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Archive-name: cbm-main-faq.3.1.p4
Comp-answers-archive-name: commodore/main-faq/part4 News-answers-archive-name: commodore/main-faq/part4 Comp-sys-cbm-archive-name: main-faq/part4 Version: 3.1 Last-modified: 1996/01/25 See reader questions & answers on this topic! - Help others by sharing your knowledge
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Table of Contents (for this file)
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6. The Online Information Reservoir
6.1. How do I download? What is a transfer protocol?
6.2. What is the difference between PETSCII and ASCII?
6.3. Where can I find Commodore programs?
6.4. What is a file extension, and what do they stand for?
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6. The Online Information Reservoir
How true this is. There is information everywhere online, just
waiting to be accessed and used. Hoever, getting at the information
can be a time consuming process.
6.1. How do I download? What is a transfer protocol?
To transfer files for another computer (another 64 or 128, UNIX, OS/2,
DOS, MVS, VMS, Amiga, Atari, or other), you should use a transfer protocol.
Although it is possible to transfer files by turning on the terminal
program's capture buffer and receiving the file, this is not very
reliable and is prone to errors. When transferring any sizable amount of
data, one should use some sort of error-correcting file transfer protocol.
A file transfer protocol splits a file into many pieces, or "packets", and
send a number of them at a time. It then waits for an acknowledgement from
the receiver that the received received the packets correctly. At this
point, the sender send the next batch of packets. This process is
repeated until the entore file is transmitted. Each packet contains
computed checksums and other error detection bytes to ensure the
received data is not corrupt.
Below are descriptions for some of the more popular protocols:
C1 (commonly called Punter Protocol)
C1 is a Commodore specific transfer protocol that used to be the
standard for file transfer. However, with the increase in IBM-based
bulleting board, it has been replaced by other protocols. Most Commodore
BBS systems still offer C1 (usually called Punter in the list) as an option,
but almost no other BBS systems have support for it. There is, however, a
C1 protocol transfer program for MS-DOS called puntr104.zip.
KERMIT
KERMIT is the name of one of the oldest file transfer protocols. KERMIT
is unique in that it can encode the file being transmitted so that
it does not contain any bytes greater than 128 and does not contain any
special control bytes that terminals use to perform special actions. As
such, this protocol is the most robust, but it is also the slowest.
A common statement is, "if you can't KERMIT it, you can't get it"
XMODEM
XMODEM comes in several varieties. Standard XMODEM sends files in 128 byte
packets. There are two standard error-correction methods with XMODEM
checksum and CRC. CRC is the more modern of the two. There is also a
version of XMODEM which supports 1K-byte packets. This version is most
commonly known as XMODEM-1K, but is sometimes erroneously called YMODEM.
YMODEM
YMODEM is a "batch" XMODEM protocol, allowing you to transfer multiple
files in one operation.
ZMODEM
A new file transfer protocol is ZMODEM. ZMODEM is theoretically the
fastest transfer protocol, but only shows a speed gain over the others
on noise-free telephone lines. It achieves this speed increase by only
replying to the sender about the bad packets.
Most terminal programs support PUNTER, XMODEM, XMODEM-1K, YMODEM, and
KERMIT. The Kermit terminal program only supports KERMIT, and Novaterm,
as of version 9.5, supports ZMODEM receives, but not sends.
6.2. What is the difference between PETSCII and ASCII?
(Note that the Amiga line of computers uses the ISO 8859-1 character
set, so this does not apply to Amiga computers)
When Commodore designed the PET line of computers, they chose for the
character set encoding a special encoding called PETSCII. This set is
similar but not the same as the American Standard Code for Information
Intercahnge (ASCII). Now, this does not cause any
problem when transferring information between or among Commodore
computers (except the Amiga, which I believe uses ASCII), but causes
problems when exchanging information with othe computer types.
The obvious solution is for all Commodore users to translate incoming
information into PETSCII from ASCII when talking to another type of
computer. However, this effectively ruins binary files, which have
no concept of character codes. Therefore, the rules are:
Do not translate when exchanging binary files with any computer
Translate all textual information exchanged with non-Commodore computers.
Translate textual information exchanged with Commodore computers only
if they are translating it as well.
If a text file you retrieve looks like the uppercase letters should
be lowercase and vice versa, then the file is in ASCII and needs to
be converted to PETSCII.
6.3. Where can I find Commodore programs?
Commodore programs are available from a number of sources. For commercial
software, please see Section 15.1 for a list of software dealers. For
shareware and public domain, you can use FTP (Section 6.9), electronic
mail (Section 6.5.2), and bulletin board system in addition to the
software dealers to download or buy programs and other software.
6.4. What is a file extension, and what do they stand for?
A file extension is a 1 or more letter suffix appended to the end of a file
name to indicate the type of file it is. The extension usually indicates
the contents of a file. The list below describes some more common file
extensions, what they are used for, and how to use the file.
Please note that these file extensions are not Commodore-exclusive. Many
computers use file extensions. Also note that some file extensions
are cumulative. IF a file is named "filename.tar.gz", this indicates that
the file is of type "gz", and the file(s) inside the gz file are of type
"tar". To use this file, one would note that both extension are
archival extensions. One would undo the "gz" archival method to restore
the "filename.tar" archive, then undo the "tar" archival method to restore
the original file.
Extension: Meaning: Notes:
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.txt Text File This file is not compressed, so it needs
no decompression step. However, the file
may be in either ASCII or PETSCII format,
so a conversion step may be necessary.
Most terminal programs can do this
conversion, and there are stand-alone
programs that do the necessary conversion
also.
.sda Self-Dissolving Just load and run the .sda file to
Archive dissolve the archive. Will dissolve
itself into its constituent files.
C64 and C128 .sda files are not
compatible with each other.
.sfx Self-Extracting Load and run just like a .sda file.
Archive The same archive can be extracted on
either a C64 or a C128, memory permitting.
.arc ARChive Use the program arc250.4 or earlier
for the 64 or arc128 for the 128 to
dissolve the archive. arc128 is available
as part of the CS-DOS package. Other
de-archive programs may exist.
.lzh LHArchive Use the program lhx in CS-DOS on the
128 to dissolve this archive. These
are not very common. This archive
uses the same format as .sfx files,
but is not self-extracting. It is
a standard format also used by
Amiga (and MS-DOS) computers. This
format originated on the PC.
.lnx Lynx Archive The above formats all compress files when
storing them; Lynx just stores them.
There are many different versions of
Lynx out there, so good luck dissolving
these.
.lbr Library Archive A format similar to lynx. Library
dissolving programs exist for both the
64 and 128 to dissolve these.
.uue UUEncoded file UUencoding is a process whereby a binary
file can be converted to an all-text
file, transferable by E-mail. This
encoded file can later be UUDecoded back
to the original binary file. Unix
has uuencoding/decoding utilities.
A program "uuxfer" for the
C64 (by Fuzzy Fox) will both uuencode
and uudecode. Note that the contents of
uue file could be another archived file.
.uua UU archive An extension of uuencoding, a uuarchive
file is a concatenation of one or more
UUEncoded files. So far as I know, this
was introduced by Craig Bruce in his ACE
shell for the C=128, and the utilities
included with that shell create and
dissolve uuarchives.
.kar Kevin's Archive Another text archive format that seems
to have originated with Craig Bruce,
this is a proscription for concatenating
a series of text files (which can include
uuencoded files) into one file. More
information can be found in C. Bruce's
documentation for his ace shell.
x!<file> ZIPCoded file ZIPCode is a program that takes an entire
disk and "compacts" it into 4 files that
have a number followed by a '!' and then
a filename. Also, ZipCode can compress
files, in which case the x is a letter
(a,b,c,d) and there need not be 4 files.
If ZipCode has compressed individual
files, there will be an "i!" or
"x!"-prefixed file on the disk that holds
the directory of the file compressed. To
make things even more confusing, there
are two versions of ZipCode (v1 and v2).
The newer version will accept v1 archives,
but not vice-versa. Use ZipCode v2 to
unpack such archives.
+ <file>_x.z64 ZIPCoded file These are ZIPcode compatible files
+ created by a DOS program called Star Zip
x!!<file> ZIPCode 6-pack This is a ZIPCode archive that takes an
entire disk and puts it into 6 files,
| each file containing GCR codes and header
info for the tracks. This is basically
a nybble copier that stores the data it
receives from the disk into files.
.bco BCODEd file BCODing is very similar to UUencoding in
that a binary file is converted into an
all-text format that is 33% larger than
the original. The difference is that the
BCODE format provides additional
information for error detection and
automatic data segmentation and
reordering. C-code versions of "bcode"
and "unbcode" are available via FTP and
Commodore versions are provided with
ACE-128/64.
.zip ZIP archive Zip is a file format used on IBM
platforms and is created by the PKZip
program that is available for some
platforms. There are two forms of zip
files that have the same extension.
Both are created by different versions of
PKZip. The first, version 1.01, can be
dissolved on a 64 by using the program
UNZIP64. The second, newer format is
version 2.04, which cannot be dissolved by
UNZIP64. Your best solution when in doubt
is to dissolve the files on another
platform. For the 128, there is a version
of the UNZIP64 program, called UNZIP128
that has been modified to run in 128 mode.
It is in a file called NZP12817.SFX. This
archive also has a 64 version.
<file>]x Compression Kit x = 4,7,8, cmd, or c(xx) to denote type
Archive of media that was compressed. The files
can be extracted only with The Compression
Kit, from Mad Man Software.
.tar TAR Archive UNIX Tape ARchiver. This program can be
used to archive files as well. The file
must be decoded using tar.
