sz.doc

开源串口利用Xmodem,Ymodem,ZModem 下载,上传的程序.在Linux,Arm-Linux 都可使用

	  conventions.	The third line transfers some ._e_x_e files.  The
	  fourth and fifth lines command Pro-YAM to change directory
	  and execute a	PC-DOS batch file _i_n_s_m_s	. Since	the batch file
	  takes	considerable time, the zzzzccccoooommmmmmmmaaaannnnddddiiii form is used to allow
	  the program to exit immediately.

	  XXXXMMMMOOOODDDDEEEEMMMM FFFFiiiilllleeee TTTTrrrraaaannnnssssffffeeeerrrr (Unix to	Crosstalk)
	  % ssssxxxx ffffoooooooo....cccc
	  EEEESSSSCCCC
	  rrrrxxxx ffffoooooooo....cccc
	  The above three commands transfer a single file from Unix to
	  a PC and Crosstalk.  This combination	is much	slower and
	  less reliable	than ZMODEM.

     EEEERRRRRRRROOOORRRR MMMMEEEESSSSSSSSAAAAGGGGEEEESSSS
	  "Caught signal 99" indicates the program was not properly
	  compiled, refer to "bibi(99)"	in rbsb.c for details.

     SSSSEEEEEEEE AAAALLLLSSSSOOOO
	  rz(omen), ZCOMM User's Manual, Professional-YAM User's
	  Manual, crc(omen), sq(omen), todos(omen), tocpm(omen),
	  tomac(omen), yam(omen)

	  Compile time options required	for various operating systems
	  are described	in the source file.



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     SSSSZZZZ((((1111))))		OOOOmmmmeeeennnn TTTTeeeecccchhhhnnnnoooollllooooggggyyyy	IIIINNNNCCCC ((((OOOOMMMMEEEENNNN))))		 SSSSZZZZ((((1111))))



     FFFFIIIILLLLEEEESSSS
	  32 bit CRC code courtesy Gary	S. Brown.

	  sz.c,	crctab.c, rbsb.c, zm.c,	zmr.c, zmodem.h	Unix source
	  files

	  /tmp/szlog stores debugging output (sz -vv)

     TTTTEEEESSSSTTTTIIIINNNNGGGG FFFFEEEEAAAATTTTUUUURRRREEEE
	  The command "sz -T file" exercises the AAAAttttttttnnnn sequence error
	  recovery by commanding errors	with unterminated packets.
	  The receiving	program	should complain	five times about
	  binary data packets being too	long.  Each time sssszzzz is
	  interrupted, it should send a	ZDATA header followed by
	  another defective packet.  If	the receiver does not detect
	  five long data packets, the AAAAttttttttnnnn sequence is not
	  interrupting the sender, and the MMMMyyyyaaaattttttttnnnn string in sssszzzz....cccc must
	  be modified.

	  After	5 packets, sssszzzz stops the	"transfer" and prints the
	  total	number of characters "sent" (Tcount).  The difference
	  between Tcount and 5120 represents the number	of characters
	  stored in various buffers when the Attn sequence is
	  generated.

     SSSSEEEERRRRVVVVEEEERRRR////NNNNEEEETTTTWWWWOOOORRRRKKKK NNNNOOOOTTTTEEEESSSS
	  Terminals on some timesharing	systems	are connected
	  indirectly to	the host with TTTTEEEERRRRMMMMIIIINNNNAAAALLLL SSSSEEEERRRRVVVVEEEERRRRSSSS operating over
	  networks.  Terminal servers often interfere with file
	  transfers by "eating"	control	characters and/or losing data.

	  Accessing a distant system using tttteeeellllnnnneeeetttt on a local Unix
	  system entails the same problems.  If	tttteeeellllnnnneeeetttt does not	work
	  well,	try rrrrllllooooggggiiiinnnn with	the ----8888 option.	Set the	escape
	  character to ^P (control P) which is protected by ZMODEM.

