We have all come across pictures from the last century, sometimes a bit faded and maybe slightly yellow, but normally it is possible to make out the image and possibly work out who or what is in the picture.

The last photo I took was with a digital camera and then viewed on the computer screen. The question to be asked is, if in 100 years time this image file was discovered in a dusty loft, would anybody be able to view it? The issues are in fact very closely related to the article on data interchange a few months ago; namely the issues of medium, file format and data structure.

In the digital camera example, the image starts on a Compact Flash (CF) card and is then loaded onto a PC or possibly a CD-ROM. The image is a compressed JPEG. In 100 years time we would need to read a hard disk, assuming it would still spin, or a CD-ROM just to extract the raw file. Over the past 30 years or so, we have seen many standard media come and go such as 8″ floppy disks, and recently 0.5″ open reel tape is now being phased out. Reading the data structure in theory may be a bit easier, as it is just software, but do not assume anything as it is not easy to read a CP/M Word Star document anymore.

Storing a photo image may not be too important (and it could always be printed out) but the example does highlight the problem of trying to keep information in a format that may be accessed over many years. It is generally accepted that the only way to tackle this problem is to update the whole storage scheme every few years. Thus one needs to look at the media, the file structure, and data structure and update to something that has a long projected life span. As a result any data on open reel tape should now be transcribed onto possibly an LTO. It is worth trying to simplify the data structure at the same time and to make sure that it is not part of a propriety application. For structured records it is best to go for fixed length or delimited records in straight text, and not any packed or binary numbers. Indexing information is normally just used to speed up access, and this does not enhance the value of data. File structure wants to be simple and avoid data compression.

If the above route is planned, there are two significant advantages. The first is that data will be accessible in several years time, and secondly the amount of media required to store the data will be considerably less. As an example an open reel tape stores approx 100MB and an LTO approx 100GB (without compression). Thus 1000 open reel tapes could be stacked onto a single LTO, but preferably duplicated a few times for security reasons.

eMag Solutions can help with transition ranging from the 8″ floppy though open reel tape and often from the lower capacity Exabyte, Dats, and DC600 drives. eMag will also advise on possible data re-structuring. Don’t forget though that all data storage needs reviewing every few years. It is a waste of money to spend money on storage for something that can not be accessed, though if you are in the state, eMag well be able to help.