[CESG] CCSDS 301.0-B-4 propsed pink sheet (Time Code B) / Backward compatibility?

Barkley, Erik J (3970) erik.j.barkley at jpl.nasa.gov
Thu Aug 4 01:33:55 UTC 2016


I too noted that it might be possible to interpret as already allowing removal of the decimal fraction/sub-second.

CESG members,

What is your taking/reading on this?  Does this already allow fractional seconds to be optional?  If not, why not?

Best regards,

From: Gian.Paolo.Calzolari at esa.int [mailto:Gian.Paolo.Calzolari at esa.int]
Sent: Monday, July 25, 2016 2:26 AM
To: Barkley, Erik J (3970) <erik.j.barkley at jpl.nasa.gov>
Cc: CESG -- CCSDS-Engineering Steering Group (cesg at mailman.ccsds.org) (cesg at mailman.ccsds.org) <cesg at mailman.ccsds.org>
Subject: Re: [CESG] CCSDS 301.0-B-4 propsed pink sheet (Time Code B) / Backward compatibility?

        from a purist point of view I think that it would be incorrect stating that the change is backward compatible as a former implementation would expect to find always the "Decimal fraction of second" and would most likely crashes when that field is absent.
Conversely a constant setting to 0 when not used would be fully backward compatible.

However it is also true that despite section "ASCII TIME CODE B,  Year/Day of Year Calendar Variation" defines only one optional field  (i.e. the time code terminator) section "SUBSETS OF THE COMPLETE TIME CODES" basically allows many fields to be optional so I wonder whether it would be more correct working on section instead of adding the optional field in section
In other words, the part of clause (c) stating that the code "may be abbreviated to the span of interest by deleting the unneeded subfields" does already allow removing the Decimal fraction of second subfield?

My cent.......

Gian Paolo

PS It looks to me that the sentence "the need to accommodate the upcoming century rollover in only 11 years" was somehow wrong in 2010 as it is now   :o)

From:        "Barkley, Erik J (3970)" <erik.j.barkley at jpl.nasa.gov<mailto:erik.j.barkley at jpl.nasa.gov>>
To:        "CESG -- CCSDS-Engineering Steering Group (cesg at mailman.ccsds.org<mailto:cesg at mailman.ccsds.org>) (cesg at mailman.ccsds.org<mailto:cesg at mailman.ccsds.org>)" <cesg at mailman.ccsds.org<mailto:cesg at mailman.ccsds.org>>
Date:        22/07/2016 01:44
Subject:        [CESG] CCSDS 301.0-B-4 propsed pink sheet (Time Code B)
Sent by:        "CESG" <cesg-bounces at mailman.ccsds.org<mailto:cesg-bounces at mailman.ccsds.org>>

CESG Colleagues,

Attached is the proposed pink sheet for Time Code B which makes the time code more suitable for such applications as publishing a standardized schedule of services for which mandatory fractional seconds is meaningless.  (By the way does anyone know what the original rationale was for requiring, at a minimum, 1/10 of second time statements?)  The proposed change is the addition of "(optional)" which is in keeping with the method by which optional is designated for the "Z" character in the recommendation.  I believe the "." subfield separator disappears of by application of clause (c).    If this change is made to Time Code B, we likely should apply it to Time Code A.

Best regards,

 [attachment "301x0b4e1-ProposedPinkSheet.docx" deleted by Gian Paolo Calzolari/esoc/ESA] _______________________________________________
CESG mailing list
CESG at mailman.ccsds.org<mailto:CESG at mailman.ccsds.org>

This message and any attachments are intended for the use of the addressee or addressees only.

The unauthorised disclosure, use, dissemination or copying (either in whole or in part) of its

content is not permitted.

If you received this message in error, please notify the sender and delete it from your system.

Emails can be altered and their integrity cannot be guaranteed by the sender.

Please consider the environment before printing this email.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ccsds.org/pipermail/cesg/attachments/20160804/156a847f/attachment.html>

More information about the CESG mailing list