How broadcast FM can wreck your receiving system

Today I came upon some news weird enough to justify a post on this long-dormant blog. Ars Technica reports that it “began on January 30 and afflicted Mazdas from model years 2014 to 2017 when the cars were tuned to the local NPR station, KUOW 94.9. At some point during the day’s broadcast, a signal from KUOW caused the Mazdas’ infotainment systems to crash—the screens died and the radios were stuck on 94.9 FM.”

That shouldn’t be possible, right? A broadcast FM signal is just frequency-modulated audio. It might deafen you or damage the speakers, but it shouldn’t make the receiver stop working! Well, actually, it isn’t just audio. Broadcasters can optionally use the Radio Broadcast Data System (RBDS), which supports encoded digital data. It uses a 57 kHz subcarrier, well above the limits of human hearing. The data is encoded at 1187.5 bits per second, a strange-sounding number that yields 48 cycles of the subcarrier for every bit. Error correction codes bring the effective data rate down to 730 bits per second.

JHOVE Tips for Developers

I got a request for my ebook, JHOVE Tips for Developers. It’s no longer for sale on Smashwords, since I haven’t updated it since 2012, but if anyone wants it, you can download JHOVE Tips for Developers from this site.

Looking at some ballot scanning issues

The town of Windham, New Hampshire, became the site of a controversy when the results of a ballot recount by hand didn’t match the original results. This has some interesting implications for ballot scanning and errors in the process, so I think it’s fair game for this blog. I’ll have to get into the politics to give it context, though.

The four winning candidates for the state legislature were found to have gotten about 300 additional votes each, while the one who requested the recount got fewer, so the results weren’t affected. Still, it was appropriate to ask why the scanners’ total was so far off. The town accordingly had an audit conducted.

“Shadow attack” allows alteration of signed PDF files

The more complex a format is, the less chance there is that its security features will work in all cases. A vulnerability has turned up that lets sneaky people alter digitally signed PDF documents. A German team discovered a “shadow attack” vulnerability in the format. It’s easiest to do this if the document’s creator designed it to be altered after signing. The victim sees one set of content and signs it; the dishonest creator gets the document back, changes its appearance, and passes it on.

Preserving Yahoo Groups

Yahoo is sending out alerts on the transformation of Yahoo Groups into a list server. The spin is ridiculous. The changes “better align with user habits,” and “we are making adjustments to ultimately serve you better.” It’s as if users had been protesting against the existence of public groups and Web-hosted discussions and Yahoo were complying with the demand.

Yahoo, in case you haven’t been keeping track (I hadn’t), now belongs to Verizon. It makes economic decisions, and one was that running public Yahoo Groups was no longer worth the cost and effort. This is the result of changing user preferences, as well as stupid policy decisions over the years that drove people away. The attempts to correct those blunders may be part of the current problem.

Nefertiti, now available as a 3D scan

One of my favorite areas in Berlin is the Museum Island. It includes the Egyptian Museum, which is part of the Neues Museum. Among its most famous possessions is a bust of Nefertiti which dates from about 1340 BCE. The museum has an entire room dedicated to Nefertiti.

More relevant to this blog, it has made a detailed 3D scan of the bust. The museum belongs to the Prussian Cultural Heritage Foundation, which is funded by the federal government and the 16 state governments. Supposedly it has an obligation to make its information public, but for reasons that aren’t clear, it held tight to that scan for a long time. It’s now available as a free download, ten years after it was made, thanks to the persistent efforts of Cosmo Wenman. He tells the story on Reason.com.

Finale and macOS

I’m not entirely sure where the right place to put this is. It’s a file format issue in part, since if people can’t keep using Finale after a macOS upgrade, they need to salvage all the files they’re created in its proprietary format.

The email which I got from MakeMusic, dated October 18, was alarming:

Finale v25.5 is not compatible with macOS 10.15 Catalina and will not be updated to support Catalina. It is our recommendation that users of Finale v25.5 not upgrade to macOS Catalina.

Fileformat.com

In my recent searches, I came across Fileformat.com, which presents itself as a guide for developers. There’s no information on the site about who’s running it, though most or all of the articles on the wiki are credited to Farooq Sheikh. The site looks worth following. The main sections of it are:

• A wiki on file formats. It isn’t as thorough as the Archive Team wiki, but it has some good technical information on the most popular formats.
• A news section, which consists of links to articles on other sites, including some of mine. Not all of them are strictly news, but they’re all relevant to people with a specialty in file formats. It has an RSS feed, though it isn’t advertised. There aren’t a lot of RSS feeds on file formats (besides the feed for this blog, of course), so it could be worth bookmarking in your reader.

I’ve added a link to the site in my sidebar.

The tape obsolescence problem

An ABC News Australia article calls attention to the problem of archives on magnetic tape. Author James Elton clearly knows something about digital preservation issues, as the article goes beyond the usual generalities and hand-wringing.

Tapes, on the other hand, can only be read by format-specific machines.

And dozens of formats of magnetic tape were created through the last century — one-inch, two-inch, various versions of Betamax.