rz
Hurricane Electric Internet Services
NAME
rx, rb, rz - XMODEM, YMODEM, ZMODEM (Batch) file receive
SYNOPSIS
rz [- +abepqtuvy]
rb [- +abqtuvy]
rx [- abceqtuv] file
gz file ...
[-][v]rzCOMMAND
DESCRIPTION
This program uses error correcting protocols to receive
files over a dial-in serial port from a variety of pro-
grams running under PC-DOS, CP/M, Unix, and other operat-
ing systems. It is invoked from a shell prompt manually,
or automatically as a result of an "sz file ..." command
given to the calling program.
While rz is smart enough to be called from cu(1), very few
versions of cu(1) are smart enough to allow rz to work
properly. Unix flavors of Professional-YAM are available
for such dial-out application.
Rz (Receive ZMODEM) receives files with the ZMODEM batch
protocol. Pathnames are supplied by the sending program,
and directories are made if necessary (and possible).
Normally, the "rz" command is automatically issued by the
calling ZMODEM program, but some defective ZMODEM imple-
mentations may require starting rz the old fashioned way.
Rb receives file(s) with YMODEM, accepting either standard
128 byte sectors or 1024 byte sectors (YAM sb -k option).
The user should determine when the 1024 byte block length
actually improves throughput without causing lost data or
even system crashes.
If True YMODEM (Omen Technology trademark) file informa-
tion (file length, etc.) is received, the file length
controls the number of bytes written to the output
dataset, and the modify time and file mode (iff non zero)
are set accordingly.
If no True YMODEM file information is received, slashes in
the pathname are changed to underscore, and any trailing
period in the pathname is eliminated. This conversion is
useful for files received from CP/M systems. With YMODEM,
each file name is converted to lower case unless it con-
tains one or more lower case letters.
Rx receives a single file with XMODEM or XMODEM-1k proto-
col. The user should determine when the 1024 byte block
length actually improves throughput without causing prob-
lems. The user must supply the file name to both sending
and receiving programs. Up to 1023 garbage characters may
be added to the received file.
Gz is a shell script which calls sz to command Pro-YAM or
ZCOMM to transmit the specified files. Pathnames used
with gz must be escaped if they have special significance
to the Unix shell.
EXAMPLE: gz "-a C:*.c D:*.h"
Rz may be invoked as rzCOMMAND (with an optional leading -
as generated by login(1)). For each received file, rz
will pipe the file to ``COMMAND filename'' where filename
is the name of the transmitted file with the file contents
as standard input.
Each file transfer is acknowledged when COMMAND exits with
0 status. A non zero exit status terminates transfers.
A typical use for this form is rzrmail which calls
rmail(1) to post mail to the user specified by the trans-
mitted file name. For example, sending the file "caf"
from a PC-DOS system to rzrmail on a Unix system would
result in the contents of the DOS file "caf" being mailed
to user "caf".
On some Unix systems, the login directory must contain a
link to COMMAND as login sets SHELL=rsh which disallows
absolute pathnames. If invoked with a leading ``v'', rz
will report progress to /tmp/rzlog. The following entry
works for Unix SYS III/V:
rzrmail::5:1::/bin:/usr/local/rzrmail
If the SHELL environment variable includes rsh or rksh
(restricted shell), rz will not accept absolute pathnames
or references to a parent directory, will not modify an
existing file, and removes any files received in error.
If rz is invoked with stdout and stderr to different
datasets, Verbose is set to 2, causing frame by frame
progress reports to stderr. This may be disabled with the
q option.
The meanings of the available options are:
a Convert files to Unix conventions by stripping car-
riage returns and all characters beginning with the
first Control Z (CP/M end of file).
b Binary (tell it like it is) file transfer override.
c Request 16 bit CRC. XMODEM file transfers default
to 8 bit checksum. YMODEM and ZMODEM normally use
16 bit CRC.
