by Alan Zisman
(c) 1993. First published in Our Computer Player, March 19, 1993
New versions of DOS are eagerly awaited. Unless you've
made the big jump to OS/2 or are using the competition, DR-DOS, you're
dependent on this product of the Microsoft money machine if you run one
of the estimated hundred million PC clones and compatibles in use
Maybe you remember the DOS 4.0 debacle. Then, late in
1988, Microsoft was to busy with (of all things) OS/2 to pay much
attention to mere DOS. Instead, IBM released an inadequately tested,
buggy PC-DOS v. 4.0, which was widely ignored in favor of the previous
standard-bearer, DOS 3.3.
Luckily, Microsoft released that DOS was still worth
doing right. For version 5, released in the summer of 1991, they
conducted their largest beta-test program to date. And that product
became an instant standard. As well as improving on DOS 4's features,
added a number of utilities, that had previously only been available
from 3rd party companies, such as undelete and unformat, and a memory
manager. As well, it was (and still is) a fairly stable, bug-free
So in the first ten years of IBM-standard personal
computing, there have been five major versions of DOS... one every two
years, on average, with DOS 5 dating from mid-1991. That means that
time for version 6. And the rumours started to fly. DOS 6 would be a
true 32-bit operating system. It would integrate DOS and Windows into a
Well, as of the time of this article, MS-DOS 6 hasn't
been released, Although a March 31st release date is being widely
predicted. Microsoft claims that this version has more changes to the
core of the system, the 'kernal' than there were from version 4 to
version 5. And the focus is on this year's buzz word, usability...
making it easier for average people, not just the guys with glasses and
Microsoft claims they started the process with a bunch
of phone calls. Not to registered users, though, but to the general
public. (They've discovered that "only power users bother to register",
according to Microsoft's Alec Saunders). Out of 3000 phone calls, they
found 700 PC owners, and asked what they wanted in an operating system.
As a result, they have been beta-testing DOS 6 for several months, with
several thousand beta-testers ranging from new users to large
work-sites. Beta-testers sign a non-disclosure agreement, swearing that
they will not discuss the features, or even the existence of the
they're testing. This makes sense, since features change from beta
release to actual commercial product, and the beta versions are, by
definition, buggier, and slower than the finished version.
Microsoft has made late beta versions available to
some reviewers, and given them permission to publish. And even though
I'm an authorized beta-tester, they have said that I could write this
article. (Really... I have it in writing). However, you should be aware
that I am looking at a late pre-release version. By the time you read
this, after the expected release date, features may have changed. As
well, there was no printed documentation available to me, so I could
easily have missed things.
First impressions... This isn't the revolution that
some rumours had speculated. It is, however, a big step up, at least in
size. DOS 5 shipped on 3 low density 3 1/2" disks. This one is on 3
density disks. It's a lot bigger. My DOS directory is up around 6 meg.
When I finish beta-testing, I'll look for ways to remove a couple of
megs of that, but still, that's a hefty increase.
By the way, I'm prepared to give this tendancy the
force of a law... let's pompously call it Zisman's First Law of
Obesity: "Every new software version will be twice as big as the
version it replaces." In 1981, DOS v.1 took one single-sided 160k
floppy. V. 2.x took two single-sided or one double-sided 360k disk.
used 3.3 took two 360k disks, and so it's continued up to now. And at
the rate we've been going, by the year 2001, DOS 10.0 will take about
96 megs of drive space. Remember, you read it here first!
The program installs similarly to DOS 5-- it creates
an OLDDOS directory, giving you the power to easily restore your old
up if you want to.
The core DOS files are a little bigger, but most of
the increase is in new utilities. Some of these are Microsoft
designed... there's a full-screen UNDELETE that looks a lot like
5's DOSSHELL, in addition to the old command-line version. As well,
(and this is a trend for DOS 6), there's also a Windows version.
More of the added heft, though, comes from several
utilities that Microsoft licensed from 3rd party sources. (Similarly,
DOS 5's MIRROR, UNDELETE, and UNFORMAT commands came from CENTRAL
of PC TOOLS fame). For example, there's now a virus checker, again from
Central Point. And a version of SYMANTEC's NORTON BACKUP and SPEEDISK
(here called, creatively, DEFRAG). Again, both the virus checker and
the backup programs come in both DOS and Windows versions. You can
choose to install either, both or neither version at install time. If
you install the Windows versions of Backup and Anti-Virus, they're
added to your File Manager menu as well as to Program Manager for easy
access. They work well, but have fewer options than the full commercial
AM I SEEING DOUBLE?
