that is
1048576 bytes, is also usually referred to as a megabyte.
Which of the two types of megabyte you're dealing with depends on the
context. For storage devices, a megabyte usually means 1,000,000
bytes. Some software uses "binary" megabytes, though, and will show a
smaller capacity than the drive label says! This includes most BIOSes.
This FAQ uses megabytes of 1048576 bytes throughout.
4. Before buying...
4.1. What should I look for in an ATA-2 (Fast-ATA, EIDE) interface?
There are a number of 'EIDE' features which can be desirable in a new
interface. Some features, however, may already be present on your
system or be unimportant to you.
!
! o The least a modern interface should provide is PIO mode 3 transfers
(up to 11.1MB/s) for drives that support it. It should also be able
to use slower PIO modes (0, 1 and 2) to ensure compatibility with
! older drives.
!
! o True direct memory access (DMA) is found mostly on interfaces
! integrated into mainboards, Intel 430*X based boards being the most
! common example. This will improve system performance in
! multitasking operating systems. Ultra-ATA will give you DMA/33,
! which actually isn't all that much faster but a lot safer for your
! data.
o Since ATAPI CD-ROMs have rapidly become very popular in the low-end
market, and ATAPI tapestreamers are similarly taking off, a
secondary port allowing you to connect a total of four ATA* devices
is hardly a luxury. Note that a few modern soundcards provide a
secondary or tertiary ATA/IDE interface instead of the traditional
proprietary CD-ROM connectors. Beware of conflicts in combination
with a dual-ported interface.
If you intend to connect harddisks to the second port and use them
with DOS or Windows 3.x, remember that many older BIOSes have no
support for the secondary channel and many interfaces do not ship
with the required drivers.
o You will want an on-card Enhanced BIOS too if your mainboard BIOS
doesn't support translation or if its support is buggy or outdated.
The interface BIOS will override the mainboard BIOS' harddisk
routines.
A BIOS ROM will, just like a mainboard with integrated EIDE, often
have the added advantage that you don't need separate DOS drivers.
The BIOS on an interface will occupy 8 to 16k of UMB space, though,
and you will still want drivers for every other operating system
you use.
o Drivers! Without well-designed drivers most interfaces could as
well be old-fashioned ISA cards for all the good they'll do. Even
if the card has a BIOS, which usually removes the need for a driver
under DOS, you will still need drivers for other operating systems,
! including Windows and Win95. Newer versions of Windows (Win95 OEM2
! and beyond) ship with a large amount of drivers.
! Note that some 'EIDE' interfaces which used to be popular were
! slightly to very buggy. This ranged from minor problems with ATA-2
! compliance to obscure things like the use of a single buffer for both
! primary and secondary channel or a badly designed prefetch buffer,
! both of which may cause data corruption under very specific
! circumstances.
4.2. Is my BIOS Enhanced? How can I recognize this?
Good question.
Unfortunately, I know no easy answer. The mere ability to specify more
than 1,024 cylinders in the BIOS setup is not conclusive. In your BIOS
setup, drive related settings like "LBA", "ECHS" or even something
silly like "Large" are telltale signs of a BIOS with translation
support, which should be good for disk capacities of up to 8GB. A
copyright before 1994, on the other hand, reduces your chances to
something close to zero :-(
o For AMI, I only have reliable information on their HiFlex BIOS; it
can be recognized by its characteristically funky orange and green
color scheme. There at least two other types: WinBIOS with a
Windows like interface, and a custom BIOS used with Intel Pentium
boards. Both may translation even if they have a (much) earlier
copyright. I have no further information on those.
AMI HiFlex BIOSes dated 7-25-94 and later and support translation.
The date is embedded in the long number displayed at the bottom of
the screen on bootup; it must be 072594 or later to support LBA.
40-0100-00101111-111192-486-ABC-F (111192 will not support LBA)
50-0100-001292-00101111-072594-ABCDEF-F (072594 will support LBA)
o Award seems to call all its BIOSes 4.50G :-) Some have translation
support, some don't, some have buggy support (see 8.2). With a BIOS
dated 12/31/1994 or later you have full translation support, with
one dated earlier (7/29/1994, perhaps earlier than that as well)
buggy support only.
o Phoenix BIOS v4.03 and later are reported to support translation.
Some revisions of Phoenix v4.03 may not support it, though,
depending on the computer or system board manufacturer.
o MR BIOS incorporated CHS translation--roughly the same as today's
Large mode--as early as 1990!
Note that only BIOSes fully implementing the IBM/Microsoft/Phoenix
standards will allow access to disks larger than 8GB. Fortunately,
these are becoming more and more common these days. We are not aware
of utilities that will detect the presence of such a BIOS.
Western Digital has a utility available by ftp that examines the
Enhanced Disk Parameter Table (EDPT), if present. If it finds one on
your system, your BIOS has all the bells and whistles to go up to 8GB
<ftp://ftp.wdc.com/drivers/hdutil/chkbios.exe>. Beware that BIOSes
conforming to the WD Enhanced BIOS specification won't build an EDPT
unless LBA is enabled. Beware also that with a WD EBIOS it is highly
unsafe to enable LBA on a disk that already contains data. This is due
to a flaw in the specification.
4.3. Is my 50MHz VL bus system compatible with ATA-2 interfaces?
It should be, but there are problematic cases.
It has been observed that some controllers will base their I/O cycle
times on the bus clock of the computer. This means that with a 50MHz
bus, the cycle time will be faster than with a 33MHz bus. This could
lead to undesirable results if these cycle times are faster than the
drive can handle. Make sure your controller supports multiple bus
speeds in the software setup, and if necessary program it correctly.
4.4. Are old IDE drives compatible with EIDE and U-ATA interfaces?
This should work fine.
Older drives do not support the high-speed advanced transfer modes
! defined by ATA-2 and, later, Ultra-ATA. To retain compatibility with
! these drives, ATA-2 and Ultra-ATA interfaces have programmable timing.
! The driver or BIOS queries the drive regarding its maximum transfer
! rate and will configure the interface to match. A few interfaces are
! jumper configurable in which case the responsibility is yours.
If you intend to put an older drive on the same cable as an ATA-2
drive, you may want to verify that your interface is capable of using
independent timing for master and slave device. Otherwise, your old
drive might end up slowing down your newer one because the controller
! is forced to use the lowest common speed. Modern interfaces like the
! Intel PIIX3 (430HX and VX and 440FX chipset), PIIX4 (430TX chipset)
! and, to a lesser extent PIIX (430FX chipset) don't suffer from this
! problem.
4.5. Can I use EIDE and U-ATA drives with my old (E)IDE interface?
Fast-ATA and EIDE devices can be used without fear on regular ISA or
VLB IDE controllers. The thing about advanced modes is that the drive
is ready for the data in the fastest mode; the slower the controller,
the easier it is on the drive. Of course you should expect the
transfer rates to come out lower than on a full ATA-2 interface.
! Likewise, an Ultra-ATA drive will do fine on an ATA-2 (EIDE)
! interface. Better even, using DMA mode 2, its performance will be
! hardly any slower than it would be on an Ultra-ATA interface.
!
It is not necessary to use an EIDE interface for harddisks of over
504MB. An Enhanced BIOS is all you need for DOS and Windows; for many
other operating systems such as OS/2 or Linux you won't need even
that.
4.6. Will an ATAPI (EIDE) CD-ROM work with an IDE interface?
Yes. These devices were designed to be compatible with ATA (IDE) from
the very start, and should work fine.
4.7. Do I need a BIOS update to connect an ATAPI CD-ROM?
No. These CD-ROMs ship with a driver that provides complete support.
The BIOS doesn't need to support them and usually doesn't even know
they're there. Some modern BIOSes are ATAPI aware and have a special
setting; barring those, you can generally leave the corresponding
harddisk entry at 'Not Installed'.
