Review of DoubleDOS
               by Andy Schwartz, (annotated by:  Mike Guffey)

    Whether you know it or not, the slowest part of your  PC  is  not  the
    hard  disk,  or  even  the  floppy disk.  No, the slowest part is that
    human animal with the nimble (?) fingers on the keyboard.

    Our PC's are actually capable of performing much  more  work  than  we
    usually  ask  of  them,  and  consequently many CPU cycles go to waste
    while waiting for results from the keyboard, [DOS commands, or from] a
    disk drive.  Wouldn't it be advantageous to be able to use this wasted
    time by having the PC do two tasks at once?

    Think of it:  rather than having to schedule  that  long  file  update
    program  during  lunch,  you  could start it going and then input some
    data into another file at the same time.  Do you run a bulletin  board
    or  some other communications process that needs to b e in a "standby"
    mode?  You wouldn't have to devote an entire machine to this task, but
    could  have  one  job  just  waiting  for  a  call  or maintaining the
    communications line, and be doing active, productive work at the  same
    time.   [There are already several BBS systems around the land running
    the BBS software while the SYSOP uses the  machine  for  other  tasks.
    There  are  also  a  few BBS's using DoubleDOS to run two simultaneous
    "nodes" on a single CPU with no hardware modifications.  Yes, there is
    some  sacrifice  in  speed, but not much when keyboard input occurs in
    both sides of the DoubleDOS environment.]

    Do you need to document the running of a program or application?

    Run it in one partition, and keep your word processor  active  in  the
    other  partition.   Switch  back  and  forth at will, writing down the
    documentation as you go along.  [DoubleDOS has a suspend key to stop a
    program on either side of the partition.]

    DOUBLE-TASKING

    The  process  just described is called "Multi-tasking", or having your
    computer do more than one  task  at  the  same  time.   In  fact,  the
    multiple  tasks  are sharing CPU cycles, or taking turns;  but, if the
    tasks fit well together, there may be little or no  noticeable  effect
    on the user.  If both tasks are trying to do exactly the same thing at
    the same time, then, obviously, one of them has to wait.  [The optimum
    combination  is  to  have  one  side running CPU intensive assignments
    while the other side runs a keyboard intensive program  such  as  word
    processing.]

    Limited  multi-tasking has been available under DOS 2.0 with the PRINT
    command, which enables you to start a file printing and then  continue
    doing something else.  The PRINT command actually sets aside a portion
    of RAM which contains the  set  of  necessary  i  nstructions.   [With
    DoubleDOS  and  the  PRINT  command it is possible to drive up to four
    printers simultaneously if  your  hardware  configuration  has  enough
    parallel  and  serial  ports to support it.  It will slow things down,
    but for some situations may be a real productivity solution.]

    DoubleDOS takes this concept a  step  further:   you  are  allowed  to
    define  two "partitions" of RAM memory, and to run any (or almost any)
    job or application in them  simultaneously.   One  job  could  be,  of
    course,  to  print a file to the printer, just as you can currently do
    with PRINT;  but rather than limiting your capabilities to  just  that
    job,  you  could do virtually any job that you would have been able to
    do without DoubleDOS.   There  are  some  restrictions,  warnings  and
    undocumented features that make the use of DoubleDOS not for the faint
    of heart or the  novice  user.   [Since  this  review  was  originally
    written,  Double-DOS has improved significantly.  It is still not, and
    never will be a program useful to unsophisticated users.  Incorrect or
    sloppy  use could trash valuable files and destroy hours of work.  For
    this reason, it is a good idea to start out with it on a  floppy  disk
    environment  or  in  a  unique  subdirectory and NEVER use it on files
    which are not backed up.]

