Imation Odyssey Removable Storage

The progress of removable hard disk drives has lasted several decades, and... has reached a deadlock. Growth of data density and transfer rates requires higher-precision mechanics, which does not go well with removable hard disks. We have to hand it to manufacturers - they fought bravely with these problems. Capacity of floppy models has grown to 3/4 GB (but this upgrade came too late, so 250 MB (or higher) diskettes did not become very popular). The progress in transfer rates is just as great. Removable hard disks did not stand still either. A large part of their history has nothing to do with personal computers, but they still registered capacities and transfer rates similar to those of old hard drives. But the new era required higher capacities and performance. And removable disks, physically separated from heads, couldn't provide them on a mass scale. Attempts to use other technologies also failed - magneto-optical disks, which had promised to become the main portable data storage media, got stuck at a gigabyte. They didn't cope with "children diseases" - a low data recording rate (the problem was solved only partially). OK, magneto-optic disks are notable for high reliability of data storage, but...

There appeared the need to transport dozens of gigabytes, and magneto-optic disks were not up to it (with a small proviso to be described later). Upgrade to tapes? Tape storage drives are too slow for all applications except for backups (when you don't need access to separate files) because of sequential data access. Some time ago optical discs seemed to solve the problem, but it didn't happen. Indeed, they are convenient to store data, but not to transport it. Besides, their capacity became insufficient soon. CD once seemed to hold huge amounts of data - just imagine, 650 MB, while most computers were equipped with 200-300 MB hard drives. But these times are gone. DVD? Again several gigabytes instead of dozens of them required. There is also little hope on Blueray - you will have to bring the drive, which costs several hundred dollars, with you in most cases. It's several hundred dollars now, but the need in high capacities appeared long ago.

But large volumes of information do not come from nowhere - you have to store data somewhere before you transport it. This growth has to do with the progress in HDD size. It slowed down from time to time, but it was still present. No matter what we grumble about the last several years, stores begin to offer terabyte hard drives (even though a lot of 10-20 GB models are still intact and working in some computers.) Hard drives below 200 GB are popular only among the most economical users! As capacities grow, compact hard drives (2.5" and 1.8") are getting more attractive from the point of view of their costs per gigabyte. Besides, high-speed peripheral interfaces have quickly become the standard in computers, so that a hard drive can be used as an external device.

As a result, we have recently seen the "ecological niche" of removable disks to be taken by USB drives and portable external hard drives with this interface. The former devices have forced out diskettes, and suppressed alternative storage devices (e.g. small optical discs or new promising devices). But they are not a panacea - convenient and simple to use, they still have a limited number of write cycles, relatively low capacity, and high price (compared to HDD). OK, you can buy a USB flash drive with several gigabytes of storage space for an acceptable price. Their capacity may grow to dozens of gigabytes in the nearest future. But there are some applications, where such capacities are required immediately. Only external hard drives remain. But it turns out that they also have some problems.

Drawbacks of classic hard disk drives

We do not mean drawbacks of hard drives as devices for storing and transporting large volumes of data - as we have already mentioned, they have no real alternative anyway (in future they may be replaced with flash memory or its descendants, but they are not ready now). We mean drawbacks of the existing classic implementation. Their interface in the first place (from the point of view of logic and physical implementation).

Let's start with logic. There has been a weak spot until recently - the "standard" HDD interface (parallel IDE) differed from external computer interfaces. So users need an adapter. It must be in each external hard drive, no matter how many. On one hand, bridges are relatively cheap. On the other hand... how many bridges should be installed? There must be at least a USB-PATA bridge - USB has become the standard interface that provides maximum compatibility long ago. But even its fastest modification is not very fast, so it has acted as a bottleneck for 2.5" hard drives for a long time. It would be better to use something faster - FireWire, FireWire 800, or eSATA. But support for these interfaces must be implemented in a hard drive itself. It will not be necessary all the time, but users will have to pay for it anyway. In other words, you can pay less money and be content with USB. But in this case, you won't be able to use a faster interface, if it's available in a computer. Or you can spend more money, but you won't use the extra feature very often - when you have to use a computer with USB only. It's tempting to have support for all external interfaces. But it's costly in financial and technical terms. Besides, it's difficult to plan anything even for a year ahead, as the IT industry is rapidly progressing. A company decides to use FireWire wherever possible, and then USB 2.0 appears. The company considers using FireWire 800 - eSATA appears on the horizon :) Another turning point happens, and what then? Change boxes? It's easy when you have only one, and what if we speak about a company? Or leave it as it is, that is to continue using a low-speed solution.