D Output file data to /dev/null; for testing. (Unix
only)
e Force sender to escape all control characters; nor-
mally XON, XOFF, DLE, CR-@-CR, and Ctrl-X are
escaped.
p (ZMODEM) Protect: skip file if destination file
exists.
q Quiet suppresses verbosity.
t tim Change timeout to tim tenths of seconds.
v Verbose causes a list of file names to be appended
to /tmp/rzlog . More v's generate more output.
y Yes, clobber any existing files with the same name.
EXAMPLES
(Pro-YAM command)
<ALT-2>
Pro-YAM Command: sz *.h *.c
(This automatically invokes rz on the connected system.)
SEE ALSO
ZMODEM.DOC, YMODEM.DOC, Professional-YAM, crc(omen),
sz(omen), usq(omen), undos(omen)
Compile time options required for various operating sys-
tems are described in the source file.
NOTES
Sending serial data to timesharing minicomputers at sus-
tained high speeds has been known to cause lockups, system
halts, kernel panics, and occasional antisocial behaviour.
When experimenting with high speed input to a system, con-
sider 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.
The TTY input buffering on some systems may not allow long
blocks or streaming input at high speed. You should sus-
pect this problem when you can't send data to the Unix
system at high speeds using ZMODEM, YMODEM-1k or XMO-
DEM-1k, when YMODEM with 128 byte blocks works properly.
If the system's tty line handling is really broken, the
serial port or the entire system may not survive the
onslaught of long bursts of high speed data.
The DSZ or Pro-YAM zmodem l numeric parameter may be set
to a value between 64 and 1024 to limit the burst length
("zmodem pl128").
32 bit CRC code courtesy Gary S. Brown. Directory cre-
ation code from John Gilmore's PD TAR program.
BUGS
Calling rz from most versions of cu(1) doesn't work
because cu's receive process fights rz for characters from
the modem.
Programs that do not properly implement the specified file
transfer protocol may cause sz to "hang" the port for a
minute or two. Every reported instance of this problem
has been corrected by using ZCOMM, Pro-YAM, or other pro-
gram with a correct implementation of the specified proto-
col.
Many programs claiming to support YMODEM only support XMO-
DEM with 1k blocks, and they often don't get that quite
right.
Pathnames are restricted to 127 characters. In XMODEM
single file mode, the pathname given on the command line
is still processed as described above. The ASCII option's
CR/LF to NL translation merely deletes CR's; undos(omen)
performs a more intelligent translation.
VMS VERSION
The VMS version does not set the file time.
VMS C Standard I/O and RMS may interact to modify file
contents unexpectedly.
The VMS version does not support invocation as rzCOMMAND .
The current VMS version does not support XMODEM, XMO-
DEM-1k, or YMODEM.
According to the VMS documentation, the buffered input
routine used on the VMS version of rz introduces a delay
of up to one second for each protocol transaction. This
delay may be significant for very short files. Removing
the "#define BUFREAD" line from rz.c will eliminate this
delay at the expense of increased CPU utilization.
The VMS version causes DCL to generate a random off the
wall error message under some error conditions; this is a
result of the incompatibility of the VMS "exit" function
with the Unix/MSDOS standard.
ZMODEM CAPABILITIES
Rz supports incoming ZMODEM binary (-b), ASCII (-a), pro-
tect (-p), clobber (-y), and append (-+) requests. The
default is protect (-p) and binary (-b).
The Unix versions support ZMODEM command execution.
FILES
rz.c, crctab.c, rbsb.c, zm.c, zmodem.h Unix source files.
rz.c, crctab.c, vrzsz.c, zm.c, zmodem.h, vmodem.h, vvmo-
dem.c, VMS source files.
/tmp/rzlog stores debugging output generated with -vv
option (rzlog on VMS).
Hurricane Electric Internet Services
Copyright (C) 1998
Hurricane Electric.
All Rights Reserved.