4.8. Can large drives be used with my old BIOS?
Yes, in principle, but there's still the small matter of the 504MB
barrier. If the new drive exceeds this capacity, you must have an
Enhanced BIOS in order to use more than 504MB with DOS, Windows or
Win95 (see Q4.10 for other operating systems). It is important to note
that this is a software only issue: you do not need a special
interface to support large drives.
BE WARNED that some older BIOSes will incorrectly handle drives with
more than 1024 cylinders. Instead of truncating the number of
cylinders to 1024, they use the cylinder count modulo 1024, which
means that a 2300 cylinder drive will appear to have just 252
cylinders. The solution is to specify 1024 cylinders in the BIOS
setup.
This becomes a real problem when a BIOS with this error also won't
allow you to enter the drive parameters manually. Among IBM systems,
the 1991-vintage PS/2 models 35sx and 40sx, the ValuePoint I, and at
least some of the ValuePoint Si models have this flaw. With these
machines, you should either try go get a BIOS upgrade from
<ftp://ftp.pcco.ibm.com> if you have a flash BIOS, or verify that the
drive you intend to use has a way to fake having no more than 1024
cylinders (Western Digital has a utility for their 540MB drive, and
many Maxtor drives have a jumper). The Promise EIDEMax is also
reported to work, and will allow you to use drives of up to 8GB in
full. Note that some operating systems, such as Linux and OS/2, allow
you to override the BIOS' drive geometry information, which may also
help addressing this problem. Another option is using OnTrack Disk
Manager version 7.
4.9. I need an Enhanced BIOS to access >504MB. How do I get one?
The options are: a new mainboard BIOS, add-on BIOS, or software.
o To upgrade your mainboard BIOS, either with a newer version of your
current BIOS or using a custom made BIOS from firms such as Microid
Research (MR BIOS), is probably the best option. It may or may not
be more effective to replace the entire mainboard and get all the
latest bells and whistles for $100 more.
o The next option is to purchase a card with an add-on BIOS that
effectively replaces the harddisk portion of your mainboard BIOS.
An example is LBA Pro from Storage Technologies, sold in the USA by
Unicore software, or AMI's AMIDisk Extender. DataTechnology (DTC)
also sell such a card.
o Most BIOSes on ATA-2 interfaces, if they have a BIOS at all, also
do this. That may be a nice way to go if your present interface
isn't up to snuff. For the ISA bus, there are a few "EIDE"
interfaces that have a BIOS: examples are the Promise EIDEMax and
the SIIG IDE Enhancer.
Either way, you will have to repartition and reformat the (large)
harddisk.
o A final option is to use a software solution, like Disk Manager or
EZDrive. Software is often supplied free with the drive and
relatively easy to install, but has inherent drawbacks. See also
Q6.8.
4.10. Can I use a large harddisk with OSs other than DOS/Windows?
Using a large harddisk is usually no big problem, even if you don't
have an Enhanced BIOS. However, some OSs don't understand translation,
which makes the combination with DOS, Windows and Win95 problematic.
With operating systems such as NetWare, Unix, Win/NT and OS/2, the
only thing you need to use large ATA disks is a BIOS that allows more
than 1024 cylinders in the drive type setup. There is one caveat
though: the BIOS is still used to boot the operating system, so you
will have to ensure that everything necessary to get the OS running in
the first place resides below cylinder 1024. Remember that if you have
an Enhanced BIOS, drives up to 8GB will appear to have no more than
1024 cylinders, so in those cases these boot restrictions are removed.
Once running, these operating systems use their own software to
control the disks (Win95 also does this, but has a special position;
see below). That way, they are not subject to the BIOS' restrictions
such as the capacity limit. Unfortunately, this also means that if
you have a translating EBIOS or software driver, the OS has to be
aware of the translation scheme used, or conflicts will arise between
the operating system and DOS/Win/Win95. If you can set up partitions
so that all DOS and boot partitions reside below the first 1024
cylinders (504MB), you can avoid translation altogether and all the
hassles with it.
Older operating systems don't understand translation at all. Newer
ones (OS/2 3.x, Linux 1.2 or better, Win95, SCO 5.0.x) will handle
standard translation schemes out of the box, but not always those
employed by some software drivers (EZDrive, Disk Manager v6.x or
older). In the case of DM 6, fixes or updates are available for some
operating systems (see above).
Novell has a NetWare driver IDE.DSK version 3.0 dated September 2,
1994. This version of the driver uses the Identify Device ATA command
to get the drive parameters and ignores the BIOS parameters. This
means that Novell now works with big IDE drives.
A final remark: OS/2 enforces DOS compatibility for FAT partitions.
That means that without an Enhanced BIOS, only HPFS partitions can
extend beyond cylinder 1024.
4.11. I heard that Win95 provides support for large IDE disks.
True, but it doesn't necessarily mean you can actually benefit from
that support in all cases.
Despite a large number of significant changes, in its way of handling
harddisks Win95 largely resembles Windows for Workgroups. Just like
OS/2, Linux and other operating systems, Win95 uses 32-bit protected
mode drivers for the harddisks (unless it's using compatibility mode),
and is happy to handle harddrives of respectable size: well over
100GB. However, unlike OS/2 and Linux, and like Windows for
Workgroups, Win95 boots from the same old DOS we all love to hate.
Even once Win95 has booted, DOS hasn't gone. Win95 always keeps it
behind the scenes and uses it to run devices in compatibility mode. In
'safe mode', important for troubleshooting, Win95 completely relies on
DOS.
What all of this implies is that even though Win95's protected-mode
disk driver may support gargantuan drives, it will never change the
setup it inherits from DOS in order to retain compatibility with the
latter. If you can only get at the first 504MB of your drive in DOS,
it will be the same in Win95. You will still need one of the usual >
504MB solutions mentioned elsewhere in this FAQ. For details, see also
Microsoft KnowledgeBase article Q126855, "Windows 95 Support for Large
IDE Hard Disks".
4.12. Can I use more than 2 or 4 hard drives?
For DOS and Windows you probably want BIOS support for all your
harddisks. Older BIOSes support drives on the primary channel only,
just two; newer ones add support for the secondary channel for a total
of four. Few BIOSes support more than that; MR BIOS is an exception.
If the BIOS supports just two drives and you want more, there's a
software solution available: 3drives (see the net.resource guide).
Some interface cards also ship with the necessary support. Creative
Labs has drivers for CD-ROMs on the tertiary and quaternary port.
Other operating systems such as Win95 and OS/2 support both primary
and secondary interface without aid from the BIOS. Linux will support
a nearly arbitrary number of interfaces; you'll have to pass kernel
parameters to specify the ones beyond the first two.
4.13. Does <insert operating system> support ATAPI (IDE) CD-ROMs?
The current versions of most operating systems support ATAPI CD-ROMs.
That includes OS/2 3.0, Linux 1.2 and above, and Win95.
Unfortunately, hardware manufacturers have started designing these CD-
ROM units while the ATAPI standard was still evolving, so there are
now a couple of versions implemented in the real world. Moreover, the
complexity and novelty of ATAPI means that there are some variations
even among implementations of the same revision. Writing an OS ATAPI
driver that works with all CD-ROMs, therefore, is a daunting task and
not all have succeeded equally well. So although these OSs all support
ATAPI, they do not work with all ATAPI equipment.
See Microsoft KnowledgeBase Q131499, "CD-ROM Drives Requiring Real-
Mode Drivers", for more details on Win95 support. For OS/2, take a
look at <http://www.austin.ibm.com/pspinfo/os2hw.html>; for updated
drivers use the latest install disk upgrade or
<ftp://ftp.pc.ibm.com/pub/os2_drivers/atapi.zip>.