	  When terminal	servers	interfere with file transfers, server
	  commands are often available to help the problem.  When
	  possible, enable the server and modems for hardware flow
	  control in and out.  Set the terminal	server to telnet
	  transparent mode.  Some typical commands are "SET TERMINAL
	  DOWNLOAD", "set session passall", and	"SET TERMINAL NO ESC",
	  but there is no standard set of commands suitable for	all
	  terminal servers.  Normally these commands are given before
	  attempting file transfers, but one user has reported that
	  the command must be given _a_f_t_e_r the file transfer is
	  started(!).  Until terminal server vendors improve the
	  quality of their product, you	may have to get	on their case
	  until	they adequately	support	high performance file
	  transfers.

	  The telnet protcol used by the _t_e_l_n_e_t	program	and terminal



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     SSSSZZZZ((((1111))))		OOOOmmmmeeeennnn TTTTeeeecccchhhhnnnnoooollllooooggggyyyy	IIIINNNNCCCC ((((OOOOMMMMEEEENNNN))))		 SSSSZZZZ((((1111))))



	  servers uses 0xFF (377 octal)	for special control functions.
	  The 0xFF character may cause problems	if it appears in the
	  data stream, especially uploading at high speeds.  With
	  ZCOMM	or Professional-YAM the	0xFF character can be
	  protected by giving the command:
	  set zmtxesc ?

	  Escaping control characters with ZMODEM (sz -e) may help if
	  the transfer gets stuck in the same place on every attempt.
	  Professional-YAM and ZCOMM allow selection of	which control
	  characters need to be	escaped.  In extreme cases 7-bit
	  transmission may be required (see the	Professional-YAM/ZCOMM
	  manual).  If you encounter problems with control characters
	  you should identify which control characters are causing the
	  problem.  Please refer to the	sz -T command in sz.doc	for
	  more help.

	  Flow control between the server and modem is often
	  defective.  This rarely causes a problem in interactive
	  applications whose short bursts (a screenfull	at most) fit
	  within the available memory buffers.	Streaming protocols
	  such as YMODEM-g, long packet	SuperKermit, and ZMODEM	can
	  overload the available buffering.  Some terminal servers
	  support commands to enable hardware flow control such	as
	  "TERM	FLOWCONTROL HARDWARE IN	OUT"; this assumes the modem
	  attached to the server is properly configured.

	  If the terminal server is too	brain damaged to support flow
	  control, ZMODEM lets you fake	it by setting a	window size.
	  Try
	       sz -w2048 file...
	  to enable software flow control.  Experiment with different
	  window sizes for best	results.

	  Terminal servers are designed	to accept keyboard input from
	  human	operators.  They may lose data when a program sends
	  more data to the host	faster than humans type.  Some servers
	  allow	larger input buffers to	support	file uploads.  If you
	  can upload short files (less than 100	bytes) but not longer
	  files, try
	       sz -w1024 file...
	  with your uploading program.	(Not all programs support this
	  option; use ZCOMM or Professional-YAM.)

	  When both flow control and character transparency are
	  problems, use
	       sz -ew1024 file...
	  as a starting	point.

	  Sometimes the	terminal server	software is defective and must
	  be corrected.	 Please	contact	the network's vendor for
	  corrective procedures.  An alternative is to install direct



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     SSSSZZZZ((((1111))))		OOOOmmmmeeeennnn TTTTeeeecccchhhhnnnnoooollllooooggggyyyy	IIIINNNNCCCC ((((OOOOMMMMEEEENNNN))))		 SSSSZZZZ((((1111))))



	  serial ports for users desiring to upload files.

	  We have also encountered problems when networking software
	  fails	to pass	data after a large amount of data has been
	  sent to the host.  This has happened on a PPP	internet
	  connection which prevented uploads of	large amounts of data
	  via either FTP or a ZMODEM upload (via TELNET).  The PPP
	  connection grinds to a standstill and	not even PING works.
	  The same ZMODEM/TELNET combination easily uploaded ten times
	  as much to a nearby machine connected	by Ethernet.