    The first restriction you need to be aware of is the  RAM  requirement
    of your software.  If you have 320k of RAM, and your primary job needs
    all 320k, then you would not be able to run under DoubleDOS.  Even  if
    the  program  needs  only 256k, and you want to run a job in the other
    partition that needs 128k, you still are out of luck.  But if you  had
    640k  RAM  installed  on  your  machine,  you would be able to operate
    DoubleDOS and do both of these jobs at the same time.  [DoubleDOS will
    theoretically  run  on  as  littl e as 192k RAM.  A minimum of 256k is
    recommended and for real utility and flexibility  512k  is  much  more
    satisfactory.]

    By  comparison,  the  new  Topview  program  from IBM is an attempt to
    accomplish some of these same results in a different manner.   Whereas
    DoubleDOS  gives  you  two  partitions and a "DOS-like" prompt in each
    partition, Topview gives you the  capability  of  creating  layers  of
    menus  and of displaying multiple windows simultaneously.  For a fixed
    environment, one in which the same tasks are performed all  the  time,
    Topview   might  have  some  advantages,  were  it  not  for  one  big
    difference:  RAM.

    DoubleDOS has some overhead that it  must  consume.   Typically,  this
    ranges  from  20  to 40k of RAM.  Topview, on the other hand, takes up
    200k of RAM, thus preventing you from  running  two  or  more  "major"
    programs  simultaneously.   There are some other drawbacks of Topview,
    but that's a subject for another time.

    With DoubleDOS, you [modify an ASCII] configuration file to  tell  the
    system  how you want your partitions created and what other parameters
    will apply.  You [may] define:

    MEMORY SIZE.  The easiest way to define RAM size is  just  to  specify
    "TOP  SIZE  = HALF" in the configuration file.  By default, the Bottom
    partition will get the other half.  You may want to be more  explicit,
    and say "TOP SIZE = 256" and let the Bottom partit ion get what's left
    over.  Similarly, you could specify the RAM for the Bottom  half,  and
    let  the Top have the remainder.  [This is something that merits care-
    ful consideration.   Assigning  insufficient  memory  may  create  the
    horrible  "Out  of Memory" message and cause a file write of truncated
    data or (still worse) nothing but nulls (FF  hex).   If  your  (older)
    software  uses  virtual  memory  to expand or update files you need to
    know how much memory is needed in addition to what the  basic  program
    consumes.   A  good  bet  is to use at least 128k for a partition even
    though a minimum of only 48k is required.]

    DISPLAY.  Choices are [DEFAULT], COLOR, MONO and [options] called  TWO
    and  BOTH, which, if you [can already drive] two monitors, assigns one
    screen to each partition.  [There is also an option  for  FAST  screen
    writes  if  your  monitor  card  does not have to wai t for a vertical
    retrace before  updating  the  screen.   Screen  buffer  size  can  be
    adjusted for various graphics card capabilities.]

    PROGRAMS.   You  can  have  DoubleDOS automatically start a program in
    each partition for you.  [This can be done with a serious of  commands
    or  by  calling  up a .BAT file.  Either or both of the partitions can
    use this auto-start feature.  Or you can have the sof  tware  load  an
    application in one part of memory while you do almost anything else on
    the other side.]

    MENU OPTIONS.   DoubleDOS  has  its  own  control  menu,  which,  once
    DoubleDOS  is  started,  allows you to perform such tasks as switching
    partitions, changing partition sizes, terminating a  job  or  stopping
    DoubleDOS.  This menu can be displayed in the Long or Short mode, and,
    if Short, can appear on any line of your choice.

    [PRINT  DRIVER.   Your  choices  are  direct  drive  with  no  buffer,
    interrupt  or  clock  driven, or a ROM BIOS printer interface.  If you
    choose to drive the printer via a buffer, it can be defined from 1  to
    64k.]

    [KEY  DEFINITIONS.   The "hot" key can be defined to conform with your
    other software or varied so as not to conflict.  It is  even  possible
    to  define  single-key  commands  to  invoke  the  various features of
    DoubleDOS, but it is not recommended.  You may also def ine  the  keys
    which  cause  the  partitions  to  be  switched,  the key to suspend a
    program.  You may also choose which key will flush the keyboard buffer
    to cancel unexecuted commands.]

