Problems with Downloads?
.... updated 4 January 2009
Glitch in .zip Downloads under Internet Explorer
You may have noticed that you get good IE downloads
of .zip files from
some sites-- WinZip unzips the files with no problem. But, from other sites,
the .zip files cannot easily be unzipped or, sometimes, not at all.
One idea I've come across is that, starting
with IE 6, Microsoft began
to require that download sites provide information about .zip files, perhaps
other kinds of files, too. If the information is supplied, the file arrives okay.
If not, you get a 'bad' .zip file.
Either way, there is nothing wrong with the
.zip file maintained on the
site. The problem is with how IE treats .zip files.
What's happening is that the bad zip files
have been gzipped and that
is how they arrive, still with the ".zip" suffix. The good zip files are either
not gzipped or, if they were, are sucessfully un-gzipped upon arrival.
WinZip, at least the versions I've tried,
is confused by a gzipped file
with a ".zip" suffix and will not unzip it. A solution that usually works is to
rename the file, say "Narf.zip", to "Narf.gz". WinZip will ungzip the file and
ask you to supply a suffix, which should be ".zip". Now, you have a .zip
file which WinZip can unzip.
The above seems to work in most cases; but,
not always. I've come
across one case where either the initial file could not be unzipped or
ungzipped or the resulting .zip file could not be unzipped. Via an ftp
connection to the site, I downloaded the file; it unzipped with no problem.
Evidently, the gzipping may introduce an error,
at least as far as WinZip
and 7-zip are concerned.
A simple solution is to use some browser other
than IE when planning
on downloading .zip files. For instance, on my Windows ME computer,
.zip file downloads from Apple II sites under Netscape 4.78 work fine.
Firefox users report the same result.
Text Mode Corruption
Unfortunately many http net servers for Apple
II software are still not
set up to supply correct type information for popular Apple II file types such
as .shk, .sdk, .dsk, .bxy, etc.. Downloads from these pages may be corrupted
for users of some browsers which automatically treat the files as Text (and
insert line-ender characters).
Archiving files in .zip form prevents 'Text
mode corruption' because all
servers recognize the ".zip" suffix as indicating a binary file.
Attaching the ".bin" suffix is another way
for an archive site to have a
file treated as binary. For instance, an Apple II site might offer the file
Gameicons_shk.bin. You are supposed to know that this is a ShrinkIt file
with ".bin" tacked onto the name to make sure it is treated as a binary file.
A good indication that you are getting a corrupted
download is if you
click on a download link for SuperGame.shk (or whatever) and your screen
starts filling up with weird looking Text.
Right-clicking on the item to download will
not circumvent the problem.
This will let you choose to download a file taken to be a Text type file
rather than have it dumped to your display (good to know). However, it will
not avoid Text mode corruption in the downloaded file.
Another pretty good sign that you are getting
of .shk, .dsk, and other Apple binary files is that the stuff you download
"never works". If you know the original length of the binary file you have
downloaded, a pretty sure check for a good download is that your copy on
hard disk has the same length as the original.
Note: Text mode corruption is not usually a problem for Apple II files
which are Text. Some line-ender characters may be added; but, this does
not appear to prevent recovery of software in binscii (.bsc) files. Plain
Apple II Text may need to have control characters removed in order to
display correctly on an Apple II. (Appleworks does this automatically.)
If you know you are getting corrupted downloads
from a particular site,
a cure which usually seems to work for downloads to a PC is to employ the
PC utility Uncook after downloading .shk, etc. files. (Uncook was
'discovered' by GS Ed, formerly the manager of the ACN Florida site).
Uncook usually succeeds in ridding a file of Text mode corruption.
After you've downloaded Uncook.zip, uncompress
it using WinZIP or a
similar utility. The best place for the file Uncook95.exe is in the directory
to which you usually download Apple files. (This saves you the bother of
browsing for the files you want to fix with Uncook.)
To use Uncook, you double-click on the name
in the window which lists
Uncook95.exe. (Or, you can set up a shortcut to Uncook95.exe on your
Windows desktop.) The Uncook window will pop up.
Under "Mode", select "Generate new files".
Then, click on "File" and
"Open" to get to a file selection window. In this window, Set "Files of type"
to "All" and click on the file to uncook. Finally, you click the "Uncook"
button. Uncook will open a box to tell you the file is uncooked and that the
name is "Copy of ..." whatever the original file is named.
The reason you pick "Generate new files" is
to avoid changing your
downloaded copy. Uncook has a bug which lets it "fix" files even if they are
okay. When it does this, it produces a copy which is usually 1-3 bytes shorter.
If your uncooked copy is only a byte or two smaller than the original, the odds
are that the original is okay. However, a moderately large difference-- like a
hundred bytes-- is not a certain indicator that the original is corrupted. So,
keep your original until you know which copy is the good one.
In most cases where you have problems with
downloads from a site, Uncook will fix the messed up downloads.
Note: Evidently, Uncook works by comparing the file contents against
copy in cache memory-- i.e. the corruption occurs in the browser's handling
of the download to create the file. So, use Uncook fairly soon after doing the
download while a good copy is in cache.
Downloads from GSWV
GS WorldView now archieves practically all
software in .zip files. To
uncompress .zip files, use WinZIP or Aladdin's "Stuffit Expander" or a
similar utility on your PC or Mac. If you download directly to an Apple IIgs,
you can use PMPunZip to unzip the .zip files.
For more about handling .zip files on Apple
II computers and links to
related utilities, see above and the Apple II FAQs File Utilities page.
ShrinkIt .shk and .sdk files
Once you unzip a downloaded .zip file, you
will find that Apple II/IIgs
software will usually be in ShrinkIt form: you will have one or more .shk file
archives or .sdk whole-disk archives. Once transferred to your Apple II
(e.g. via a NULL modem connection), you can use 8-bit ShrinkIt (v3.4) or
GS-ShrinkIt to uncompress most of these files. For ShrinkIt file (.shk)
archives of IIgs software, you may need to use GS-ShrinkIt in order to
correctly unshrink forked files.
For more about ShrinkIt files and download
links for ShrinkIt and
GS ShrinkIt see the Apple II FAQs File Utilities page. For more about
file transfers, see the Apple II FAQs Telecom-1 Page.
Disk Image (.dsk) files
Another popular format, especially for software
on 5.25" disk, is .dsk
disk image. Once unzipped, the .dsk files can be used as virtual disks with
Apple II emulators (such as AppleWin) running on a PC or Mac.
A .dsk file can be transferred to your Apple
II (e.g. via a NULL modem
connection) and converted to diskette form using DSK2FILE or ASIMOV.
Usually, the resulting diskette will be bootable on your Apple II. Nearly all
.dsk files are of 5.25" diskettes and can also be transferred and converted
to diskette on an Apple II using ADT or ADT-GS.
For more about .dsk files and download links
for DSK2FILE and
ASIMOV see the Apple II FAQs File Utilities page. For more about
file transfers and getting ADT, see the Apple II FAQs Telecom-1 Page.