Avalon - 3D Objects & Resources/Avalon.iso/macutils/compress/ziputils/macgzip0/mac_docs/lloydwoo.dsf

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From: Lloyd Wood <[e-mail]>
Subject: A real-life use of MacGzip for Mac users!
To: [e-mail]
Date: Fri, 28 Jan 94 23:29:44 GMT
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(C) L.H.Wood <[e-mail]>. All rights reserved.
Comments and corrections welcome.

First release. There must be some glaring errors here...


USING src.doc.ic.ac.uk (146.169.3.7) AS YOUR MAC ARCHIVE SITE

A guide to European/UK Mac users wanting to get the most out of
a local Mac software archive mirror.

US Mac users should look first to wuarchive.wustl.edu as the primary
mirror of both info-mac and umich.


src.doc.ic.ac.uk is a large ftp site based at Imperial College
in London, England. It mirrors two of the important Mac sites -
umich and sumex, or info-mac, and it's updated frequently.

Since src.doc allows up to 300 simultaneous users, it would be a
good idea to use it as your local Mac mirror, especially if you're
in the UK. However, a few eccentricities of the site in comparison
with usual Mac archives means that some extra thought is needed in
getting files to a Mac. Here's what I've learned. This information
is applicable to many other sites which have 'smart' ftp daemons, so
it will be useful to know even if you never use src.doc.

Login as usual:
ftp> name: anonymous
ftp> password: name@site

Putting the email address in your password is just the usual courtesy
that lets an archive's maintainers know who is using it.
(You can contact src.doc's maintainers at [e-mail])
Look at the readmes at the top level of the archive for
up-to-date information on how to retrieve files.

The Mac archives of interest are as directories in packages:
/packages/info-mac -
   a mirror of the info-mac archives at sumex-aim.stanford.edu
/packages/umich -
   a mirror of the umich archives at mac.archive.umich.edu
and under those you'll find the familiar directory structures
you know and love^H^H^H^Hloathe^H^H^H^H^H^Hadmire for their logical
structure, making searching for the file you want immediately
obvious if you already happen to have that file's pathname in full.

However, you'll be surprised when you come to look at a file -
instead of the usual .hqx endings, you will see .hqx.gz
instead.

The .gz indicates a gzipped file. Gzip is a fairly new unix-originated
compression system from the GNU Foundation. It's aimed at replacing
the popular unix 'compress' format. [Gzip can also be indicated by
.z, although this caused confusion, as other filetypes use the same
indication. Not to be confused with .Z, which indicates unix compress
files.]

To save space on their hard drives, src.doc automatically compresses
each of the .hqx files after a while. As this compression is
being done on unix boxes, the files are compressed into gzip, rather
than being debinhexed and converted to Macbinary as you might expect.
It's simply easier for them to do - and as a side-effect it ensures
that all files are compressed, even lone Mac files that have been
binhexed directly without using a Mac compression package.

This has a number of ramifications, though, that affect the way
you get files from src.doc.ic.ac.uk.

You have two choices here when retrieving files:


1) Get src.doc to give you the expanded, ungzipped form
of the file. Normally, you do this by requesting not the filename
you are shown, but that filename without the .gz suffix.

So, if to download an upgrade to AutoDoubler from src.doc, when it
is on info-mac as:
info-mac/cmp/autodoubler-203-updt.hqx.gz
you would type:
ftp> get /packages/info-mac/cmp/autodoubler-203-updt.hqx

IF YOU USE FETCH, where you normally just double-click on a file,
you must command-click on the highlighted file(s) so that nothing is
highlighted. Pressing 'Get File...' button will then give you a dialog
asking for the filename. Type in the filename, but without the .gz suffix.

[It's annoying that you can't simply copy the filename from the list,
and paste it into the Get File dialog, at least with Fetch 2.1.1.
Just deleting the .gz suffix would be easier than remembering long
filenames with randomly-place-ddashes-likethis-1.0.sit.hqx]

Using ftp or Fetch, this gets you a binhex file, which is decoded as
normal to give you a Mac archive. You should be thinking 'What an
awkward way to use an archive!' And you're right. Try logging in to
src.doc again, but this time with a plus as the first letter of your
password (i.e +name@site). You will see that all of the .gz suffixes
have vanished, as that plus tells src.doc to hide them. You can then use
src.doc like any other Mac archive site, pointing and clicking
as normal in Fetch, and that extra compression/translation stage is
completely hidden from you and from your ftp tools.

