Utilizing High Capacity ATA-6 Drives in FireWire Enclosures

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Interesting reading: http://www.wiebetech.com/ATA6firewire.htm

This stuff is related to Oxford 911 firewire based cases.

“Utilizing High Capacity ATA-6 (>137GB) Drives in FireWire Enclosures”

by James Wiebe, CEO
WiebeTech LLC
October 21, 2002
www.wiebetech.com
© 2002 WiebeTech LLC. All rights reserved.

This paper may be reproduced, but only in its entirety, and only if credit is given to the author and linkage provided to the WiebeTech website.

INTRODUCTION

The purpose of this White Paper is to document the technical path which has occurred that now allows FireWire enclosures from WiebeTech LLC to ship with capacities higher than 137GB. The reader will be given a very abbreviated history of FireWire, as well as background information on the Oxford Semiconductor OXFW911 FireWire bridge chip, used in many FireWire storage devices. Finally, the reader will be shown what has recently happened that allows the OXFW911 to provide support for high capacity OXFW911 drives.

FIREWIRE AND STORAGE DEVICE ARCHITECTURE

Originally envisioned by Apple Computer, Inc., FireWire is most commonly used for Digital Video image transfer and for external storage. FireWire drives are have become the preferred external storage medium for personal computers.

Ironically, Microsoft first provided driverless Plug and Play functionality to FireWire drives with Windows 98SE. Eventually, Apple provided similar driverless capability when OS 9.2 was introduced (with FireWire capability cascading backwards to OS 9.1). Today, FireWire is plug and play under the following operating systems: Win98SE, WinME, Win2K and WinXP. Apple provides similar support under OS9.1, 9.2, and OSX. FireWire Drivers are also commonly used with earlier versions of Apple’s OS; albeit with third party drivers.

FireWire enclosures contain three critical components: The drive mechanism, the FireWire bridge, and a FireWire interface chip which connects the FireWire port to the FireWire bridge. (This third component is commonly called a “PHY” – and is often ignored, even though it is an important component of overall FireWire performance.) Of concern to this paper is the FireWire bridge, because it provides the key functionality and is the major performance arbitrator between FireWire storage vendors.

Several different companies have competed to provide FireWire bridge devices to the marketplace. These are the devices which are contained within every FireWire hard drive enclosure, and are responsible for converting the FireWire protocol to that of the hard drive protocol. Without digging too deeply into the details of the various protocols (because there are several in operation all the time, both on the FireWire bus and communicating to the drive through the PHY), this paper will focus on the protocol and hardware used to communicate with the hard drive from the FireWire bridge chip.

One of the companies which has provided FireWire bridge chips to the marketplace is Oxford Semconductor of Oxford, England (see www.oxsemi.com). They have produced two different FireWire bridges which are commonly used in FireWire storage devices. The first of these was the OXFW900, still used in older, slower FireWire drives, and the OXFW911, which is, in the opinion of the author, the volume leader in the marketplace. While the original OXFW900 was not fast enough for many applications, the OXFW911 has proven to be a sturdy and zippy performer, compatible with most hard drives and most operating systems. It is commonly used for Digital Video editing. In summary, the OXFW911 achieved market success for four reasons:

* It is very fast. As processors have gotten faster, the benchmarks of the OXFW911 have also edged up as well, today producing benchmarks for sustained transfer rates of about 35MB/sec.

* It is compatible with a wide range of drives. It is difficult to find a drive which the OXFW911 has not been successfully interfaced to. For instance, the OXFW911 has been successfully connected by WiebeTech to 340MB IBM MicroDrives (platter size a matchbox 1 inch) all of the way up to 180GB IBM Deskstars (platter size of 3.5 inches) – a capacity range of over 500 to 1 on rotating media hard drives currently shipping from one vendor!

* It is compatible with a wide range of operating systems. As mentioned, it has been made to work with the major personal computer releases. Occasionally, software glitches have been corrected either by the OS vendor or by firmware upgrades to the OXFW911.

* It is easy to use. Successful operation is achieved by attaching a 911 to a PHY and a hard drive and applying power. (Important nuances, such as PHY selection and Firmware make differences in performance.)

While the first and last bullet are inherent in the design of the part, the middle two bullets are a direct result of Oxford’s decision to use an embedded reprogrammable ARM processor within the part. As a result, Oxford and third parties are capable of doing amazing things with OXFW911 FireWire bridges. Whenever an operating system glitch occurred, firmware could be manipulated to solve the problem. As a result, the OXFW911 has not been obsoleted and clearly has a long future still ahead of it.

A HINT OF A PROBLEM

Desktop drives, also commonly called 3.5 inch or IDE drives, communicate with their host through an interface protocol. The protocol most readily in use is the ATA-5 specification, which allows for attachment of drives with capacities to 137GB to a computer system. The addressing limitation occurs because of a limitation on the number of active addressing lines.

Various hard drive vendors and computer system manufacturers could easily see that the limit would easily be broken by advancing storage technologies. As a result, a new specification with support of up to 144 Petabytes was adopted by the industry. An excellent resource for understanding these limitations is provided by Maxtor at the following address:

http://www.maxtor.com/en/documentation/white_papers/big_drives_white_papers.pdf

On October 29, 2001, Maxtor Corporation introduced a new series of drives which had capacities up to 160GB, thus breaking the 137GB barrier established in the ATA-5 interface with a commercially shipping mass market product. Maxtor’s new drive was compatible with the next generation ATA-6 protocol. It appeared that Maxtor’s new drive would not be compatible with FireWire bridge devices designed to support only ATA-5 devices, such as the Oxford OXFW911.

