Over the years, Apple has taken its share of criticism for the sparseness of the release notes that accompany its software updates. This lack of information can make it difficult to determine exactly what has been fixed--or whether a supposed fix actually does its intended job.
Such is the case, even more so than usual, with the release notes for Safari 5.1.2. For those of you seeking more guidance, I offer this closer look at the four cited "improvements" contained in the latest Safari version:
• Improved stability: Presumably this means assorted bug fixes. This is fairly typically Apple jargon. To some extent, I give Apple a pass here. It's not necessary to air all your dirty laundry. By listing every little thing that you've fixed, you wind up emphasizing every little thing that was wrong with the previous version. This doesn't make for good PR. Still, many other software companies do exactly that--and remain successful. Especially if you've been bothered by a particular bug, it would be nice to know whether or not it's been fixed.
Based on what I read on the Web, Safari 5.x has been less-well received than prior Safari versions--due to various bugs and performance issues. With people abandoning the Safari ship for Firefox or other browsers, more details here might help to bring people back.
• Address issues that could cause hangs and excessive memory usage: This is precisely one of the performance issues that has bothered users. It would be great if memory usage declined significantly with this update. Unfortunately, I could not detect clear evidence of this. I checked in with Activity Monitor. As seen in the figure below, Safari Web Content (a component of Safari) is using more memory than any other process. Add in the memory allocation for the separate Safari process, and the memory usage of the combined processes far surpass any other software.
Perhaps Safari 5.1.2's memory allocation is lower than it would be with the prior version. Maybe. Even so, it's hard to consider this issue "fixed."
• Address issues that could cause webpages to flash white: A problem here is that Apple does not exactly make clear what it means by "webpages to flash white." We are left to guess. Most people are guessing (and hoping) that Apple is referring to a problem I covered in a prior Bugs & Fixes column: "If you have multiple tabs open in a Safari window, you may find that when you click to change the active tab, the newly selected page temporarily goes blank as it reloads."
This irritating symptom typically happens if and when Safari Web Content crashes. So, to see if this had been fixed, I forced the process to quit. The result was unchanged: blank pages still popped up and reloaded. Again, something may have been improved (perhaps the frequency with which the symptom occurs is now less), but it's hard to tell.
If you search the web, you may come across a suggested work-around for this symptom: Enable Safari's Debug menu and de-select the "Use Multi-process Windows" menu command. While this appears to work, I would stay away from the solution. Its side-effects are worse than the symptom it fixes. Not only does the work-around disable other useful features of Safari (such as extensions), but Safari may begin to crash repeatedly. That's what happened when I tried it; others are reporting this as well.
• Allow PDFs to be displayed within web content: This is another case where Apple's language is sufficiently sparse that its meaning is not immediately clear. Indeed, when I Googled this phrase, every article I checked quoted Apple's text but did not further elaborate on what the fix meant. When I queried my Twitter followers, they came up nearly empty as well. One person suggested that it likely referred to embedding a PDF document within an HTML page (as covered in an eHow article). This seemed logical to me. Embedding isn't done nearly as often as opening a PDF as a separate URL. But there are webpages that do this.
Confirming this explanation, when I tested out pages that contained embedded PDFs (such as this one), they loaded fine in Safari 5.1.2 but resulted in a "Missing Plug-in" error on a Mac still running 5.1.1. Wherever the plug-in is located, it's not within the Safari app itself. When I launched a copy of Safari 5.1.1 on a Mac where 5.1.2 had already been installed, it loaded embedded PDFs correctly. I'm guessing the plug-in is in one of the frameworks in /System/Library.