[rrd-developers] [PATCH] generalisation of rrd_open API

Daniel.Pocock at barclayscapital.com Daniel.Pocock at barclayscapital.com
Mon Oct 20 11:54:11 CEST 2008

> I think the best would be if you started writing 
> documentation for the functions you are implementing / 
> planning as well as some general notes on the design ideas.
> To become realy useful, the abstraction may have to be pushed 
> even further ... keep in minde that as we go to a new cross 
> platform data format, the on disk structures will change, I 
> would like for that new abstraction to work with this.

My goal is to provide an alternative to directly invoking the C library
filesystem functions (open, read, write) without  needing to understand
the data format.

There are only a couple of areas where the file format does become an
issue for such a low level API:

- specifying the file size, so that mmap can be done behind the scenes

- how to generalise madvise (my striping implementation potentially
needs to extrapolate madvise to all the headers)

- whether to treat different parts of the file in different ways (e.g.
no striping for headers so that they can be mmaped, striping the RRAs
behind the scenes)

- how to (not) align the RRAs - this could actually be specified
independently, although it is convenient to bundle this logic with the

Rather than hammering out an API spec and then finding that it has to be
changed, I would like to get my stripe implementation running this week,
test it a little, and use feedback from that to guide decisions on the




This e-mail may contain information that is confidential, privileged or otherwise protected from disclosure. If you are not an intended recipient of this e-mail, do not duplicate or redistribute it by any means. Please delete it and any attachments and notify the sender that you have received it in error. Unless specifically indicated, this e-mail is not an offer to buy or sell or a solicitation to buy or sell any securities, investment products or other financial product or service, an official confirmation of any transaction, or an official statement of Barclays. Any views or opinions presented are solely those of the author and do not necessarily represent those of Barclays. This e-mail is subject to terms available at the following link: www.barcap.com/emaildisclaimer. By messaging with Barclays you consent to the foregoing.  Barclays Capital is the investment banking division of Barclays Bank PLC, a company registered in England (number 1026167) with its registered office at 1 Churchill Place, London, E14 5HP.  This email may relate to or be sent from other members of the Barclays Group.

More information about the rrd-developers mailing list