On the other hand, these problems can be solved. It will require some expenses, but not very high. What's more unpleasant - low mechanic reliability of the standard connectors. People usually don't think about it, but a "large" USB or FireWire connector must guarantee only 1500 connections. That's quite a lot for an individual, but it's not that big a figure if we speak of mass usage. We don't have exact information about reliability of mini-connectors. But they are constantly trying to raise it, that speaks volumes. We haven't come across problems with A-type connectors very often, but "dead" miniature connectors are a common situation. Sometimes you don't even have to torture them for a long time - just plug them accidentally upside down and that's it :) It often happened with 4-pin FireWire connectors. But the number of users who manage to do it with USB mini-B is constantly growing.

Low mechanic reliability is not the only drawback of manually plugged storage drives. Sometimes, you may have a nastier problem (it's more likely) than the death of your storage drive - data loss. It's easy to have it done - don't use "safe removal" when the system is still writing data to the drive, that's all. If you are lucky, only the last files will be damaged (the ones that were being written when you disconnected the drive). If you are not, you may lose all data (if the system was modifying file allocation tables at that moment). This problem cannot be solved completely for any external storage drive (it has to be connected to a computer, so it can be disconnected). But when manual disconnection is the standard procedure, chances for disconnecting a cable in the wrong time are significantly higher.

Speaking of cables - don't forget that you must bring them with you as well. At least one. If your drive supports several interfaces, you may have to carry more than one cable with you. If you want to make sure you have no problems with power supply, you shall take even more cables, sometimes with a power supply unit. Extra complications.

Active promotion of SATA and eSATA seems to solve this problem. We've got a single interface - both in the computer and in the hard drive, so there is no need in extra conversions. Besides, the interface is quite fast - even 3.5" hard drives cannot load the peak bandwidth of SATA II, to say nothing of smaller models. And the guaranteed number of plug/unplug cycles of eSATA is no less than 5000, which seems sufficient. But don't relax yet. Firstly, you still connect a drive to a computer manually. And it's practically impossible to protect a device from a strong fool of marked initiative :)) - everything that can be broken shall be broken sooner or later. Engineers can try to make it later than sooner, but it's still impossible to eliminate the chance of a wrong connection. Secondly, this higher reliability is questionable, because you must connect two cables, not one. I don't know what developers of this standard thought about (frankly speaking, it's hard to think of a single good reason), but eSATA connectors do not have pins for power supply - you will have to use a separate power connector. Any 2.5" hard drive. That is eSATA has no extra drawbacks for 3.5" hard drives compared to USB (you have to use the second connector for power supply anyway), and it has evident advantages. But you should think twice what interface is better for compact storage drives. Perhaps, it makes sense to sacrifice some performance to convenience. By the way, we shouldn't forget that an eSATA cable can be 2 m long maximum versus 5 m of USB and 4.5 m of FireWire (active hubs can significantly increase cable length of the last two interfaces).

You may have noticed that the existing designs of external hard drives are not very convenient. It works perfectly for individuals (advanced users - at least advanced enough to try to be careful and plug cables correctly :)), who need to transport an external hard drive or a usual hard drive inside an inexpensive enclosure from time to time. Drawbacks of this solution will hardly appear in this case (at least users will make no expensive mistakes), and advantages are obvious - low costs, acceptable performance, and sufficient convenience. More serious applications require other solutions.

Emulating a removable hard drive

We cannot say that nobody was looking for possible solutions. For example, the omnia mea mecum porto problem is solved by Smart Family from ViPower. This initiative implies separating the interface converter from the box with a storage drive. This is a good idea on the face of it - you buy "smart" cables with necessary interfaces, that's it. There can be several different cables and boxes. When you replace one component, you don't have to replace the others. But in practice, the company failed to promote this initiative. It was to late, so the idea did not survive. Besides, this approach could solve only a part of problems, not all of them: you still have to connect the device manually (so there may be mistakes).

All these problems can be solved only if we treat hard drives just like floppy discs or Zips. That is to treat them not like storage drives, but like data media. In a compact case optimized for this usage model. A special docking station (internal or external) should act as a drive. It should be almost always connected to a computer, so the problem with plugging/unplugging cables is eliminated. And discs can be designed to mate with the drive with maximum reliability in mind. It's desirable to provide for a self-load mechanism, so that even a strong user can break nothing.

No wonder that the idea was first implemented by the companies manufacturing removable hard disks. To be more exact, it was one company - by this moment Iomega bought its largest competitor, SyQuest, and almost monopolized this market segment. The first model (that appeared as soon as users needed something more than 1-2 GB Jaz discs) was Peerless. It physically consisted of three parts:

• The interface module - USB (unfortunately, it was only slow Full Speed at that time), FireWire, or SCSI
• The docking station with the cartridge soft load mechanism
• This cartridge is a usual 2.5" hard drive (10 GB or 20 GB) in a special hermetic case