18. CHANGES Be sure to save your serial number/password (SNP) card and the putsnp program you received from Omen to use with future versions of DSZ you may download! The current DSZ version is maintained on GEnie (IBM Roundtable), EXEC- BBS, CompuServe (IBMCOM and CONSULT SIGs) as well as TeleGodzilla. DSZ is a popular program which has been the object of virus attacks. Pirated/hacked versions of DSZ have cost users and DSZ's developer thousands of dollars in lost time and other expenses, in addition to injuring of Omen Technology's reputation. Virus and Trojan code hidden in hacked/pirated copies of DSZ and programs claiming to "register DSZ" have caused loss of data. Name Length Date Time CRC dsz.com 51628 Crunched 14% 44432 26 Jun 90 1:26p e884 dsz.exe 62001 Crunched 19% 50759 26 Jun 90 1:22p b308 PKZIP -vt 32 bit CRC: C06F1F5B 51628 dsz.com PKZIP -vt 32 bit CRC: 5A198AC3 62001 dsz.exe Your copy of DSZ should show this information as provided by arc v dsz or pkxarc -v dsz lharc v dsz ARC, and LHARC use a 16 bit CRC. ZIP uses a 32 bit CRC compatible with the Professional-YAM and ZCOMM "crc" command. pkzip -vt dsz The following Pro-YAM/ZCOMM command gives the 32 bit CRC for DSZ.COM: EXAMPLE: >>>c: crc dsz.com If your copy shows a different CRC or file length, insist on a legitimate copy and report the source of the bogus/pirated copy to Omen Technology Inc. Omen Technology has received reports of serious problems caused by unauthorized patches to DSZ, and cannot assume liability for the performance of the resultant code. COM7 and COM8 are changed; see the "port" command above. A problem in the 1/17/89 and 2/2/89 versions corrupts files under Chapter 18 Pg 50 DSZ Reference Rev Jun-26-90 Typeset 6-26-90 unusual circumstances. Please delete all instances of the 1/17/89 and 2-02-89 version. A reminder: the -Z option is effective only when it is given to the sending program unless both are Omen Technology products revised Jan 22 1990 or later. If you use PREFIX= or ONAME= with the "sb" or "sz" commands, these pathnames must be entered in lower case unless the underlying file system supports upper AND lower case. A boundary condition bug in the implementation of the rz/sz -rr option has been corrected. When using the -rr option, both sending and receiving programs should be a March 8 1990 or later version. Otherwise, files may be needlessly retransmitted. This problem does not affect the -r option. June 25 1990: When a ZMODEM block length is forced, the receiving DSZ writes the data to disk before acknowledging the block. With DSZ.EXE and its maximum 16384 buffer size, you may be able to avoid overrun (Line Status Register 02) problems receiving to slow disk drives by using: dsz pB16384 z pl16384 rz ZMODEM-90(TM) speeds up GEnie ZMODEM downloads; see DSZOPTS in Chapter 6. The "sz" command had an undocumented fallback to YMODEM, this has been removed for reliability reasons. The SlugBait (-s) option now causes DSZ to return success (0 exit code) if at least one file is transferred. April 11 1990: Enhancements for more efficient multitasking under DESQview and DESQview 386. Code which prevented IRQ conflicts between COM1/COM3 and COM2/COM4 has been removed to allow use of COM7 and COM8 without interference from DSZ running on COM1 or COM2.. ZIP replaces ARC as the standard download distribution format on new files. March 21 1990: DSZ now sends the CANCEL sequence if it runs out of disk space while receiving a file with ZMODEM. DSZ now defaults to "handshake both" if the clear to send signal is high when DSZ selects the comm port regardless of the initial "baud rate". The P parameter can be set to -1 to disable the FIFO on the Western Digital WD16550 chip. The WD16550 FIFO has been observed to lose characters when transmitting at slow baud rates. A more elegant software solution to this hardware problem may be discovered in the Chapter 18 Pg 51 DSZ Reference Rev Jun-26-90 Typeset 6-26-90 future. Feb 25 1990: Doco change only. The "R" numeric parameter or the "restrict" command may be used to force partially received files to be deleted. These features have been in DSZ for a long time, but never got into DSZ.DOC. Feb 18 1990: DSZPORT now accepts "portx" style arguments in addition to the traditional decimal number. The -Wn option has been improved. Jan-28-1990: Doco improvements, especially to the "In Case of Difficulty" chapter. BBS registration clarified for those that bother to read it. Qmodem batch files fixed. No change to the DSZ software. Jan-22-1990: ZMODEM-90(TM) extensions: Receiver specified window size: The -Wn option operates similarly to the -wn option. The -Wn option is specified to the receiver, which sends this information to the sender. Pro-YAM, ZCOMM and DSZ versions beginning with Jan 22 support this. Specified extra escaped characters: The "zmtxesc" and "zmrxesc" allow extra characters to be escaped when sending (zmtxesc) or receiving (zmrxesc). Zmtxesc is effective sending to any ZMODEM program. The sz