Wednesday, 10 June 2009

Need to read a CT scan from an old Magneto-optical disk

Philipp Westebbe from Berlin wrote to me:
“I am working at Rathgen Research Laboratory (National Museums in Berlin) in Germany. I have some valuable old data (computer tomography images) on MOD [Magneto-optical disc – CR] format. I am aware this is not the usual topic of the list, but we cannot think of a better place to start with. I am working on a project using an old MOD (Laser Drive Media LM1200-002) for recording computer tomography images. I'm looking for an old PC and the belonging software with which I can read this old MOD from 1992.”
In a later email, he wrote:
“At the moment I am coordinating the project about the Egyptian Queen Nefertiti bust [see Wikipedia- CR]. 1992 the Charite hospital in Berlin made a CT from the bust to analyse the internal structure. The CT images were saved at that time on a MOD LM 1200-002. The data are unfortunately no longer readable, because the Charite hospital doesn't have the specific computer any more. The only things I have in my research lab are the drive and the MOD with Nefertiti's scan on it. I got over long paths to your email. I am looking for someone who has such a computer with which I can read my old MOD from Nefertiti, and for a possibility to copy this old format into a new digital format. Nevertheless, I hope to get a contact, which helps me to read the old MOD from Nefertiti. It would be very nice if the person who reads this mail could help me handling my problem, or could send the email to someone who is still working with such an old CT system. It is quite difficult to get an old MOD from 1992 back into a common digital format.”
In a third email, he made clear that he has one disk, on which the CT scans are stored, and that the data are regarded as very valuable, as the bust is too fragile to scan again. He didn’t say, but perhaps the importance (and hence the value) of these data is increased by a current controversy over the authenticity of the bust.

Documents from NARA and other places show that the LM1200 disk is 12” Write-Once, Read-Many (WORM) dual-sided media, capable of holding 1 GByte each side. A catalogue from Siemens identifies it as Plasmon (Philips) WORM Media. These media are reputed to have a long life expectancy.

As far as I can tell, this drive will have been part of an embedded computer in the CT machine, although we don’t at this stage know the brand of the CT machine (or the type of embedded computer; many such machines of that vintage would have been “mini-computers” rather than PCs). The UK-based Plasmon PLC bought Philips LMS, the company that produced Philips 12” optical disks and drives, in 1999. It looks like Plasmon failed at the end of last year, and was in its turn bought by Alliance Storage Technologies in the US.

Their technical support points out that reading the data off the disk may not be enough, because of the proprietary formats involved at the time. “Your best bet is to contact a data migration company that has experience with the application that wrote the data or the company that wrote the software. If you have trouble reading the media because of a problem with your drive we may be able to help but there are few parts left for the drive… Sorry to provide such a bleak outlook. Medical companies tend to maintain legacy equipment the longest so there is some hope.”

Nevertheless, before there is a chance of interpreting the data, Phillip needs to get it off the disk. Does anyone know of a contact who could read and interpret such a disk?

1 comment:

  1. It may be worth directing him to the ClassicCmp ( mailing list. Several subscribers offer commercial and voluntary services to recover data from obscure media and obsolete hardware.



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