======== Newsgroups: comp.sys.cbm Subject: COMP.SYS.CBM: General FAQ, v3.1 Part 4/9 From: brain@mail.msen.com (Jim Brain) Date: 13 Aug 1996 00:41:53 -0400 X-Posted-By: YPost, version 0.08 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: 1996/08/12 --------------------------------------------------------------------------- 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 ison, 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.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 However, with the increase in IBM-based bulleting board, it has been replaced by other protocols.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) 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 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. ...
Amiga7878