Re: FCS3.0 Standard

From: Adam Treister (adam@treestar.com)
Date: Sun Feb 04 2001 - 14:30:32 EST


----->>> On  2-Feb-2001, filipesan@teleweb.pt wrote:
>   As part of my pos-graduate studies, I am developing a
>   software cytometer simulator to help high school and college
>   students in learning flux cytometry. I would like this
>   simulator to read FCS3.0 files, but unfortunately I can't
>   find any on the Internet to help me.
>
>   Can you help me on this matter? I would like a file with a
>   primary and supplemental TEXT segment, so I could see how the
>   $BEGINSTEXT and $ENDSTEXT keywords work.
>
>   I also can't help notice that when I search Yahoo or
>   Altavista for "FCS3.0", all I get are discussions that
>   abruptely end in 1997. What happened? Did the standard died?

As I understand it, FCS 3.0 was accepted by ISAC as the current standard,
in 1998.  Yet, I don't know of any instrument or acquisition system that
writes them.  The de facto standard remains FCS 2.0.

Consequently, I've never run across files that use the $BEGINSTEXT and
$ENDSTEXT keywords.   I can see that it might be potentially useful for
capturing auxilliary information such as instrument settings, or to snap a
picture of the operator when the cells are run and hide that in the FCS
file, but you probably don't need to use this, so you'd just add
$BEGINSTEXT/0/$ENDSTEXT/0/ to your text section, and don't worry about it.
And when reading FCS 3 files, just ignore the values you find in those
tags.

If you do choose to read supplemental text (and more importantly, when you
the read primary text section) make sure you use the the END keyword
correctly.  It points to the LAST byte used,  NOT the next byte, as most
programmers want it to.  The length of the section is (end - begin - 1)

I have C++ or Java code for reading/writing FCS files, which you can have,
but it relies on all sorts of other libraries and objects, so it might be
hard to use once extricated from the rest of FlowJo.   But let me know if
you're interested, and I'll send you the files.  There has been talk for a
long time about writing a public domain library for reading and writing
files, but it never has come about.  The nice thing about there being a few
cytometer vendors who are slow to make changes is that data compatibility
has never been a big issue.

Adam

------------------------------------------------------------
Adam Treister	   Tree Star, Inc.
ph: 1-650-508-9349  fax: 1-650-508-9186
adam@treestar.com   <http://www.treestar.com>
------------------------------------------------------------



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