Date   : Fri, 02 Dec 1983 11:05:43 EST
From   : Keith Petersen <w8sdz@brl>
Subject: XMODEM81 now available

     XMODEM81 is now available from SIMTEL20.  Newest features -- can
be assembled with ASM.COM even if LOGCAL is YES.  All overlays renamed
so they will remain independent of XMODEMxx updates.

     The following files are available from SIMTEL20 in the
MICRO:<CPM.RCPM> directory:

XMODEM.81ASM - Source for the main program
XMODEM.81INF - Information about XMODEM81 and its overlays
  XMAC.1ASM  - for Apple users with the Novation APPLE-CAT modem
  XMDP.1ASM  - for Datapoint 1560 with 8251A I/O and CTC baud rate timer
  XMDC.1ASM  - for Apple users with the D.C. Hayes modem
  XMEX.1ASM  - for computers with 8251 I/O and external modems
  XMH8.1ASM  - for Heath/Zenith H8 or H89 users with external modem
  XMHZ.1ASM  - for Heath/Zenith -100 users with external modem
  XMIN.1ASM  - for those using the Compupro Interfacer 3/4 modem
  XMMM.1ASM  - for Apple users with the Micromodem II modem
  XMPM.1ASM  - for S-100 users with PMMI modem boards
  XMSM.1ASM  - for D.C. Hayes Smartmodem users
  XMTV.1ASM  - for TeleVideo 802 computers

     The overlays contain instructions on how to then use DDT (or SID)
to easily adapt the external overlay to the main program.

     XMODEM is a program used primarily on remotely operated RCPM systems
that allows program transfer to and/or from remote users.  It can trans-
fer any type of CP/M file including absolute binary files (.OBJ).

     Originally written by Keith Petersen and based at that time on Ward
Christensen's MODEM ver 2.0 it has since undergone extensive revision.
Although the original checksum verification system is still available on
request, the primary system is CRC - cyclic redudancy checking.

     The current version is XMODEM 8.1  The 8.x series has a number of
features which give it a tremendous flexibility.  Some of them are:

     1) A general purpose menu.  Just type:

          A0>XMODEM <return> 

          This menu includes the drive/user area for normal uploading,
          which lets the user check to see if adequate space is remain-
          ing for uploading new files at that location.

          NOTE:  The A0> prompt in this and subsequent examples is used
                 as a typical possibilty of a drive/user area.

     2) Ability to send (download to the remote user) member files from
          a library group (.LBR)  without having to copy the entire li-
          brary file.  (Use a separate program called LDIR.COM to find
          the member names of a library group.)
               
     3) Ability to specify what disk/user area from which to send a pro-
          gram so the remote user doesn't have to go to that area first:

          A0>XMODEM S B6:HELLO.DOC

          (An option limits the maximum user area.)

     4) Programs can be uploaded to a special non-public user area for
          the exclusive use of the SYSOP.  These can include replacement
          programs for one already on some public area, experimental
          programs you wish him to test before making them public, pre-
          typed notes for his exclusive reading or any program you wish
          him to see that is not appropriate for public use at that time.

     5) Ability to download from a special area.  This enables the SYSOP
          to place special programs, pretyped messages, etc. in this
          area.  He can then leave a private message on his bulletin
          board to the person for whom the program is intended.  Al-
          though any user COULD download that program, only the SYSOP
          and his intended recepient know its correct name as well as
          the correct drive/user area.  This provides excellent security
          The SYSOP can thus make any person an instant temporary priv-
          ileged user.  This gives him a tremendous flexibility.

     6) Spaces can be used without error.  Example:

          A0>XMODEM   L   B7:        CATALOG    CAT2.DOC

          will send a file called CAT2.DOC from the CATALOG.LBR library.
          NOTE:  The  .LBR extent need not be included.  If not, it is
                 added automatically.
               
     7) Files which are partially completed will be erased if the disk
          becomes full or if the sender aborts by hanging up (or if the
          connection is broken).

     8) A simple system of adopting the program without the necessity of
          looking up the CONTOUT address.

     9) USEMAX feature which automaticaly sets the maximum drive and the
          maximum user number from ZCPR values.   (Can still be set
          normally if USEMAX is NO.)