PriceSCAN Blog

It is now a commonplace for machines, both desktop and laptop, to have storage measured in Gigabytes. And as individual users begin to build archives of photographs, videos, music and TV shows, storage requirements that approach Terabytes are not out of the question.

There seem to be three ways that this kind of storage can be made available in current systems. First, it can be built-in. This is simple and straightforward. These days if you buy a desktop machine that is described as a media center, or its equivalent, you will typically get somewhere between 200 and 500 Gigabytes of storage directly built in to the machine, just as you'd expect to find a hard disk configured. In a notebook, you'd expect to find 40 to 100 Gigabytes of storage. These numbers are reasonable tradeoffs between the desktop and laptop worlds, and the only additional requirement is that the disks involved rotate quickly enough to that it is possible to stream images off at a rate sufficent for display television. Current specs seem to indicate that 5400rpm is sufficient, while slower rotational speeds are not.

Second, there are storage devices that connect to machines via firewire and/or USB 2.0. This configuration differs from the built-in configuration principally in that it is easy to move the disks from one computer to another. Typically all that need be done is for the cable to be moved. These days 250 to 400 gigabytes of such storage is (physically) quite portable, so it becomes a natural way of carrying a huge amount of storage from one system to another. And the speeds which can be achieved in the connection channels are of sufficent power that the transfer of information can proceed at a comfortable rate. In this case a "comfortable rate" can be defined as a rate sufficient to keep up with the display of images on a TV screen.

Third, there is Network Attached Storage. These boxes share many common properties with the portable disks just described above, but in addition they have enough computational capability that they are able to support the interpretation of a file structure and an IP node. Thus, instead of hooking up to a machine, they hook directly on to the net, and stand ready to serve any of the machines that have access to the net. All of the security issues are dealt with just as one would expect on a network.

The economic analysis of these devices can lead to some strange anomolies in cost. This is probably just the effect of the information about alternative devices and capabilities as it flows out to the marketplace. It was regarded as a giant breakthrough when the price of a terabyte of storage dropped to $5,000. Now it is available, in a very convenient form, for about $1 per Gigabyte, or $1,000. And the price continues to drop.

The cost of this kind of storage has two components. One is the raw cost of the storage. This applies to those devices that connect via a USB port or through Firewire. If we are talking about Network Attached Storage then there is some additional cost of providing the hardware that effects the management of the network and its relationship to the storage devices.

Sometime this leads to strange design decisions. For example, Linksys has a Network Storage Link which is supposed to take USB devices and convert them into Network Attached Storage by performing the appropriate translations and providing the appropriate interface. It does, indeed, do this, but in doing so it insists on reformatting the storage to its own specification. This, in turn, means that the storage devices become useless unless they are attached to systems via a NSL. Thus the storage no longer has any value on a stand-alone---where we might want to run without any net---or in moving from one system to another, unless we are willing to move the NSL as well.

Given the number of machines that are sitting around these days, it seems that a more practicable solution is to simply devote some old machine to the role of attaching one or more storage devices to the network. I would imagine that lots of users have now accumulated some ancient machines which they would be willing to sacrifice to this role. It would seem to be a superior way to connect things up.

In any case, this kind of storage is now both accessable and affordable. It's not a bad approximation to assume that you ought to be able to get lots of storage at about $1/Gigabyte. That means that for about $1000 you can buy a terabyte of storage and have room for a week's worth of TV, a year's worth of Music, or a lifetime worth of photos.