From the MARC documentation [1]:

"Field 856 is repeated when the location data elements vary (the URL in subfield 
$u or subfields $a, $b, $d, when used). It is also repeated when more than one 
access method is used, different portions of the item are available 
electronically, mirror sites are recorded, different formats/resolutions with 
different URLs are indicated, and related items are recorded."

So it looks like however the URL is handled, a single 856 field should be used 
to indicate the location [2]. I am not familiar enough with MARC to say how it 
"should" have been done, but it looks like $q and $u would probably be 
sufficient (if they're in the same line).

However, since the field is repeatable, the parser shouldn't be choking on it, 
unless it's choking on it for a sophisticated reason (e.g., "These aren't the 
subfield tags I expect to be seeing"). It also looks like if $u is provided, the 
first subfield should indicate access method (in this case "4" for HTTP). Maybe 
that's what's causing the problem? [3]

Anyway, I think having these two parts of the same URL data on separate lines is 
definitely Not Right, but I am not sure if it adds up to invalid MARC.

-dre.

[1] http://www.loc.gov/marc/bibliographic/bd856.html
[2] I am not a cataloger. Don't hurt me.
[3] I am not an expert on MARC ingest or on ruby-marc. I could be wrong.

On 5/19/2011 12:37 PM, James Lecard wrote:
> I'm using ruby-marc ruby parser (v.0.4.2) to parse some marc files I get
> from a partner.
>
> The 856 field is splitted over 2 lines, causing the ruby library to ignore
> it (I've patched it to overcome this issue) but I want to know if this kind
> of marc is valid ?
>
> =LDR  00638nam  2200181uu 4500
> =001  cla-MldNA01
> =008  080101s2008\\\\\\\|||||||||||||||||fre||
> =040  \\$aMy Provider
> =041  0\$afre
> =245  10$aThis Subject
> =260  \\$aParis$bJ. Doe$c2008
> =490  \\$aSome topic
> =650  1\$aNarratif, Autre forme
> =655  \7$abook$2lcsh
> =752  \\$aA Place on earth
> =776  \\$dParis: John Doe and Cie, 1973
> =856  \2$qtext/html
> =856  \\$uhttp://www.this-link-will-not-be-retrieved-by-ruby-marc-library
>
> Thanks,
>
> James L.