     PPPPOOOORRRRTTTT WWWWAAAATTTTCCCCHHHHEEEERRRRSSSS
	  Some systems enforce a timeout which disconnects a user
	  after	several	minutes	of keyboard inactivity.	 Long, error
	  free ZMODEM transfers	do not generate	keyboard activity
	  (this	is why ZMODEM is so efficient).	 Restricting the
	  window size with
	       sz -w16384 file...
	  option generates terminal input at regular intervals even
	  when no error	correction is needed.  If problems persist,
	  try setting a	packet length.
	       sz -l1024 file...
	  (The default ZMODEM packet length is the file	length.)

     NNNNOOOOTTTTEEEESSSS
	  SSSSzzzz,,,, ssssbbbb,,,, ssssxxxx,,,, (Reg.)and	zzzzccccoooommmmmmmmaaaannnndddd are hard links	to the
	  compiled sz program.	These links are	generated by the
	  Makefile.

	  SSSSzzzz is	now compiled with internal buffering to	allow sending
	  datasets piped to its	standard input (286 version excluded).
	       ps -ef |	sz -
	  The file is sent as "szPID" where PID	is the process ID of
	  sending sz.

	  Particular attention must be paid to flow control.  The
	  modem	and Unix must agree on the flow	control	method.	 Sz
	  does not set or reset	flow control modes (if any).  Most
	  Unix systems use XON/XOFF ("software") flow control.

	  Telebit modems must not be set to "spoof" UUCP, XMODEM,
	  YMODEM, or KERMIT.  Setting one of these spoofing modes
	  interferes with other	protocols.  Telebit's YMODEM spoofing
	  interferes with YMODEM transfers.

	  If a program that does not properly implement	the specified
	  file transfer	protocol causes	_s_b to "hang" the port after a
	  failed transfer, either wait for _s_b to time out or keyboard
	  a dozen Ctrl-X characters.  Every reported instance of this
	  problem has been corrected by	using ZCOMM, Pro-YAM, DSZ, or
	  other	program	with a correct implementation of the specified



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     SSSSZZZZ((((1111))))		OOOOmmmmeeeennnn TTTTeeeecccchhhhnnnnoooollllooooggggyyyy	IIIINNNNCCCC ((((OOOOMMMMEEEENNNN))))		 SSSSZZZZ((((1111))))



	  protocol.

	  Many programs	claiming to support YMODEM only	support	XMODEM
	  with 1k blocks, and they often don't get that	quite right.
	  XMODEM transfers add up to 127 garbage bytes per file.
	  XMODEM-1k and	YMODEM-1k transfers use	128 byte blocks	to
	  avoid	extra padding.

	  YMODEM programs use the file length transmitted at the
	  beginning of the transfer to prune the file to the correct
	  length; this may cause problems with source files that grow
	  during the course of the transfer.  This problem does	not
	  pertain to ZMODEM transfers, which preserve the exact	file
	  length unconditionally.

	  Most ZMODEM options are merely passed	to the receiving
	  program; some	programs do not	implement all of these
	  options.

	  Circular buffering and a ZMODEM sliding window should	be
	  used when input is from pipes	instead	of acknowledging
	  frames each 1024 bytes.  If no files can be opened, sssszzzz sends
	  a ZMODEM command to echo a suitable complaint; perhaps it
	  should check for the presence	of at least one	accessible
	  file before getting hot and bothered.

	  Unix Professional-YAM	provides higher	performance and	other
	  features not supported by _s_z.	Please contact Omen Technology
	  Inc for product information.

	  http://www.omen.com

	  Omen Technology INC
	  Post Office Box 4681
	  Portland OR 97208
	  503-614-0430 (Sales)


     BBBBUUUUGGGGSSSS
	  Some third party software packages do	not properly implement
	  the ZMODEM protocol.	This often causes problems when	users
	  attempt to use the -a	or other options.

	  On at	least one BSD system, sz would abend it	got within a
	  few kilobytes	of the end of file.
	  Using	the "-w8192" option fixed the problem.	The real cause
	  is unknown, perhaps a	bug in the kernel TTY output routines.

	  The test mode	leaves a zero length file on the receiving
	  system.





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