[Lazarus] bad luck

[Mark Morgan Lloyd]

Marc Santhoff wrote:

>> Good /God/ man, is that all? I opened this expecting to find that a 
>> member of the community was in real trouble (frankly, the sort of thing 
>> I was almost in over the last week).
> 
> It's enough. Costs me hour of frustrating work recreating anything,
> doing nothing fruitful. Moreover I'm sitting on a time bomb, because I
> really do not know, what other files may have been damaged. Last time
> this happened I had some failures in other software that was detected
> weeks(!) after the incident.

I'm currently using an elderly Toughbook, because something else in my 
workroom took the power out sufficiently viciously that the lights 
flickered 300m away and I've been too busy to go around everything with 
a PAT tester to find the culprit. And that's been the least of the 
problems over the last few days... curiously, some of them have been 
caused by my strident insistence that colleagues should exploit our 
central servers (which have RAID etc.) rather than relying on the aging 
hardware and OSes under their desks.

> So, what know? Taken seriously I have to restore the complete system and
> data from backup.
> 
> Seems I deserved some trouble because I'm not running development tools
> on a dedicated machine or inside a virtual environment...
> 
>> What OS are you running, and how much privilege had you given yourself? 
> 
> FreeBSD 9, simple user having sudo privilges but nothing run as root or
> by sudo. The session was the same as ever - besides Lazarus.
> 
>> Frankly, I think the suggestion that Lazarus /might/ have caused a 
>> system crash is more serious than the discovery that a system crash 
>> probably corrupted files.
> 
> You're right. That's why I told the story as introduction.
> 
> What I asked for is help locating and understanding Lazarus' file
> handling. Some standard errors like unneccessarily holding files open
> when not in use can be avoided easily.

Yes, that's a good point although there's also issues about whether the 
underlying OS, computer and attached peripherals really are syncing data 
as reliably as expected. The bottom line- of which I was reminded 
regularly during my unhappy time running OS/2- is that an OS will 
attempt to preserve the integrity of its filesystems but makes no 
guarantee about individual files, and that there's no way of determining 
that a file's been sacrificed. It's interesting to speculate on whether 
something like Lazarus could benefit from storing projects onto a 
transaction-aware database server rather than as individual files.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]