commands in Omen products after Jan 22 1990 except for DSZ.COM recognize incoming "zmrxesc" requests. TThe zmrxesc and zmtxesc string parameters consist of one or more printing characters corresponding to the control characters to be escaped. To escape NULL: set zmrxesc "@" Since DSZ does not support string parameters, a -Q option unique to DSZ performs the same function as zmrxesc and zmtxesc. If the Q option is used in DSZOPT, it must be last. To escape NULL: dsz sz -Q@ file.ext MobyTurbo(TM): MobyTurbo optimizes throughput on ZIP, ARC, and similar files without sacrificing ZMODEM's famous reliability on noisy lines. MobyTurbo works with standard modems, error correcting modems with hardware flow control, and over paths that support ZMODEM and do not "eat" or otherwise respond to control characters. This includes all paths that support YMODEM-g (or would except for errors). Activate MobyTurbo with the -m option to one or more of: sz command, rz command, or DSZOPT environment variable. ZMODEM over 7 bit paths: (Not supported in DSZ.COM) A pair of ZMODEM-90 programs with 7-bit support operating over a 7 bit path should detect that fact and switch to one of two 7-bit path compatible encodings. For testing, this can be forced with a "-E" Chapter 18 Pg 52 DSZ Reference Rev Jun-26-90 Typeset 6-26-90 option. Default 7-bit mode is RLE compression and 8th bit quoting similar to Kermit but more efficient because not so many control characters are quoted. Use this default for text files. Rubout and all control characters can be escaped with the -e option. Individual control characters can be escaped with "zmtxesc" and "zmrxesc". Pack-7 instead of quoting is activated with the -P option. (-P has no effect on 8 bit paths.) Pack-7 packs 4 bytes into 5 printing characters. This is more efficient than quoting for files where 25% more 8th bits appear than the number of characters saved by RLE compression. (This statement applies to GIF, ARC, ZOO, and ZIP files. It may or may not apply to other binary file formats, depending on the data.) Pack-7 will match or beat standard Kermit on ZIP files, even when Kermit has use of all 8 bits. SUPK412.ZIP 75136 bytes sent at 2400 bps direct connect from an Everec 1800 AT clone 8mHz/0ws to an 18 mHz Intel 386 motherboard. 8-Bit line cps Protocol/command 156 MS Kermit 3.00 to MS Kermit 3.00 (defaults) 182 MS Kermit 3.00 to MS Kermit 3.00 (windows=2 length=2000) 184 MS Kermit 3.00 to Pro-YAM 17.51 (windows=2 length=2000) 231 Pro-YAM 17.51 ZMODEM (defaults) 237 Pro-YAM 17.51 ZMODEM-90(TM) MobyTurbo(TM) (sz -m) 7-Bit line cps Protocol/command 156 MS Kermit 3.00 to MS Kermit 3.00 (windows=4 length=2000) 190 Pro-YAM 17.51 ZMODEM-90 PACK-7 (sz -EP) Kermit transfers used 8 bit CRC, ZMODEM used 32 bit CRC. ************************************************************************ ************************************************************************ WHAT TO LOOK FOR: Performance difference with MobyTurbo, possible side effects/incompatibilities. MobyTurbo logic tests for software flow control incompatibilities: when does this test fail? Automatic detection of 7-bit paths. Spurious detection of 7-bit paths and failure to detect 7-bit paths. (DSZ.EXE only) 12-13-89 The Virus check was removed because of user confusion and slow startup under certain conditions. Code has been added to prevent and/or Chapter 18 Pg 53 DSZ Reference Rev Jun-26-90 Typeset 6-26-90 recover from "line status register 18" errors. 10-28-89 A T may be appended to DSZOPT or "dsz t -T" may be used to force DSZ to exit after it has recognized a ZMODEM AutoDownload(TM) request. 10-24-89 BBS registered copies (serial numbers 8000-8999 and 20000- 23999) are now fully featured. The BBS registration form has been modified. Please read this form carefully before applying a BBS serial number. Use of BBS serial numbers (4000, 20000 series) acknowledges acceptance of this contract. The IMP/KMD compatibility file length information in the YMODEM header generated by the sb command now uses the correct byte ordering. Changes to the XMODEM/YMODEM sz/sb commands were made to accommodate programs that ise CK or CKL. (As predicted in 1985, networks sometimes interfere with these sequences.) Files passed over because of creation errors at the receiving end are now counted by the "sz" command as errors. The receiving program must be a 9/89 or later version for this to be effective. The specified directory form of the rz and rb commands has been enanced to accommodate certain forms of erroneous syntax. 6-19-89 A documentation error (concerning DSZPORT) was corrected in the DOC file. 5-25-89 Corrects a protocol negotiation problem encountered when the rz or sz -e option is used. Host programs can now specify an alternate CANCEL sequence (not used for DOS and Unix). The ZMODEM "Slow Send" mode inserts a brief pause after each subpacket when invoked with the -F option, or automatically when the "sz" command detects failing flow control. The zmodem F numeric parameter (default 1) sets the pause in tenths of seconds. 