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From: jhannah@netcom.COM (Jamal Hannah)
Newsgroups: comp.sys.mac.misc
Subject: Re: Mac GIF --> IBM GIF?
Message-ID: <1991Jun18.072524.12241@netcom.COM>
Date: 18 Jun 91 07:25:24 GMT
References: <1991Jun6.051440.9591@agate.berkeley.edu> <1991Jun13.153606.13977@dvorak.amd.com>
Organization: Netcom - Online Communication Services  UNIX System {408 241-9760 guest}
Lines: 61

In article <1991Jun13.153606.13977@dvorak.amd.com> wwilliam@dvorak.amd.com (Wade Williams) writes:
>In article <1991Jun6.051440.9591@agate.berkeley.edu> garya@plague.Berkeley.EDU (Gary Arnold) writes:
>>
>>Could anyone out there give me any information on how to transfer Mac GIF
>>files to an IBM over the modem?  GIF is a "standard" graphics format, so
>>it should work on the Mac and the IBM.  Do I need to convert the Mac file to
>>pure data (no resource)?  If so, how?  How about transferring from IBM to
>>Mac?  Thanks a bunch!
>>
>>Gary Arnold
>>garya@plague.berkeley.edu
>
>Hi, I would like to add my .02 to this question.. I have a question which
>specifically involves the way Macintosh systems handle files.  I can
>successfully down load, link, and uudecode files on a Sun.  I then transfer
>the files to my Mac via ftp.  Once the files are on the Mac, I always must
>edit the file type to GIFf and often the creator to BOZO before Giffer or
>QuickGIF will recognize the file as a GIF picture.  Once I do this, I can
>just click on the particular picture and GIFFER will automatically launch
>itself and load the picture.
>
>
>So you ask, what is the problem?  Well, it seems that somehow the actual
>gif files are being modified so if anyone would like to copy them for use
>on a Sun or other UNIX or GIF viewing system, the files will not work.
>Does anyone know how the Mac modifies GIF files, and how to change them
>back once they are on a Mac?  I have looked at the files with DiskTop and
>there appear to be only data forks, and no resource forks have been created.
>That was my first guess since Mac files often are created with two separate
>forks and create binary transfer problems on other systems.
>
>Wade                   wwilliam@dvorak.amd.com

First of all, there is NO significant difference between a GIF file on
a Mac and one on an IBM.. you just need to know what to do with the data
you have.. in other words: whenever transferring, rememeber to be
in BINARY mode.. not "MacBinary", and not "ASCII".. also, a GIF file on
the Mac dosnt have to have it's type set to "GIFf" to be viewed
by QuickGIF.. QuickGIF will open and convert it (set the type and
creator for you) if the file has a ".gif" or ".GIF" on the end of the
name.  As for Giffer, (version 1.0d1 should be out now) I think it
is smart enough to open any text file on the assumption that it is
a GIF, but I am not sure.. (a GIF file viewed with a text editor should
have the ASCII chars "GIF87" or "GIF89" as the first 8 bytes of data.
(you may have to use ResEdit or DiskTop to set TYPE to GIFf still)

When transferring a GIF to a Sun, Amiga, IBM, or whatever, whether you
use FTP, Xmodem or Zmodem, you must make sure you are in binary
transfer mode.. that means that the file's data fork is sent.. in it's
entirty (No, not with the Mac-Spacific 512 byte header.. thats what
MacBinary mode does).. if you use ASCII mode, youre asking for trouble,
becouse it will do things to bytes that would be interpited as certain
control-characters. (such as linefeeds)

If your SUN still dosnt recognise the GIFs after you transfer them
in binary mode, something else must be wrong.
-- 
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| Jamal Hannah   | Internet: jhannah@netcom.com                            |
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