Adobe's Acrobat document format, known to many simply as PDF, has become a popular means of distributing files over the web in a way that preserves their original formatting. Long available for desktop machines, Acrobat Reader has now been released as freeware in both Palm and Pocket PC versions, but will this make PDF a truly cross platform format ? Read on to find out.

Over the last few years handheld computers have become an indispensable aid to people like myself who wish to carry around documents normally kept on their desktop computers. Gradually the number of document formats that can be copied/converted to a handheld format has increased. Word, Excel and PowerPoint documents can be viewed and even edited on my Palm or Pocket PC. But, until the recent release of Acrobat Reader there has not been a free solution to view the numerous PDF files I keep on my laptop at home. Acrobat was developed to provide a means of distributing files made on different operating systems in such a way as to preserve the document's formatting. A document made using Microsoft Word and converted to a PDF should then appear the same on a PC or Mac. Acrobat's success has led it to now be accepted as one of the world's most commonly used file formats, so I was very keen to try out the new reader software on my Palm and Pocket PC. What follows is a description of my experiences using the software.

Installation

Both Palm and Pocket PC versions of Acrobat Reader are available as a free download from the Adobe web site. The application is provided as a self extracting .exe file which installs both the Acrobat Reader and desktop conversion software. The download is a little large at approximately 6MB and 8MB for the Palm and Pocket PC versions respectively, but the size of the installed application on the handheld is smaller at 150KB on my Palm Vx and 1.7MB on my iPAQ.

Getting PDF files onto your handheld

The installation process adds a user guide in PDF format for you to read, but if your like me you will be keen to copy across one of your own files. As an example I have chosen the 'Handbook of Anesthesiology' from Current Clinical Strategies Publishing. This is a 758KB textbook of Anaesthesia that contains 200 pages of both text and graphics and is just the sort of document that I would like to carry with me. To copy the file to my Pocket PC all I had to do was select 'Explore' from Microsoft ActiveSync and drag the PDF file to my mobile device. ActiveSync then handles all the conversion. Copying the file to my Palm Vx was also a breeze. I simply needed to drag the file across to the Acrobat for Palm Desktop (Figure 1) which is then copied to your Palm on the next HotSync.

	Figure 1: Acrobat for Palm Desktop.

If your PDF file was created with the latest version of Acrobat then that's all there is to the installation process. Odds are though that most of your PDF documents were created with versions preceding v5.0 so here comes the first problem. Whereas PDF documents may have been designed to look the same on different machines, this cannot simply be extended to include handhelds when you consider the small screen sizes. Yes you could simply drag the PDF file across to your Pocket PC then use a great deal of zooming and scrolling to view the document but this is hardly the most efficient way to read text. Aware of this, Adobe has added the option in the latest version of Acrobat to 'tag' files to make them easier to read on a handheld. What this means is that files which have been 'tagged' contain additional information about the structure of the text so that it 'reflows' better on a smaller screen removing the scrolling from side to side. All is not lost however if your PDF file was created with an older version of Acrobat. The Palm Desktop or Microsoft ActiveSync can try to add the extra information needed to untagged files so that they reflow correctly. In Figures 2a and 2b you can see an example of the same page on my Pocket PC. In Figure 2a is the untagged page which you need to scroll around to read all the text. In Figure 2b is the same page that has been reflowed so that the text now fits the screen correctly.

	Figure 2a: Text before reflow to fit screen.

	Figure 2b: Text reflowed to fit screen.

Reading PDF files on your Palm or Pocket PC does seem to come with a large memory cost. The Anaesthesia text I have used in the above examples occupies 758KB on my laptop, but when it is converted to a handheld format the file size increases. In Figure 1 you can see that the same file size on my Palm is 1286KB (or 1242KB without images) and on my Pocket PC it becomes a massive 1.77MB. Despite the increasing availability of high capacity low cost memory cards, for me such an increase in file size represents a major drawback.

Reading your PDF files

PDF files are normally created with the larger screens of desktop machines in mind. As I already mentioned though, tagging of files when they are created or allowing Acrobat Reader to reflow the documents largely eliminates the need to scroll from left to right. Basic navigation of files then is achieved by using the scroll bar, the up/down keys on your device or by dragging the document with the stylus. With larger files the table of contents can be used to jump straight to the section you wish to view. ( Figure 3 )

	Figure 3: Table of Contents allows easy navigation.

The table of contents is supported in both Palm and Pocket PC versions of Acrobat Reader but the larger screen of the Pocket PC allows the contents to be viewed at the same time as the text by using a split screen mode. The larger screen of the Pocket PC has a second advantage in supporting the rotation of text to display more of each page at a time. ( Figure 4 )

	Figure 4: Landscape mode, full screen, on a Pocket PC.

The Find feature seen in the desktop version of Acrobat Reader has been included also, but when searching larger PDF files I found it rather slow on both my Pam Vx and Compaq iPAQ 3850. Speed is not so much of an issue with smaller files, but with the ability to search for text generally being better suited to larger documents, this feature is rather disappointing. When using the example 200 page Handbook of Anesthesiology on both Palm and Pocket PC devices, find was so slow as to make it impractical taking several minutes to search the document.

Acrobat files are not only used for distributing text but also support the use of images and tables. ( Figure 5 ) As expected, a certain amount of zooming and scrolling is necessary to get the most out of embedded pictures but the results are still rather good, particularly on colour machines.

	Figure 5: Viewing image embedded in PDF file.

Summary

If you have purchased a new desktop/handheld computer lately it is likely that the documentation came on a CD rather than in a printed form. It is also quite likely that any electronic documentation was present in PDF format. So, with PDF files now readable on a variety of machines and resolutions is PDF the universal document format? Well, Adobe has overcome many of the problems of displaying documents designed for larger screens on smaller devices but unfortunately this still leaves the PDF reader too slow and memory hungry for many to use. But, for those like me who have a large number of PDF files on their desktop, a free handheld solution for reading them is very useful despite these limitations. I found that smaller technical manuals and journal articles work very well but larger documents, although perfectly readable, are far too slow to search effectively. The dramatic increase in the size of some files is rather disappointing but, with the reader allowing the use of expansion cards for document storage, it is still possible to carry around several large PDF files at once.

In this review, I have only really considered Adobe's own software but, as it is freeware and other applications involve stripping the PDF file to text only, I feel the Adobe Acrobat Reader remains the best solution for handling PDF files on a Palm or Pocket PC. I do not think though that PDF is the best format to distribute documents on handheld computers. It's use still remains better suited at present to desktop machines. For those of us that need a portable means of viewing our existing PDF files however the reader software remains very welcome.

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Written by Chris Hopkins who runs the PDA Anaesthetic web site.