4.14. I need a PCI ATA-2 interface that uses only one slot.
There is a problem with PCI and multi-I/O or dual-ported IDE
interfaces. Such interfaces need two or more predetermined interrupts
which cannot be shared with other PCI devices, which is probably
impossible with your PCI slots. The usual workaround consists of
either integration of I/O functions on the mainboard, or the use of a
tiny 'paddle' board that plugs into an ISA slot.
This is not so much a weakness in the design of PCI, but a conflict
between PCI's plug'n'play philosophy and the requirement that these
interfaces be fully compatible with oldfashioned I/O cards.
Some vendors use PCI interfaces that rely on a proprietary extension
of the PCI bus. This is obviously not portable; you often can't even
move the card to a different slot in the same machine. Moreover, such
extensions may cause compatibility problems since they use PCI signals
reserved for other purposes.
4.15. Will adding an Ultra-ATA interface help my drives' performance?
A new interface may or may not help; it is possible to make a rough
prediction if a better interface would really speed things up.
Hardware vendors and marketing people would love to see everyone rush
! out and buy the latest generation of 'Ultra-ATA' adapters. To achieve
! this noble goal they tend to juggle with too-good-to-be-true
! performance figures. The relation between this advertising hype and
! the real world is shaky at best.
The main point to remember is: a slow drive is a slow drive no matter
how good the interface is. If the speed at which the drive physically
transfers the data to/from the media is the limiting factor in
performance, and it often is, the only way to make things go
significantly faster is to purchase a better drive. Note that the
! transfer modes supported by modern drives (those 33MB/s figures) have
! little to do with their real-world performance.
! In addition, an 'ordinary' ATA-2 (EIDE) interface already offers
! respectable bandwidth---the fastest ATA-2 transfer mode is
! theoretically 16.6MB/s, which is more than any Ultra-ATA drive on the
! market today can sustain. In addition it usually supports the CPU-
! cycle-saving DMA modes. An IDE interface, on the other hand, makes a
! much better candidate for replacement since it rarely has a bandwidth
! over 2.5MB/s, which is cramped by today's standards, and doesn't
! support DMA.
How to determine if the drive is the bottleneck? You can get a rough
idea using Coretest version 3 <ftp://ftp.rahul.net/pub/lps/hard-
disk/core303.exe>. This version of Coretest gives two performance
figures of interest here: the (B)uffered transfer rate which is an
indication of the bandwidth between drive and interface, and the
(S)ustained rate which is related to the speed of the drive media. If
your drive has a small buffer cache, you may have to use the /B16
option to get the correct buffered transfer rate.
Usually you'll find that the first figure exceeds the second by a
considerable margin (say, a factor two or more). This means that the
physical properties of the drive itself are the bottleneck, and
improving the interface speed any further won't help much. The only
thing that may improve performance somewhat is using block mode (using
either a BIOS option or a driver). Only if the drive throughput
starts to approach the interface bandwidth will you have a fair chance
that a new interface will have a large impact on performance, provided
the drive supports faster modes than the one currently used.
This is not an endorsement of Coretest as a disk benchmark; there are
more reliable ones around, such as QBench
<ftp://ftp.rahul.net/pub/lps/hard-disk/qbench.zip>.
Be sure to read question 7.2 to get a more complete picture.
5. Installation
5.1. Which drive/device should be Slave?
o A single device on a cable, either a harddisk (ATA) or CD-ROM
(ATAPI), should according to the specs never be configured as
slave. However, as any ATAPI CD-ROMs come preconfigured as slave,
most software works with a masterless slave CD-ROM simply because
it saves tech support calls. Moreover some BIOSes have trouble with
an ATAPI device jumpered as master. Formally it isn't a valid
configuration though; remember this if you have trouble getting the
CD-ROM recognized.
o Two harddrives on one channel should be configured as master and
slave, respectively. It usually doesn't matter which is which, but
older harddisks may not work in all configurations if they predate
the standardization of the master/slave protocol. In that case a
degree of experimentation will be necessary. Some Conner drives
have an ATA/ISA jumper: ATA is the now-standard protocol, ISA is
used by older Conners.
o Two ATAPI devices such as CD-ROMs and tapes should work fine as
long as one device is master and the other slave, just like
harddrives.
o If you need to put a harddisk and an ATAPI device on the same
cable, the spec says the harddisk must be the master. Although the
reverse will usually work as well in practice, still you'd better
avoid the configuration.
5.2. Does it matter how I connect the devices to the cable?
Not much. If you have only one drive on the cable, it is best to put
it at the very end, especially when you're using any of the faster
modes. For two devices, it doesn't matter where you put the master and
the slave, or which end of the cable you plug into the controller.
Just take care that you plug them in the right way: the red wire is
supposed to correspond to pin 1.
When Plug'n'Play ATA arrives the Cable Select (CS) setting will be
used, and all of this will change. Some name brand machines may
already employ a similar setup.
5.3. Does an old HD or CDROM slow down a new drive?
This is not necessarily the case. Still, it is generally preferable to
connect older drives and CD-ROMs to the secondary channel.
If this is not feasible, or if you're wondering if you should upgrade,
a few points.
o The speed loss usually referred to is in the interface timing, i.e.
the speed at which the devices communicate with the computer. This
does not necessarily translate into a real world performance
penalty.
! o This is mostly an issue with older ATA-2 (EIDE) interfaces and some
! VL IDE ones. If you have an ordinary ISA IDE interface, it can't
! get any slower.
! o All modern interfaces support distinct timing for master and slave.
! With these, the slow device does not directly affect the fast one.
! o Many CD-ROMs support at least PIO mode 3. This is enough to operate
! most harddisks on the market today near their maximum speed.
You can use Coretest <ftp://ftp.rahul.net/pub/lps/hard-
disk/core303.exe> to determine if and how performance is affected;
see Q4.15 for a recipe.
OS/2 and Unix users have another reason to put slow ATA devices such
as tapes and CD-ROMs on a channel of their own. As long as one unit on
a given channel is executing a command, the other is inaccessible. A
CD-ROM can easily occupy the channel for 300ms that way.
5.4. I need a longer IDE cable; how long can I make it?
Less than 18 inches. In some cases, the limit is no more than 7
inches.
The cable is a pretty weak link in the whole ATA-2 interface. For the
fast transfer speeds used in 'EIDE' systems, there aren't enough
ground signals; the cable is unterminated and unshielded. Noise is a
! real problem. All of this applies to ATA-2 (EIDE) systems more than
! Ultra-ATA systems, since the latter use checksums to ensure data
! integrity.
!
! For those reasons, you should take the 18" limit specified by the
! ATA(-2) standard pretty seriously if you want to avoid data corruption
! and system hangs. Even worse, some dual-channel 'EIDE' interfaces
! such as CMD640x based ones have a peculiar design employing only a
! single buffer for both cables. Most signals on the two cables are
! directly connected with each other: this means that electrically, the
! cable lengths add up. Take into account that the copper traces on the
! circuit board are often a couple of inches long as well and you're
! facing a maximum cable length of roughly 7" per cable if you want to
! remain within spec.
If you have difficulties fitting everything in with a standard length
cable, consider adding a new plug to it or rolling a complete cable
yourself. It's not hard to do, or to track down a friend willing to do
it, and you can buy the parts in all electronic parts stores. Do use
quality parts, work carefully, and watch that length.
Disregard the above at your own peril. Noise induced problems usually
pop up sporadically, can be very hard to detect and even harder to
track down. Not least because they may appear completely unrelated and
involve devices other than the harddisk.
5.5. Can I safely move my harddisk between computers?
Transferring a partitioned and formatted harddisk between computers is
potentially dangerous if they use different translation schemes (see Q
6.3). This includes moving a disk from an old computer that doesn't
support translation to a new one that does. This is really a little
known issue. Usually everything goes smoothly, but you would not be
the first to be caught by surprise.
