On Mar 12, 2011, at 4:22 PM, Beatrice Hopkinson wrote:
I need some help analysing why some PC owners cannot open my
attachments
to an Email.
What do they say is wrong with the attachment? What happens when they
try to open it? Can you give some examples of the kinds of things you
attach that they can not open.
I send them as Base64 encoded, though there are other
options I don't understand: BinHex, UUencode, Apple single and Apple
Double!
Base64 is the best option by today's standards. If you are still
regularly sending older Mac specific files, then you can make your
default AppleDouble instead. I'd avoid AppleSingle and UUEncode.
For those that care, Base64 is *the* standard for sending file
attachments in emails. It won the format war a long time ago. Every
mail client these days can work with Base64. The downside to straight
Base64 is it only encodes the Mac Data fork, and throws away the
Resource fork. This is not a problem for any modern Mac file
attachment as OS X did away with the Resource fork, so very very
little software still uses it in document files. Older programs (OS 9
and earlier era) may still use it however, depending on the program.
You can also get around this problem by flattening the file using a
standard method (such as Stuffit or Mac aware Zip programs like OS X's
built in Compress ability).
AppleDouble is essentially Base64, but it splits the Mac Data fork and
Resource f ork of the file (if it has both halves) into two Base64
encoded attachments and includes a little extra header info so
anything that properly handles AppleDouble (ie: Macs) can reassemble
the file correctly. This is good for sending attachments that need the
resource fork, and you can't reliably flatten it and use Base64.
Anything that can not handle AppleDouble will usually see it as two
Base64 encoded file attachments, one of which will work, the other
will not (the one that will not will have the same name but proceeded
by an underscore character).
AppleSingle flattens the two forks into one Base64 encoded file. Alas,
in programs that don't know AppleSingle, they will not be able to
decode a usable file from this. Most Windows programs don't know
AppleSingle (and newer Mac ones may not as well).
UUEncode is an old Unix way of encoding things and has long gone the
way of the dinosaur. Modern mail clients on all systems likely can't
handle UUEncode.
I was told this morning I should use for pictures '.jpeg' endings
instead of 'jpg', but as this is true also for endings with .doc it
must
be something else? Can someone please help.
Windows programs *REQUIRE* a 3 letter extension on the end of all file
names. That is how Windows knows what to do with the file. So JPEG
picture files *MUST* end in .jpg, MS Word documents *MUST* end
in .doc. Newer versions of Windows can also handle 4 letter extension
codes (so .jpeg would work or .docx if it is the newest version of MS
Word).
If you are sending document files to Windows users and not including
the appropriate 3 letter extension code on the end of the file name,
then the user will not be able to double click the attached file to
open it. They can (in most cases) still run the appropriate program
that uses the document and then open the file attachment from inside
that program. The file is still good, Windows just doesn't know what
it belongs to. But to do that requires the person actually save the
attachment out of the email instead of double click it in the email.
It requires they know what program opens the file. It requires they
run the program manually, go to the File menu, choose Open, navigate
to where they saved the attachment, tell the Open dialog to display
All Files, and then select the file. For a person with a brain, this
is easy and takes all of about 30 seconds. Windows users don't have
brains. Think of windows users like a household pet, a cat, or a dog,
because that is about as smart and computer literate as they get. You
will have lost them at the step of saving the attachment out of the
email instead of just double clicking it. They are likely unaware
there is any other way to open the file. (Ok, I'm not really serious
that they are that stupid, but yeah, in some sense I am, as I have
regularly dealt with high level Windows techs that can't think past
the 'normal' way of doing things to do an alternate method to resolve
their own problems, there is just something about people that only use
Windows that lines up with a personality of not being able to problem
solve and do anything beyond the way they have always done things).
Sorry, didn't mean to go off on Windows users like that, after all,
for all I know, you are sending them something they really can't open.
But my guess is, you are simply sending stuff without the 3 letter
extension, which means if they spent more than 8.5 seconds of effort
on it, they would be able to open it just fine.
-chris
<www.mythtech.net>
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