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- ZCOMM Notes 8-19-87
-
-
- ***************************
- **** W A R N I N G **** Don't throw away your ZSNP Card!
- ***************************
-
- Serializing your copy of ZCOMM enables the following commands, plus
- the full YAM 24k circular buffer.
- egrep egrepm expand split ss
- The PUTSNP program serializes your copy of ZCOMM.
-
- Some of the changes listed below may apply to Pro-YAM features not
- included in ZCOMM.
-
-
- 16.88 The K numeric parameter controls the accessing of extended
- key codes on 101 key keyboards. For PC/XT computers, this must
- be set non zero if your BIOS supports extended keyboards. It is
- set automatically with AT class computers.
-
- 16.87 CIS B Protocol support has been enhanced with special code to
- encourage timely abend of downloads when CIS fails to recognize the
- first Abort packet.
-
- TurboDial 2.22 The "U" test condition evaluates true if YAM
- was unrestricted before the current set of scripts was called.
-
- 16.86 Doubling of keyboarded characters in the "chat" command
- was eliminated.
-
- Before awaiting each call in Host Operation, YAM changes to the
- disk drive that was the default when the "host" command was given.
-
- 16.85 The "!" command now returns exit status to the "?" numeric
- parameter. This will be useful if COMSPEC points to a COMMAND.COM
- replacement that returns valid exit status.
-
- 16.84 The zmodem "w" parameter is now reset to 0 by the "call" command.
- The "sz" command now recognizes the -u option, to unlink (remove) the
- file after it is sent successfully.
-
- This version introduces enhancements and changes to the XMODEM and
- B-Protocol OverThruster(TM). OverThruster gains speed by throwing
- caution (error recovery) to the winds. OverThruster is useful when
- there are no line hits, or with MNP modems or X.PC link level error
- protection (yamxpc.exe). OverThruster can be fine tuned with the "O"
- numeric parameter as follows:
-
- Compuserve XMODEM: negative numbers control the number of
- bytes added to the window; -512 adds 512 bytes to the window.
- Large numbers cause improperly interfaced MNP modems on CIS
- nodes to drop characters under stress.
-
- Example: pO-512; ro file1.ext
-
- Other XMODEM: positive numbers up to a system dependent value
- less than the protocol's block size increase throughput.
- Excessively large values induce timeouts and/or retransmitted
- blocks. The optimum value must be determined by experiment;
- 60 usually give best results with MNP modems at 2400 bps.
-
- Example: pO0; ro file1.ext
-
- Compuserve B Protocol: Larger positive numbers up to 511
- increase throughput. Large numbers cause improperly
- interfaced MNP modems on CIS nodes to drop characters under
- stress.
-
- Example: pO200; t -oc (enables B protocol in term function).
-
- 16.83 adds the "kermreset" string parameter. A string (up to 32
- characters) may be sent by Pro-YAM's Kermit when it attempts to
- recover from a transmission error. The default value for this string
- is empty. Two metacharacters are special: \336 inserts a one second
- pause, \335 sends a break.
-
- B Protocol has been tweeked to accomodate the "new B" level 5.
-
- 16.81 Improves the operation and error recovery of ZMODEM downloaded
- commands. Error recovery in the context of file skipping was corrected.
-
- The "sz" command no longer allows fallback to YMODEM (this was a
- reliability problem); the "szb" command does allow YMODEM fallback.
-
- 16.80 The "plog" string parameter enables file transfer performance
- logging. The default empty value disables this function. The
- performance log keeping does not affect the "nolog" command. An entry
- is shown below. Fields are: speed, log code, "L" for loss of carrier
- (otherwise blank), file name, length, average transfer rate
- (characters per second), transfer time in seconds (file open to file
- close), number of seconds required to start the transfer, number of
- errors (retransmissions), flow control transistions, block length (at
- end of file), measured round trip delay time in hundredths of seconds,
- the command (or facsimilie thereof), and the directory entry or
- caller's name.
-
- 2400 Z ZCOMMEXE.ARC 153760 186 826 1 20 260 256 234 sz guess who
-
- The above example shows 1 second to start the transfer, 20
- retransmissions, and 260 times that YAM had to wait for flow control
- release. This unusual set of figures is the result of a "networked"
- transfer through the "cu" program on a Unix system to a PC, not a
- normal connection or PC-Pursuit access.
-
- The count of flow control transitions gives an indication of flow
- control restraint applied by the modem, network, or receiver. Since
- it counts the times YAM has entered a wait because of flow control
- restraint and not the total amount of time spent in that state, it is
- not an accurate quantitative measure.
-
- The file transfer time and throughput calculation now excludes the
- time required to start the transfer, since that time is often not
- under the protocol's control.
-
-
- 16.77 The "zmodem o" OverThruster(tm) numeric parameter modifies the
- operation of the "ro" command and the "o" file transfer option
- (XMODEM, ZMODEM-1k, YMODEM downloads). 0 gives best throughput with
- Compuserve, higher values up to a system dependant limit increase
- throughput with other systems.
-
- Setting the "N" numeric parameter to 32 reverses the function of
- Num-Lock when keyboard mapping is enabled with the "display
- kbmapenable" command. This makes VT52/VT100 emulation less
- accurate but more useful.
-