Re: SEAs?

[David.Empson@bbs.actrix.gen.nz]

In article <92321.123328TS8RBOTW@MIAMIU.BITNET> Radagast <TS8RBOTW@MIAMIU.BITNET> writes:
> Why are Sefl-Extracting Archives (particularly GSHK) called self-
> extracting when they don't?  That's annoying having to change the
> file type and aux type like we have to do with GSHK.  Is GSHK the
> only SEA like that, or do all have to be manipulated?  GSHK is the
> only SEA I've ever seen.

Self-extracting archives must be handled carefully in order to work
properly.  An SEA on a BBS _must_ have a Binary II header, which should
be removed by your comms program as the file is downloaded (or remove
it using BLU to get an executable file).

The same goes if the SEA file is stored in Binary form on an FTP site -
it should have a Binary II header.

It the SEA has been encoded using BinSCII (e.g. the copy made
available through comp.binaries.apple2) you have two options:

1. Download the BinSCII archive to your IIgs, then decode it using the
BINSCII program.  You can't use GSCII+ at present, because it adds a
few dummy bytes to the end of the file.  This should be fixed in a
future version.  The ProDOS-8 BINSCII program doesn't have this problem.
This isn't a problem for most files, but IIgs executable files must
have exactly the right length, or the IIgs won't load them.

2. Use SCIIBIN on a UNIX system to convert the BinSCII archive into a
Binary file.  Download this file to the IIgs using YModem batch or
ZModem, _not_ XModem - the file length must be maintained.  In this
case you have to set the file type back to S16/$DB07, because Unix
systems have no way of retaining the filetype information that was in
the BinSCII header.


You can only retain the filetype information if the BinSCII or Binary
II file is decoded on the IIgs.


When this topic was discussed earlier, someone pointed out that it
would be very handy to have a UNIX utility that could decode a BinSCII
archive and place a Binary II header onto the file, so that the file
type, modification date, file size, etc. were retained when the file
was downloaded to the Apple II.

Unfortunately no such program exists at present.
-- 
David Empson

Internet: David.Empson@bbs.actrix.gen.nz    EMPSON_D@kosmos.wcc.govt.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand