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Subject: COMP.SYS.CBM: General FAQ, v3.1 Part 4/9

This article was archived around: 5 Apr 1998 00:00:45 -0800

All FAQs in Directory: commodore/main-faq
All FAQs posted in: comp.sys.cbm
Source: Usenet Version

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
--------------------------------------------------------------------------- Table of Contents (for this file) --------------------------------- 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? --------------------------------------------------------------------------- 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 However, with the increase in IBM-based bulleting board, it has been replaced by other protocols.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: ----------------------------------------- .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/