dos_compilers/Microsoft COBOL v21/UPDATE.DOC

Microsoft COBOL  MS-DOS Release 2.1

UPDATE.DOC

December 13, 1985

Significant changes in this release:

1) Any programs compiled under earlier versions of MS-COBOL
   should be recompiled before running; an error message
   indicating incompatible systems will appear otherwise.

2) There are numerous differences between MS-COBOL 2.1 and 
   MS-COBOL 1.0.  These are explained in detail in Appendix
   A of the Microsoft COBOL Compiler User's Guide.

   In particular you should be aware that:

   - Microsoft COBOL 2.1 is validated at LOW-INTERMEDIATE
     level; however, more standard COBOL features,
     including multiple-key Indexed files and dynamically
     called subroutines, are available for program use
    
   - MS-COBOL 2.1 will run only under version 2.0 or later of
     MS-DOS.
 
   - MS-COBOL 2.1 does not use a link step. Programs may be compiled
     then run. Programs are run by entering RUNCOB <filename>.

   - If file I/O is to be done, you should have a CONFIG.SYS file
     in your root directory with the FILES command  set to at 
     least 20 (FILES=20). This allocates buffer space in MS-DOS
     for files.

     If no CONFIG.SYS file is present, the default is FILES=8,
     which is too small. See your MS-DOS manual for details.

   - Indexed (ISAM) files use Microsoft ISAM, which must be loaded
     before running programs that use Indexed files. (See Appendix
     G in the Microsoft COBOL User's Guide). The MS-DOS ASSIGN
     command must not be used while ISAM is active.

  -  See the README.DOC file for information concerning the use of 
     ISAM files in an IBM PC-NET environment.

   - The non-network version of ISAM.EXE shipped with Cobol 2.1,
     version 2.30, is not compatible with earlier versions of Cobol,
     and previous versions of Cobol are not compatible with 
     ISAM.EXE version 2.30.  THEREFORE, ENSURE YOUR APPLICATIONS 
     COMPILED WITH COBOL 2.1 INCLUDE ISAM VERSION 2.30 WHEN DISTRIBUTED.

   - Indexed file formats are different from those in MS-COBOL 
     Version 1.0; the REBUILD utility will convert files from one
     format to the other.

   - Sequential and Line Sequential files have the same format as
     those in MS-COBOL 1.0, except that the end of file is indicated
     without terminating CONTROL-Z characters. Files created under
     COBOL 1.0 may be used except when the OPEN EXTEND option is used.
     In that case, files should be generated by or copied using an 
     MS-COBOL 2.1 program to produce the correct end of file.

   - Cobol 2.1 does not truncate trailing blanks in a Line Sequential
     file.  However, if an attempt is made to REWRITE a record longer
     than what was originally written, only the number of bytes orig-
     inally written will be rewritten.  See discussion of /C switch
     below under 5) Enhancements and corrections....

   - Assembly language subroutines must be linked with the runtime
     executor (RUNCOB.EXE) instead of with your COBOL program. This
     is explained in Chapter 10 of the User's Guide.

   - There are several built-in subroutines which may be called to
     perform tasks such as deleting and renaming files, converting
     to upper or lower case, and getting the current cursor position.
     These are described in Chapter 10 of the User's Guide. Additional
     routines are described in the file UGUIDE.DOC.

   - Default tab stops are now set at every 8 characters. A compiler
     switch (/O) is available for programs that have tabs set for
     the default MS-COBOL 1.0 settings.

   - Both RUNCOB.EXE and DEBUGCOB.EXE should be configured using the
     INSTALL utility before any programs using screen I/O are run.
     DEBUGCOB.EXE should be configured even if your program does no
     screen I/O. INSTALL accepts a file name to be configured, but
     will not accept paths. Files configured must be in the same
     directory as the INSTALL files, or in a directory on a different
     disk drive or device.

3) Additional documentation which appeared too late to be included
   in the Microsoft COBOL Compiler Reference Manual and User's 
   Guide is available in the files REFMAN.DOC, for Reference Manual
   information, and UGUIDE.DOC for User's Guide information.

   Included in these files is information concerning COMP-0 and
   COMP-4 variables, some error messages, some new extension
   subroutines, an undocumented compiler switch, and an undocumented
   file status.

