Conference hydra::axp-developer

3088.0. "SIS" by HYDRA::AXPDEVELOPER (Alpha Developer support) Mon Jan 27 1997 08:49

    Company Name :  SIS
    Contact Name :  Myriam Uytterhoeven
    Phone        :  
    Fax          :  ++32-16-234166
    Email        :  [email protected]
    Date/Time in :  27-JAN-1997 08:49:24
    Entered by   :  Simon Cole
    SPE center   :  REO

    Category     :  unix
    OS Version   :  
    System H/W   :  


    Brief Description of Problem:
    -----------------------------

From:	SMTP%"[email protected]" 26-JAN-1997 22:08:08.08
To:	[email protected]
CC:	
Subj:	Tool for reading optical disks

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Date: Mon, 27 Jan 1997 04:05:59 +0100
To: [email protected]
From: Myriam Uytterhoeven <[email protected]>
Subject: Tool for reading optical disks

Dear Msr, Dear Sir,


I need to develop a tool for reading optical WORM discs in a special way.
If I am informed correctly, the group specialized in OSMS is located
in the United states. I hope they can help me.

A client has several optical discs, WORMS, screwed up causing a severe 
loss of data. However, data can never be overwritten on a WORM disc. 
Instead, data are "masked" or made invisible in an "artificial" way.
What probably happened is that the inode on the disc are not correct 
anymore so that the operating system can not see particular files, 
although they are still present on the WORM.

Indeed, when I mount the WORM on an older date, 
for example 1/9/1996, I see the situation of the disc as it was at 
that time. Files which were created after 1/9/1996 are not visible, while 
files "deleted" after 1/9/1996 become visible. In this way I can make
the lost data re-appear. 

Mounting 100 optical disks in the past until I find all data is a 
pretty time consuming task and does not always solve our problem.
Rather, I need to develop a tool for UNIX (3.2C), probably in C 
programming language, which recuperates the data on the WORM. 
I believe this can be done by reading the sectors containing 
information on the location of the file, their position, inodes, ... 

Is there already an utility to perform this task? If not, could I 
receive examples program or routines or even fragments of programs?
If I succeed in developping a good tool, I will make it available.

You can contact me at the following telephone number: +32-3-2855102
at my clients' place. Or, by E-mail.


Thank you very much for your quick response,



Myriam Uytterhoeven
Subscription number: D60743









****************************
Myriam Uytterhoeven

SIS-Consult
Rotspoelstraat 361
3001 Heverlee
Belgium
Tel./Fax. ++32-16-234166
[email protected]
****************************

From:	KZIN::ASAP         "ASAP support" 30-JAN-1997 08:17:12.77
To:	lords::cole
CC:	
Subj:	FWD: note 3088

From:	HYDRA::AXPDEVELOPER "[email protected]"   29-JAN-1997 
22:20:02.72
To:	KZIN::ASAP
CC:	AXPDEVELOPER
Subj:	note 3088

From:	NABETH::alan "Alan Rollow - Dr. File System's Home for Wayward Inodes." 
27-JAN-1997 11:18:41.60
To:	hydra::axpdeveloper
CC:	
Subj:	Re:  FWD: Tool for reading optical disks

I don't know much about optical devices or OSMS, so asking them
directly may be a better choice.  The group handing the drives
has a VAXnotes conference somewhere.  I don't know the hostname,
but the conference name is "OPTICAL".  ASK_SSAG on SSAG may be
a better place to start.

There are three ways to read raw sectors:

o  Install the SCSI CAM Layered Components OP driver and just
   open the raw device and read sectors.  If they have OSMS
   installed, they'll have this driver installed.

o  Write a program using the CAM User Agent to send SCSI Read
   commands.  Difficult, but not impossible.

o  If the particular optical has a switch or mode page setting
   that turns it from an optical device to direct-access device
   use the base systme disk driver.

From:	VBORMC::"[email protected]" "Myriam Uytterhoeven"  2-FEB-1997
17:59:40.18
To:	"Simon Cole 830 4084 - Software Partner Engineering -
[email protected]" <[email protected]>
CC:	
Subj:	Re: Tools for reading optical disk.

Dear Simon,

Thank you for the information. It seems to me that the first of the
possibilites you described is the preferred one. CAM is installed. I started
reading the manual on CAM. If I could have some example programs, or even
fragment on how to read the sectors,  I would be very happy. 

Thank you very much for your help,



Myriam





>There are three ways to read raw sectors:
>
>o  Install the SCSI CAM Layered Components OP driver and just
>   open the raw device and read sectors.  If they have OSMS
>   installed, they'll have this driver installed.
>
>o  Write a program using the CAM User Agent to send SCSI Read
>   commands.  Difficult, but not impossible.
>
>o  If the particular optical has a switch or mode page setting
>   that turns it from an optical device to direct-access device
>   use the base systme disk driver.
>
>
>
>


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% Subject: Re: Tools for reading optical disk.