Mike Richter wrote:
> Andes, Donald wrote:
>> As some of you may have already guessed, I'm open to crazy ideas, so 
>> I'll pursue the logic of creating 78's as an archival medium, since 
>> they have been hanging around in vaults for a good long time.
>>
>> But I have the following questions in regards to 78's:
>>
>> What is the maximum uninterrupted record time?
>> What is the maximum fidelity expectation?
>> Could the format possibly handle multi-channel recordings?
>> If there any way to embed a video track (if you will) to address audio 
>> that is required to sync with a video source?
>> Could you possible embed a data track to handle metadata since 
>> Physical labels have limited space, can fall off, or become obscured?
>> In today's world of chemical regulations, is it still legal to make a 
>> 78 record, or does include some gaseous by-product, or radioactive waste?
>>
>> Without viable real world answers to ALL the questions above, I 
>> believe I for one would take the idea of using 78's as non-viable.
>>
>> Any takers?
> 
> I'll give you a cut based on conventional analogue recordings.
> 
> Maximum time: 4.5 minutes per side
> 
> Modest - optimisitically, 50-12000 Hz (db tolerance unspecified)
> 
> Multichannel would be practical only with diagonal recording - for which 
> recording hardware would need to be devised.
> 
> No possibility of a video track, but one could perhaps devise a timing 
> reference which could be synced with video - again, requiring new hardware.
> 
> Any or all of the storage could be digital, but to what advantage given 
> the need for new hardware is hard to guess.
> 
> "78-rpm" records are still being made, though they are pressed in vinyl 
> rather than in 'shellac'. In principle, virtually any medium could be 
> used, so surely an ecologically acceptable one is available.
> 
> Mike

78s could comfortably hold 6 minutes per side by the 1950s, and HMV got 6'45" 
onto one in the early 30s (Busch Quartet).

Video was produced on fast-spinning discs in the 80s..remember the CED? That 
ran at about 400RPM as I recall. A bit too fast for our purposes.

dl