WARNING. Do not assume it won't happen to you just because it works
out fine most of the time---it has destroyed data, and will do so
again.
6. Configuration
6.1. Should I use my interface's device drivers?
Yes. Often these drivers are essential to get any kind of performance
out of your interface.
The PIO or DMA mode used when transferring data is determined by the
interface card. Some cards have jumpers that determine the speed in
hardware; these work in the fast mode from the microsecond you switch
on the computer.
Most interfaces, however, are software configurable. At bootup, they
default to the slowest possible speed. Somewhere during the boot
process, a piece of software belonging to your adapter figures out
what kind of transfer rates the drives support and configures the
controller chip to match. There are a couple of cases to distinguish:
o Onboard I/O with full BIOS support. The controller is fully
configured when your computer boots. You can usually set the
desired mode for each harddisk in the CMOS setup. Many modern
boards fall in this category.
o Onboard I/O with incomplete BIOS support. For some unfathomable
reason, some mainboards do not support or only imperfectly set up
their integrated I/O ports. In that case, you'll have to use DOS
or other drivers to get full functionality.
o Interface card with BIOS. This is similar to the two categories
above. The main difference is that these cards don't necessarily
have setup screens; in that case, they must use other means to
determine the transfer mode to be used. For example, the Promise
2300+ uses a combination of jumpers and a table in ROM containing
the parameters for a number of different drives. It may or may not
be necessary to use drivers for best performance.
o Interface card without BIOS. Since there is no way the mainboard
BIOS can know how to set up all those different interface cards out
there, you must use the supplied device drivers to profit from the
fast modes. That is, unless your card is hardware configurable
using jumpers, which is quite rare.
Usually, there are drivers for other operating systems as well, such
as Windows, Win95, OS/2 and so forth. These serve a couple of
purposes.
o The driver may be necessary to configure the adapter as described
above. This doesn't apply to Windows, where the DOS device driver
usually has already done that job.
o The standard drivers built into operating systems don't support all
of the advanced features of your interface and drives. Examples are
32-bit transfers, block mode and DMA.
o Windows only: the standard driver (*wdctrl) that ships with Windows
and Windows for Workgroups has some serious restrictions. See Q8.10
for details.
In view of this it is rather unfortunate that so often, the drivers
supplied with an interface are of mediocre quality.
6.2. What should I use: Normal, LBA or Large?
The difference between the three is this.
o 'Normal' causes the BIOS to behave like an old fashioned one
without translation. Use this if your drive doesn't need it (ie.
has fewer than 1024 cylinders) or if you want to use the drive with
an operating system that doesn't understand about translation.
o 'Large' or ECHS or XCHS tells the BIOS to use CHS translation. It
uses a different geometry (Cylinders/Heads/Sectors) when accessing
the drive than when talking to the software through int13. This
type of translation works with all drives.
Note. Some BIOSes have a braindead Large implementation which works
only for disks of up to 1GB. Fortunately, all larger disks support
LBA.
o 'LBA' differs from 'Large' in that it uses LBA addressing to
access the harddisk. The advantage is that it theoretically is a
little faster. The disadvantages are that some older drives don't
support it, and it often turns out to be slower, depending on the
drive.
WARNING. Some BIOSes change the (translated) geometry if you change
from Normal or Large to LBA. The same thing may happen if you transfer
a disk that has been formatted on an old, non-LBA computer to a new
one that uses LBA. This has destroyed data. Don't let it happen to
you.
Section 10 tells more about the differences between these three.
6.3. Can I safely change the BIOS' xlation mode (None, LBA, Large)?
Unfortunately, no. Proceed with care.
While with many BIOSes, the sectors on the disk are addressed in the
same order independent of the translation mode, a few use a different
type of translation algorithm. The latter type of BIOS will shuffle
your data as if it were a deck of cards if you alter the translation
mode.
Moreover, BIOSes that conform to the WD Guide may use completely
dissimilar drive geometries in the software (int13) interface
depending on the translation mode. If this happens it will wreak havoc
with your data. This represents a major flaw in the WD EBIOS
specification.
In both of these cases, after changing the translation mode, you must
repartition and reformat your disk.
6.4. Should I enable EIDE busmastering in my BIOS?
The only reason why you would want to enable this option is that DMA
modes are less likely to corrupt data than PIO modes. There will be no
difference in CPU usage. (when DMA/33 arrives, the improved bandwidth
will be another reason).
Unfortunately, at least one user has reported a drastic decline in
drive throughput with DMA enabled. The reasons are unclear, so YMMV.
6.5. FDISK sees only 504MB of my disk!
First and foremost, do you have an Enhanced BIOS? See section 2.8 and
Q1 for more details. If you do have an EBIOS, make sure you have
enabled translation: usually, either 'Large' or 'LBA'. If you see no
such options in your BIOS setup, remember that some types of BIOS
offer them only when you tell it to autodetect the drives.
Last but not least, remove all old partitions before trying to create
new ones after changing the translation mode.
6.6. FDISK will partition only 2GB.
There's nothing wrong; this is a limitation of the DOS FAT and Win95
VFAT filesystems. You will have to create multiple partitions in order
to use the full drive size.
This limitation has been addressed in Microsoft's new FAT32
filesystem, currently only available in the Win95 OEM 2 release. It
allows giant multi-gigabyte partitions. At the time of writing this
release can be sold with new hardware only and is unavailable to
ordinary mortals.
6.7. I have no fancy EBIOS, but I have an 1GB partition and it works.
Some try to work around the 504MB / 1024 cylinders issue by making a
large partition using a friend's computer, Linux' fdisk, or something
else. They use it for a day or two, conclude that it works, then post
a triumphant article claiming that they found the Solution To
Everyone's Problems[TM].
It will work... for precisely 1024 cylinders. The very moment the OS
or anything else attempts to write something to cylinder 1025 through
int13 calls, the write wraps around to cylinder 0. This cylinder
happens to hold some of the most important data structures on the
disk: the Master Boot Record, partition table, both FAT copies and the
root directory of the first partition. Overwrite these and probably
only a specialized data recovery company will be able to salvage your
data.
Try it if you must. If you know exactly what you're doing, you can
make it work using Win95. Sort of. The first error will be fatal. But
please don't post any stories about it, recommending the procedure to
everyone. The spectres of their valuable data will come back to haunt
you.
6.8. I have software to break the 504MB barrier. Should I use it?
This is a convenient option, but there are caveats.
The software, sometimes bearing an exotic name depending on the
licensee, is usually a version of either MicroHouse's EZ-Drive or
OnTrack's Disk Manager. Disk Manager, when used on the boot drive, has
to resort to some trickery in order to be loaded very early during the
boot process (which is necessary for technical reasons). This is
accomplished by modifying the Master Boot Record (MBR), the first
piece of code the BIOS loads and executes when the computer boots, and
storing a Dynamic Drive Overlay (DDO) on the very first disk track.
EZ-Drive works in a similar fashion.
An annoying side effect of using a software solution is that operating
system installations, which often overwrite the MBR, will render the
contents of your harddisk inaccessible. You will need to restore the
MBR from the installation floppy to regain access to your partitions.
Moreover, such software tends to create partitions quite different
from 'standard' translation schemes as used by most Enhanced BIOSes.
Many device drivers dealing with the disk will fail even if they work
fine with other schemes. Important examples are (E)IDE interface
drivers; remember that without these drivers an interface will in
general be much slower. You'll need drivers that are specifically
aware of the translation software you use. Also, many operating
systems other than DOS will not be able to access or use the drive, at
least not 'out of the box'. Disk fixing utilities may fail to work if
the partition table or the overlay is damaged.
