vmsbugs.doc

一个很好的压缩与解压程序

 3.  Get back to your local Kermit and tell it to receive a binary file.

          (type escape sequence to get into local mode)
          MS-Kermit> set eof noctrl-z
          MS-Kermit> receive
          (transfer takes place)


                         FILE TRANSFER SUMMARY

Here are pictorial summaries of the steps involved in performing file
transfers of zoo archives using Kermit.

======================================================================

DOWNLOADS:
                                           files on a VMS
                                         system to be archived
                                               using zoo
                                                    |
                                   archive created  |
                                   using zoo.exe    |
                                   or zoobig.exe    |
                                   on a VMS system  |
                                                    v

zoo archive on VMS      bilf b           zoo archive on VMS, in
in fixed-length     <----------------    in stream-LF format
binary format
      |
      |
      | archive transferred
      | from VMS to microcomputer
      | using Kermit; receiving
      | Kermit must be told this
      | is a binary file; sending
      | Kermit may need to be told too
      |
      v
zoo archive
on microcomputer
system

======================================================================

UPLOADS:

zoo archive
on microcomputer
system
    |
    |
    | archive uploaded to VMS using Kermit;
    | receiving Kermit on VMS must be given
    | command "set file type binary"
    | (NOTE:  "set file type fixed" will
    | usually not work);  sending Kermit
    | must be told this is a binary file
    |
    v
zoo archive on VMS,       bilf l         zoo archive on VMS, in
in variable-length    ---------------->    in stream-LF format
binary format                                      |
                                                   | extract
                                                   | normally using
                                                   | zoo on VMS
                                                   |
                                                   v
                                         files extracted from zoo
                                          archive on a VMS system

======================================================================


                       ENSURING ARCHIVE INTEGRITY

After performing a transfer of a zoo archive using Kermit (and perform-
ing any file conversion necessary for VMS), make it a habit to immedi-
ately test the integrity of the transferred archive with the -test com-
mand of zoo, illustrated for VMS:

     $ zoo -test stuff

In addition, also get a listing of the archive contents:

     $ zoo -list stuff

If neither command reports an error, it is reasonable to assume that
archive integrity was not harmed by the Kermit transfer.

The -test command tests the integrity of each stored file.  The -list
command tests the integrity of the internal archive structure.  Both are
checked using separate cyclic redundancy codes, one for each archived
file, and one for each directory entry in the archived. (Actually, the
-list command ignores deleted entries, so if the archive contains any,
use the "ld" command instead.)


                               WILDCARDS

All implementations of zoo on all systems use the same wildcard charac-
ters:  "*" matches any sequence of zero or more characters, and "?"
matches any one character.

ADDING FILES:  For specifying directory names when adding files, use the
usual VAX/VMS syntax.  Thus, to recursively archive all files in the
current directory and all its subdirectories, the command syntax is:

     $ zoo a stuff [...]*

 The character range wildcard of the form "c-c" is also available, which
 will select all files beginning with the specified character range.
 For example,

      $ zoo a stuff [...]a-d [...]x-z

 will archive all files beginning with the characters a through d, and
 with the characters x through z, in the current directory and all its
 subdirectories.  A side-effect of this is that during addition to
 archives, dots in filenames must be explicitly matched.  Thus to add
 all files with an extension of DOC, you would type:

      $ zoo a stuff *.doc

 and "*doc" will not work.  As a special case, a trailing "*.*" in any
 filename you specify can always be replaced by just a trailing "*".
 The safest rule to follow when adding files is to always specify the
 dot in each filename.

 EXTRACTING FILES:  During extraction, both the directory name and the
 filename must be specified according to zoo syntax.  Thus you could say

      $ zoo x stuff [*xyz*]*.doc

 to extract all archived files with filenames that match "*.doc" and
 that contain the string "xyz" in the directory name.  Note that VMS
 syntax for selecting directories won't work here:

      $ zoo x stuff [...]*.doc        ! won't work for extraction

 If you do not specify the directory name at all, zoo will only perform
 the match against filenames;  thus

      $ zoo x stuff *.doc

 will extract all files matching *.doc regardless of the directory name.

 Also note that if you specify extraction of "*.*", as in

      $ zoo x stuff *.*

 it will result in the extraction of files whose filename contains at
 least one dot.  Similarly, the command

      $ zoo x stuff *_*

 will select all filename containing at least one underscore.

 To extract all files, specify no filename, e.g.

      $ zoo x stuff

 or use "*" rather than "*.*".

 SAFEST RULE OF THUMB:  WHEN SELECTING FILES ON DISK, SPECIFY THE DOT IN
 EACH FILENAME;  WHEN SELECTING FILES INSIDE A ZOO ARCHIVE, SPECIFY A
 DOT ONLY IF YOU NEED ONE.  But to select all files, you can always just
 use "*".


                            FILE GENERATIONS

 When a file is added to an archive, the generation number (if any) that
 it is given in the archive is not related to the generation number it
 had in the VAX/VMS filesystem.  At extraction time a new version is
 always created for an extracted file.  The overwrite option ("O") does
 not cause overwriting, but simply suppresses the warning message that
 zoo normally gives when it finds that a file about to be extracted
 already exists.


                             FILE STRUCTURES

 At extraction time, zoo preserves all data bytes in binary files, and
 stores all text files as lines of text terminated with linefeeds. The
 internal file structure maintained by DEC's RMS is not currently
 preserved.  (Support for this is planned for the distant future.)
 Thus, the following two types of files can be safely archived and
 restored:

    - All text files are extracted in stream-LF format.  Most VMS utili-
      ties that accept text files will accept such files.  The EDT edi-
      tor may complain, but will still work.

    - VMS executable files, when stored and then extracted, are
      extracted in stream-LF format.  Such files can be restored to
      their original state using Bilf with the "b" option.  (However,
      current versions of VAX/VMS seem to be able to load and execute
      stream-LF files, so conversion may not be necessary.)

 HANDLING VMS EXECUTABLE FILES.  You can archive an executable program
 called "xyz.exe":

      $ zoo a stuff xyz.exe
      $ delete xyz.exe;*

 Now the only copy of xyz.exe is in the archive "stuff.zoo".  Extract
 it:

      $ zoo x stuff xyz.exe

 The extracted copy of "xyz.exe" is in stream-LF format and VMS may or
 may not execute it.  Now we convert it back to fixed-length record for-
 mat thus:

      $ bilf b xyz.exe
      $ purge xyz.exe

 Now "xyz.exe" has been converted to binary format and can be executed.
 It should be identical to the original copy of "xyz.exe" that was
 archived.

 TEXT FILES FROM OTHER SYSTEMS.  A text file archived on a different
 computer system will use either linefeeds, or carriage returns plus
 linefeeds, as line terminators.  Text files with linfeeds only can be
 be extracted and used exactly as if they had been archived on a VAX/VMS
 system.  Text files containing carriage returns plus linefeeds will,
 when extracted, contain a spurious carriage return at the end of each
 line.  This extra carriage return can be removed using EDT's "substi-
 tute" command while in screen mode.  Simply replace all carriage returns
 with nothing.  The VMS C compiler currently appears to accept trailing
 carriage returns in files without any trouble.

 Text files trasnferred from MS-DOS or CP/M or similar systems may con-
 tain a trailing control Z character.  This may cause problems on VMS
 and should be edited out with a text editor.

                                     -- Rahul Dhesi 1988/02/04
                                            Revised 1991/07/07