[Oberon] Reason for 'read pio error' ?

[cglur at onwe.co.za]

Andreas D„rr <andreas.doerr at workingobjects.de> wrote:
> > I have successfully installed Bluebottle on a Dell Inspiron 7500.
> > Currently I use a 5GB partition for Bluebottle. While trying to format a 
> > second 5GB partition with AosFS I got an error '2820' at lba 12991229.
> > Does anyone know what is a typical reason for such an error?
> 
> Pieter wrote:
> I'm not sure why the driver sees this ERR bit, and as you say, modern 
> disks should remap bad sectors automatically.  I'm not sure if they 
> can do this without OS support.  Perhaps the OS is required to retry 
> a failed transfer?  But then a second Partitions.Format should work...
> 
> > The only workaround I currently know is to define a small partition that 
> > includes the conspicuous block. This partition will not be used. Since the 
> > number of partitions is limited this is not a very good workaround :-(
> 
> Unfortunately this is currently the only workaround, since the AosFS
> file system does not handle bad blocks.  What needs to be done is:
> 
n-o formatting (as I remember) prompts "OK" (or not).
I guess it's not actually checking for valid read/write ?  So fast ?

> 1. detect bad blocks in Partitions.Format
> 2. create a file that contains all these bad blocks
> 
> This will ensure that the bad blocks are ignored by the file system.
> Part 2 is file system specific.
> 
> If someone wants to attempt this, I suggest taking the relevant 
> Format code from Partitions.Mod and rewriting it in a new module.

I did similar:
   Copied Partitions.Mod and modified to get:
   CG2Partitions.ShowBlocks IDE<No>#<PtNo>  <1st>  <NoOf> ~
to allow me to find/recover data from a n-o partition.

Since backingUp partitons is currently very tedious, I wondered if
one could backUp between IDE0/1 by having the same size 
for corresponding partitions, and copying blocks n to last, where
n is the first few that have the 'partition linking info' ?
I.e copy the contents and don't mess with the 'house-keeping'.
Is this viable (for say 16 to 64 Mb sizes) ?

PS. as I remember Partitions.Mod also has much undocumented
facilities ?

-- Chris Glur.