4-24-89 The -rr option has been improved. Long file compares are done in two stages to save time when the first portions do not match. Diagnostic code and undocumented commands have been removed to decrease the program size. The 4-18 version introduces ZMODEM variable length headers of up to 16 bytes information field instead of the previous fixed 4. Selection of variable length header capability is automatic and downward compatible. Variable length headers allow future extensions to ZMODEM's capabilities. Chapter 18 Pg 54 DSZ Reference Rev Jun-26-90 Typeset 6-26-90 ZMODEM Crash Recovery now understands the -rr option to compare the CRC-32 of the assumed common file segment before continuing an incomplete file transfer. The "zmodem R" numeric parameter may be set to limit the number of bytes in the files that are compared; the default R value of 0 allows all of the file to be compared, an R value up to 32000 (up to 2 billion on 32 bit flavors) limits the comparison to the first R bytes of the two files. The ZMODEM -rr option is supported by Omen Tech versions April 18 1989 and later. When ZMODEM Crash Recovery detects incompatible source and destination file contents, the destination file is now truncated to zero length before proceeding with the transfer. Crash Recovery requires the destination file to be no longer than the source file. Error reporting on unregistered copies has been enhanced to point the user to solutions described in the relevant chapters in DSZ.DOC. 3-18-89 In order to work around a bug in the new TCOMM bbs, DSZ now defaults to "handshake on" if the speed is greater than 2400 and the clear to send signal is high when DSZ selects the comm port. The "o" command has been added to disconnect the modem after a terminal session: "dsz t o" disconnects the modem when the terminal session is completed. The "P" (capital P) numeric parameter (q.v.) has been added to display and control the UART fifo on some clone chips. BBS registrations postmarked after Feb 28 1989 must be accompanied by a paid DSZ registration. The free program expired Feb 28 1989. Outside help has been hired to process and verify applications received under that program. 2-23-89 The term function now sends BREAK in response to the ALT-B key. Handling of the Ctrl-Break vector has been changed so an untimely keyboarded Ctrl-C or Ctrl-Break will not hang DOS. 2-15-89 DIRRX is enabled for BBS registrations (8xxx numbers). Logic has been added to simulate transmit interrupts on chips that have problems in this area. The "A" command does not require registration. An interaction between ONAME= or PREFIX= and the file count display has been removed. Time/date conversion routines have been enhanced to deal with files with missing dates. The "v" command has been added to allow bbs programs to interrogate DSZ's serial number. 2-06-89 A spurious error message at the completion of YMODEM downloads with a download directory specified on the command line has been eliminated. 2-05-89 DSZ now returns a non 0 status unless at least one file has been transferred. An inappropriate pathname/disk specifier check on Chapter 18 Pg 55 DSZ Reference Rev Jun-26-90 Typeset 6-26-90 specified download directories has been removed. Previous versions: Added the "A" command to prevent pcAnywhere host mode from locking up DSZ. SlugBait logic has been simplified, reporting any failed file transfer where any of the last 1K of the file was sent with Q status. Introduced ZMODEM RLE compression with the -Z option. (registered DSZ copies also accept "Z" in the DSZOPT environment variable.) ZMODEM RLE compression packs runs of the same character in two or three character sequences. Compression is useful for screen dumps, uncompressed workspaces, compiler listings, and other files rich with strings of repeated characters, but not .ARC, .ZOO and other compressed files. Compression percentages range from -1 per cent for already compressed files to more than 1000 per cent (10x speedup!) for the Personal Computing text file benchmark(!). When sending to programs that do not support ZMODEM compression, the -Z option is ignored. The -Z option is effective when specified to the sending program only. Good news for tired frog stompers! The ZMODEM rz/sz programs are now available in a VMS C flavor. The VAX/VMS source files are contained in the RZSZ.ARC (RZSZ.ZOO) archive file. "Handshake slow" has been added to disable the RTS signal to the modem while writing to disk, even if the interrupt buffer is not chock full of bytes. This should help systems with excessive interrupt latency on disk writes. Setting the v (verbose) parameter to 1 or greater causes serialized copies to ring the bell when a transfer is done. DSZ.DOC has been extensively rewritten and reorganized. DSZ supports the advanced buffering of the National NS16550AN, NS16550AFN and Intel 82510 serial interface devices. Please refer to the subchapter on "Brain Damaged UARTs".