rz.doc

支持ZModem协议的串口通讯程序

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	  transparent mode.  Some typical commands are "SET TERMINAL
	  DOWNLOAD" and	"SET TERMINAL NO ESC", but there is no
	  standard set of commands suitable for	all terminal servers.

	  Escaping control characters (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 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, you can fake	it with	ZMODEM.	 Try "sz -
	  w1024	file..." to enable software flow control. Experiment
	  with different values	to find	the best throughput.

	  Terminal servers are designed	to accept keyboard input from
	  human	operators.  They may lose data when a program sends
	  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 upgraded.	Please contact the network's vendor for
	  corrective procedures.  An alternative is to install direct
	  serial ports for users desiring to upload files.

	  Some systems enforce a timeout which disconnects a user
	  after	several	minutes	of no keyboarding.  This can cause
	  problems in long, error free ZMODEM transfers.  Restricting
	  the window size with a "-w8192" option provides terminal
	  input	at regular intervals even when no error	correction is
	  needed.  If problems persist,	try setting a packet length



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	  (sz -l1024).

     NNNNOOOOTTTTEEEESSSS
	  ZMODEM's support of XOFF/XON flow control allows proper
	  operation in many environments that do not support XMODEM
	  uploads.  Unfortunately, not all Unix	versions support input
	  flow control.	 The TTY input buffering on some systems may
	  not adequately buffer	long blocks or streaming input at high
	  speed.  You should suspect this problem when you can't send
	  data to the Unix system at high speeds using ZMODEM,
	  YMODEM-1k or XMODEM-1k, but YMODEM with 128 byte blocks
	  works	properly.

	  The DSZ or Pro-YAM zzzzmmmmooooddddeeeemmmm llll numeric parameter	may be set to
	  a value between 64 and 1024 to limit the burst length
	  ("zmodem pl128").  Although this compromises ZMODEM's
	  throughput, ZMODEM's superior	reliability remains intact.

	  If a program that does not properly implement	the specified
	  file transfer	protocol causes	_r_z to "hang" the port after a
	  failed transfer, either wait for _r_z 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
	  protocol.

	  Many programs	claiming to support YMODEM only	support	XMODEM
	  with 1k blocks, and they often don't get that	quite right.

	  In the case of a few poorly designed microcomputers, sending
	  serial data to a tty port at sustained high speeds has been
	  known	to cause lockups, system halts,	kernel panics, and
	  occasional antisocial	behaviour.  This problem is not	unique
	  to _r_z; newer versions	of Kermit, CRT terminals with screen
	  transmission,	and line noise have the	same effect.  When
	  experimenting	with high speed	input to a system, consider
	  rebooting the	system if the file transfers are not
	  successful, especially if the	personality of the system
	  appears altered.

	  The Unix "ulimit" parameter must be set high enough to
	  permit large file transfers to Unix.

	  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.

	  32 bit CRC code courtesy Gary	S. Brown.  Directory creation
	  code from John Gilmore's PD TAR program.

     NNNNEEEETTTTWWWWOOOORRRRKKKK NNNNOOOOTTTTEEEESSSS



     PPPPaaaaggggeeee 5555					     ((((pppprrrriiiinnnntttteeeedddd 2222////11118888////99994444))))






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	  Escaping all control characters (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
	  Professional-YAM/ZCOMM manual).  7-bit transmission requires
	  rz version 4.50 or higher.

	  Please refer to the sz -T command in sz.doc for more help.

     BBBBUUUUGGGGSSSS
	  This version of _r_z does not support some ZMODEM features.
	  Unix flavors of Professional-YAM may be linked to "rz" to
	  support these	features.

	  The ASCII option's CR/LF to NL translation merely deletes
	  CR's;	undos(omen) performs a more intelligent	translation.

     ZZZZMMMMOOOODDDDEEEEMMMM CCCCAAAAPPPPAAAABBBBIIIILLLLIIIITTTTIIIIEEEESSSS
	  _R_z supports ZMODEM command execution (zcommand), incoming
	  ZMODEM binary	(-b), ASCII (-a), newer(-n), newer+longer(-N),
	  protect (-p),	Crash Recovery(-r), clobber (-y),
	  match+clobber	(-Y), compression(-Z), and append (-+)
	  requests.  Other options sent	by the sender are ignored.
	  The default is protect (-p) and binary (-b).

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

	  Omen Technology INC
	  503-621-3406
	  Post Office Box 4681
	  Portland OR 97208


     FFFFIIIILLLLEEEESSSS
	  rz.c,	crctab.c, rbsb.c, zm.c,	zmr.c, zmodem.h, rz.1

	  /tmp/rzlog stores debugging output generated with -vv	option














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