This also makes it difficult to upgrade to a BIOS based solution.
OnTrack Disk Manager version 7 includes a migration utility for the
purpose and improves on version 6 in a number of other ways. It allows
multiple operating systems and is compatible with most interfaces and
drivers, including those for ATAPI CD-ROMs. Owners of version 6.03,
which is still often included with hard drives, can download an update
patch from OnTrack <http://www.ontrack.com/pub/software/dmpatch.zip>
that gives some of the benefits of version 7. View
<http://www.ontrack.com/dm.html> for general information.
For older versions of Disk Manager, IBM and Microsoft have fixes for
OS/2 (in FixPak 5 or later, or out of the box in Warp FullPack and
Warp Connect) and NT (Service Pack 2). Win95 should support Disk
Manager and EZDrive out of the box (see Microsoft KnowledgeBase
article Q126855, "Windows 95 Support for Large IDE Hard Disks"). More
about Disk Manager in section 13.1.
6.9. Can I keep my Disk Manager/EZDrive partition with a new BIOS?
If you have a Disk Manager or EZDrive partition and are upgrading to a
translating BIOS, you have three options.
o The utility is compatible with LBA translation, or has a migration
feature. This makes for a smooth upgrade path. (I'm only certain
about Disk Manager v7).
o The above isn't true and you don't want to go through a backup,
repartition, restore cycle. Tell the BIOS to use Normal mode for
the harddisk and the utility should continue to work as usual.
o Backup, repartition, restore. See 6.10 if you experience
difficulties removing the utility.
Always back up your data before doing a system upgrade.
6.10. I need to remove Disk Manager/EZDrive.
This software is usually installed in the boot drive's Master Boot
Record (MBR). Normal repartitioning and reformatting of the drive
usually does not refresh the MBR, which can make for a frustrating
experience. Fortunately, it's not very hard once you know how.
The best way to deinstall is to follow the procedure outlined in the
utility's documentation. If this is not available, the following
procedure usually works: boot from a clean floppy with at least DOS,
FORMAT.COM and FDISK.COM on it. Then type FDISK /MBR. This should
refresh the code in your MBR. After that, repartition and reformat as
usual.
For reasons I do not understand, some Disk Manager versions are
reported to cling to life rather tenaciously (perhaps due to
overambitious virus protection by the BIOS?). In that case, you need
DM.EXE. Type DM /Y-. If that fails as well, the following procedure
was reported to work by Mark Brown (mrkbrown@netcom.com).
1. run DM (in this case, v.6.03)
2. press ALT-T
3. select (D)isk Sub-System Overview
4. select appropriate hard drive
5. press CTRL-F10 to clear out the MBR
6. press Y to confirm
7. press ESC to exit out of DM, rebooting from a clean floppy
If you have faced similar situations and can add to this, please share
your knowledge. A good candidate would be a utility that simply zaps
the partition table---any takers?
WARNING. Disk Manager and EZDrive partitions differ from those created
by a translating BIOS. Expect your data to be inaccessible after this
operation. An exception is v7.x of OnTrack's Disk Manager; DM.EXE has
a Migrate feature that works with many BIOSes.
WARNING. Some controllers and security software stores information on
track 0 which FDISK /MBR will clear. In this case, the data on the
disk is lost anyway, but there are a number of circumstances where
this command can destroy data.
6.11. I can enable write caching on my harddisk. Should I?
Do not confuse this with Smartdrive (or whatever) lazy writes: what is
meant here is altering the drive's buffer cache management algorithm.
This is possible using newer versions of Drive Rocket, with hdparm
under Linux, and probably other utilities too. Provided, of course,
the drive supports this feature. Sometimes it can also be done using
jumpers on the drive.
There seem to be problems with this, if a program will issue a soft-
reset (which on Intel Pentium Motherboards also issues a hardware-
reset) as soon as it sees the last IRQ, which overall ends up
corrupting data. Use with care, and backup.
6.12. My drive letters have changed!
MS-DOS assigns drive letters as follows.
o Letters a: and b: are reserved for floppy drives.
o All primary partitions on all (system and adapter) BIOS supported
harddisks get their drive letters starting from c:, in order.
Normally, you can have just one primary DOS/Windows partition on
every drive.
o Only then, all logical drives inside extended partitions get their
letters. This means, for example, that if you had one drive with c:
and d:, adding a second drive with one primary partition on it will
bump the former d: partition up to e:. If you want to avoid this,
do not define primary partitions on all drives except the first
one.
o After that, MS-DOS parses the CONFIG.SYS and AUTOEXEC.BAT files.
Some devices such as CD-ROMs have no BIOS support and get their
drive letters only here.
Remember that some programs, including disk compression software,
may do shuffling tricks with drive letters. Be also warned that
some BIOS setup screens, in a misguided attempt at user
friendliness, refer to harddisk units using drive letters. In
trivial cases, this may be right, but in nontrivial setups the BIOS
may be all wrong.
7. Performance
7.1. Why isn't my drive as fast as it's advertised to be?
Good question. The basic answer is that the advertised modes are
theoretical transfer rates.
This is the case at two levels. First and foremost, the oft-quoted
rates do not represent the speed at which the drive can actually read
data from, or write data to, the magnetic media. Instead, they give
the speed at which data can be exchanged between the drive's buffer
cache and the CPU. While the latter gives the more imposing figures,
the former has greater impact on real world performance. "It is really
as if the government had had a speed limit of 250 km/h on the
highways, then raised it to 1600 km/h and tried to impress you by
telling you that now you can drive faster"--Aaron Bilger
(bilgerar@mentor.cc.purdue.edu).
Second, even once you accept that these transfer rates can be achieved
only when the drive happens to have the data ready in the buffer
cache, these figures are pretty optimistic. Realistically, drives do
more than just give data to the host out of the cache. For each sector
transferred to the host, the drive's controller needs to get one from
the media; internal controller processing, table updates, positioning
and buffer cache management all take some of the controller's
attention. All reduce the throughput from the cache to the host.
On top of that, depending on the benchmark used to determine the
'throughput', the rate can vary from 3MB/s to 30MB/s and upwards, all
on the same drive. This depends on what the utility actually
measures, how it measures it, and even where on the drive it measures
it (different zones on the same drive can vary up to a factor two in
speed). Plus, system configuration (MHz CPU, RAM, harddisk cache,
processor cache) make a difference as well.
Bottom line is, whatever benchmark you use, you will not 'see' the
advertised transfer rate. The real test is how well it improves your
day to day applications. The rest is just fluff.
7.2. Why is my new EIDE, U-ATA interface no faster than my old one?
! There are several reasons why it is possible that an Ultra-ATA
! interface is no faster than an older one even if the drivers are
installed and everything works properly. The first, and most
important, is that the bandwidth of the fastest ATA-2 mode, 16.6MB/s,
exceeds the real world transfer rate of most drives on the market
today by a considerable margin. If this is the case for your drive,
increasing the interface bandwidth beyond this will have no noticeable
effect.
! A further possibility is that your drive does not support the Ultra-
! ATA transfer modes at all. In that case, an Ultra-ATA interface may
! improve performance relative to an old-fashioned ISA bus or VL bus
! interface, but it will be no faster than a good PCI ATA-2 (EIDE)
! interface.
7.3. I benchmarked my drive and it's getting slower!
Believe it or not, but this is completely normal. First, filesystem
fragmentation affects some benchmarks; try defragging the drive.
Second, not all parts of the drive are equally fast.
Physically, a harddrive consists of one or more rotating platters,
where the tracks are concentrical circles on these platters.
Obviously, the outermost tracks are longer than the innermost ones.
Because they are longer, they can hold more sectors. As you work your
way inwards and the track length decreases, the number of sectors
decreases in a number of steps. This is referred to as Zone Bit
Recording (ZBR).