4) File and record locking syntax are accepted by the MS-COBOL compiler
   under MS-DOS 2.x, but are IGNORED at runtime. This means that files
   used in a multi-user environment under MS-DOS 2.x are UNPROTECTED
   by MS-COBOL.

5) Enhancements and corrections from version 2.0

   Both compiler and runtime speed have been significantly increased
   compared to version 2.0. Compile speed is roughly three times 
   faster than version 1.12 and twice as fast as version 2.0. Runtime
   speed is generally comparable to version 1.12, and ISAM processing
   is faster than in 1.12.

   A runtime switch, /C, has been added.  The product no longer
   defaults to truncation of trailing blanks when writing records to
   a Line Sequential file.  However, if the /C (for Compress)
   switch is specified, trailing blanks will be truncated.

   Corrections

   - An error in which low level I/O failure, such as no space on a
     disk file, would cause the runtime to crash has been corrected.

   - If INSTALL has not been run, and MS-COBOL screen extensions are
     requested, the job will be canceled instead of producing a long
     list of messages.

   - Subprograms with USING lists in their PROCEDURE DIVISION headers
     can no longer be invoked except through a CALL. Also, an error
     is reported if the number of parameters in a calling program
     does not match the number in the called program.

   - Non-COBOL subprograms whose names are the same length and
     differ only in the last character are now correctly
     differentiated.

   - COMP-3 variables may now be used as subprogram arguments.

   - An error is detected if DECLARATIVES is declared without a matching
     END DECLARATIVES.

   - A problem with DIVIDE with REMAINDER using very large operands
     and a signed quotient which caused the runtime to crash has 
     been corrected.

   - Variables with subordinate LEVEL 88 items were treated as
     group items for MOVE. This has been corrected.

   - A bug was fixed in which a paragraph containing exact multiples
     of 512 characters of literals would pick up the wrong text
     for the literals.

   - Several problems involving COMP-4 variables have been corrected,
     including improper initialization and erroneous moving of a 
     sign character into the data following an unsigned DISPLAY 
     format receiving field of a MOVE.
     
   - ACCEPT from LINE NUMBER now returns the two digit field "00"
     instead of a five-digit program line number. This change was
     done for compatibility with version 1.x.
    
   - A problem where the compiler did not reject illegal characters
     inside the parentheses of a PICTURE clause has been corrected.

   - The version number now appears correctly in the listing file.

   - Problems compiling programs with more than 32K of generated object
     code have been fixed.

   - Previously, if no object file was produced, and a program had overlay
     segments, strange characters were written to the screen during a
     compile. This has been fixed.

   - Alternate collating sequences of more than 128 characters should now
     work. HIGH-VALUES is now hexadecimal 'FF' instead of '7F'.

   - START with WAIT or LOCK previously generated invalid object code.
     This has been corrected.

   - FULL and REQUIRED for group items no longer generates a compiler
     error.

   - Several problems regarding printing have been corrected.

   - CHAIN and CALL in certain circumstances could cause memory
     management problems.  These have been corrected.

   - A bug was fixed where more than 7 identifiers in and UNSTRING
     would cause an error in phase 3.

   - INSTALL option 1, (install your own terminal) now works properly.
     
     NOTE:  When using the "Define your own terminal" option of INSTALL:
            If the terminal you wish to Install, and are using, is con-
            nected to the COM port, some characters may be lost when
            defining single keys (such as Function keys, cursor keys, or 
            keys on the numeric keypad) which generate multiple character
            sequences.  An approach which will work in all cases is to
            explicitly type in the character sequence that defines
            the key.

   - A correction has been made such that the ON OVERFLOW clause in the
     CALL statement now works properly.

   - A bug in handling relative files has been corrected.

   - A syntax error involving BLANK now generates a syntax error rather
     than a compiler error in phase 3.

   - REWRITEing a record in a LINE SEQUENTIAL file no longer clobbers
     the first byte in the following record.

   - The cursor is no longer hidden after certain runtime errors.

   - An arithmetic expression in a PERFORM statement now computes
     properly in all cases.

   - The compiler will now give an error if there is no period following
     a required paragraph name.

   - The compiler now works properly when REDEFINES clauses are sub-
     ordinate to data items containing an OCCURS clause.