For a copy of Maxtor’s press release, see:

http://www.shareholder.com/maxtor/ReleaseDetail.cfm?ReleaseID=66904&reltype=Product&ma..._section=press

also see: www.maxtor.com/BigDrive

The OXFW911 was designed to support ATA-5 (but not ATA-6) devices, which, by definition, are less than 137GB in capacity. Maxtor cleverly solved their own problem when they introduced a FireWire drive with support for their own 160GB drive mechanism.

(See:http://www.shareholder.com/maxtor/ReleaseDetail.cfm?ReleaseID=68896&reltype=Product&ma..._section=press)

This FireWire drive appears to solve the ATA-5 / ATA-6 protocol problem by communicating with the drive through a backdoor hack designed into the drive, not through a rigorous implementation of ATA-6 control. (The author believes these comments to be correct, but they must be considered conjecture.) In other words, the FireWire bridge inside Maxtor’s own FireWire enclosure was probably not ATA-6 compatible, but it could be made to work with their drive through a hidden protocol. The ATA-6 problem became (temporarily) irrelevant.

Other companies were also successful in writing a firmware hack for the Maxtor 160GB drive using the ARM processor which is embedded in the OXFW911. It is important to understand that this was not ATA-6 support at all, although there was an impression that this might have been. These hacks are the basis of all use of the Maxtor 160GB drive in conjunction with OXFW911 based FireWire storage devices.

Other than Maxtor, no other drives have been released with capacities greater than 137GB in the last year.

RECENT HISTORY, BIGGER PROBLEMS

A few weeks ago, Western Digital started shipping drives with capacities of 180 and 200GB, and it became obvious that OXFW911's didn't work (especially with the 200GB version). These new drives were true ATA-6 devices, and the OXFW911 did not 'speak' true ATA-6 protocol.

There was no backdoor hack to be found. For the first time, the OXFW911 had hit a brick wall.

Even more recently, IBM started shipping 180GB drives that did not work with the OXFW911. Sadly, the operating system would see all such drives as having lobotomized capacities of 128GB.

Finally, Maxtor has come full circle and announced even higher capacity drives which are ATA-6 compatible.

Would the OXFW911 be able to meet this challenge? This is one feature that has set the OXFW911 apart from competition: everytime a new drive or OS came out, the OXFW911 ably rose to the challenge. Solutions always made it to the marketplace via OS changes or Firmware changes.

However, this time the OXFW911 had finally come up against a limitation that couldn't be met in firmware: true ATA-6 support required firmware changes and physical design changes to the FireWire bridge board.

A RESOLUTION AND CONCLUSION

The situation today is that OXFW911 based solutions are now shipping with ATA-6 support. In order to guarantee compatibility with all ATA-6 devices, new firmware and new circuitry are shipping to the marketplace. These new products work extremely well and ably provide the ability to create FireWire drives with ultra large capacities. 200GB units are shipping now from WiebeTech, and other vendors of FireWire enclosures are certain to follow.

There are implications to the consumer which are immediately obvious: most OXFW911 designs currently shipping are not capable of providing ATA-6 support (unless the vendor specifically provides and supports an upgrade program). Products currently sitting on retail shelves are certainly not capable of accepting all of the new ATA-6 drives. Users who are not careful in their product and vendor selection run the risk of purchasing products that will not meet their needs in the long run.

The OXFW911, when modified with ATA-6 support, remains the preferred solution for FireWire drives. It is a market leader because it is compatible with all major operating systems and drives. It is very fast, and very easy to use. From the user’s point of view, it provides plug and play external storage solutions.

The recent introduction of high capacity ATA-6 drives into the marketplace briefly confounded the OXFW911, but this has now been resolved through a redesign of the external circuitry and by firmware update.

WiebeTech is now shipping FireWire storage solutions which incorporate these improvements into the product line. WiebeTech is also supporting an upgrade program for most of its products. These upgrades allow the consumer to pay a modest fee and receive back a FireWire enclosure with ATA-6 support. Note: The Upgrade program was discontinued on Dec. 31, 2002

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The release document of the Oxford 911 firmware 3.7 (27-Jan-2003), firmware file named fw20030127.bin, specifies that ATA-6 compatibility is possible only if the bridge board was especially modified to support it. If the new firmware does not find such modifications, only ATA-5 will be possible and the maximum capacity for a disk will be 128 GB.

However this firmware supports non-standard vendor specific ATA-6 protocols. There is no mention on what vendor implements such protocol, but I think Maxtor is one of them.

If you have an older firewire case with Oxford 911 chipset and you own a disk bigger than 128 GB, please try this firmware with your case and tests if you could use your drive at its full capacity.

To get the firmware read this thread: https://www.videohelp.com/forum/viewtopic.php?t=130579

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It’s confirmed. According to the Oxford 911 firmware 3.1 (11-Feb-2002) firmware named fw20020211.bin, release document confirms that proprietary 48 Bit support was added for the Maxtor 160 GB drive.

If you what to use a bigger disk than 128 GB, Maxtor 160GB is the way to go. Maybe bigger disks are supported but we need someone to flash its case with the latest firmware and to try the big puppy.

Please remember that Oxford 911 firmware 3.7 appears to support another brand of HD besides Maxtor. If you have a big non-Maxtordrive please test it and report your findings.

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*** Edited: 9-APR-2005 ***

Found latest Oxford 911 firmware V4.0 (dated OCT-2004). Please read about it in here:

https://www.videohelp.com/forum/viewtopic.php?p=691487