This links to a much more complete article from the SWling Post, but unlike most of my external-link posts, I have quite a bit to say about this. The gist is that there’s a pair of antenna arrays in Colorado broadcasting an analog and digital signal on 60kHz. The proposed FY19 PresBud proposes shutting this radio transmitter down. I’m a radio nerd, and an analog nerd, and I’m always lamenting over technological shifts and shutdowns that nobody else cares about. Like, say digital transmissions on the AM band. But this is different. Part of NIST, WWVB broadcasts an incredibly accurate time signal across the U.S. If you have a clock or watch that describes itself as ‘atomic’, it maintains its accuracy because of this radio transmission.
WWVB sits next to WWV, which started its life in Washington, DC in 1920. For nearly a century, we have had an official radio broadcast of the time. In 1983, Heathkit released the GC-1000 clock which automatically synched with WWV. It was quite possibly the first clock for consumers to receive radio direction for impeccable accuracy, and one of the only radios to use WWV before WWVB went online. These clocks still routinely sell for upwards of $200, with an unbuilt kit selling on eBay this month for $810. I’m sad to see AM going digital, SW dying out partly because of such a rich legacy of receivers out in the wild. To an extent, this is no different – be it WWV, WWVH (on shortwave, similar to WWV but in Hawai’i), or WWVB, millions of devices seemingly magically pull an impossibly accurate (and official) time standard out of the air.
As the linked post mentions, most people likely have no idea how their ‘atomic clocks’ work. A lot of people seem to think that anything that happens automatically is just the internet at work. Time signals are also by necessity provided by GPS. But a ubiquitous (stateside) terrestrial signal that is easily interpreted and worked into signals… it’s obvious why that caught on (again, with millions of clocks out there in the wild). It’s incredibly disheartening to think that an open, official time broadcast will just disappear… but it’s far beyond disheartening to think about how that will affect millions of clueless users.
The array (originally built in the 1960s) has been upgraded and refurbished several times over the years, and in fact within the past decade. The bottom line is that an official standard is available to the entire nation via an easily received and decoded signal. This standard is time itself. This may seem trivial, but it’s important. Though from a budgetary standpoint it truly is trivial. This administration cuts every tiny thing it feels it can mock while lining the pockets of defense contractors and other private-industry capitalists. If you’re reading this, and you care about the free spread of information… things like WWVB are the prototypical information age. Contact your representatives, and let it be known that this is an unacceptable cut.
One of the stranger accessibility myths that I often run into is that merged cells in tables are to be avoided at all costs. This is entirely antithetical to semantic structuring of data and really points to a larger issue: often, folks who are doing and talking about accessibility have no concept of tabular structure, data relationships, and the importance of context. This goes both ways – often, folks that I receive documents from will have put multiple pieces of data in a single cell, either because they don’t know how to make the cell border invisible, or because they’re afraid to merge a cell that spans all the pieces of data.
One of my favorite accessibility myths is this pervasive idea that alternate text is some kind of accessibility panacea. I get it – it’s theoretically a thing that content creators of any skill level can do to make their content more accessible. Because of these things (and because it is technically a required attribute on
<img> tags in HTML), it seems to be one of the first things people learn about accessibility. For the uninitiated, alternate text (from here on out, alt text) is metadata attached to an image that assistive tech (such as a screen reader) will use to present a description of an image (since we don’t all have neural network coprocessors to do deep machine-learning and describe images for us).
This is all very good, if we have a raster-based image with no other information to work with. The problem is, we should almost never have that image to begin with. Very few accessibility problems are actually solved with alt text. For starters, raster images have a fixed resolution. And when users with limited vision (but not enough-so to warrant use of a screen reader) attempt to zoom in on these as they are wont to do, that ability is limited. Best case scenario, the image is at print resolution, 300dpi. This affords maybe a 300% zoom, and even then there may be artifacting. Another common pitfall is that images (particularly of charts and the like) are often used as a crutch when a user can’t figure out a clean way to present their information. Often this means color is used as a means of communicating information (explicitly prohibited by §508), or it means that the information is such a jumble that users with learning disabilities are going to have incredible difficulty navigating it.
Talking about certain files as ‘binaries’ is a funny thing. All files are ultimately binary, after all, it’s just a matter of whether or not a file is encoded as text. Even in the world of text, an editor or viewer needs to know how the text is encoded, what bytes map to what characters. Is a file ASCII, UTF-8, PostScript? Once we know something is text or not text, it’s still likely to be made to the standards of a specific format, lest it be nothing but plain text. Markdown, HTML, even PDF are human-readable text to an extent, with rules about how their content is interpreted. A human as well as a web browser knows that a
<p> starts a paragraph, and this paragraph continues until a matching
</p> is found.
If we open a binary in a text editor, we’ll see a lot of familiar characters, where data happens to coincide with printable ASCII. We’ll also see a lot of gibberish, and in fact some of the characters may cause a terminal to behave erratically. Opening a binary in a hex editor makes a little more sense of it, but still leaves a lot to be answered. In one column, we’ll see a lot of hexadecimal values; in another we’ll see the same sort of gibberish we would have seen in our text editor. In some sort of status display, we’ll also generally see a few more bits of information – what byte we’re on, its hex value, its decimal value, etc. Why would we ever want to do this? Well, among other things, binary file formats have rules as well, and if we know these rules, we can inspect and navigate them much like an HTML file. Take this piece of a PNG file, as it would appear in
bvi (my hex editor of choice).
00000000 89 50 4E 47 0D 0A 1A 0A 00 00 00 0D 49 48 44 52 .PNG........IHDR
00000010 00 00 02 44 00 00 01 04 08 06 00 00 00 C9 50 2B ...D..........P+
00000020 AB 00 00 00 04 73 42 49 54 08 08 08 08 7C 08 64 .....sBIT....|.d
00000030 88 00 00 00 09 70 48 59 73 00 00 0B 12 00 00 0B .....pHYs.......
00000040 12 01 D2 DD 7E FC 00 00 00 1C 74 45 58 74 53 6F ....~.....tEXtSo
"ban_ln_560_NLW.png" 14498451 bytes 00000000 10001001 \211 0x89 137 NUL