Now that most of the new PCs are being delivered with the 64-bit versions of the new Windows operating systems (Windows 7 and Windows Server 2008), some confusion has developed around implementation of TWAIN-based scanners. The TWAIN Working Group released the 2.0 spec for TWAIN and a new 64-Bit Data Source Manager a couple of years ago. However, many of the currently available scanners do not yet come with true 64-Bit TWAIN drivers.
The situation is even more confusing when you realize that in the 64-Bit version of Windows, you can run 32-Bit applications, and use 32-Bit drivers. But the 32-Bit applications will only use the 32-Bit drivers, and the 64-Bit drivers will only work with true 64-Bit applications. We and other software application suppliers (such as Adobe) find ourselves in a transition between 64-Bit and 32-Bit operating systems. For this reason, Alto is providing both versions of our applications.
Hence, for example, Image Arranger comes in both flavors. If you install Arranger on a 32-Bit OS, only the 32-Bit version will be installed; if you install on a 64-Bit OS, both the 32-Bit version and the 64-Bit version can be installed. So, if you have a scanner which does not yet come with a 64-Bit driver, then you can run the 32-Bit version of Arranger and it will look for drivers in the 32-Bit Data Sources folder. If you run the 64-Bit version of Arranger, it will look for the drivers in the 64-Bit Data Sources folder. To our knowledge (based on examining a fairly large number of popular scanners), there are no 64-Bit TWAIN drivers available. They are all running in 32-Bit compatibility mode on 64-Bit PCs. This means that the 32-Bit versions of the apps can use the 32-Bit TWAIN drivers and access a scanner as it would in the 32-Bit OS. But, the 64-Bit versions of the apps cannot access the 32-Bit drivers.
Some scanner suppliers are apparently advertising drivers as 32/64-Bit compatible. This could mean that they are packaging both versions in the driver install file. But, please be aware that in most cases we have seen, it only means that the drivers will work in both 32-Bit and 64-Bit versions of Windows. As discussed above, you can use the 32-Bit drivers in 64-Bit Windows, but only with 32-Bit applications.
Why does it matter? The migration to 64-Bit environments is based on the need for a much larger memory space for modern high-performance applications. If you are working with large, high-resolution image files, and, especially for full-color documents, then the memory requirements can easily get into the multiple Gigabyte range. Since Windows 32-Bit operating systems are limited to about 3 GB of application memory space, this can seriously constrain the size and complexity that a document can have. Additionally, the 64-Bit data pathways are twice as wide, and therefore, large amounts of data can be moved around and manipulated at least twice as fast. Our experience with running the 64-Bit version of Arranger is that it is "blazingly" fast compared to the 32-Bit version – on the same hardware. This is why you ultimately want to purchase scanners with a true 64-Bit TWAIN Data Source – so you can enjoy the increased performance of the 64-Bit application. You cannot scan using the 64-Bit version of Arranger unless you have a real 64-Bit TWAIN driver. A good way to view the situation is that we're in a transition period. Until you can replace your scanner's driver with a 64-Bit TWAIN driver, you can still operate with the 32-Bit version of Arranger and the 32-Bit TWAIN data sources; but as soon as possible, you can benefit by going the full 64-Bit route, either by updating your driver, or replacing your scanner with a new one that has a 64-Bit driver. Be sure to ask if it is a "true" 64-Bit driver or you may be surprised by the marketing "trickery" mentioned above.
Since there are distinct advantages to having the 64-Bit app, they are both included. For example, the 32-Bit version of Arranger, using the 32-Bit TWAIN driver, can scan a document needing some amount of editing/make-ready work. This document can then be edited and printed from the 32-Bit application the same as it was before the existence of 64-Bit versions of the OS. However, if the document has certain properties that make it too large or cumbersome to work with in the 32-Bit version of Arranger, the document can be saved as a TIFF file and opened in the 64-Bit version for the editing work. Until there are true 64-Bit drivers for one or more of the production level scanners, this compatibility dichotomy is unavoidable.
The 64-Bit version of Arranger, just like the 64-Bit version of Photoshop and other imaging apps, is very much faster and capable of working with immense amounts of memory, providing a superior application experience. This is the primary reason to launch the 64-Bit apps and hope that the scanner manufacturers will see the merits of catching up with their scanner drivers.