It seems like Microsoft's versions of DOS are always
catching up with Digital Research's DR-DOS series (now owned by Novell,
and with its own version 6 out for over a year). DR-DOS 6 includes a
disk compressor, similar to the popular STACKER, but licensed from
ADDSTOR's SUPERSTOR utility. Obviously, MS-DOS 6 would have to have
An unconfirmed rumour says that Microsoft licensed the
core of its disk compressor from DOUBLEDISK, calling it DOUBLESPACE.
They then proceeded to completely rework the code to make it better
integrated with the operating system as a whole. Like the better known
STACKER and SUPERSTOR, if used, it creates a large hidden file on your
'host disk', and compresses your data onto it. Its competitors use a
device driver, run at boot-up, that permits you to read and write to
this compressed file, on the fly. DoubleSpace, however, makes use of a
new hidden DOS file, DBLSPACE.BIN, that's run before your CONFIG.SYS.
You don't notice it's there... it just appears that your hard drive has
a lot more room than before.
This strategy makes the disk-compression more user
friendly than the earlier generation of commercial products; Stacker,
for example, ends up with two versions of your set-up files. When new
software changes CONFIG.SYS or AUTOEXEC.BAT, Stacker has to stop the
bott-up process to adjust things. Since DoubleSpace is loaded as one of
the initial DOS files, these sorts of changes don't affect it. As well,
since DBLSPACE.BIN is a hidden system file, it can't be deleted
Since DoubleSpace is being included as a basic feature
of DOS, Microsoft has published the specifications for it, calling it
the MS Real-time Compression Interface -- MCRI) so that 3rd party
utility programmers can work with it, making sure it will be compatible
with upcoming utilities. By making its compression part of the
kernal, Microsoft is setting it up to be a new standard. Users can even
convert existing Stacker or SuperStor partitions to DoubleSpace
partitions. (Meanwhile, the makers of Stacker, have filed suit against
DOUBLESPACE has some nice features, including some
that I haven't seen (at least in STACKER v.2 or SUPERSTOR v.2). For
example, you can make your compressed partitions larger or smaller, in
real time. The new size takes effect immediately, without needing a
re-boot. While on older XTs and slower 286s, there will be a noticeable
speed penalty using disk compression (with DOUBLESPACE or its
alternatives), on more recent computers, there should be no loss of
performance, and may even be a small speed increase. File compression
ratios vary depending on the type of files compressed; already
compressed files like ZIPs or GIF graphics will show little if
any improvement, while other file types may compress as much as 40 to
1. I got compression ratios that were about the same as with competing
products on the two partitions that I compressed.
One feature of the commercial products currently
missing in DoubleSpace: while you can compress floppies, they can't be
read on machines that don't have DoubleSpace installed. Both Stacker
Superstor manage to let their compressed floppies be used on any
computer, whether their products are present or not.
A few warnings if you use this feature (and this is
also true for the commercial equivalents):
-- For the DOS 6 DOUBLESPACE partitions, you're best off to use the
DEFRAG utility provided. (Similarly, STACKER, SUPERSTOR, et al provide
their own equivalents). While other utilities such as Norton's
will defragment a compressed drive, it won't be able to compact it,
closing up the unused spaces. DEFRAG automatically switches to
DOUBLESPACE to compact the compressed partition.
-- Don't try to make a Windows permanent swap file on a compressed
partition, from DOS 6 or from the commercial alternatives. If
DOUBLESPACE finds a permanent swap file when it is installed, it will
automatically make sure it is placed in the un-compressed part of your
-- Currently, DoubleSpace partitions are not supported by the next
generation operating systems: OS/2 or even Microsoft's current NT beta
versions. (The same is true of Stacker and SuperStor). Don't count on
disk compression as a way to get enough free drive space to try out one
of these large operating systems.
-- All of these programs are very safe, and have been tested widely.
Accidents do happen, however, so for your own peace of mind, have a
recent backup on hand before installing. Really.
While DOS 5 included the ability to load device
drivers and TSRs into high memory on a 386 or better, the process had
be done by hand-editing the CONFIG.SYS and AUTOEXEC.BAT files. DOS 6
automates that, with a MEMMAKER utility, adding a feature that
commercial utilities like QEMM and 386MAX have had for some time. It
me little good, however. I had followed the instructions in the DOS 5
manual to optimize my memory, and with DOS 6 and MEMMAKER, I got...
(drum roll please) exactly the same amount free. On the second machine
tested, however, MEMMAKER did free up a reasonable amount of memory. If
you have been (understandably) hesitant to muck about with your setup
by hand, this will get the job done for you.
