Special considerations for PC and Macintosh files
Last revision July 22, 2004
If you want to transfer a PC or Macintosh file to or from an offsite colleague, the most satisfactory solution would be a direct network transfer between the two PCs or Macintoshes. This is possible if you install ftp "server" software as well as client software on the computers, but then you must be very careful to set up access controls (accounts) so that your computer's disks aren't open to the world. And you have to arrange with your colleague to have the remote computer turned on, with ftp server software running, at the time when you want to make the file transfer. Free or shareware ftp server and client software is available for PCs and Macintoshes at internet archive sites.
Remember that most PC or Macintosh programs, such as word processors or spreadsheets, use non-printing control characters to store formatting information. From the point of view of network services like ftp or email, this makes them binary data files. And of course, all graphics files are binary data. Such files should be routinely transferred via binary ftp format, or encoded into a text format if sent via email.
Many people run MIME compliant email programs on their PCs or Macintoshes, such as Eudora. If you are sure that your colleague has an equivalent program, you can simply send your PC or Macintosh file to him through email as an attachment. The program will automatically encode it to pass through the email system. But it is very frustrating to receive such an email when you don't have a program that can properly read it, so check that first. Be aware that Eudora users in Earth Sciences generally use pangea as their email server. In that case, email file attachments sent from or to your PC or Macintosh via Eudora are subject to the same 50 megabyte size limit as email sent directly from or to pangea.
It is also possible to use a Unix system as an intermediary when transferring PC or Macintosh files to a colleague. Use an ftp client program on the PC or Macintosh to push the files up to a Unix system, where the colleague can find it and pull it down with his ftp client. Or, push it up to a Unix system, and then attach it to an email there. In this case, it is preferable to use an encoding option supplied by the ftp client software on the PC or Macintosh, such as zip or binhex format, rather than encoding it on the Unix system. This is particularly important for Macintosh systems.