








                       New information is inserted at the end.


          Beta V0.25
          ----------

          Corrected  problem introduced  in  0.25 where  many OS2  programs
          could not drop DTR.

          Beta V0.26
          ----------

          If a set DCB  IOCTL is issued, and if pending reads/writes exist,
          the suspended threads are restarted.

          Previous versions always placed port  addresses in BIOS memory at
          40:0 (DOS sessions) for  both COM1 and COM2.   The port addresses
          starting at 40:0 are no longer filled in for COM1 and COM2 if SIO
          did not detect a port there or if the mouse is using the port.

          I believe the problem of DOS sessions being put to sleep has been
          solved.  V0.30 works well on my system with default DOS  settings
          and default CONFIG.SYS entries as follows:

               In the DOS settings
               IDLE_SECONDS = 0
               IDLE_SENSITIVITY = 75

               In CONFIG.SYS
               MAXWAIT=3
               PRIORITY_DISK_IO=YES

          Note that I  said these default settings work  well with V0.30 ON
          MY SYSTEM.   The above  settings may have  to be changed  on your
          system.

          Beta V0.30
          ----------

          An error has  been corrected in the code for DOS sessions dealing
          with the comm port addresses at 40:0.

          Beta V0.31
          ----------







          Beta V0.31
          ----------

          Bit 6  of the virtual  Line Status  Register (LSR) was  stuck on.
          This  has been corrected and it probably caused some DOS programs
          problems.

          After two days  of testing  why incorrect "COMn  already in  use"
          errors  were occurring in DOS  sessions, I traced  the problem to
          the Novell Lan Drivers that I am using.  It seems that the Novell
          OS2 requester drivers are  using memory that is not  allocated to
          them.  I have  worked around this problem successfully  by making
          the Novell drivers the last thing in CONFIG.SYS.

          Corrected a problem in the handling of DSR.

          Corrected a problem  that caused erroneous "COMn  already in use"
          in OS2 sessions.

          Added OSDR and IDSR modes or operation.

          If  SIO/VSIO  seems  not  to transmit  anything,  where  previous
          versions  transmitted okay, then set  your modem to  force DSR ON
          or, set ODSR OFF with the MODE command.

          If  SIO/VSIO  seems  not  to  receive  anything,  where  previous
          versions received okay, then set  your modem to force DSR ON  or,
          set IDSR OFF using the MODE command.

          Support added for forcing 16550A chip type. (COM1,3F8,IRQ4,,F)

          Corrected a serious problem with multiple comm ports  sharing the
          same IRQ.

          Beta V0.34
          ----------

          Corrected a  problem in the  Virtual Line Status  Register (LSR).
          This problem showed up in DOS sessions as a very slow transmit at
          speeds below 9600 baud.

          Corrected a problem in the Virtual Interrupt Enable register.

          Corrected  errors in  the  implementation of  DTR  enable/disable
          mode.

          Corrected and error that may have caused problems at shutdown.

          An  apparent OS2  problem  of "LOCKED"  memory erroneously  being
          moved  has been worked around.   This could  cause many problems.
          Most often,  erroneous "port  already in use  messages" and  just
          plain crashes.

          Beta V0.40








          Beta V0.40
          ----------

          Corrected a problem of crosstalk from COM3 to COM2.

          Changed  the method  of memory  allocation.  On  my system,  I no
          longer have to load SIO.SYS after the Novell drivers.

          Corrected  a  problem in  cleanup  when an  open of  a  comm port
          failed.   This  problem showed  up as  a dead  port once  a "port
          already in use" was issued.  The correction of this error  should
          allow SIO and PMfax to get along better.

          Beta V0.43
          ----------

          Corrected  a problem in  Device Close  operations.   This problem
          prevented serial  printers, and  modem commands from  batch files
          from working.  This problem could show itself in many other ways.

          Additional  corrections to clean up after a "port already in use"
          occurs.  Again, SIO and PMfax should get along better.

          Added PROBLEM.TXT to the distribution file.

          Beta V0.45
          ----------







          Beta V0.45

          The method of issuing an EOI to the interrupt controller has been
          changed.