.Z Compress archive Compress is a program on UNIX that will
shrink a single file. It is usually used
on .tar files in UNIX to reduce their
size. The file must be decoded by the
uncompress program, available on UNIX, PC,
Mac and other platforms.
Also, a very old version of GNU Zip used
this extension, although the file is not
fully compatible with the compress format.
.gz GZIP Archive GZIP is a free program developed by the
Free Software Foundation to freely shrink
their software. the resulting file must be
decoded by GUNZIP, available on many
platforms, before using.
.taz Compressed TAR This is a file that should have the
extension "tar.Z", but has been shortened
for MS-DOS. Run uncompress, then tar on
this file.
.tgz Gzipped Tar File This is a file that should have extension
tar.gz, but has been shortened for MS-DOS
Run gzip or similar on the file, then tar.
.gif Graphics This is a compressed graphics format
Interchange created by Compuserve. To view this file,
| Format one must find a GIF viewer program:
+ GEOGif.SFX - Converts GIF to GEOPaint.
+ VGIF.SFX - 64 mode viewer.
+ GDS.SFX - 128 mode viewer.
.jpeg Joint This graphics format can use one of two
Photographers compression algorithms. One, called DPCM
Expert (Differential Pulse COde Modulation)
Group retains all of the information in the
original file, which is usually a picture.
The more common algorithm, called DCT
(Discrete Cosine Transform), relies on the
inability of the human eye to distinguish
among some colors. DCT "throws away" some
information in the file (picture), while
still retaining the essence of the picture.
To view these pictures, one must either
obtain a JPEG veiwer or convert them to
GIF format.
.jpg JPEG This is an MS-DOS named .jpeg file.
.tiff Tagged This is a graphics format used on high
Image performance workstations. To view this
File graphics format, you will need to convert
Format something else.
.pcx IBM Picture This is graphics format used in DOS on
IBM machines. Convert this file to a
GIF file to view.
.pict Mac PICTure This is a graphics format used on Apple
Macintosh machines. Convert this file
to a GIF file to view.
.d64 1541 Disk Image This file stores an image of one entire
.x64 disk, for use with Commodore emulator
programs. Several programs exist to
extract the image onto a disk or place a
disk onto an image. The only difference
between the .x64 and .d64 file types is an
added 64 byte header on a .x64 file.
.t64 DataSette Image This file is analogous to the .d64 file
type, but for tapes.
.p00 PC64 (Emulator) This file encapsulates a Commodore program
Program File Image or data file. To extract the original
file, remove the first 26 characters. In
addition to .p00, there is .s00 (SEQ), and
.u00 (USR) files, but are very rare.
.bmp Windows Bitmap This is a format used for graphics in
Microsoft Windows and OS/2. Convert this
file to a GIF to view.
.pbm Portable Bitmap
.xbm X bitmap This is a format used for graphics on the
X windowsing system. Convert this file
to a GIF to view.
.html HyperText This is a WWW hypertext document. To
Markup view this file, you will need a WWW
Language browser of some kind. See Section 6.8
for more information on WWW.
.doc Document This file could be a word processing file
from a program like Word for Windows,
Wordperfect, or any other word processor.
Also, some text files that contain
documentation use this extension.
.cvt GEOS file GEOS files use a special file format. The
files are called USR files, but they have
special information in the file that
normal files don't, so you cannot just
upload a GEOS file like any SEQ or PRG
file. You can pack all the extra
information and the data into a regular
Commodore SEQ or PRG file with a program
Called Convert. It has a version 2.5 and
a 3.0. The files that result from this
conversion have the extension. The file
must be processed again by Convert before
it can be used with GEOS.
.N64 64NET file Since the 64NET system works by allowing
an MS-DOS machine to be used as a large
disk drive, a way was developed to map
CBM filenames into the MS-DOS limitations.
The .N64 filenames indicates such a file.
+ .D71 64NET GEOS File These are 64NET extensions used to
+ .D81 emulate a 1571 and 1581 disk drive,
+ respectively, under GEOS.
If the file type indicates an archive, there are many programs available
that will handle most archival methods. One of these is called Omega-Q II,
which includes one-stop compression and decompression of many of the above
archival types.
If you use a host system to download the files from, you may want to
decompress the files before downloading. Even though the files will be
larger to download, the time to decompress them offline will not be a
factor. However, those who pay by-the-minute for download time would
probably want the smallest possible file, which implies decompressing on
the local machine, except in the case of a UU encoded file. These files
are actually bigger in the 'UU' format.
--
Jim Brain, Embedded System Designer, Brain Innovations, Inc. (BII) (online sig)
bii@mail.jbrain.com "Above views DO reflect my employer, since I'm my employer"
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times! -Me-
BII Home: http://www.jbrain.com CBM Info: http://www.jbrain.com/vicug/
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