Disk archival techniques

[Vintage Computer Festival]

On Tue, 17 May 2005, Jules Richardson wrote:

> > I think the optimum format for doing this isn't a single file, but a
> > collection of files bundled into a single package.  Someone mentioned
> > tar, I think, and zip would work just as well.
>
> The only danger there is that the two become separated over time, but in
> my mind it's an acceptable risk. It's sort of like a librarian losing a
> few volumes from a set of encyclopedia I suppose - something that you'd
> have to be really careless to do.

I have in the past and still completely disagree with this.  If the image
is structured, including the metadata is naturally obvious and
unobstrusive to the data stream.  Having separate metadata invites future
error.

> > I don't think there's any real need to document the physical properties
> > of the media for EVERY disk archived -- there should probably be a
> > repository of 'standard' media types (1541's different-sectors-per-track
> > info, FM vs MFM per track information, etc) plus overrides in the media
> > metadata (uses fat-tracks, is 40 track vs 35, etc).
>
> Now risk of seperation there might well be a problem if there's a single
> copy of some metatdata for more than one disk image. I'd say that each
> 'bundle' forming a disk image (raw data + metadata) needs to totally
> describe that disk...

Correct, and the descriptive metadata to describe the attributes of a
particular medium would take up less than 1K characters, in most cases FAR
less.

-- 

Sellam Ismail                                        Vintage Computer Festival
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International Man of Intrigue and Danger                http://www.vintage.org

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