          SIO will now share an IRQ with another device driver  (if allowed
          by OS/2).

          SIO will  now automatically locate  the IRQ  that a comm  port is
          attached  to.   The  IRQ used  by SIO  for a  given comm  port is
          assigned in the following manner:

          1 - If an IRQ  is specified in the SIO command line then that IRQ
          is used.  However, SIO will  display a warning message if the IRQ
          seems to be other than specified.

          2  - If  no IRQ  is specified  in the  command line,  and if  SIO
          detected the IRQ then the detected IRQ is used.

          3 -  If no IRQ is specified in the  command, and if SIO could NOT
          detect  an IRQ then  the default IRQ  for the comm  port is used.
          SIO will also display a warning message in this case.

          The  automatic detection of the  IRQ has worked  correctly on all
          systems on which it has been tested.  However it would be wise to
          check that  the displayed  IRQ(s) is/are  the correct  IRQ(s) the
          first time that SIO V0.50 is used.

          The following STYLE command  line is recommended for all  but the
          most unusual systems.   That is, specify only the port number for
          those above COM2 (to tell SIO to support those ports) and let SIO
          do the rest.

          DEVICE=SIO.SYS (COM3) (COM4)

          If you do not have a COM3 or  COM4, or if the mouse is using  the
          only  comm port above COM2 then the following command line should
          be used.

          DEVICE=SIO.SYS








          Beta V0.50
          ----------

          A  bug was introduced  in 0.50 which allowed  SIO to always touch
          COM3 and  COM4.  This problem  showed up as a  blanked display at
          boot time.  This problem has been corrected.

          A  serious problem was corrected in maintenance of the Com Status
          word.  This caused an incorrect error condition to be returned in
          several IOCTL functions.   This  bug has, no  doubt, caused  some
          application programs to be unstable.

          Code required for the OS2 V2.1 beta of March 1993 has been added.
          This required code affects only DOS and Windows comm programs.

          Beta V0.57
          ----------

          INT 14h is now virtualized by SIO/VSIO.

          VX00.SYS is now included  in the distribution file.   It provides
          FOSSIL  support for DOS programs.  FOSSIL aware DOS comm programs
          should now work as well as native OS2 comm programs.  VX00.SYS is
          a  DOS device driver with no command  line parameters.  It should
          be  installed in  the  DOS_DEVICE  DOS  setting  or  in  the  OS2
          CONFIG.SYS.  If installed via  the OS2 CONFIG.SYS, VX00.SYS  will
          be  loaded in  all DOS VDMs.   If  installed via  the DOS_DEVICE,
          VX00.SYS will only  be loaded for  that VDM.   Do not try  to use
          XU.EXE with VX00.SYS, it will not work!

          Code has been  added for the March, 1993 beta of OS2.  SIO should
          now work with VMBs with the March beta.   Additionally, this code
          allows Windows programs to access and to release comm ports while
          Windows is still active.

          I  made changes  to  the UART  virtualization  that MAY  fix  the
          problem of very slow transmit that a few users have had.

          Beta V0.60
          ----------








          Beta V0.60
          ----------

          I finally figured out the net effect of  loading COMDD.SYS.  That
          effect  is now taken  care of by  SIO/VSIO.  Those  that found it
          necessary  to load  COMDD.SYS should  find that  it is  no longer
          necessary to load COMDD.SYS.

          VSIO no longer issues an open of the comm port  via the operating
          system.   An  internal  (to SIO/VSIO)  open  is used  when a  DOS
          session accesses/uses a comm port.

          VMBs hogging all  the ports  has now been  corrected for all  OS2
          versions (above 2.0).

          A new  DOS Setting has  been added, SIO_Virtual_RTS_is_HS.   This
          setting defaults  to on.   When on,  VSIO treats RTS  from a  DOS
          session as a  handshaking signal.  When  off, the RTS  setting is
          passed directly to the hardware.  This setting MUST be on for all
          high speed DOS  comm applications!  The  only case, known to  the
          author,  where this  signal may  (should) be  turned off  is half
          duplex DOS comm applications which are very rare.

          Added the UART's loopback mode to the virtualization.

          Beta 0.64
          ---------
