home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
BBS Toolkit
/
BBS Toolkit.iso
/
rbbs_pc
/
msgtos13.zip
/
SPAZ_140.ZIP
/
TECHNOTE.DOC
< prev
Wrap
Text File
|
1989-04-10
|
3KB
|
57 lines
-----------------------------------------------------------------------
SPAZ, Revision: 1.40 Compiled: April 10, 1989
-= Technical and Application Notes =-
SPAZ is Copyright (c) MCMLXXXIX by Dan A. Thomson and Andrew D. Farmer.
-----------------------------------------------------------------------
The following are just a few ramblings to allow 'inquiring minds' to
see how SPAZ does it's thing.
After parsing the command line options, SPAZ opens any file matching
the wildcards or specified name. (This includes text files, binaries,
and even archives).
It then reads in the first 2 bytes and the last 2 bytes of the file.
These four bytes determine which type of archive is being worked on.
Detailed below:
1. Last 2 bytes = 'WC', assume DWC archive. This is checked first in
case an arc file is the first file in a DWC archive. (Which would
place a 1Ah at it's beginning....see number 4 below).
2. First 2 bytes = 'PK', assume PKZIP. Not alot of research here, but
the first 2 bytes of a ZIP file always seem to be PK....
3. First 2 bytes = 'ZO', assume ZOO format. If this is detected, an
attempt is made to run LOOZ which is a smaller extract only util.
If not found, ZOO is hunted for and executed.
4. First byte = 1Ah. Standard ARC<tm> format. SPAZ tries to sort this
archive by date/time, if /N was not used on command line. The sort
process allows SPAZ to determine if 'CRUSHED' files were included.
If so, PAK is called to undo it. If not SPAZ runs through a list of
un-archivers in the following order: PKUNPAK, PKXARC, PAK, ARCE.
These are all skipped if the /A option is used in which case only
ARCE is attempted.
Problem Areas: A minor problem occurs with DWC type files. If a file
was transfered via modem using YModem or XModem, it's file length is
adjusted to the next highest block. This fills the end of the file
with nulls. As SPAZ only reads the last 2 bytes, it will 'miss' the
'DWC' id mark.
One thing to remember, (which I have gotten a few queries on) is that
SPAZ can't do a thing by itself. In order for it to work you must have
the needed Un-archivers available on the default drive or somewhere in
your specified PATH statement.
I think that about covers it.
Dan Thomson
Ottawa, Canada
April 10, 1989
----------------------------------------------------------------------