[Info-vax] analyze/disk errors

[David Froble]

Simon Clubley wrote:
> On 2013-12-06, Stephen Hoffman <seaohveh at hoffmanlabs.invalid> wrote:
>> On 2013-12-06 06:19:40 +0000, Paul Sture said:
>>
>>> Popcorn anyone?
>> Some folks are just good choices for quality, documentation and testing 
>> projects.  Some folks can find and identify the darndest bugs, and 
>> pursue them with gusto.    As was mentioned upthread and in an earlier 
>> era, I'd be working to offer access to beta software to these folks, if 
>> not them to the testing team wasn't on the table,  (Folks often 
>> underestimate the value of the ability to break stuff; it's a skill.)
>>
> 
> The problem with us programmers is that we tend to have highly structured
> and boolean logic type mindsets and sometimes we need people who don't
> have that type of mindset to break our code. :-)
> 
>> It never would have occurred to me to try to "repair" BADBLK.SYS here, 
>> nor apparently did this thought occur to whoever was testing the 
>> ANALYZE /DISK tool.  (Unfortunately, disk errors are like other 
>> hardware errors; they seldom perform as expected and when desired.)
>>
> 
> Does analyze/disk check the FIDs on all the reserved files ?
> 
> Obviously, that's a bit meaningless for, say, 000000.dir, but what about
> some of the other FIDs ?
> 
>> Which reminds me: might anyone have a stash of bad 2.5" SFF SAS or SATA 
>> disks in a drawer, and that they might be willing to part with a few?  
>> I'm looking at hacking around in the area of device errors, and might 
>> be looking for some bad disks for error-management "target practice".  
>> (Might end up reposting this part separately.)
>>
> 
> Unfortunately no, but you have just brought back some memories. :-)
> 
> Back when I was writing my ODS-2 reader, I used to have a bunch of floppy
> disks with bad sectors to see how VMS handled them.
> 
> I don't know if it's just me, but I think disk failure patterns have changed.
> Back in the 1990s, I did see disks with bad sectors developing over time,
> but these days, I can only think of one disk over the last 5 years or so
> which developed bad sectors while continuing to stay online.
> 
> Most of the time these days the disks I have experience with either start
> to fail by dropping offline and then maybe comes back online after a power
> cycle before dropping off again, or just outright fail with no warning.
> 
> Simon.
> 

As mentioned earlier, while back in the day the file system handled bad 
blocks, thus BADBLK.*, today's disks handle them transparently.  That 
part of the VMS filesystem just isn't needed anymore.

I also would never have tried to mess with BADBLK as a file, because it 
really isn't a file, it's part of the structure placed on a disk that 
the ODS-* file systems require.

Yeah, get Steve those bad disks, don't know how else to test for bad disks.