[BBF Standards] Sequences and Formats and Devices, oh my! [Re: data exchange issue 1: Abstraction]

[Ralph Santos]

Jake,

That's a good point.  I like the concept and the example.

---ralf

Jake Beal wrote:
>> (1) Associate the ID numbers with the precise sequences
>> * pro: ID's of classic biobricks keep their identity
>> * con: same function registered under multiple ID's for repackagings in 
>>   different formats
>> * con: forces folks who've repackaged existing bricks in non-classic 
>>   formats to reidentify their samples
>>
>> (2) Biobrick ID's associated with function
>> * pro: functional classifications of biobricks remain the same
>> * con: will lead to mixups between people because formats might not match
>>     
>
> A nice mid-point between these two options is found in the TTL
> Databook approach to classifying digital circuits packages.  The IDs
> of TTL devices encode their function, format, tolerance, and package
> in different portions of the ID.  This entire functional family is
> listed in a single datasheet, with notes about values that vary by
> family.  (It may be noteworthy that the opacity of chip packaging means
> that, like BioBricks, it extremely hard to determine the function,
> format, or other characteristics of a chip except by its ID).
>
> For example, flipping open my TTL databook at random, I find the SN-86
> family: "QUADRUPLE 2-INPUT EXCLUSIVE-OR GATES."  This 5 page datasheet
> describes a family of 6 devices with different IDs, available in 13
> ID/package combinations.  Pages 1 and 2 give all of the functional
> information for the devices, as well as all of the critical
> information about how the family varies.  The remaining three pages
> give differences in interface and environmental characteristics.
>
> The six devices are the SN5486, SN54LS86A, SN54S86, SN7486, SN74LS86A,
> and SN74S86.  These numbers decompose into four fields:
> - The SN prefix is assigned to all the TTL devices in the book
> - 54 means milspec tolerances, 74 means civilian tolerances
> - the middle letters (LS, S, or nothing) indicate the implementation
>   technology: Standard TTL, Schottky, or Low-Power Schottky
> - 86 indicates the functional family (quad 2-input xor gates)
> - the A on the end of the 'LS86s indicates it is the first revised verions.
>   Maybe something was wrong with the original 'LS86 design?
>
> Finally, these are available in a few different packages:
> - SN5486: J or W package
> - SN54LS86A, SN54S86: J, W, or FK package
> - SN7486: N package
> - SN74LS86A, SN74S86: D or N package
>
>
> A similar decomposable ID scheme for BioBricks would satisfy the
> needs for unifying function while distinguishing formatting,
> versions, and classic biobricks.
>
> Thanks,
> -Jake
>
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