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Older (PZF and PZFX) files

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The default file format for Prism 10 is the new PRISM file format (with the .prism file extension). Sometimes, you may want to save a file in one of Prism's older file formats in order to maintain compatibility with others who are using older versions of the software. This page describes the other two file formats that Prism 10 can save as, and some differences between them.

The two legacy file formats

PZF format: This is a binary format that can be opened by Prism 4 or later, but not by other applications.  

PZFX format: This is a format that can be opened only by Prism 5 or later. The first part of the file contains all the data tables and info sheets in a plain-text XML format that can be viewed by other programs. After that comes information about results, graphs and layouts in a format that is incomprehensible to any program but Prism.

Advantages of the PRISM format over both PZFX and PZF

First and foremost, the new PRISM file format is different from any other format that Prism had previously offered in that it is an open file format. All of your data, analysis parameters, results, graphs, and layouts can be accessed and viewed even without using Prism. Navigating through the file format manually may take a bit of practice, so you shouldn't feel like you HAVE to know how to do it. But with this change, your Prism file can serve as a complete record of your experimental data and results, and allows ANYONE to see the work that you've done just by providing them with a copy of the file (it won't matter if they're a Prism user or not).

The new PRISM file format is also generally faster to work with than the other legacy formats. This is especially true when dealing with large amounts of data and performing operations like opening or saving the file, switching between sheets, or exporting graphs and layouts.

Advantages of PZFX compared to PZF

The PZFX format is a bit more secure for long-term backing up. Even without access to Prism, the data in the file are in plain text that can readily be viewed.

Files saved in PZFX format tend to be much smaller (about 10% the size) than the same file saved as PZF. We recommend that you use PZFX files routinely. Even though PZFX files are almost always smaller, they may be faster or slower than PZF files to save and open, depending on how large your data tables are and whether you included pictures in your graphs or layouts.

The data (and info and scripts) are in a plain text format at the beginning of the PZFX file. It is possible to create a program that swaps out the saved data with new data. Open that altered file, and the new data will instantly be analyzed and graphed.

Disadvantages of PZFX compared to PZF

Prism 5 was the first version that understand the PZFX format, so these files cannot be opened by Prism 4.

Avoid the .PZFX format if you plan to post the file on a web site. Web browsers sometimes detect the XML format, and try to open the file with some program that understands XML rather than opening with Prism. In contrast, .PZF files generally just open in Prism, as they should.

The PZFX format never contains analysis results, so Prism needs to recompute the results when it opens the file (or when you view those results pages or graphs that depend on them). If your analyses are very slow to recalculate, choose the PZF format with the Compact option turned off (see below). These files will contain analysis results, so Prism will not need to recalculate anything when you open the file.

With large files, it takes about ten times longer to save or open a PZFX file than a PZF file. This is because the information about graphs and layouts is compressed in PZFX files, and compressing/decompressing can be slow.


What if you have files with the .prism, .pzf, or .pzfx extensions but with the same name?

Prism opens the file you ask it to open. It won't even "notice" that there is another Prism file with the same name (except extension). It won't coordinate the two files.

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