Back to the benchmarks. Since the platter spins at a constant rate,
more sectors in a track give a proportionally higher transfer rate.
The very first cylinder of your drive is right at the edge of the
platter, in the fastest zone. This is the area that was tested when
you got your drive and tried to find out how well it performed. As
your drive fills up, you start using higher cylinder numbers---and
slower zones. Depending on the type of benchmark you use, this may be
reflected in lower scores.
The difference in sectors per track (and hence transfer rate) between
the fastest and the slowest zone may be as much as a factor two.
Typical drives have anything from five to twenty zones, all with a
different number of sectors per track.
7.4. A guy on the net has the same drive and he gets 33MB/s!
"Usenet is like a herd of performing elephants with diar-
rhea--massive, difficult to redirect, awe-inspiring, enter-
taining, and a source of mind-boggling amounts of excrement
when you least expect it."
-- Gene Spafford (spaf@cs.purdue.edu), 1992
7.5. Busmastering drivers don't do much...
First of all, busmastering will generally not do much with the
transfer rates themselves. What it does is relieve the CPU from the
chore of shovelling data around, so that it can do something more
useful. However if you tend to do only one thing at a time, or you're
running a benchmark, the extra CPU time can't be used for anything and
busmastering will have no appreciable effect.
Second, you will not see any decrease in CPU usage with the System
Monitor in Win95 because it tracks the amount of time spent in the
"system idle" loop. However, with a pending I/O operation, the system
doesn't spend its spare cycles there, but in the "waiting for I/O to
complete" loop.
! Third, you need to use DMA to profit from the improved data integrity
! and enhanced transfer rates of Ultra-ATA.
!
8. Troubleshooting
8.1. Why do I get NO ROM BASIC, SYSTEM HALTED?
This should get a prize for the PC compatible's most obscure error
message. It usually means you haven't made the primary partition
bootable or, in Microsoft-speak, 'Active'. Use FDISK to fix this.
Don't fret, you won't have to repartition or reformat anything unless
you have no primary partition at all.
The earliest true-blue PCs had a BASIC interpreter built in, just like
many other home computers those days. Even today, the Master Boot
Record (MBR) code on your harddisk jumps to the BASIC ROM if it
doesn't find any active partitions. Needless to say, there's no such
thing as a BASIC ROM in today's compatibles, and this action ends in
the above error message.
8.2. I have problems with my Award 4.50G BIOS and large drives.
If your 4.50G BIOS is dated earlier than 12/13/1994, the address
translation table is faulty. To access drives with more than 1024
cylinders, you cannot use address translation (Large) but must use
LBA. In versions dated 12/13/1994 or later this has been fixed. Be
warned that switching to LBA will probably force you to repartition
and reformat your drive; do back up your data.
8.3. My 2GB+ drive is not recognized or crashes.
Many BIOSes dated before 1996 contain bugs making them incompatible
with drives of more than 4096 cylinders, which works out to be about
2GB in size. Some BIOSes have similar problems at the 8192 cylinder
boundary (4GB). The effects may range from not being able to use the
full capacity to a crashing BIOS during bootup or upon detecting the
drive.
Possible solutions include
o a flash BIOS update, if you've got a flash BIOS and your board
manufacturer makes a fixed BIOS image available;
o non-flash BIOS ROM ugrade;
o a software disk manager like using OnTrack Disk Manager or EZDrive;
o if the BIOS allows a user definable drive type, manually setting
the cylinder count to 4095 (8191). This means you can use no more
than the first 2GB (4GB) of the drive.
In the last case, you can use the remaining capacity of the disk to
give Linux a test drive.
8.4. My 4GB+ drive has problems in MSDOS 6.22 or below.
Some BIOSes assign a drive of over 8192 cylinders a translated
geometry with 256 heads. MSDOS 6.22 and below fail when they try to
access the last head.
If your BIOS allows a user definable drive type, use a geometry with
15 heads and 16/15 times the original number of cylinders, rounded
down. Thanks to universal translation you can always do this. Remember
to write down the geometry somewhere so that you can reproduce it if
necessary! If no user definable drive type is possible, there's little
you can do about this except upgrade to Win95.
!
!
8.5. Help! I have OnTrack Disk Manager installed and now...
OnTrack has a web site: <http://www.ontrack.com/>. Most importantly,
you can find their Disk Manager FAQ at
<http://www.ontrack.com/ontrack/faqhome.html>. There's also a bit
about DM in section 13.1. If all of that doesn't help, contact OnTrack
tech support at tech@ontrack.com.
Beware that some licensed versions are supported by the OEM rather
than by OnTrack. In such cases the OEM usually offers help, FAQs etc.
on their web site.
8.6. My mode 3-4-5-6 drive has data corruption problems.
Try using a slower mode or disable fast modes altogether. Mode 3 and
especially mode 4 are very sensitive to timing problems, and not all
adapters follow the ATA-2 specification really closely. Don't dismiss
the possibility too easily: if you changed anything on your system, it
is very well possible that a drive which marginally worked so far now
starts to corrupt data.
Some controllers seem to configure themselves according to the
capabilities of the master drive. This can mean trouble if the slave
handles only slower modes.
Moreover, check your cables, and ensure they aren't too long (see
Q5.4). Removable drive brackets may also cause problems with fast PIO
modes for roughly the same reasons.
8.7. Are there supposed to be bad sectors on the drive?
No. All modern drives support error management, which completely hides
any bad sectors that may be on the disk before leaving the factory.
Even a single bad sector is sufficient grounds to return the drive
under warranty. If you want to continue using it, the drive should be
viewed with the utmost suspicion.
Western Digital's wdat_ide.exe utility can hide grown bad sectors on
many Caviar disks.
There is one exception. Under rare circumstances, use of bad (too
fast) timing by the disk adapter can cause bad sectors on a disk. This
type of error can be fixed simply by writing fresh data to these
sectors, as there is no actual media defect.
8.8. I keep getting CRC errors and serial overruns.
Often, this is caused by the use of block mode (see Q10.6 for an
explanation). Large blocks can take a long time to transfer; during
the transfer, interrupts are disabled and the serial ports are not
serviced by the CPU. Eventually, the buffer for incoming data may
overflow, leading to overruns and CRC errors.
The solution is to reduce the number of sectors per block, if
possible, or disabling block mode altogether. 16550 compatible serial
ports have a larger buffer, but with excessively large block sizes
this problem may still occur.
8.9. Can my drive do 32-bit access?
There appears to be an awful lot of confusion about this subject,
partly due to some unhappy terminology.
In the most literal sense, no ATA(-2,-PI) drive will allow 32-bit
access. Data is transferred to and from the drive over a 16 bit bus.
However, many local bus interfaces are capable of combining two 16-bit
words into a 32-bit doubleword when reading data from the disk, and
the reverse when writing. This way, data transfer between the CPU and
the interface can be done in 32-bit chunks. This is often called
'32-bit access', although '32-bit host bus transfers' would be a
better name.
With 32-bit host bus transfers, more efficient use is made of the
computer's bus and CPU. On the other hand, these are seldom the
bottleneck, so don't expect miracles from this feature. Windows'
32-bit disk and file access are completely unrelated issues and the
subject of question 8.10 and 8.11.
8.10. Help! Windows 3.x 32-bit disk access doesn't work anymore!
There are numerous reasons why this can fail; you will more easily be
able to do something about it (or decide if you want to fix it in the
first place) once you know some background.
Windows' 32-bit disk access (32BDA) is a bit of a misnomer, actually,
since it has nothing to do with 32-bit data transfers. A slightly
better name for it is 'FastDisk'. It is a feature of Windows in 386
Enhanced mode that allows one to replace the BIOS' disk routines by
Windows' own routines that work in protected mode. A much better name,
then, would be "protected mode controller access". For some reason
Microsoft decided not to use the latter.
