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The Icon Bar: General: Magazine coverdisk preservation
 
  Magazine coverdisk preservation
  pwx (13:03 11/3/2013)
  swirlythingy (16:11 11/3/2013)
    CJE (12:17 12/3/2013)
    pwx (12:48 12/3/2013)
  filecore (08:03 12/3/2013)
    pwx (12:58 12/3/2013)
  sirbod (19:35 12/3/2013)
 
Philip Webster Message #122020, posted by pwx at 13:03, 11/3/2013
Member
Posts: 227
Hi,
I'm currently imaging my collection of floppies, which includes a large number of Archimedes World, Micro User, Acorn User and Acorn Computing coverdisks and subscriber disks.

Obviously these are all under copyright, so I'm not distributing the image files for now.

From a strictly technical perspective - is there any advantage to using ADFFS over straight ADF images for disks that have no copy protection?

I've noticed that some coverdisks in my collection (acquired from other people) have odd datestamps - some months later than the date on the label. I've assumed that these are back issue coverdisks that have been produced by copying files rather than imaging. They're clearly wrong, and fortunately I have non-back issue copies of some coverdisks for magazines I subscribed to.

Does anyone have an alternative explanation for these odd dates?


Phil
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Martin Bazley Message #122022, posted by swirlythingy at 16:11, 11/3/2013, in reply to message #122020

Posts: 460
I've noticed that some coverdisks in my collection (acquired from other people) have odd datestamps - some months later than the date on the label. I've assumed that these are back issue coverdisks that have been produced by copying files rather than imaging.
Copying files preserves the original datestamp, and doesn't stamp the copies with the current date. It seems more likely that the files have been modified, especially as you cannot vouch for the discs' sources.

Some applications (especially of that era) will automatically write new copies of e.g. high scores or options files inside themselves when quit. It could be that even running any of the applications on that disc could be enough to 'corrupt' (or at least 'un-preserve') it.
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Jason Togneri Message #122024, posted by filecore at 08:03, 12/3/2013, in reply to message #122020

Posts: 3867
From a strictly technical perspective - is there any advantage to using ADFFS over straight ADF images for disks that have no copy protection?
Read through the ADFFS thread at http://www.iconbar.com/forums/viewthread.php?threadid=11846&page=1#119561
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Chris Evans Message #122026, posted by CJE at 12:17, 12/3/2013, in reply to message #122022
CJE Micros chap
Posts: 198
I've noticed that some coverdisks in my collection (acquired from other people) have odd datestamps - some months later than the date on the label. I've assumed that these are back issue coverdisks that have been produced by copying files rather than imaging.
Copying files preserves the original datestamp, and doesn't stamp the copies with the current date.
True for files but not necessarily directories.
RISC OS 5 keeps directories date stamp but RISC OS 4 doesn't unless 'interactive file copying' is turned off.
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Philip Webster Message #122027, posted by pwx at 12:48, 12/3/2013, in reply to message #122022
Member
Posts: 227

Some applications (especially of that era) will automatically write new copies of e.g. high scores or options files inside themselves when quit. It could be that even running any of the applications on that disc could be enough to 'corrupt' (or at least 'un-preserve') it.
They're magazine coverdisks though - always archived using ArcFS, with a read-only version of ArcFS included on the disk. The datestamps are all within minutes of each other, as would be expected if someone had copied the files onto the disk to produce a master for duplication.

My current guess is that back issue coverdisks weren't imaged from the original master - the files were copies by hand onto a disk.

What this means is that back issue coverdisks aren't suitable for preservation, as the datestamps aren't authentic.
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Philip Webster Message #122028, posted by pwx at 12:58, 12/3/2013, in reply to message #122024
Member
Posts: 227
From a strictly technical perspective - is there any advantage to using ADFFS over straight ADF images for disks that have no copy protection?
Read through the ADFFS thread at http://www.iconbar.com/forums/viewthread.php?threadid=11846&page=1#119561
I've been following that thread for a while now. Having just re-read it, there seems to be no advantage for non-protected floppies such as magazine coverdisks.

This is a relief, considering how many I've imaged so far!
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Jon Abbott Message #122035, posted by sirbod at 19:35, 12/3/2013, in reply to message #122020
Member
Posts: 563
From a strictly technical perspective - is there any advantage to using ADFFS over straight ADF images for disks that have no copy protection?
The advantages of JFD over ADF aren't really relevant to magazine cover discs, but are:

- Metadata is stored in the image. CPU / OS compatibility, frame rate, settings to preserve CMOS / Modules etc.
- They're compressed and can store just the sectors with data on
- You can add a boot script (used to fix issues with loaders etc)
- Will eventually allow for delta writes (useful where floppies are patched so the original is kept intact)
- Disc protection remains intact

For magazine cover discs, ADF is perfectly acceptable and probably preferable due to the convoluted recording process for JFD's. I will eventually add an imaging option to ADFFS, to grab floppies straight to JFD and ADF, it's on the list of things to do.

If you want to send me scans of the relevant magazine pages / floppy images and scans I'll start adding them to the archive.

[Edited by sirbod at 05:15, 13/3/2013]
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The Icon Bar: General: Magazine coverdisk preservation