Defects on ADFS floppies

on-topic acorn-related discussions not covered by the other forums
Post Reply
bjn
Posts: 41
Joined: Wed May 06, 2020 4:24 am
Location: Vancouver, BC
Contact:

Defects on ADFS floppies

Post by bjn » Fri May 22, 2020 1:19 pm

If...

- a "verify" operation finds defects
- they're all in the last few pixels of the progress bar
- the "free" dialogue says there's some free space
- all files happily copy from the floppy to the hard drive

are the defects likely in free space? Is everything likely fine?

Could the defects even be part of some fancy copy protection? ("Attempt to read sector x; if it succeeds, then this isn't a legit copy" -- I've heard of stuff like this being done on Amiga games or similar.)

User avatar
danielj
Posts: 8182
Joined: Thu Oct 02, 2008 5:51 pm
Location: Manchester
Contact:

Re: Defects on ADFS floppies

Post by danielj » Fri May 22, 2020 1:24 pm

If you do a *MAP on the floppy it should say where the free space is (but it's likely to be towards the end!) - if you didn't get an error when copying you should be fine.

Certainly there are a number of varieties of copy protection that'd cause a disk to fail to verify - and quite often these are on high numbered tracks. If this is commercial software I'd suspect copy protection. Give an example?

d.

bjn
Posts: 41
Joined: Wed May 06, 2020 4:24 am
Location: Vancouver, BC
Contact:

Re: Defects on ADFS floppies

Post by bjn » Fri May 22, 2020 2:35 pm

danielj wrote:
Fri May 22, 2020 1:24 pm
If you do a *MAP on the floppy it should say where the free space is (but it's likely to be towards the end!) - if you didn't get an error when copying you should be fine.
Excellent, thanks. I'll give that a try next time I come across such a disk.
Certainly there are a number of varieties of copy protection that'd cause a disk to fail to verify - and quite often these are on high numbered tracks. If this is commercial software I'd suspect copy protection. Give an example?
The one which prompted me to ask was the game Magic Pockets.

User avatar
danielj
Posts: 8182
Joined: Thu Oct 02, 2008 5:51 pm
Location: Manchester
Contact:

Re: Defects on ADFS floppies

Post by danielj » Fri May 22, 2020 3:13 pm

Games, it'll probably be copy protection assuming the game itself appears to work ok...

User avatar
geraldholdsworth
Posts: 627
Joined: Tue Nov 04, 2014 9:42 pm
Location: Inverness, Scotland
Contact:

Re: Defects on ADFS floppies

Post by geraldholdsworth » Fri May 22, 2020 5:17 pm

bjn wrote:
Fri May 22, 2020 1:19 pm
Could the defects even be part of some fancy copy protection? ("Attempt to read sector x; if it succeeds, then this isn't a legit copy" -- I've heard of stuff like this being done on Amiga games or similar.)
EGO: Repton 4 on the Archimedes (and later on, the new version of Archimedes Repton 3) had this protection method. Easy to bypass too (there's a patch on the Repton Resource Page website for both games).
Gerald Holdsworth
Repton Resource Page
www.reptonresourcepage.co.uk

Post Reply

Return to “general”