bryce@COGSCI.BERKELEY.EDU (Bryce Nesbitt) (07/20/87)
I have several different terminal emulator programs for the Amiga. All support
XMODEM transfer. Only one supports XMODEM CRC. XMODEM CRC is *EASY* to add,
and gives a big reliability boost for transfer over noisy lines. I'd like to
have this feature on all the programs I use, and to this end I have dug up
the actual specification for XMODEM and XMODEM CRC. Write to me and ask for
it if you don't already know the formats.
(Send your order before midnight tonight and at no extra charge I'll throw in
source code for not one..., not two..., not even three..., but, yes FOUR
common programming languages!!!! (C, 68000, pascal and 8088))
(I would have done 6502 also, but I doubt it would ever get used... I recall
reading in "The Regional Enquisitor" that all existing 6502 CPUs ceased to
function sometime in late 1986 :-) :-) :-) :-) :-)
(For those of you that don't know, XMODEM uses a single 8 bit exclusive-or'ed
checksum for each 128 byte "packet". On a noisy line this will often MISS
errors. XMODEM CRC uses a 16 bit "cyclic redundancy check". Most of the
extra reliability comes from the larger size of the check value.)
-----------------------------
|\ /| . Ack! (NAK, EOT, SOH)
{o O} .
( " ) bryce@cogsci.berkeley.EDU -or- ucbvax!cogsci!bryce
U "Success leads to stagnation; stagnation leads to failure."walton@tybalt.caltech.edu (Steve Walton) (07/20/87)
In article <8707200126.AA15199@cogsci.berkeley.edu> bryce@COGSCI.BERKELEY.EDU (Bryce Nesbitt) writes: >I have several different terminal emulator programs for the Amiga. All support >XMODEM transfer. Only one supports XMODEM CRC. XMODEM CRC is *EASY* to add, >and gives a big reliability boost for transfer over noisy lines. I'd like to >have this feature on all the programs I use, and to this end I have dug up >the actual specification for XMODEM and XMODEM CRC. While we're wish-listing for terminal programs, here's mine in order of importance: (1) Kermit--the single best protocol for communication between heterogenous machines. The basic protocol can be implemented with very few lines. Also has options for 1-byte checkum, or 2 or 3-byte CRC's. (2) Long packet XMODEM--same as normal XMODEM but with 1024-byte packets. A big win over packet switched networks. CRC nearly mandatory here. (3) Batch XMODEM, sometimes called YMODEM--Simple: interpret the first 128-byte packet you receive as containing a null-terminated file name. Also contains the exact length of the file in bytes--no more chopping! Optionally contains file mod date and mode. (4) Windowed protocol, Kermit (hard) or WXMODEM (somewhat easier)--These are full duplex protocols which simultaneously send data both ways. I find 1200 baud WXMODEM achieves an 1150 baud transfer rate over good ol' Telenet. Steve Walton, guest as walton@tybalt.caltech.edu AMETEK Computer Research Division, ametek!walton@csvax.caltech.edu "Long signatures are definitely frowned upon"--USENET posting rules
shanzer@mit-caf.UUCP (Mike Shanzer) (07/21/87)
In article <3280@cit-vax.Caltech.Edu> walton@tybalt.caltech.edu.UUCP (Steve Walton) writes: >In article <8707200126.AA15199@cogsci.berkeley.edu> bryce@COGSCI.BERKELEY.EDU (Bryce Nesbitt) writes: >>I have several different terminal emulator programs for the Amiga. All support >>XMODEM transfer. Only one supports XMODEM CRC. XMODEM CRC is *EASY* to add, >>and gives a big reliability boost for transfer over noisy lines. I'd like to >>have this feature on all the programs I use, and to this end I have dug up >>the actual specification for XMODEM and XMODEM CRC. > >While we're wish-listing for terminal programs, here's mine in order >of importance: >(1) Kermit ... >(2) Long packet XMODEM--same as normal XMODEM but with 1024-byte packets. > A big win over packet switched networks. CRC nearly mandatory here. >(3) Batch XMODEM, sometimes called YMODEM ... >(4) Windowed protocol, Kermit (hard) or WXMODEM (somewhat easier)--These > are full duplex protocols which simultaneously send data both ways. > Steve Walton, guest as walton@tybalt.caltech.edu > AMETEK Computer Research Division, ametek!walton@csvax.caltech.edu The following has been posted from a friends account and is just my opinion... I think what you want is Diga! It has Xmodem CRC, Xmodem, Ymodem, Compuserve-B, Kermit, ASCII & Doubletalk. Diga is loaded with features and beats the 5-6 other amiga modem programs I have used hands down. I have used it for over a month now and have not encountered any major bugs. Besides the incredible file transfer section, is features a display section that comes with a VT100, VT52 and TEK4010 emulations. You can have up to 50*132 characters on the screen and use your own fonts. There also is a remote section that you can set up so that other people can call up your computer and up & download files without you having to be there. It has a basic type language built in, so you can write your own scripts. What makes Diga really good are the little things. Unlike other modem programs it doesn't save after every block it receives during file transfer. You can adjust the buffer yourself. You can use keystrokes to do everything, there is an easy to use fast menu, etc, etc... I am sorry that this has turned into a review of Diga. Believe it or not I don't have any connection with Aegis. I am just a very satisfied customer. Mike (My watch has job control) Mayer -- Mike Shanzer ARPA: shanzer@caf.mit.edu UUCP: mit-eddie!mit-caf!shanzer Unix, Live free() or malloc()
markr@garfield.UUCP (07/22/87)
Please send me the XMODEM info. My site will not send to you for some reason.