    [OTHER  OPTIONS.  You may assign which partition has control over each
    COM port.  This is necessary because  some  software  resets  the  COM
    port(s)  on  startup  or  seemingly  at  random.  You may decide which
    partition receives the higher priority as CPU time is di vided.  There
    is  also  an option to invoke screen blanking after a specified period
    of no keyed input.]

    Installation of DoubleDOS on my hard disk was simple...  It took [only
    a  few]  seconds  to  install  the programs...  [The time to load will
    depend on whether you choose  to  have  DoubleDOS  automatically  load
    software on startup.]

    MIXED RESULTS

    To  initiate DoubleDOS, at the DOS level you type "DOUBLEDO", which is
    the name of the .COM  file.   (Remember,  DOS  filenames  can  have  a
    maximum  of  8 characters.  I renamed my file "DD.COM" just to make it
    easier.)

    The regular DOS prompt is now replaced with one that tell you:

    1.  You are under the control of DoubleDOS 2.  [Which subdirectory you
    are  in]  3.  The partition you are in (this is really important).  4.
    How much RAM has been assigned to the partition.

    I say that it's really important to know which partition you  are  in,
    because  if you've ever been confused about which subdirectory you are
    in, now the problem is compounded.  You can be in one subdirectory  in
    one partition and in another subdirectory in t he other partition.  At
    the  DOS  level,  DoubleDOS  tells  you  which  partition,  but   your
    application  program  will  not remind you.  Care must be taken.  [You
    may redefine the prompt with  the  MSDOS  "prompt"  command,  but  you
    should include the identification of whi ch partition you are in.  Any
    action taken with the "prompt" command only affects the partition  you
    are in when the command is executed.]

    Other than the new prompt, and a few minor undocumented features which
    I will discuss below, you can now go ahead to run whatever you want to
    in  each  partition.   DoubleDOS  calls  the partition you can see the
    VISIBLE program, and the other one, the INVISIB LE  program.   A  good
    example  might  be  a  print  or  a  file  update  taking place in the
    INVISIBLE partition, and keyboard entry taking place  in  the  VISIBLE
    portion.

    Remember,  the  VISIBLE  partition can be either the top or the bottom
    partition.  You can toggle  back  and  forth  between  them  with  the
    SUSPEND  KEY  combination.   Or  you  can  go to the DoubleDOS menu to
    perform the same task.

    Who gets priority?  I tried to answer this  question  by  running  two
    BASIC programs simultaneously.  Each program consisted of 3 lines that
    incremented a counter, printed the new value to the screen,  and  then
    looped  back to the 1st statement.  The result of t his experiment was
    that the program in the [TOP] partition counted twice as fast as  that
    in  the [BOTTOM] partition.  When the [TOP] was at 10000, the [BOTTOM]
    was at only 5000.  [As noted above, the priority may be defined in the
    configuration file to be so mething besides the default 2:1 ratio.]

    But  normally,  you  would not be using the same computer resources in
    both partitions.  Let's say you  were  doing  keyboard  entry  in  the
    VISIBLE partition.  You might experience the "sticky keyboard" results
    that users have found with the PRINT program.  The le tters  you  type
    would  not  immediately appear on the screen, and then [might] show up
    in bunches.  This may or may not disturb you.

    If a sticky keyboard is the  only  problem  you  experience,  consider
    yourself fortunate.  Since DoubleDOS gets to the "heart" (not just the
    brain) of the PC, several  other  problems  can  occur,  with  varying
    levels  of  resolution.  [The "sticky keyboard" problem can usually be
    resolved with a little planning or forethought.]

    The first thing you must know is that some programs,  for  reasons  of
    speed, write directly to the screen, without going through DOS.  Lotus
    1-2-3 is probably the most common offender, so DoubleDOS comes with  a
    special  "driver"  to  handle  the  situation.  The driver, in effect,
    forces 1-2-3 to direct its output to the correct area  of  memory,  so
    that  when you go back to that partition, your output is there waiting
    for you.  [Since this review was written,  drivers  for  many  popular
    direct-screen-write  programs are available from Soft Logic.  In fact,
    most of them are in a subdirectory on the master disk.]

