Friday, June 12, 2009

Math on Kindle DX

My Kindle DX arrived yesterday. I loved my first Kindle which I used for reading books and the New York Times. But the Kindle couldn't handle mathematical papers. The DX has native PDF support. So how well does it do for our community's papers?

I tested the DX on PDF documents, postscript won't work. I chose papers from STOC, CACM, Springer and Elsevier journals, ECCC, my own PDFlatex generated papers and the open access Theory of Computing and the ACM Transactions on Computation Theory journals. 

The math looks great. The resolution (1200x824) looks fine, the formulas and diagrams show up as good as on regular paper. No color but that's not an issue for most of our papers.

The papers take a couple of seconds to load and usually (but not always) quick to change pages. I had the worst experience on a scanned paper (Valiant's permanent paper) which took a very long time to load and change pages and looks as lousy on the Kindle as it does printed.

There are two ways to view a paper: portrait and landscape. Let me discuss each separately.

Portrait: A page of the PDF is filled into the screen area. The screen is about 3/4 the height and 2/3 the width of the US standard 8.5x11 paper so some papers are slightly squished, particularly multicolumn STOC and CACM papers have this problem. The ToC and ToCT papers looked the best. The text, formulas and diagrams are also shrunk but still quit readable as long as I am using my reading glasses (yes I've gotten old).

Landscape: You get to landscape mode simply by turning the screen (or manually with the Aa button). The landscape mode keeps the original aspect ratio but you only see part of the page. The width of screen in landscape mode is about the same as the width of regular paper so the type size is about right. You can move through the rest of the page with the Next Page/Prev Page buttons but otherwise no scrolling. The 5-way button seems to have no effect on PDF documents.

Extras: You can do a basic text search within a PDF document but not between documents or in scanned documents. Unlike normal Kindle documents you can't change the type size, add notes, highlight text, convert text to speech or move to a word to get its definition. You can bookmark a page but otherwise the only way to navigate is via the next page/prev page buttons. No way to click on links within a PDF file.

You can move documents quickly through the USB cable. The Kindle has tons of memory and can hold lots of PDF files. You can move whole directories but the Kindle flattens them out listing every file (by file name) separately on the main home page. You can also email papers at $0.15/MB and most of our papers are well under a megabyte.

Many of the issues above could be fixed by software updates but no guarantees Amazon will do so. Also it shouldn't be hard to produce DX-friendly PDF documents, with the right aspect ratio and large font size. If the DX gets popular than publishers might start producing Kindle-friendly versions of their papers. The old Chicken v. Egg problem.


  1. The Amazon web-site says that its in stock from Jun 17. So how did you manage to get it a week early ? But thanks for the thoughtful review. At $489 a piece its not an easy decision by any stretch.

  2. I also tried math pdfs (along with tables with data, and graphs) on Kindle DX, and they look fantastic (thought sometimes too small, when the original paper has small margins and small font to begin with). What would be nice is a LaTeX-to-KindleNativeFormat compiler...

  3. A bit annoying that there is no support for directories. Especially since my plan was to load every STOC/FOCS paper on the device...but if the files are flattened so they all appear on the same homepage, it will be a pain to access them.

  4. There are out there alternatives with support for directories. I am thinking on the "Irex DR1000S" device.

    It is a bit more expensive, but besides the support for directories it also allows to annotate the pdfs using a pen (this is great).

  5. On the Kindle, can you add comments/notes to PDFs, like electronic margin notes or "sticky notes" that you can save and search for later?

  6. Dave: Would be nice but I don't see any way to add notes to PDF documents on the Kindle.

  7. I bought a Kindle 2 and had it for three weeks. I just couldn't wait for the DX. When the DX arived I returned the kindle 2. I am completely satisified with the Kindle DX. I think it is a great piece of engineering technology.

  8. Does the brand new Kindle DX support folders? I love my kindle 2 and everything but I can't stand that I can't have folders to organize my stuff!

  9. My Kindle DX just arrived. It exposes a basic divide in digital print, between HTML-style flowable, scalable documents, and PDF-style representations of physical pages. Mathematics is mired on the wrong side of this divide. Knuth may have famously said that "premature optimization is the root of all evil", but TeX's decision to lay out a predermined physical page is an embodiment of this exact evil.

    I'm an old gheezer, and I remember being stunned by my first experience programming an IBM 360 mainframe at a terminal: It wanted me to work with virtual punched card images. What!? Come up with a dozen adjectives describing how absolutely idiotic this is, then ask why no one is applying these same adjectives now to virtual page images. Let's not celebrate the Kindle DX support for PDF documents; PDF here is the root of all evil. The Kindle shines with math that has been converted to its native, flowable, scalable format. Where are the tools to allow free journals such as published by the AMS to provide this format, without getting monetized by Amazon's business model?

    It's a slanderous old chestnut that computer scientists only use their computers for email, but I smile at the attention this blog post brings to multicolumn STOC and CACM papers. These formats conjure up horrifying images of computer scientists still using paper. Apparently one cannot become an editor of one of these journals without ossifying to the point where new centuries begin unnoticed. These multicolumn papers are painful enough to read on a 1920 x 1200 landscape monitor, nearly impossible to read on a laptop, and pure idiocy on a Kindle DX. Can we start a cream pie conspiracy to keep these editors from conferences until these formats change?

    Meanwhile, one can cope with multicolumn documents by using PDF software to cut each page in four. Then they actually look pretty good on the Kindle DX. Go figure.

  10. Dave: As Lance said, no, you can't modify PDFs like that.

    Buy Kindle: I just use the open source software at to manage my content. I think support for Kindle DX is still in beta, though, but it still works pretty well. This piece of software does support many other readers as well, and even the iPhone.

  11. I still can not decide between Kindle 3G Wireless and Kindle DX. At this moment money is not the issue, but the size and weight of this device is important to me. SO I am still on the fence. LOL

  12. I heard about this Chinese APP for the kindle called DUOKAN or DUAKAN. Does this APP make life easier for PDF's on the kindle DX? thanks

  13. It's normal for a scanned paper to load slowly because it cannot recognize letters so it's saved as a picture in pdf or other format, and pictures are big and slow loading

  14. I am close to making the change from Kindle 2 to DX. I really want the extra screen acreage, for landscape viewing of news and PDFs. Since you wrote this there have been some improvements in the DX.
    Thanks for the great article.