[delphizip] Re: Span volume problems
- From: "Russell Peters" <russellpeters@xxxxxxxxxxx>
- To: <delphizip@xxxxxxxxxxxxx>
- Date: Sat, 7 Dec 2002 08:56:11 +1100
That's how I am doing it except that when reading spanned in IsRightDisk
check previously format of FInFileName and keep to that format.
I don't think that the Drive type needs testing so often - can it actually
change while doing spans?
I am in favour of using AddOptions instead of separate properties but there
are advantages and disadvantages of either way (a big minus is that they can
be used outside of Add operations that is I thought of using separate set
but ...).
In the beginning of the low level format function I added a test of drive
type to only allow removable disks to be formatted, perhaps there should be
similar for erasing disks (don't allow erase from root on hard disk?).
Am inclined to change the name of the function CheckIfLastDisk to
OpenIfLastDisk!
Should widen setting of ZipBusy and UnzBusy (replace with Busy?) to show
when is in an operation, not when dlls are in use (It is possible to call
add while still doing anything else including add).
Then need to make span functions able to be 'cancelled' like the dlls.
Russell Peters
http://www.users.bigpond.com/russellpeters/delphizip.html
----- Original Message -----
From: "Roger Aelbrecht" <Roger.Aelbrecht@xxxxxxxxxx>
To: <delphizip@xxxxxxxxxxxxx>
Sent: Saturday, December 07, 2002 4:45 AM
Subject: [delphizip] Re: Span volume problems
>
> Hi Russel
>
> For Reading
>
> As it is implemented now in ZipBuilder
> Start with ZipFileName = filename.zip
>
> If present test if spanned, spanned means on removable disk
> with volume name set to PKBACK ###
>
> If not present start search for filename###.zip
> If on hard drive search for the last volume this should be the last part
>
> If on removable disk ask for last disk each time adapting filename
>
> For Writing I added a bool property (can be replaced by member of set)
> NoVolumeChange in that case we use the filename###.zip for each part
> no difference between hard disk and removable
>
> Another bool property WinZipNames if true
> changes both Reading and Writing by using the filenumber scheme
> to Fielname.z## except for the last part
>
> I defending these schemes for two reasons
> I already made it ;-)
> The first part was already there but only for hard disk, so changing
number
> schemes will give backward compatibility issues
>
> I use separate Boolean properties but these van very easily changed into
> members of the AddOptions set
> But had problems with having an AddOption influencing the Reading part
> therefore choose to use separate property
>
> Roger Aelbrecht
> http://web.wanadoo.be/driehoeksw
> ----- Original Message -----
> From: "Russell Peters" <russellpeters@xxxxxxxxxxx>
> To: <delphizip@xxxxxxxxxxxxx>
> Sent: Thursday, December 05, 2002 9:56 PM
> Subject: [delphizip] Span volume problems
>
>
> >
> > I am trying to get around volume name problems but it is rather involved
> > (you have to be able read them back readily)
> > I thought to check in following sequence
> > if not filename###.zip (## is number) assume must be last disk (error
> unless
> > Volume name is normal span volume name).
> > if filename###.zip must be part of span set (CheckForLastDisk(EOC,false)
> > returns false)
> > if filename.z## must be part of span set (CheckForLastDisk(EOC,false)
> > returns false).
> >
> > Then use new add options AddSpanNoVolumeNames and AddSpanCompat to
control
> > generating the zipfiles. AddSpanNoVolumeNames would make it generate
> > numbered files instead of numbered volume names and AddSpanCompat would
> make
> > it generate WinZip type names.
> > (Personally I would prefer filename.zip.nnn )
> > Thinking of template using brackets thus - filename[,nnn].zip or
> > filename.z[ip,nn] or filename.zip[,.nnn] where [ final , parts ].
> > Russell Peters
> > http://www.users.bigpond.com/russellpeters/delphizip.html
> >
> > ----- Original Message -----
> > From: "Alistair George" <bigal@xxxxxxxxxx>
> > To: "Roger Aelbrecht" <delphizip@xxxxxxxxxxxxx>
> > Sent: Friday, December 06, 2002 7:18 AM
> > Subject: [delphizip] Previous spanned reported spanned error
> >
> >
> > >
> > > Hello Roger,
> > >
> > > Just figured out what is wrong. I made the spanned set on hard disk,
> then
> > copied
> > > the spanned volumes to CDR (this means the Volume name is wrong, or
non
> > existent :-(
> > > What I have been doing is to write volume sequence number on the
disks.
> Is
> > there
> > > an easy way around this (can you suggest what is needed to make
> zipmaster
> > accept
> > > unnamed volumes) as it is preferable to write CDROM directly off the
> file
> > > on Hard Disk for obvious reasons.
> > > Cheers,
> > > Alistair+
> > >
> > > Friday, December 6, 2002, 6:48:14 AM, you wrote:
> > >
> > > RA> ----- Original Message -----
> > > RA> From: "Alistair George" <bigal@xxxxxxxxxx>
> > > RA> To: "Roger Aelbrecht" <delphizip@xxxxxxxxxxxxx>
> > > RA> Sent: Wednesday, December 04, 2002 7:33 PM
> > > RA> Subject: [delphizip] Re: Maxdisksize FreeSize
> > >
> > >
> > > >>
> > > >> Hello Roger,
> > > >>
> > > >> >> A major weakness of the current ZIP format is its slowness in
> > returning
> > > RA> a
> > > >> RA> file
> > > >> >> within a spanned archive. Usually I make CDRW archives in
> segments,
> > so
> > > >> RA> that retrieval
> > > >> >> is within the same disk.
> > > >>
> > > >> RA> To be honest I think this was the way it was originlly inteded
to
> > be.
> > > >> RA> The whole issue of wrting to CD and CDRW came up long after the
> > PKZIP
> > > >> RA> format was defined.
> > > >>
> > > >> RA> Personnly I still don't understand why the Central Directory
has
> to
> > be
> > > RA> at
> > > >> RA> the end
> > > >> RA> (or last disk) in fornt or onthe first disk would make things
> much
> > > RA> easier.
> > > >> RA> But then again we are restarting the discussion of a new
> format.;-)
> > > >>
> > > >> Would having a central directory on each disk stuff up multi-disk
> > backward
> > > >> compatibility?
> > >
> > > RA> I cannot answer that without going the procedures and maybe do
some
> > testing
> > > RA> But as it is written today, the central directory needs to be one
> and
> > > RA> complete
> > > RA> So putting it on each disk will not always guarantee that you have
> the
> > right
> > > RA> disk
> > > RA> in the reader, and then we end with the same problem
> > >
> > >
> > > RA> This is a major problem with disk spanning if you have several
> > > >> CDRW with data it takes forever to restore a single file but if you
> > have
> > > RA> each
> > > >> disk 'just filled' and do several separate archives the restore
> > function
> > > RA> is very
> > > >> fast.
> > > >>
> > >
> > >
> > >
> > > >> Anyway, having the ability to write fixed size to various disks if
> you
> > > RA> could
> > > >> impliment it without too much ado would be appreciated by me - if
> > anyone
> > > RA> is
> > > >> against it please put your pennyworth in thanks.
> > > >> Alistair+
> > > >>
> > >
> > >
> > > RA> Roger Aelbrecht
> > > RA> http://web.wanadoo.be/driehoeksw
> > >
> > >
> > >
> > >
> > >
> > > --
> > > Regards,
> > > Alistair+
> > >
> > >
> > >
> >
> >
> >
> >
>
>
>
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