Versions of DOS : Which should you be using?
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       There are now 4 versions of the operating system PC-DOS  in  use  on
    the IBM Personal computer.  These are versions 2.0 2.1 3.0 and 3.1, the
    latter has only become generally availible within the last few  months.
    There  is  also  an  earlier  version  (  1.1  ) but you will only have
    encountered this if you imported your PC before  they  were  officially
    availible  in  this  country.   The  question to ask therefore is which
    version should you be using and is there any advantage in upgrading  to
    a more recent version?  Until about 18 months ago all PCs were supplied
    with PC-DOS version 2.0, probably the majority of PCs are  still  using
    this  version.  It was replaced with PC-DOS 2.1 which is still shipping
    with all new PCs, the differences  between  2.0  and  2.1  however  are
    hardly discernible.

       PC-DOS 3.0 was supplied on the AT when it first became availible, if
    you buy an AT today you will probably  still  get  3.0,  otherwise  you
    might  get 3.1 if the dealer has it.  Contrary to popular understanding
    all 4 versions of PC-DOS will run ( with varying degrees of  success  )
    on  all  members of the personal computer family ( portable, PC, XT, AT
    ).  On the AT only versions 3.0 and 3.1 will pick up the date from  the
    built  in real time clock on power up.  Also if the 20Meg internal disk
    is formatted with 3.0 or 3.1 then it is not readable with  2.0  or  2.1
    because  of  the  use  of  16  bit  FAT entries.  here is a list of the
    significant enhancements on going from one version to the next:

       2.0 -> 2.1 very few, a few bugs fixed.  2.1 -> 3.0  support  for  AT
    high  capacity  diskette,  uses  16  bit  FAT  entries  on  the AT 20Mb
    winchester, extra user commands:  ATTRIB LABEL SHARE and ramdisk driver
    VDISK.SYS,  support  for different countries so that the date can be in
    british format ( DD-MM-YY ) for example.  3.0 ->  3.1  network  support
    system calls, extra user commands JOIN and SUBST.

          Should you upgrade to 3.1 on your PC ?
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       IBM's marketing philosophy has been to ship PCs and XTs with 2.1 and
    ATs with 3.0, 3.0 and 3.1 work equally as well on the PC or XT  however
    so  is  it  worth upgrading?  Doing so will cost about £50-60 from your
    local dealer.  The answer depends on your machine and what it  is  used
    for.   If you are not running on a fixed disk then the answer is almost
    certainly no, ie it is only worth considering on an XT or a PC  with  a
    hard disk upgrade.

       If  you  have bought ( or are thinking of buying ) a large disk ( 20
    Mb or more ) then you should definitely go for 3.0 or better still 3.1.
    This  is because its space will be allocated in 2Kb clusters instead of
    4Kb clusters which can save 20 to 25 % of wasted space on a full  disk.
    On  a  10Mb XT or PC with 10Mb disk upgrade the balance is more closely
    matched, a 10Mb disk formatted with 3.0 or 3.1 is  still  allocated  in
    4Kb clusters ( as under 2.0 or 2.1 ) so there is no space saving on the
    disk.  The SUBST and JOIN  commands  under  3.1  may  be  worth  having
    however.   SUBST  makes  a  subdirectory  of  one  disk accessible as a
    seperate drive letter.  This is very  useful  for  wordstar  and  other
    programs  which  have  no  built  in  support  for sub-directories, for
    example I use the line

    SUBST D: C:\WS

    in my AUTOEXEC.BAT file,  \WS contains all the wordstar files.

       I have installed Wordstar so that it looks for its overlay files  on
    D:  I can now use wordstar in all subdirectories without having to copy
    the .OVL files there first.  JOIN provides an opposite type of  effect,
    a  whole  drive  may be tacked on to the directory structure of another
    drive so that it appears as a sub-directory of the first  drive.   This
    is  somewhat analogous to the UNIX mount command.  This could be useful
    in overcoming the 32Mb limit of DOS as 2 or more 20-30 Mb partitions of
    a large disk can be logically connected so they appear as one disk.

       If  you dislike U.S date formats then a line of the form country=044
    in your CONFIG.SYS file will allow british date formats (  in  3.0  and
    3.1  )  eg  DIR  listings  and  the  DATE command will use this format,
    application programs might also if they are written properly to use the
    "get country dependant information" DOS system call.

       The  SWITCHAR  command in CONFIG.SYS files is no longer supported in
    DOS 3.0 and 3.1, in DOS 2.0 and 2.1 you can put the statement:
  SWITCHAR=-
       in your CONFIG.SYS file, this will  cause  the  switch  character  (
    normally  '/'  )  be  become '-' and the directory seperator ( normally
    '\' ) to become '/'.  This provides a closer approximation to UNIX, ie
    one might type:
        DIR -W /mydir  instead of  DIR /W \mydir
       but this will not work under 3.0 or 3.1
         Graham Cole 9/2/86