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RE: Proposal: new fsfs.conf properties

From: Markus Schaber <m.schaber_at_codesys.com>
Date: Tue, 11 Jul 2017 13:39:56 +0000

Hi, Paul,

From: Paul Hammant [mailto:paul_at_hammant.org]

> Markus - I've read your section on deltification and I can see evidence in what you wrote that you're concurrently in favor of and against it (the file-suffix exclusion idea). Can you re-read and clarify?

>> I agree partly. Skipping compression for known "incompressible" formats like mpX, png or gif can come with performance benefits, saving some CPU cycles (see the recent performance disccussions on this list)

>> However, I'm not sure whether the same amounts for deltification. There are editing tasks which do not reencode the whole image / movie, and they can profit from deltification, for example:

>> - Lossless rotation / cropping of jpeg images.
>> - Editing / stripping the EXIF data of jpeg images.
>> - Embedding / dropping the preview thumbnail of jpeg images.
>> - Lossless MP3 editing (e. G. via mp3DirectCut).
>> - Editing MP3 meta data (e. G. Song Title)
>> (... and more...)

>> In all those cases, skipping deltification can drastically increase storage.

To summarize it up:

I expect significant benefits in some use cases by skipping the compression, thus I'm +1 if benchmarks prove it's worth the effort.

I see the danger of drastically increased bandwith and storage size (transferring/storing the whole mp3 instead of just some changed meta data bytes) in some common use cases when deltification is skipped. Thus, I'm skeptical (count it as -0), and I'd kindly suggest to do some benchmarks for those cases before implementation, and clear documentation of the possible negative effects if it's implemented.

Best regards

Markus Schaber

CODESYS® a trademark of 3S-Smart Software Solutions GmbH

Inspiring Automation Solutions

3S-Smart Software Solutions GmbH
Dipl.-Inf. Markus Schaber | Product Development Core Technology
Memminger Str. 151 | 87439 Kempten | Germany
Tel. +49-831-54031-979 | Fax +49-831-54031-50

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Best regards

Markus Schaber

CODESYS® a trademark of 3S-Smart Software Solutions GmbH

Inspiring Automation Solutions
________________________________________
3S-Smart Software Solutions GmbH
Dipl.-Inf. Markus Schaber | Product Development Core Technology
Memminger Str. 151 | 87439 Kempten | Germany
Tel. +49-831-54031-979 | Fax +49-831-54031-50

E-Mail: m.schaber_at_codesys.com | Web: codesys.com | CODESYS store: store.codesys.com
CODESYS forum: forum.codesys.com

Managing Directors: Dipl.Inf. Dieter Hess, Dipl.Inf. Manfred Werner | Trade register: Kempten HRB 6186 | Tax ID No.: DE 167014915
________________________________________
This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received
this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorised copying, disclosure
or distribution of the material in this e-mail is strictly forbidden.
Received on 2017-07-11 15:40:12 CEST

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