关于“向后兼容”（backward compability）的含义

收到《自由软件杂志》08年1月13日发的newsletter，其中一篇文章《**Microsoft's half-hearted support for old office formats** 》对微软的Office套件的做法提出了批评。

“I don’t know about you, but I wonder how a company like Microsoft can boast about “maintaining backwards compatibility” when it uses such cheap tricks: I mean, they created OOXML to “properly support and convert legacy file formats to XML”, and at the same time, under the only suites that are supposed to natively support this “newer” format, you can’t open legacy formats!”

“Right now, it seems that on the matter of document formats, Microsoft thinks that backward compatibility can be summed up by “support only our 10-year old formats, and dump them into a pseudo-XML file”, while the competition seems to think that backwards compatibility means being able to open older files the best one can, if possible also output files in those formats, and port them to a file format geared towards storing as many different types of data as possible (if you look at what existing standards ODF 1.2 will support, then compare with OOXML’s reuse of existing standards—or lack thereof; it’s no wonder ODF, although ‘only’ 1000 pages long, is better appreciated than OOXML’s 7000 page long specification!).”

“Method 1: the easy way out --This is the solution Microsoft has chosen, telling everybody the excuse that the file formats in question are old, and some were not created by them: it is thus considered too hard to support and fix this “old” code; so they merely disable it. They don’t want to correct their old binary file parsers, and don’t even think about reverse engineering other formats: if this area of code falls prey to bit-rot while there are still people interested in using them, no matter how much the suite costs, they’ll merely amputate it.”

“Method 2: the hard solution--This solution is the one retained by most other office suites authors, both proprietary and open: reverse-engineer older formats better, rewrite parsers to make them more efficient, cleaner and less prone to crashing.”