SIO.SYS and VSIO.SYS open beta.

                                  Copyright, 1993 By
                                   Raymond L. Gwinn
                                 12469 Cavalier Drive
                              Woodbridge, Virginia 22192

          USE THIS SOFTWARE AT YOUR OWN RISK.

          SIO.SYS and  VSIO.SYS are functional, but  not exact, replacement
          for OS2's COM.SYS and VCOM.SYS.  Documentation, beyond that given
          here, is not available.

          A  supporting  FidoNet  echomail conference  called  SIO_BETA  is
          available from Bob Juge at 1:106/2000 (1-713-980-9671).

          Messages/reports   from   program   authors   will   be   greatly
          appreciated.   Messages  may  be sent  directly  to the  SIO/VSIO
          author via CompuServe, 72570,157 (Ray Gwinn).   Messages may also
          be  sent via FidoNet netmail, using host routing, to 1:265/104 or
          directly  to  1:265/104 from  3:00am  to  6:00am  EST (8:00am  to
          11:00am UTC).

          SIO.SYS and VSIO.SYS are intended  to be high performance  Serial
          Input/Output  routines.   Some brain dead  software may  not work
          with  these routines.  Also, some perfectly good software may not
          work with these routines.  In any case, if you have programs that
          do  not  work with  SIO/VSIO installed  let  me know  and, PLEASE
          CONTACT THE AUTHOR of that software also.  Ask them to get a copy
          of SIO/VSIO and report any errors they find.  It is not practical
          for me to set  up and test  all communications programs that  are
          being used by OS2 users.

          It is intended  that SIO.SYS  will accept the  same command  line
          parameters that COM.SYS uses.  Unlike VCOM.SYS, VSIO.SYS requires
          no  command   line  parameters.    VSIO   obtains  all  necessary
          information from SIO.SYS.

          If you  are using a serial mouse, the mouse device driver must be
          loaded before SIO/VSIO.

          There seems to be  some mis-behaved device  drivers for OS2.   If
          you  have  problems, try  moving  device drivers  around  in your
          CONFIG.SYS.  In  particular, I  have had a  lot of problems  that
          seem to be the fault of Novell's OS2 requester device drivers.









          Some (but not all) differences between COM.SYS and SIO.SYS are:

          1  - SIO.SYS insists  upon using 16550A  (or up)  fifos.  SIO.SYS
          does not allow application programs to disable the fifos.

          2 - SIO.SYS will accept any number above 50 as a baud rate.

          3 -  The last decimal  digit of a  given baud rate must  be zero.
          For example, 50, 110, and 115200 are valid while 75 and 134.5 are
          not.  A baud rate of 75 will  be rounded to 80 and 134.5 will  be
          rounded to 130.

          4  - SIO.SYS  is considerably  faster than  COM.SYS.   Any timing
          dependant software (intentional or unintentional) may croak.

          5 - Half duplex has not been tested and probably does not work.

          Some (but not all) differences between VCOM.SYS and VSIO.SYS are:

          1  - VSIO.SYS  creates  a virtual  16550A  instead of  a  virtual
          8250/16450.

          2 - VSIO.SYS does not virtualize the loopback mode of the 16550A.

          3  - VSIO.SYS is considerably faster than VCOM.SYS.  Well written
          DOS  programs  can  achieve  throughput  far  in  excess  if 1000
          characters per second.

          Sample CONFIG.SYS statements:

          DEVICE=C:\SIO.SYS (1,3F8,4) (COM2,2F8,IRQ3)
          DEVICE=C:\VSIO.SYS