home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Tech Arsenal 1
/
Tech Arsenal (Arsenal Computer).ISO
/
tek-20
/
tn210.zip
/
NETWORK.EXE
/
R95.TXT
< prev
Wrap
Text File
|
1992-05-27
|
4KB
|
81 lines
RADIX 95
--------
COMMENTS ON RADIX 95
BY JACK TAYLOR, N7OO
************************
RADIX 95 is a binary to text conversion program written by James Jones, WD5IVD
and Dhanapong Saengrussamee for packet radio. Transfer of 8-bit data on packet
can be accomplished with appropriate parameter settings on the TNC. However
problems arise when sending 8-bit data through the current Bulletin Board
store and forward network. The reason for this is because the BBS codes use
certain 8-bit characters for control purposes. Binary data can fail due to
8-bit data characters being interpreted by the BBS ode as a BBS control
function.
A need arises then for a way to convert binary data to a 7-bit format which can
be transmitted through the BBS network, and then be converted back to the
original 8-bit data. Existing conversion schemes can accomplish this, but they
all increase the original file size. For instance the HEX encoding process can
increase the original file size by as much as 100 percent. Character Prefixing
conversion methods typically increase the original file overhead by 84 percent.
The RADIX 64 conversion method reduces the overhead amount to typically 33
percent.
With RADIX 95, overhead is further reduced, varying between 17 and 24 percent,
depending upon file content. Other 8-bit to 7-bit conversion schemes may
reduce overhead even further, but suffer from increased processing time in
accomplishing the conversion.
A convenient procedure to process binary files is to first use one of the
compression programs, such as PKZIP on the binary format. PKZIP typically
reduces the file size by 40 percent. The ZIPPED file is then converted to the
RADIX 95 format. Using this procedure, the processed file size is then
nominally 25 percent smaller than the orignal.
One nice feature of RADIX 95 is it allows a large file to be split into smaller
segments. These segments can be sent one at a time over the system. After all
of the segments have arrived at the receiving end, they can be recombined into
the original file.
To summarize the procedure, PKZIP is used to compress a file. The compressed
file is "R95ed". It is then split into a series of 2 to 3Kbyte files. The
split files are sent, as convenient, over a period of time. The receiving end
recombines the split files into a single "R95ed" file. This is then "de-R95ed"
back to the compressed format. It is then PKUNZIPed into the original file.
It would seem this process could be fully automated and incorporated into BBS
software for use on forwarding networks. With a potential savings of better
than 25 percent on traffic loading, RADIX 95 has definate advantages.
RADIX 95 format
---------------
The top line of a RADIX 95 file will read:
(RADIX 95 - [filename:date])
Filename is the first 8 characters of file name.
Date is - MM/DD/YY.
Each line of RADIX 95 produced will be 70 characters long. No other
information should appear after the 70th character.
The file ends with:
(RADIX 95 - END FILENAME)
Where filename is the first 8 characters of the file name.
RADIX 95 will search a file's first 10 lines (one that is to be converted back
to 8-bit data) for "(RADIX 95" before attempting a file conversion. If
"(RADIX 95" is not found within the first 10 lines, then the program will
provide an error response and abort.
Overall commands and operational information are available within the RADIX 95
program at "F1". For more information see the article on RADIX 95 in the ARRL
7th Computer Networking Conference proceedings, page 107.
An added benefit of RADIX 95 is in the way binary control functions are
encoded, users along the circuit with their TNC MONITOR function "ON" will not
experience disruptions to their screen. Monitor lockups are agrevatingly
common when exposed to transmissions of standard binary content.