News Group Posts

dostar dos-tar span floppies

From: Jeff Hyman <scolist@cactus.com>
Subject: Re: big Unix file to dos
Date: Wed, 12 Dec 2001 17:49:12 GMT

Recently, Robert Carnegie wrote:
> Jeff Hyman <scolist@cactus.com> wrote in message news:<m16DnKt-0007LpC@cactus.com>...
> > Recently, Rob S wrote:
> > > On Fri, 7 Dec 2001 16:02:21 GMT, Jean-Pierre Radley <jpr@jpr.com> wrote:
> > > 
> > > -
> > > -Why in the world would you use zip instead of gzip, or, still better,
> > > -bzip2?
> > > 
> > > It works.
> > > It's compatible with PKZIP on DOS
> > > Ditto Winzip
> > > Freeware
> > > Has every option I need (other than spanning disks)
> > > Openserver ready-compiled versions are easily available on the 'net
> > > It would do what the original poster asked
> > > 
> > > Do the other progs you mention fulfill all these criteria and do spanning JP?
> > > 
> > > regards
> > > -Rob
> > > robatwork at mail dot com
> > 
> > If you need to span disks, try DOS-TAR. Has compression and 
> > bit-level verification too.
> > 
> > Jeff Hyman
> 
> This one?  http://www.cactus.com/products/cactus/dostar.html
> Interesting and potentially useful, though you can't but mock this:
> "Data compression guarantees to at least double the capacity of any
> seeking device such as floppy or a named file on your hard disk."
> 
> And perhaps too much effort if you only have to do it once -
> although if the file is commercially important then getting a
> quick solution is better than getting a cheap one.
> 
> Of course there are many dozens of disk spanners for DOS or Windows,
> although I got stuck when looking for one particular feature for
> archiving - _redundant_ disk spanning.  [snips rambling about CRCs
> across volumes to create a checksum disk, crypto one-time-pad tools]
> 
> And come to think, any DOS tool which can grab images of diskettes
> would copy the data off basic UNIX tar disks, with only the 512 bytes
> header as added nuisance (plus if you're not using tar then you don't
> know where end-of-file is).  Windows InfoZip, for one, seems happy to
> ignore a tar header when reading a "tar cvAf" archive, and get to the
> zipped data inside; so apparently you could use any UNIX zip tool,
> "tar cvA6" to write disks, any DOS/Windows diskette imager, the DOS
> "copy" command to reassemble pieces, and any DOS/Windows unzipper,
> to transfer data.
> 
> As far as I know, this wouldn't be the same as PK Zip disk spanning;
> I believe that that uses regular files on MS-DOS formatted diskettes,
> and tar of course just dumps data onto the medium from sector zero on
> (well, data from sector one).
> 
> I haven't taken the trouble to get acquainted with gzip and bzip2
> beyond knowing the names - for managing our fleet of servers, and given
> some logistical and contractual issues, neither is a good fit for us -
> and when I Googled them I glimpsed the word "incompatible" in relevant
> texts, which, while not absolute, suggested "more trouble than it's
> worth for a one-off job by a novice - don't bring it up".  So I stopped
> at suggesting uuencode, ASCII split, and doscp as my all-SCO solution.

I watched this thread for some time before making a comment.
Bottom line is DOS-TAR _does_ span floppies. 
If compressing Ascii text will reduce number of floppies by 80+ %.
It's also compatible with all the super-tars  UNIX <--> DOS.
It's no big deal as I was just making a suggestion and not
trying to make a sales pitch. Any solution that is free on the
web will usually get my vote too.

- Jeff Hyman
 

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