Anyway, the main advantage of this feature is that it allows Windows
to use virtual memory for its DOS sessions. Without 32-bit disk
access, DOS sessions cannot be swapped out and every DOS box takes
640k of real memory. Because it also reduces the number of switches
between virtual and protected mode Windows has to make, it gives a
slight performance improvement as well, but usually nothing dramatic.
Only if 32BDA is used together with Windows for Workgroups' 32-bit
file access feature, it will eliminate these mode switches altogether
(at least for most disk operations), which gives a far more
interesting performance boost.
Unfortunately, the standard FastDisk routines that are internal to
windows, called *wdctrl, are severely limited in their capabilities.
The *wdctrl software understands nothing of non-IDE hardware (e.g.
SCSI), more than two harddrives, drives with more than 1024 cylinders,
32-bit host bus transfers, block transfers, or ATAPI CD-ROM drives on
the primary channel. If you use any of these things, 32-bit disk
access won't work unless you have a *wdctrl replacement.
Today, that means that 32-bit disk access won't work 'out of the box'
for most of us.
Most interfaces that are incompatible with *wdctrl come with their own
FastDisk routines (usually with a .386 extension). For the rest of
you, many drive manufacturers offer replacement FastDisk software.
Many drive manufacturers have such drivers on their WWW sites these
days; take a look in the net.resource guide below. You can also
contact your vendor to find out what is available. Last but not least,
the ontrackw.386 driver in
<ftp://ftp.ontrack.com/pub/software/dmpatch.zip> is reported to work
fine on all drives even if you don't use Disk Manager.
Most of these drivers won't give you 32-bit disk access if you have an
ATAPI CD-ROM on the same cable as the harddisk. Only a few CD-ROMs
come with a special VxD driver which does the job.
Note: these drivers are incompatible with the Stealth feature of some
versions of Quarterdeck's QEMM. Quarterdeck's fix can be found on
<ftp://ftp.wdc.com/drivers/hdutil/32bda.com>.
8.11. Help! Windows for Workgroups' 32-bit file access fails!
The idiosyncrasies of the 32-bit disk access feature with respect to
disk hardware has led to the popular myth that 32-bit file access has
similar problems. However, that's all it is: a myth. If 32-bit file
access fails, you should first check your filesystem and the programs
that use it. As little as a single open file, e.g. from a printer
spooler, will cause 32BFA to fail. Oh, and put
DEVICE=C:\WINDOWS\IFSHLP.SYS in your CONFIG.SYS, and make sure your
SYSTEM.INI contains the correct magic incantations (vfat.386,
vcache.386). If this doesn't help, there's a first rate FAQ on this
topic (see the net.resource guide for details).
8.12. Help! Win95 indicates my drive uses compatibility mode!
The culprit usually is a virus. Do get a recent virus scanner.
If that turns out negative, it may also be DOS (real-mode) driver that
loads in the CONFIG.SYS or AUTOEXEC.BAT, or an old version of
EZDrive/Disk Manager loading from the MBR.
8.13. My partitions become a mess in MS-DOS mode.
See the next question.
8.14. Win95 sees my partitions, but DOS doesn't.
If you've used Win95's fdisk utility to partition your drive, you may
run across a nasty bug.
Win95 supports extended int13 calls to break the 8GB barrier. To avoid
problems with old versions of DOS, partitions extending beyond 8GB
must be made invisible. Unfortunately, the Win95 FDISK sometimes hides
partitions this way even if your drive is much smaller than 8GB.
Incidentally, this also hides them from all other operating systems,
including old versions of DOS, and can cause all kinds of problems.
Under circumstances, these new partition types can completely mess up
things when going from the Win95 graphical shell to MS-DOS mode. Drive
contents may appear to be corrupted or be replaced by the contents of
C:. Don't try anything fancy when this happens; it is really easy to
corrupt your data. Don't use the "Restart in MS-DOS mode" option and
don't run programs configured to run in MS-DOS mode. MS-DOS windows
are still fine.
The most comfortable way to fix this is to change the partition types
using Partition Magic <http://www.powerquest.com>, but ONLY version
2.03 or later. You can get an update patch for older versions.
The alternative is to back up your data and repartition using FDISK
/X, which disables the use of the new partition types, or DOS 6 FDISK.
Also be sure to apply the Win95 ios bugfix and other fixes available
from Microsoft's web site.
8.15. Win95 keeps losing my second IDE channel!
If you have a Triton II or Natoma based board, the retail version of
Win95 may not recognize the PIIX3 interface. This will trigger an
entertaining bit of Plug'n'Pray magic which eventually causes the BIOS
to disable the secondary IDE channel on the next reboot.
To determine if this is really your problem, go into the device
manager and click on Hard Disk Controllers. If you see the following
devices listed:
o Primary IDE Controller (single FIFO)
o Standard Dual PCI IDE Controller
o Standard IDEESDI Hard Disk Controller/
your Win95 mshdc.inf needs a little update. You can download this
from <ftp://ftp.intel.com/pub/patch/ideinfup.exe>.
8.16. The Win95 busmastering drivers won't work.
The Win95 busmastering drivers sometimes have trouble co-operating
with older harddisks and ATAPI CD-ROMs. Try installing the latest
drivers.
If that doesn't help, you could try this registry hack. Move all old
devices to the secondary port. Back up the registry (system.dat and
user.dat in the Win95 directory). Start regedit and look for
HKEY_LOCAL_MACHINE/System/CurrentControlSet/control/Services/hdc
Here is where the entries for both ports should be located. In the
second entry, change the key PortDriver from "ideatapi.mpd" to
"esdi_506.pdr". This will cause the secondary channel to be handled by
the default driver.
8.17. My ATAPI (IDE) CD-ROM driver won't recognize the CD-ROM.
If the CD-ROM is connected to the secondary channel, make sure this
channel is enabled. Some BIOSes will enable the channel only if one or
more harddisks using this channel are defined in the setup; in that
case, you can't avoid putting the CD on the same cable as a harddisk
until you manage to get your BIOS updated.
You may also get trouble if the CD-ROM is jumpered as slave and
there's no master on its channel.
Finally, the PIO mode (speed) used by the interface may be too high,
especially if the CD-ROM shares its cable with a harddisk. Many
interface drivers and BIOSes are not ATAPI-aware and don't take the
CD-ROM into account when determining the maximum possible speed. The
best fix is to move the CD-ROM to a different channel. Manually
lowering the mode a notch or two should also help; this is usually
done either through the BIOS setup or by passing options to a device
driver in the CONFIG.SYS.
9. The user's net.resource guide
There are a large number of FAQs and other resources on the net.
Daniel Tauritz (dtauritz@WI.LeidenUniv.NL) no longer maintains his
EIDE Mini-FAQ that contains a short but potentially useful list of
available interfaces; it needs to be expanded and maintained---any
takers? There is another, technically oriented, FAQ on ATA-2, EIDE
! etcetera by Hale Landis (hlandis@ibm.net). All of this and more can
! be found on
o <ftp://ftp.wi.leidenuniv.nl/pub/faqs>
o <http://www.wi.leidenuniv.nl/ata>
An incredible range of hardware related issues is addressed by the
comp.sys.ibm.pc.hardware FAQ, maintained by Ralph Valentino
(ralf@wpi.wpi.edu). It can be found on comp.answers and the FAQ
repository <ftp://rtfm.mit.edu>. It incorporates the world-famous
'Jumper FAQ' <ftp://rtfm.mit.edu/pub/usenet/news.answers/pc-hardware-
faq/part3>.
