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Comment by sehugg | Hacker News Reader

WWVB (the NIST atomic clock signal) encodes at 1 bit per second, it would be easy to hook a receiver up to the cassette port and decode this -- I'd guess someone even tried this back in the day. Though you have to wait 60 seconds for a full timestamp, and doing it in the background might be tricky.

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The Apple II cassette port had layers of awesomeness to it that still go unappreciated today, even by the platform's hardcore devotees.

For one thing, it was about as fast as a Commodore 64 disk drive, although that was due more to incompetent engineering on Commodore's part than brilliant engineering on Woz's part. (There was plenty of unpicked low-hanging fruit in Woz's own Disk II system.)

For another, you could connect it to an old telephone hybrid and get a free 1200-baud modem, albeit a nonstandard one. Perfectly adequate for allowing two Apples to talk to each other.

And yes, I don't see why you couldn't rig it up to decode WWV(B) transmissions with a minimal amount of external hardware, especially in conjunction with an interrupt-driven timer like the one described in the article.

> There was plenty of unpicked low-hanging fruit in Woz's own Disk II system.

Do you have more details about this? Usually when the Disk II is brought up it's praised for its simpleness and utility.

I'm guessing what could be considered low-hanging fruit would be that the original 4&4 encoding was later surpassed by much more efficient 6&2 encoding a few years later. And even then, the 6&2 encoding scheme chosen wasn't ideal as it took too long to decode. Later intrepid programmers were able to decode an alternate scheme of 6&2 in time to read an entire track within the revolution of the disk and get closer to ideal performance and data density.

The floppy interface was indeed an incredible piece of work, but the big forehead-slapper is the ~5x speed increase that you get from reading sectors in descending order, e.g. from 15-0 instead of 0-15. This makes the difference between having to wait for an extra spindle rotation and being correctly positioned to take advantage of the next one.

How he managed to overlook that is one of life's great mysteries, at least to me.

There was a module for the Commodore 64, made in Germany, that used the atomic clock signal sent from Frankfurt, the Auerswald ACC-64:

https://forum.classic-computing.de/forum/index.php?thread/92...

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