[fpc-other] disk "glasses"

[duilio foschi]

>but having two or more applications that concurrently write to a single file is a bad(TM) idea

all operating systems and all db services like VirtualBox, Firebird
etc allow that.

The product I look for must be smart enough :)

Thank you
Duilio

2014-08-13 7:42 GMT+02:00 Sven Barth <pascaldragon at googlemail.com>:
> On 12.08.2014 22:56, duilio foschi wrote:
>>
>> I successfully use TrueCrypt in order to protect my source code.
>>
>> TrueCrypt creates a password protected crypted disk in my PC.
>>
>> I can freely leave my PC unattended: nobody will be able to steal my code.
>>
>> However when my PC is connected to a net, I cannot be so confident.
>>
>> In fact when the crypted disk is mounted by windows, everybody
>> connected to my PC can read (and possibly steal) disk data.
>>
>> I wonder if some software product X exists where the a crypted disk is
>> NOT mounted by the OS but _by the application_
>>
>> 2 applications using X should be able to concurrently read/write dato
>> from/to the crypted disk.
>>
>> Any application not using X should see only a fixed size (2GB?) file.
>>
>> Does this product exist ?
>>
>> It should be possible to use it from a pascal or delphi application.
>
>
> In theory something like this could exist (I'm not aware of anything for
> TrueCrypt protected files), but having two or more applications that
> concurrently write to a single file is a bad(TM) idea. Imagine both
> applications want to write to the end of the file at the same time. Which
> application's content will then be in the file? Maybe that of the first one.
> Maybe that of the second one. Maybe a mix of both. Especially in the last
> case you can consider the file corrupted. If two or more applications should
> access a file in a writeable manner they should go trough a third "service"
> which controls accesses and writes to the file (like is usually done with
> e.g. databases). And simply spoken the OS is such a kind of service (though
> its not running as a separate process per se). Another possiblity would be
> to have a real service...
>
> A little bit more on the topic of "world writable files":
> http://blogs.msdn.com/b/oldnewthing/archive/2004/11/22/267890.aspx
>
> Regards,
> Sven
>
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