    [Programs which  can  be  patched  with  files  on  the  Master  Disk:
    CROSSTALK  3.4  -  3.6,  dBase  III  1.0-1.1,  EMAIL, Leading Edge WP,
    MetaFile 8.0, MultiMate 3.2-3.3, NutShell 1.28 or 1.29,  PFS:   Write,
    Relay,  SideKick  (see  note below), SmartCom 1.1-2.1, SuperCa lc 2.0,
    Symphony 1.0, VolskWriter  128k  version  and  Deluxe,  WordStar  3.3.
    Other,  newer  patches  may be obtained free from the tech support BBS
    (number listed above).]

    Some interesting results happen  without  a  driver  when  you  run  a
    program  that  writes directly to the screen.  I fired up SMART in the
    top partition, and, before the screen  appeared,  I  switched  to  the
    bottom  partition.  After a few seconds, the SMART main me nu appeared
    ...  in my bottom partition!  This was not what I wanted at all, so  I
    cleared  the  screen and went on.  However, when I went back to my top
    partition to continue with SMART, what  did  I  have?   NOTHING!   The
    screen was blank, of course, since I had cl eared the screen.

    That  should  be  easy  to  solve  by  getting get a SMART driver from
    SoftLogic Solutions.  "SMART?  No, we don't have a driver for that one
    yet,"  I  was  told.   They  do  have drivers for Multimate, Wordstar,
    Crosstalk, Symphony and dBase II and possibly dBase III.  [No, not all
    programs  have  had  patches  written for them by Soft Logic, but give
    them time.  They will talk to you about it on the voice tech.  support
    line (listed above).]

    What  do you do if you have the need for a driver, but don't have one?
    The only answer is to take it slow and easy, or execute those portions
    of  the  job that do not write to the screen.  If I had waited for the
    SMART main menu to come up, before switching to the bottom  partition,
    I  would  have been OK.  Waiting for a process to finish takes some of
    the benefit away from DoubleDOS,  but  you  may  be  able  to  operate
    anyway.

    Some  other  problems  I  have found have been easily resolved.  I was
    running Wordstar (without a driver) and was having some  trouble  with
    the  Control  key  functions working.  Try as I might, some would just
    not work.  I had some other questions for SoftLogic,  so  I  placed  a
    "help"  call.  Yes, they were aware of the problem, and was I familiar
    with DEBUG?  So, on the phone, the support staffer walked  me  through
    the DEBUG process to patch my program.  [The patch files now available
    work automatically in combination with DEBUG.  A nice touch.]

    You may be able to get around other problems by yourself.  In Personal
    Editor,  for  example, a Ctl-Backspace deletes a line.  Even after the
    patch which solved the Control key problems in WordStar, I still could
    not  delete  a  line in Personal Editor.  Fortuna tely, PE allows your
    own key function definitions, so I simply defined  an  additional  key
    combination to perform the delete line.  Problem solved.

    Some  other  handy utilities I have always had in my AUTOEXEC.BAT file
    have had to be removed and executed either after I got into DoubleDOS,
    or,  in  one  case, not at all.  DoubleDOS does give you fair warning:
    "If you have another device which uses IRQ7, th en  you  must  include
    BUFFERS = 0 in your DDCONFIG.SYS file." Thanks.  I needed that.

    Some  problems have remained a mystery.  One application I was running
    reported an error message and froze the keyboard, forcing me  to  turn
    the  power  off.   The  same error, without DoubleDOS, gave me just an
    error message.  I have also had the cursor disappea r from one of  the
    partitions.   [Most  problems  such  as  this  have  been  solved by a
    modified ANSI.SYS file on the Master Disk.  This modified ANSI  driver
    allows  an  extended  keyboard  buffer in both partitions (among other
    things).]