SO WHAT ELSE IS NEW?
There are newer versions of HIMEM.SYS, EMM386.EXE, and
SMARTDRV.EXE to replace the DOS 5 versions. The new EMM386 will share
its expanded memory pool with other applications needing the memory.
These new versions are all DoubleSpace aware, however, which may let
Smartdrv hold more data in the same sized cache. (There is, also, a
SMARTMON... a Windows utility that shows how well SMARTDRV is working)
Like the Windows 3.1 version, SMARTDRV is much improved over the DOS 5
version. If you're already using QEMM or 386MAX, there may not be much
reason to switch to DOS 6's equivalents.
DOS 6 does help you relate to some newer technology.
The MSCDEX driver for CD-ROMs and multi-media is included.
There are a few new command line utilities... some of
my favorites include:
-- DELTREE. This lets you remove a whole 'bough' of your directory
tree, including contents, all in one action. Use with care!
-- MOVE. At last. Copy and delete the source.
-- POWER. For portable computer users, to conserve battery life.
As well, there are lots of new switches and features
in the old standby commands. DIR /C shows you compression ratios, for
example. MEM /P pauses at each page (about time!). There are lots more,
including many that I haven't had the opportunity to find yet. As with
DOS 5, typing the command, followed by /? will get you a brief
explanation of the command, as well as a list of switches, along with
But while the DOS 5 HELP command simply gave you that
same explanation, the DOS 6 HELP is much more powerful. Here, you get a
real help system, patterned on the WINDOWS HELP function. You can
for related information, or browse an index. You really can leave
the manual in the box, most of the time.
And along with the ease-of-use features, there's
finally something for the hackers-at-heart as well. For those of us who
find ourselves forever tinkering with our computer's setup, DOS 6 has
some nice features. When it starts to boot up, you'll see "Starting
MS-DOS" on screen for a few seconds. If you press F5 during that time,
you'll get a clean boot. Your CONFIG.SYS and AUTOEXEC.BAT will simply
ignored. Pressing F8 steps you through your CONFIG.SYS one line at a
time... you're prompted to load that line or not. You're also asked
whether to run your AUTOEXEC.BAT. Chose YES, and the whole thing runs.
As well, the list of CONFIG.SYS commands has been
expanded to let you include multiple configuration setups, with the
ability to choose one from a menu at boot time. Similarly, a new
command, CHOICE, lets you choose options from your AUTOEXEC.BAT,
interactively. If you've needed multiple configurations so that you
could either run your network drivers, or WINDOWS, but not both, here's
a way to simplify the process.
Don't hold your breath, but in a recent interview,
Bill Gates dropped some hints on what to look for with DOS 7, currently
under development. The NEXT generation promises even more 386-or-better
functions, and on those machines will move everything to protected
improve the file system, and even support real filenames... no more
8-letter mysteries. Gates suggests that DOS 7 will be merged with the
next version of Windows-for-DOS (not Windows-NT), so that there'll be a
DOS 5.1 ANYONE?
In the meantime, should you upgrade? If you have an
older, limited system, with a small hard drive, the benefits may not
warrant the increased disk space. As well, if you already have a 3rd
party disk compressor, virus checker, backup program, and memory
manager, you may find much of DOS's bulk unneccesary. DOS 6 is not a
revolutionary change in the way your computer works. While I like
it, despite the improved ease of using memory management and help
other improvements), it doesn't feel like as big an improvement over
DOS 5 as that upgrade was over DOS 3.3 or 4. (Microsoft may hate me for
saying it, but DOS 5.1, anyone? After all, 5.1 has been a lucky number
for Word Perfect).
In essence, it includes some nice improvements
along with a group of utilities derived from other companies, and added
hooks to Windows 3.1 and multi-media. The interactive boot capability
a particularly nice feature. Some of us, however, NEED to have the
latest version of everything. For us, it's no question. When DOS 6 is
officially released, we'll be lining up at our nearest software store
(Note from the year 2003): The above
article was originally published in 1993, as a review. A decade and
later, I've gotten a series of emails from DOS fans hoping that I could
sell them a copy of this software or direct them to a place where it is
still available. While I have reviewed software since 1991, I am not a
vendor of r any products. I suggest to everyone looking for copies of
older software to check at eBay or at OldSoftware.com.If
on my Files webpages, you'll find links to a number of (mostly
freeware) downloadable software, some of which may be good replacements
for older programs.
-- AZ (September 15, 2003)