Alles Voor Internet / Tout Pour Internet/alles voor internet.iso/MacInternet™/Unix/mcvert2.15.shar/README-conversion

Text File | 1993-11-25 | 7.5 KB | 155 lines

Overview of file conversion

More details regarding file formats may be found in the mcvert.1 man
page, but basically, there are native Mac files that live (only) on
the Mac (since they have interesting internal structure), and
representations of Mac files.

One very important representation is called MacBinary.  It is nothing
but "data".  But it is 8-bit data, and that confuses some things some
times, like mail programs and modems.  So, there are encodings of
MacBinary files as ASCII only files, and one very important one is
called BinHex4.0.  So far, so good.

mcvert runs under UNIX and converts between different representations
of Mac files.  One very common conversion is between BinHex4.0 and
MacBinary.  So know we know how to do that (on a UNIX box).  On the
Mac, I prefer the CompactPro shareware for doing this conversion

A MacBinary file must be converted into the actual native Mac file it
represents.  One such program, which runs on the Mac, is binhex4.0.
Often, though, programs like telnet from NCSA, kermit, White Knight,
or any number of other communication programs will convert MacBinary
files into the native Mac files they represent during transfer.

Files can be very large, and rather redundent.  So it makes sense
to compress the files to save space and reduce transfer cost.
There are compressed file formats.  Two popular ones are StuffIt
and CompactPro.  But if a file is compressed, something must
uncompress it.  There are unstuffers and extractors, which are
separate programs which work on the compressed files.  Some files
are "self-extracting", which means the files are actually Mac
programs which, when run, recreate the original file.

Files are often identified by extensions, those .ext suffixes at the
end of the name.  Common suffixes include:

    .bin    MacBinary
    .sit    StuffIt
    .cpt    CompactPro
    .hqx    BinHex4.0
    .sea    self extracting archive

It is not uncommon for multiple transformations to be applied, so if
one had a file called foo.sit.bin, that likely means that it's a
MacBinary format of a StuffIt archive file.  So, to convert it, you
must turn the MacBinary file into a native Mac file, and then run
[un]StuffIt (or CompactPro, which can handle many StuffIt formats).

There's more information in the info-mac archives about getting files.
For example, here's info-mac/help/accessing-files.txt, as of 13Jun93:

>------ Begin Included Message ------
> To access binaries in the Info-Mac archive at sumex-aim, use your
> machine's ftp program.  Type "ftp sumex-aim.stanford.edu".  Use the
> account name "anonymous" (lower-case) and enter any password. Then
> "cd info-mac" to enter our directory. You should be able to transfer
> binaries with a statement like "get app/silly-paint.hqx".
>
> NOTE: Almost all files (even binaries) in the Info-Mac archive are in
> text format, even though they may not be human-readable. Hence, a FTP
> transfer using a text-only option, often called ASCII, should work in
> all common cases.
>
> In order to provide a reasonable level of performance and avoid
> causing Internet overload, there is a 35-user limit for anonymous ftp
> into sumex-aim during working hours, which we define as 8AM to 5PM
> Pacific time, Monday through Friday. When sumex is busy, use one of
> the many mirror archives around the world (see info/comm/ for a list
> of other archive sites, including sumex mirrors.) Gopher is another
> alternative; as a more modern alternative to ftp, it imposes less of a
> burden on sumex, so there is no user limit.
>
> Here are some simple commands to move you around the directory structure.
> This example assumes that you started in the /info-mac directory.
>     cd app         # move into the app directory
>     ls             # list the files there
>         get planet.hqx # transfer a file to your computer
>         cd ..          # move back up to the parent directory
>         cd help        # and so on...
>
> Most Info-Mac files are stored in BinHex 4.0 format.  We have adopted
> the common practice of labeling such files with .hqx extensions.  To
> take these files and use them on your Macintosh, you must first run
> them through a program which will convert them from .hqx format into a
> regular Macintosh file. On Unix systems, you can use the mcvert
> program, stored as cmp/mcvert.shar. You can also do the conversion on
> your Macintosh by using any of a number of utilities, including BinHex
> 4.0, StuffIt, or Compact Pro. We recommend using Compact Pro because
> it is slightly more convenient and reliable than the other tools.
> Note: do NOT use BinHex 5.0 as it is incompatible, for some very
> brain-damaged reasons.
>
> Note that some of our files were split into smaller pieces so that
> they could be mailed more easily.  Most such files are old, as we no
> longer split new submissions.  You must join split files together
> before running BinHex or StuffIt. Hqx files can be edited as normal
> text; therefore, you can use any word processor or append command on
> your host to stitch the pieces together. There are some utilities
> (unity and united) in disk/ to do this step for you.
>
> Many of our files also have been compressed to save space. You'll know
> that they have been when the file name after converting to Macintosh
> format ends with a .sit, .cpt, .sea, or .pit extension. Here is a
> table to help you with the reconstruction:
>
> Extension    Created By    Recommended unpacker    Notes
>
> .pit        PackIt II    StuffIt            obsolete format
> .sit        StuffIt        Compact Pro/StuffIt    has type SIT!
>         StuffIt Deluxe    Stuffit Expander    has type SITD
> .cpt        Compact Pro    Compact Pro
> .sea        various        itself (double-click on it to unpack)
>
>
> In summary, there are generally five steps to pulling .hqx files from our
> archives:
>     1. Transfer them to your computer with FTP.
>     2. Transfer them to your Macintosh somehow.
>         3. If necessary, put separate pieces together.
>     4. Run a de-binhexing utility to convert the .hqx files into either
>            real Macintosh files or compressed Macintosh files.
>     5. If they are compressed, use the appropriate decompression
>            program to decompress them.
> People using Unix may be able to skip steps 3 and 4 by using the program
> mcvert on their Unix system before transferring the program
> to their Macintosh.
>
> If you don't already have BinHex 4.0, it would be easiest to get it
> from a friend or user group. Or, if you know how to do an 8-bit binary
> download, you can FTP it from us as cmp/binhex4.bin. Unfortunately, a
> little bit of pulling yourself up by the bootstraps is required.
> StuffIt Expander is a more modern and useful program which incoporates
> the functionality of Binhex, while also decompressing files. It is
> also available in cmp/ in both binary and binhexed forms.
>
> A CD-ROM of the archives is commercially available from Pacific HiTech.
> They can be contacted by phone at 800-765-8369,
> fax at 801-278-2666, and email
> at [e-mail]. The CD-ROM is approximately $45 including
> shipping and handling.
>
> Please note that we cannot test software for reliability on all Macintosh
> configurations. As the software in this archive is generally non-commercial,
> it may be less reliable and more prone to crashes than you are used to.
>
> We highly recommend that you maintain an active backup procedure to protect
> yourself even in the event of a system crash that results in the loss of
> some of your data. Download and use all software in this archive at your own
> risk.
>
> The Info-Mac Moderators
> [e-mail]
>
>------  End Included Message  ------