VACS of version 2.1.3 comes as a 32-bit version and 64-bit version.
Both versions can be installed in parallel. They are file-compatible unless the size becomes too large for 32-bit as described below.
The major difference and also the main driver behind the development of the 64-bit version is memory allocation. 32-bit applications are restricted to allocate no more than 2 giga byte of memory. This has to do with the range of a digital 32-bit number. The range of a 64-bit number is of course much larger. Hence the 64-bit compilation of VACS allows to allocate a wast amount of memory. VACS keeps all data in memory and because of this the size of the project-file is limited.
The 64-bit version is useful if you expect to work with big data-sets. For example, if you are going to process data of balloon measurements. For example, a single balloon measurement of Nf=4096 frequency points of complex valued data for every 5 degree on a sphere yields: 8·Nf·360·180/5 = 425 MB. Hence with the fifth such data-set the 32-bit version would go out-of-memory (of course, down sampling on the frequency grid to Nf=200 would help).
Keep an Eye on File Size
The 64-bit version allows for big data. This is great. However it also has disadvantages. In general if you put a lot of information into a single data-file the likelihood of failure raises and you may loose it. It is advisable to make sure that VACS-project are of medium size. Then open- and save-operations are faster. Copy operations would be more save. And if there is a process which would stall VACS then only part of data would be lost. As a recommendation we suggest not to store too much information into a single file although the 64-bit version would be capable to do so. May be a good limit is that the file-size stays smaller than 300 MB.
There is a difference relating to the import drivers of the 32-bit and 64-bit versions. If available both versions should yield the same result. Currently available are following drivers for direct import of measurement data:
Import drivers are constantly developed. With time also the 64-bit version will support all formats of the 32-bit version.