    Another user of DoubleDOS reported  to  me  that  the  CHKDSK  command
    destroyed his directory, but I have not had this happen, nor do I want
    to try to duplicate it.  [It is a good idea and sensible computing NOT
    to use disk-checking utilities while using this software.  If you have
    a file open under one partition and run an analytical program  in  the
    other partition, you may be asking for for trouble.]

    ENHANCEMENTS OUTDATE DOCUMENTATION

    Documentation,  as I started to point out, is typeset on heavy, glossy
    paper and comes in a binder  with  a  fine  looking  slip  case.   The
    manual's instructions were clearly written, but since the software has
    changed so much, the authors have had to include a n extra green sheet
    to  provide  new  instructions  on  the  installation process, and the
    READ_ME.1ST file  to  give  even  more  timely  information.   If  the
    software  keeps  changing as fast as it has, they will have to reprint
    the manual every month.  [Since this was written,  both  documentation
    and support have improved.]

    WHAT'S NEXT?

    What  does  the  future hold for DoubleDOS?  Clearly, when some of the
    bugs get worked out, DoubleDOS will have more widespread appeal.   The
    addition of various drivers will broaden the attraction;  if SoftLogic
    is charging only 5.00, why not raise the price b y  10.00  or  so  and
    give  away  the  drivers  at  the  time  of  original  purchase?  [The
    modification drivers/patches no longer cost you anything.  If they are
    not on the Master Disk, check in at the tech.  support BBS.  DoubleDOS
    is not without "bugs".  But many/most/ all problems directly relate to
    the  fact that when you use this software, you are on the frontiers of
    computing.  Just as you are with much of the  "advanced"  hardware  on
    the market.]

    DOS,  as we know, can address only 640k of RAM.  If you physically had
    1 meg of RAM, the possibility exists for DoubleDOS to each  have  512k
    for  its own use.  Then you would be able to run two major jobs at the
    same time.  [Yes, DoubleDOS is still under devel opment, just  as  DOS
    is.   The  likelyhood  that  MicroSoft  will solve the addressable RAM
    dilemma is not on the horizon.  You may need to look at other software
    and/or hardware for this.]

    Does DoubleDOS allow you to run a multi-user machine?  If you ran CTTY
    in one partition, the possibility exists.  But  watch  out  ...   your
    software  had better be "well behaved," because you are up against the
    restrictions of both DoubleDOS and CTTY.  [The use of  two  COM  ports
    and other software may solve this problem, as it has with some BBS's.]

    USE WITH CARE

    Will I continue to use DoubleDOS?  My answer is a strong "YES." In the
    right circumstances, I have found it to be invaluable.  Will I ever be
    thoroughly  comfortable  using it?  Not in its present release.  There
    are too many unusual and unknown results.  Would I recommend  the  use
    of  DoubleDOS  to  others?   At  this  point,  I would recommend it to
    individuals who either  have  an  overwhelming  need  for  the  unique
    DoubleDOS capabilities or those who feel comfortable dealing with some
    of the peculiarities of the product.  SoftLogic offers a 30 day  money
    back  guarantee, so if you think DoubleDOS is the product for you, you
    may want to give it a try.  [Make no mistake, this software is not for
    the  faint-of-heart  nor  for the casual user.  But for about $50, you
    can give your P C/XT/AT (or compatible) capabilities that IBM has  yet
    failed  to seriously consider.  It is an interesting product of use to
    some, dangerous for others.  Like other products from Soft  Logic,  it
    is unique.]

    Product name:  DoubleDOS
    Authors:       SoftLogic  Solutions
                   530  Chestnut Street
                   Manchester,
                   N.H.    03101
                   [800-272-9900 for ordering]
                   [603-644-5555 for voice techniacal support]
                   [603-644-5555 for technical support BBS]
    Catagory:      Multi-Tasking Utility Software
    Price:         [$49.95 + $5 shipping (originally $109 + $6)]
    requirements:  DOS 2.0+