How to read floppy 1.44 compressed with doublespace (1.8MB)

November 16, 2016 at 12:05:28
Specs: MSDOS 6
Hi to everyone,
I have an issue I need to recovery info from a floppy disk (1.44MB). This floppy was compressed with doublespace (in my opinion) and there is also a label on the floppy with this text: "1.8MB". Unfortunately who compressed floppy can not help me anymore. I have MS DOS 6 and 6.22 (bought in a flea market) emulated with vmware. I have tried a little bit but I need help to understand the right procedure that i must follow.

I hope that someone can help me because i'm not so good with MS DOS.

Thx in advance

Rytx


See More: How to read floppy 1.44 compressed with doublespace (1.8MB)

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#1
November 17, 2016 at 03:44:36
Blooming heck, I haven't used DOS 6/Win 3.11 for almost 20 years! Even then I never risked data loss by using compression.

Doublespace was included with DOS 5 but was removed from later DOS versions (6, 6.22 etc) because Doublespace was found to be unreliable.

In DOS 6/6.22, Doublespace was replaced by Drivespace, and the two are incompatible, but conversion from older to newer is possible.

More info here:

http://www.vfrazee.com/ms-dos/6.22/...


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#2
November 17, 2016 at 09:21:46
Hi Rytx,

Have you tried loading the floppy disks on a pc?

You may be able to see the file name(s) and type.
Is so, please advise what some are.

Double space was more for use with hdd's.
Thus I find this surprising and wonder if PKZIP or similar compression program was used.

Google 'dos doublepace' - Interesting reading here:-

https://en.wikipedia.org/wiki/Drive...
https://msdn.microsoft.com/en-us/li...

Good Luck - Keep us posted.


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#3
November 17, 2016 at 21:13:55
I believe doublespace needs to be installed on the computer in order to access the disk. I wouldn't risk installing it on a VM setup. It might start compressing stuff you didn't want compressed.

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Related Solutions

#4
November 20, 2016 at 02:10:34
Hi to everyone,
thx for the assistance I hope that with your help we can find a solution ^_^

@Mike Newcomb: I have tried to load floppy on a pc using different OSs (Win7, Dos.6.22 and Fedora) but I cannot find any file. They suggest me to format disk or they try to reload disk without results. I have also find other 27 disks with the same label (I think that also these one were formatted with double space) and I have tested other 3 floppies but I obtained the same results.

@DAVEINCAPS: Why do u think that can be dangerous install doublespace on VM? The Hard disk is not emulated with file(s) so I think it does not dangerous. Am I doing it wrong?

P.S. I also try to recover my old 286 but i'm not sure that it is still working.


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#5
November 20, 2016 at 02:45:43
Hi Rytx,

the next step is (as you are undertaking) find a dos pc with DBLSPACE on it. .
If you do not have one, a local pc repair center should have - maybe just to borrow or use onsite..

Bear in mind the cmos battery on your old 286 may have failed, causing some bios parameters to reset to factory setting. If so, not a problem, just re-enter.

Finding DBLSPACE and/or dos should not be a problem.
Googling 'dblspace command' finds much info, such as :-

http://info.wsisiz.edu.pl/~bse26236...


Appear DBLSPACE can be run as a freestanding program.

As a matter of interest where are you based (City / State)?
I am in London.

Good Luck - Keep us posted

message edited by Mike Newcomb


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#6
November 23, 2016 at 12:01:23
Sir/Lady ,

MS-DOS 6.0 and 6.2 included DoubleSpace disk compression. MS-DOS 6.22
includes DriveSpace compression instead of DoubleSpace. DriveSpace appears
similar to DoubleSpace, but stores compressed information in a different
format. (If you are currently using DoubleSpace, you can continue to use it
with MS-DOS 6.22.)
---------------------------------------------------------------------------
DRVSPACE /MOUNT

Establishes a connection between a compressed volume file (CVF) and a drive
letter so that you can use the files the CVF contains. DriveSpace usually
mounts CVFs automatically. You need to mount a CVF only if you previously
unmounted it, or if the CVF is located on a floppy disk and Automount is
disabled.

Syntax

DRVSPACE /MOUNT[=nnn] drive1: [/NEWDRIVE=drive2:]

Parameter

drive1:
Specifies the drive that contains the compressed volume file you want to
mount. You must specify a drive letter.

Switches

/MOUNT=nnn
Directs DriveSpace to mount the compressed volume file with the filename
extension specified by the nnn parameter. For example, to mount a CVF
named DRVSPACE.001, you would specify /MOUNT=001. If you omit the nnn
parameter, DriveSpace attempts to mount the compressed volume file named
DRVSPACE.000. The /MOUNT switch can be abbreviated as /MO.

/NEWDRIVE=drive2:
Specifies the drive letter to assign to the new drive. This switch is
optional; if you don't specify a drive letter, DriveSpace assigns the
new drive the next available drive letter. This switch can be
abbreviated as /NEW.


To mount a compressed floppy disk in drive A, you would type the following:

drvspace /mount a:

To mount the compressed volume file DRVSPACE.001 located on uncompressed
drive D, you would type the following:

drvspace /mount=001 d:

---------------------------------------------------------------------------

If you currently use DoubleSpace, you can continue using it with MS-DOS
6.22. Or, you can convert your system and all your DoubleSpace drives to
DriveSpace.

NOTE The uncompression process can take a long time, especially if your
DoubleSpace drives contain a lot of data. You might want to plan
to carry out the process overnight.

To convert your system from DoubleSpace to DriveSpace:

1. Back up the data on each DoubleSpace drive, if you have not already
done so.

2. Run DoubleSpace, and choose the Uncompress command from the Tools menu.
When DoubleSpace prompts you to uninstall DoubleSpace, type Y.

DoubleSpace uncompresses all mounted DoubleSpace drives, and then
removes DBLSPACE.BIN (the part of MS-DOS that provides access to
DoubleSpace drives) from memory.

3. Install DriveSpace by typing DRVSPACE at the command prompt.

Good Luck

message edited by TechDOS


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#7
December 4, 2016 at 09:41:09
Hi to everyone, I have tried but I lost also the hard drive of Windows 7. Do u have other ideas?

P.s.i live in Como near Milan

P.p.s. i found the old 386 that could read this floppy but I do not have idea di It is works and how to copy data into Windows 7 system

message edited by Rytx


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#8
December 4, 2016 at 14:13:07
So you have a 386 with doublespace loaded so it can read the compressed disk? It's probably easiest then to copy the compressed disks back to the 386 hard drive and then copy the files back to a floppy without using compression. It might take a few extra disks but at least the windows 7 OS will be able to read them.

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#9
November 8, 2017 at 12:36:32
Humm. It might be a 2.8MB floppy disk.You will need a 2.8MB floppy drive to read it. A 2.8MB floppy drive can read a 1.4MB floppy.

Good luck!


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