mdavis@CHEM.UCSD.EDU (Morgan Davis) (07/31/87)
This is mainly directed to Larry Virden, though I suspect that others have already beaten me to the punch... The net cannot handle 8-bit binary data through the various mailers. Therefore, a SQueeze type program, which creates 8-bit binary data files, is not useful for passing information through the net as regular mail. The Executioner will take 8-bit data and create a special text version of a file by using a 6-bit packing scheme. This allows all the printable ASCII characters to make up the contents of the file so that they can be passed through a regular text network without getting munged. Almost all text mailers will strip the high-bit off of each byte, and they may act up if spurious control characters are found in messages. While one would be correct in saying that Executioner doesn't do any compression, technically speaking, its 6-bit packing mode will create smaller text files than would an ordinary hex dump. In fact, a 49-block object file (like TIC) will create a 158-block hex dump file. But if a 6-bit encoding scheme is used, TIC can be converted to a 68-block text file - - a SIGNIFICANT savings. In that sense, Executioner does provide compression for a text-based network. The ULTIMATE method would be to use an 8-bit squeezing program (like Don Elton's ASQ utility) to compress a binary file first. Then use Executioner to convert it to a transmittable text file with 6-bit encoding. Not everyone has the ASQ/AUSQ utilities, though. And the overall savings may or may not be that big of a deal. UUCP: [ ihnp4 cbosgd hplabs!hp-sdd sdcsvax nosc ] !crash!pnet01!pro-sol!mdavis ARPA: crash!pnet01!pro-sol!mdavis@nosc.mil INET: mdavis@pro-sol.CTS.COM BITNET: mdavis%pro-sol.cts.com@ucbvax.berkeley.edu (I hope this works)
lwv@n8emr.UUCP (08/03/87)
In article <8707312136.AA02715@crash.CTS.COM> sdcsvax!LOCAL.UCSD.EDU!pnet01!pro-sol!mdavis@ucbvax.Berkeley.EDU writes:
-->The net cannot handle 8-bit binary data through the various mailers.
-->Therefore, a SQueeze type program, which creates 8-bit binary data files, is
-->not useful for passing information through the net as regular mail.
-->
Just so you know, I am quite aware of the text limitations. If you will
re-read my note CLOSELY, I was responding to a request to post things IN
BINARY II format - which IS an 8 bit data format.
-->The Executioner will take 8-bit data and create a special text version of a
-->file by using a 6-bit packing scheme. This allows all the printable ASCII
-->characters to make up the contents of the file so that they can be passed
-->through a regular text network without getting munged.
-->
Sounds to me like a fine way of compressing A SINGLE file.
-->
-->The ULTIMATE method would be to use an 8-bit squeezing program (like Don
-->Elton's ASQ utility) to compress a binary file first. Then use Executioner to
-->convert it to a transmittable text file with 6-bit encoding. Not everyone has
-->the ASQ/AUSQ utilities, though. And the overall savings may or may not be
-->that big of a deal.
-->
I agree that using ASQ - a free/or low cost ware item by the way - doesnt
give a lot of savings. What _I_ am proposing is to port the Squeezing
version of arc to the Apple, then post it in executioner format, then using
THAT format, uuencoded, to transmit files, at a 47 to 65% savings!
It then takes many more steps to get the files, BUT you can get LOTS more
files at one swell foop!!
--
Larry W. Virden 75046,606 (CIS)
674 Falls Place, Reynoldsburg, OH 43068 (614) 864-8817
cbosgd!n8emr!lwv HAM/SWL BBS (HBBS) 614-457-4227.. 300/1200 bps
We haven't inherited the world from our parents, but borrowed it from our children.