[iyonix-support] Re: CheckMap problems

Thank you for your reply, Kade. It arrived today (8 April) but I 
gather that others on the Iyonix list saw it much earlier.

In message <47F5F9A7.1050407@xxxxxxxxxxxxxxxx>
          Kade Hansson <kade.hansson@xxxxxxxxxxxxxxxx> wrote:

> ralph_valmai@xxxxxxxxxxxx wrote:
>> I accidently pressed the re-boot button while my Iyonix was booting.
>> Messenger complained and told me to use CheckMap (I *think* it also
>> said that the map was inconsistent but I cannot be sure).
>> 
> I'd say you have a broken directory, not a problem with the map per se.
> The map might have an allocation for a block or two that never got
> claimed by a directory entry, but that's hardly a fatal flaw, and one I
> believe DiscKnight can cope with.
> 
> If you are really worried about this (and its not entirely unjustified),
> and given that you do have a spare (identical) disc, my advice would be
> to move all files to the good disc (where not already present), wipe the
> "bad" one and start again by copying all files back across. There is a
> risk the good disc could go bad during the copy, but you'd have to be
> pretty unlucky. Make sure all apps are closed during the copy-
> particularly Messenger.

After I had sent off the request for help to the list a similar idea 
occured to me. This was to copy everything from HardDisc 4 to 
HardDisc5, then re-initialise or re-format HardDisc 4 and copy all the 
stuff back again. This is probably more drastic (and a wee bit more 
risky) than your suggestion. I think I can find time to try out your 
proposal tomorrow or Thursday.

Do you think that a re-format might be necessary?

>> I then ran CheckMap for the original disc (4) without Messenger on the
>> icon bar. It did run for longer but an identical freeze occurred
>> eventually. Even removing every application off the icon bar did not
>> prevent a freeze from occurring. However DiscKnight declares the disc
>> to be good.
>> 
> I'd trust DiscKnight. However, I don't know if it will detect broken
> directories, which is what I suspect is crashing *CheckMap. It could be
> a bad map (an ID partially written, is one example I could see
> happening), but that would indicate a bug in DiscKnight if it is
> declaring the disc as good.
>> It looks like I do have inconsistent maps on HardDisc4, so how can I
>> get CheckMap to repair whatever damage has been done if running it
>> causes a freeze? Is it possible to ask CheckMap to do a repair without
>> doing a check first? *help CheckMap doesn't give an argument to do
>> this.
>> 
> *CheckMap can only replace the primary map with the secondary map.
> However, due to the way RISC OS writes both maps simultaneously, it is
> unlikely to have any real effect. If one is corrupted, then it is likely
> that both maps are corrupted in the same way.
> 
> I don't have DiskKnight (well, probably a demo) but if anything can help
> you in this situation, it can. Leave *CheckMap alone: it is a very
> optimistic piece of code for something supposedly designed to recover
> from the most dire of situations. It basically assumes the map is good,
> and then proceeds to check its assumption by walking the directory tree.
> If the directory tree or map is broken, it is more likely to lock up
> than give a thumbs down.

It looks as though I shall have to find out how DiscKnight deals with 
map problems.

> 
> At any rate, you'd be wise never to run a disc utility in a Task Window,
> particularly one as arcane and prone to crashing as *CheckMap.

Thanks for the advice. I wasn't aware of that. But it does leave open 
the question of how to find out if the problem is solved doesn't it?

Thanks again,

Ralph

-- 

Ralph & Valmai Stevens
In leafy Epping
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