[occi-wg] Incorporating units into OCCI

[Benjamin Black]

ian,

having recently attempted the task of translating seamlessly between XML
->JSON->ruby hashes, i have a very low opinion of this sort of type
declaration.  it makes moving between representations a bear and most
commonly results in eliminating the unit-specifier and normalizing to a
known base (see option 4 below).

a 3rd option you did not mention is something like this:

<memory>
   <size>2</size>
   <units>GB</size>
</memory>

a 4th option, which i rather prefer since the units stuff tends to be
relevant to and consumed by humans via UI rather than machines via API, is
not to use units at all.

<memory>2147483648</memory>

either of the above is far easier to transform to and from non-XML
representations, in my experience, with the latter being zero effort.  a
couple extra bytes won't harm us and we adhere to my first engineering rule:
the best solution to a problem is not to have it in the first place.


b

On Tue, May 26, 2009 at 8:56 AM, Ian Stokes-Rees <ijstokes at spmetric.com>wrote:

>  I finished my PhD thesis on a RESTful model for grid computing a few years
> ago.  I did some work on formalizing XML-based descriptors, including
> units/scaling.  You may find that some of the material in Appendix B and C
> is useful:
>
>
> http://crystal.harvard.edu/~ijstokes/thesis/RESTfulGrid-StokesRees-Thesis.pdf<http://crystal.harvard.edu/%7Eijstokes/thesis/RESTfulGrid-StokesRees-Thesis.pdf>
>
> I envisioned two options: i) units were specified in attributes on an
> element:
>
> <memory type="GB"> 2 </memory>
>
> ii) units were specified in-line and needed to be parsed:
>
> <memory>  2 GB </memory>
>
> At the time I felt that "type" provided a more generic modifier on a value
> than "units", and would allow things like:
>
> <start type="USDate">5/21/2009</start>
>
> or
>
> <start type="EUDate">21/5/2009</start>
>
> I provide 5 sets of "type" modifiers: time, frequency, metric, binary,
> transfer.  No rocket science, but perhaps providing an cut-down portion of
> the schemas will be helpful, so I include them below.
>
> Ian
>
> <xs:simpleType name="TimeTypeList">
> <xs:enumeration value="fs"/>
> <xs:enumeration value="ps"/>
> <xs:enumeration value="ns"/>
> <xs:enumeration value="us"/>
> <xs:enumeration value="ms"/>
> <xs:enumeration value="s"/>
> <xs:enumeration value="sec"/>
> <xs:enumeration value="second"/>
> <xs:enumeration value="min"/>
> <xs:enumeration value="minute"/>
> <xs:enumeration value="h"/>
> <xs:enumeration value="hr"/>
> <xs:enumeration value="hour"/>
> <xs:enumeration value="d"/>
> <xs:enumeration value="day"/>
> <xs:enumeration value="wk"/>
> <xs:enumeration value="week"/>
> <xs:enumeration value="mon"/>
> <xs:enumeration value="month"/>
> <xs:enumeration value="yr"/>
> <xs:enumeration value="year"/>
>
> <xs:simpleType name="MetricTypeList">
> <xs:enumeration value="f"/>
> <xs:enumeration value="p"/>
> <xs:enumeration value="n"/>
> <xs:enumeration value="u"/>
> <xs:enumeration value="m"/>
> <xs:enumeration value="K"/>
> <xs:enumeration value="M"/>
> <xs:enumeration value="G"/>
> <xs:enumeration value="T"/>
> <xs:enumeration value="P"/>
>
> <xs:simpleType name="FrequencyTypeList">
> <xs:enumeration value="Hz"/>
> <xs:enumeration value="KHz"/>
> <xs:enumeration value="MHz"/>
> <xs:enumeration value="GHz"/>
> <xs:enumeration value="THz"/>
>
> <xs:simpleType name="BinaryTypeList">
> <xs:enumeration value="B"/>
> <xs:enumeration value="KB"/>
> <xs:enumeration value="MB"/>
> <xs:enumeration value="GB"/>
> <xs:enumeration value="TB"/>
> <xs:enumeration value="PB"/>
>
> <xs:simpleType name="TransferTypeList">
> <xs:enumeration value="Kb/s"/>
> <xs:enumeration value="Mb/s"/>
> <xs:enumeration value="Gb/s"/>
> <xs:enumeration value="Tb/s"/>
> <xs:enumeration value="Pb/s"/>
>
>
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>
>
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