On the tangential subject of Windows for Workgroups' 32-bit file
access, Mike McCormick (m.mccormick2@genie.geis.com) has a good FAQ,
posted on comp.os.ms-windows.windows.setup and many other groups. It
can also be found on comp.answers and therefore on rtfm.mit.edu as
well.
Roedy Green's (roedy@bix.com) "PCI EIDE controller flaws" FAQ is
included with his EIDE test
<ftp://garbo.uwasa.fi/pc/diskutil/eidete17.zip> program. The latter
will test your system for the bugs that may arise if it has a CMD640
or RZ1000 interface chip (used on many pre-Triton Intel Pentium
boards, for instance). With either of these, your data is in danger
every day you postpone reading this.
The SimTel repository, the primary mirror of which is
<ftp://ftp.coast.net/SimTel> or <http://www.coast.net>, contains an
immense number of useful programs (PD, freeware and shareware). A tiny
selection, all from /SimTel/msdos/diskutil/:
o ideinf10.zip (will determine the properties of your
harddisk(s)--not a benchmark).
o 3drvs260.zip (gives support for 3 harddisks under DOS).
o dqwik211.zip (block mode driver).
o no_idle.zip (disables the auto-idle power saving feature of some
harddrives).
o 1seagate.zip (specs for *all* Seagate harddrives).
o wasted15.zip (shows wasted space due to cluster size).
o presz111.zip (nondestructive partition resizer). r
Note that the version numbers may have changed; also, you should
preferably use a mirror close to you instead of the oakland site.
A more manageable selection of useful utilities, drivers and
information (this FAQ :-) can be found on
o <ftp://ftp.netcom.com/pub/cl/clau/ide_ata>
(this represents the latest known location of Chung Y. Lau's famous
wandering FTP site)
o <ftp://ftp.rahul.net/pub/lps/hard-disk>
One of the most thorough low level harddisk benchmarks on Earth,
Marnix Timmermans' Check Harddisk, is in beta. Check it out at
<http://huizen.dds.nl/~checkhd>. Of course, the usual precautions
with beta software apply.
SimTel has a copy of TheRef[TM] by F. Robert Falbo, a giant hardware
reference; it is rather outdated, but fortunately you can access a
more up to date copy on the web at <http://theref.c3d.rl.af.mil>.
Frank Pikelner (frank@cs.yorku.ca) has compiled an excellent, up to
date list of >500MB harddisk and >4x CD-ROM drive specifications. You
can access it through
<http://www.cs.yorku.ca/People/frank/Welcome.html>.
9.1. The user's net.resource guide: I/O card drivers
! DriversHQ <http://www.drivershq.com> is one of the most well known
! sources for drivers.
!
In Finland, someone got the immensely useful idea of setting up a site
with all kinds of IDE card drivers. You can find it on
<ftp://ftp.funet.fi/pub/drivers/pc/disk/ide_ata>. If you can't find a
driver here and manage to pick it up somewhere else, please upload it.
Help making the net work.
9.2. The user's net.resource guide: hardware manufacturers
A number of disk and controller manufacturers now have FTP and web
sites; these are
o CMD
<http://www.cmd.com>
o Conner
<http://www.conner.com>
o Creative Labs
<http://www.creaf.com>
Among other, non EIDE related items, this site has drivers for the
tertiary ATA/IDE port found on some SoundBlaster cards.
o DTC
<http://www.datatechnology.com>
o Fujitsu
<http://www.fujitsu.com>
o Hewlett-Packard
<http://www.hp.com>
o IBM
<http://www.storage.ibm.com/storage>
<ftp://hddtech.millcomm.com>
<http://www.pc.ibm.com> (PC Company)
o Iomega
<http://www.iomega.com>
o Maxtor
<http://www.maxtor.com>
<ftp://ftp.maxtor.com>
All files from their BBS are on the FTP site, including
biosbnch.zip, a benchmarking utility; greendrv.zip, to set the
sleep mode timer on 'green' drives; and the latest version of
MaxBlast (OnTrack Disk Mananager) at
<http://www.maxtor.com/readme/dm.html>.
o Promise
<http://www.promise.com>
<ftp://ftp.promise.com>
support@promise.com
This site doesn't only contain drivers for Promise products but
also for clone cards such as the VG4.
o Quantum
<http://www.quantum.com>
No official FTP site, although drivers to use Quantum's large
harddisks with a non-translating BIOS can be found in
<ftp://ftp.rahul.net/pub/lps/hard-disk/ide_dos.exe>. This is NOT an
official Quantum support site and may disappear. This site contains
miscellaneous storage-related programs and information too, not
least the white papers on topics such as S.M.A.R.T., PRML channels,
MR heads and more: <http://www.quantum.com/products/whitepapers/>.
o Seagate
<ftp://ftp.seagate.com>
<http://www.seagate.com>
This includes specifications of ALL Seagate drives, including
detailed diagrams/pictures. The Seagate 32-bit disk access driver
is available as <ftp://ftp/seagate.com/techsuppt/sea32bit.exe>;
there is a FAQ on this driver at
<http://www.seagate.com/techsuppt/win32drv.html>. There is some
general technical information available, on topics such as MR
heads: <http://www.seagate.com/new/sep96/mr_techp.shtml>. A
formatting utility for Seagate drives, sgatfmt4, is also available.
o Tekram
<http://www.tekram.com>
o Tyan
<http://www.tyan.com>
o Western Digital
<ftp://ftp.wdc.com>
<http://www.wdc.com>
Many drivers and utilities, some of which won't work if you don't
have at least one WD Caviar drive in your system. Goodies to be
found: a good Windows FastDisk driver in /drivers/hdutil/win31.exe;
a Windows helpfile explaining Enhanced IDE in /docs/eide.exe; a
utility to examine the Enhanced DPT of your BIOS:
/drivers/hdutil/chkbios.com.
o Winbond
<http://ntwww.winbond.com.tw>
Drivers are in the /DNLOAD/ directory.
Pointers to sites offering software from other manufacturers would
be appreciated.
9.3. The user's net.resource guide: software and BIOS houses
o AMI
<http://www.megatrends.com>
<ftp://ftp.megatrends.com>
o Award
<http://www.award.com>
o IBM
<http://www.ibm.com>
<http://www.pc.ibm.com> (PC Company)
<http://ps.boulder.ibm.com> (a really good link for OS/2 install
and update info)
<ftp://ftp.pc.ibm.com>
Flash BIOS upgrades for the IBM ValuePoints are in /pub/valuepnt/.
o MicroHouse
<http://www.microhouse.com>
Drive specifications and jumper settings:
<http://www.microhouse.com/mtl/vip/hd.htm>. EZDrive FAQs and files
can be found on FAQ/ALLKEY.htm and FTP/EZ.htm respectively.
o Microsoft
<ftp://ftp.microsoft.com>
<http://www.microsoft.com>
General Windows and DOS updates, fixes and Microsoft Knowledge Base
articles can be found on the Microsoft FTP site. Unfortunately,
the structure of this site can hardly be called intuitive (which,
some would argue, is characteristic of Microsoft products in
general). The WWW site allows searches in the Knowledge Base, which
is much more useful.
o MR BIOS
<http://www.mrbios.com>
mrbios@mrbios.com
Information on MR BIOS bioses. Contains downloadable shareware BIOS
images for some popular boards with Flash ROM as well.
o Novell
<http://www.novell.com>
<http://www.netware.com> (Netware info)
o OnTrack
<http://www.ontrack.com>
tech@ontrack.com (tech support)
sales@ontrack.com (sales)
o Phoenix
<http://www.ptltd.com>
o SCO
<http://www.sco.com>
o Unicore software
<http://www.unicore.com>
Calls itself a BIOS solutions site. Contains, among other things,
information about the LBA Pro BIOS add on board.
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