Comment by redis_mlc | Hacker News Reader

Comment by redis_mlc | Hacker News Reader

I was one of the first people in North America to create CDs, in 1984.

I was working with a scientist who had connections with Sony Japan, who had 6'-tall rackmount CD writers.

We would mail a 9-track tape to Tokyo with sample remote sensing data, and they'd mail back a CD. Although it didn't contribute to the scientific projects directly, we were able to demonstrate the new technology to various groups at a national lab.

Overall the feeling was that it was very cool to have that amount of data on a device that small.

I'd say the first pressed data CD I saw was the Microsoft Encarta (encyclopedia) CD around 1993:

https://en.wikipedia.org/wiki/Encarta

About a year or so later I was one of the first users of the Optimem 1 GB 12" optical drives. We used that to archive large amounts of software and experimental data. It was nice to be able to write your media incrementally. One small project was to copy the world's freeware (about 500 5.25" floyy disks) onto a single optical disk for users to find sample code and utilities.

I printed out an index on paper and distributed that to several programmers, and they would let me know what they needed.

You were burning data CDs in '84? That is impressive. How did you read it? I mean, I think the first general availability for data CD readers was in the NeXT computers in the '89 or so?

I don't think anyone was burning CDs in 1984, unless you mean literally burning pits and lands into the master CD to make the inverted submasters (jargon here is probably wrong) that then go on to press/mass produce the actual CDs that ended up on shelves.

This technology was developed in the 1970s.

So, if you want to record 60 minutes of CD-quality digital audio you need about 600 MB of raw data storage. In the 1970s this was an impossible amount of data. 600 MB of hard drive space would cost as much as a house.

Without a way to easily store that huge amount of data, the CD could not be developed. And in the 1970s the computer industry had no answer to that problem.

The solution was ingenious.

They take a stream of digital bits, convert it in to standard broadcast video, and record it with a plain old VCR.

Broadcast video refreshes at 60 FPS, 245 scan lines per frame. If you draw 96 black-and-white pixels per scan line, that works out to three 16-bit stereo samples per scan line.

3 samples X 245 lines/frame X 60 frames/second = 44100 samples/second. Hence, the CD audio standard that we still use today.

So, to answer your question, they weren't burning CDs in '84. They encoding 600 MB of data on to plain old VHS tapes, and sending those off to be mastered.

Broadcast video was 60 fps in the 70s and 80s? I thought NTSC was 29.97 fps.

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