On Wed, 11 Aug 2004, Steve Thatcher wrote:
I did not say it was the primary purpose. The data
blocks work hand in
hand with the formatting information. It is fine to make a standard
extensible, but what good does it do if the (I hate the use the word)
file can't be gotten without jumping through major hoops because how the
data was stored in the image file wasn't extended out to make blocks. If
you have to iterate through formatting information to get data then you
have to be intimately familiar with the disk format in use. It means any
GENERAL utility to read an image file for data access will have to KNOW
about all machione supported rather than just getting some type of data
identifier and reading the data out.
I think part of the problem here is that the word file is being taken
literally to mean filename, size, data, etc. I am using in the context
of a block of data. It has NOTHING to do with how the data is on the
disk, where it is stored, the recording format, etc. It is just a piece
of data...
One way to resolve this is to put comments in the image file pointing out
where a block of data ("file") starts and how long it is. This can also
be built into the spec as a tag, rather than relying on human readable
comments to effect this.
I am talking about two separate sections inside the
same image file. One
of the sections contains data blocks. The other has specific formatting
information and POINTS to the data in the data blocks. A utility program
could then SIMPLY get any type of data out of the image file without the
utility being out of date as soon as someone added a new physical
format.
The spec COULD be made to allow for this, and I don't see a reason why
not. It's just an organizational attribute. I'll add it to the notes.
--
Sellam Ismail Vintage Computer Festival
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