However, that gzipping means extra compression - which means less time
to get the file you want to you. What if you grabbed the smaller
gzipped file as it is, and then decompressed it at your end? This brings
us to method 2).


2) Get the gzipped file as you would any other, and un-gzip it
on your unix box or back at your Mac. A gzipped binhex file is much
smaller than the original binhex.

This requires that you transfer the file in BINARY mode, which is selected
by:
ftp> bin
or, if you use Fetch, by clicking on the Binary radio-button.

Un-gzipping locally requires that you have received the file successfully
in binary mode - if you can't un-gzip the file correctly, it's likely that
you haven't got a reliable binary path between src.doc and your machine.
If you can't transfer files reliably in binary mode, stick to logging
in with + at the start of your password.

If you are bringing the file to a unix box, you can un-gzip it there -
talk to your systems manager to see if the gzip software you require is
present. You'll then have a binhex file to copy to a Mac.

Alternatively, you can un-gzip the file on your Mac. This requires MacGzip
0.2, a port of unix gzip 1.2.4, which you'll find in the compression
folders of the mac archives - e.g. info-mac/cmp/macgzip-02.cpt.hqx

Once MacGzip has un-gzipped the file, you'll have a binhex (.hqx) file
ready for debinhexing. Depending on the debinhexer you use, you may
need to change the filetype to 'TEXT' (this is done by MacGzip when
'ascii' menu item is selected; simply open MacGzip, set the menu to
ascii and quit, this will be remembered in MacGzip preferences) so that
your debinhexing utility can see it in its Open dialog. (Compact Pro
requires this; Stuffit Lite does not.)

Note that MacGzip has the following peculiarities:
a. Gzipped files, should be of type 'Gzip'. You can set this with Fetch,
or by using ResEdit or a file utility like FileTyper 4.1.
If you set the creator to 'Gzip' as well, you will see MacGzip's
icon (a tiny g in a small page) for the file.
b. MacGzip will only see and open files with suffixes matching the
suffix in its preferences dialog and ".gz", ".z", ".Z", ".taz", ".tgz",
"-gz", "-z" or "_z". The best option is to simply delete the suffix
preference and leave it blank, so that you can see all files with
standard suffixes.
c. MacGzip expands the files if they are opened with MacGzip closed. If
You haven't set the 'Quit when done' preference, you must ensure that
'uncompress' is selected in 'gzip' menu.
(this is true for older versions of MacGzip. In 0.3b you can open
files at any time. -but not while MacGzip is processing a file- )

IF YOU USE FETCH, it's a good idea to tell it that gzipped files
must be fetched in binary mode, so that it can automatically select
it without you having to remember to set binary mode explicitly each
time.

To do this, use the 'Suffix Mapping...' option under Fetch's
'Customize' menu, setting type and creator to 'Gzip' as described
in a. above, so that MacGzip can see the files that Fetch creates.

Then set the 'Post-Processing...' option on the same menu to
get Fetch to run MacGzip automatically for you, so that pointing
and clicking in Fetch gives you a recognizable .hqx file.
[If you figure out how to get Fetch 2.1.1 to un-gzip and *then*
debinhex an archive automatically, let me know! Debinhexing is
is MacGzip's 'Things to Do' list, so this may soon be automatic.]

To get a non-gzipped file to be gzipped before it is sent to
you, so that it spends less time in transit to your modem,
command-click on the highlighted file(s) so that nothing is
highlighted. The 'Get File...' button will then ask for a filename.
Select this, and enter the filename, with an extra .gz suffix.
If you've set Suffix Mapping and Post-Processing correctly,
Fetch will have the file un-gzipped for you automatically once it
has been completely downloaded.


A little thought, and smashing the keyboard because I couldn't
get into US archives, even on weekends, became a thing of the past.
I wonder how long it will be before I can't get into src.doc either?

END.

 -- L.
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