Future of CDROM, DVD, etc.

[christian thompson]

Yes, there has been a constant evolution (revolution)) in digital archive media: from 9-track tape to the current CDROM. But there are a few factors which most don't know about or appreciate. Despite the evolution from 8 to 5 to 3 inch disks, etc., many organization, such as US Government, were conservative in ARCHIVE medium and did not endorse the intermediate formats. So, while these various disk sizes were common, archive data was still put on 9-track tape. 

But CD-ROM has been accepted as a true archive medium as it has a long shelf live (it does not lose its digital message over time like tape and magnetic disks do, etc.). But most importantly, the new formats are in essentially backward compatable.  A DVD disk is the same physical size, etc., it only has more "tracks" and more "points" to be read. That is, the laser read/write head is of smaller size and more tightly controlled.  So, the ability to read a more "primitive" disk, such as CDROM, is merely a software problem, that is, writing the appropriate driver.  Obviously, a smaller laser read head can always be programmed to recognize a large point, etc.  So, what is driving the technology is smaller read/write lasers, not changes in the physcial size of the medium.  This means that with the appropriate software, one can read the older formats, such as CDROM in a DVD player, etc. And then when you consider that IBM has already announced a new format that uses a read/write in the two or three micron range so that hundreds of gigabytes of data can be stored on a single CDROM disk, one realizes that the 4 ½ inch CDROM disk size will have a long archive life, much longer than ours.

So, I don't worry about the life of a "CDROM" disk format.  This year we will write the Diptera Data Dissemination Disk again in ISSO 9660 format, maybe next year it will be a DVD format, but it will be the same disk in the same plastic Jewel box, etc..  But I am sure that libraries at least will alway have machines which will be able to read the earlier (primitve) formats when CDs are no longer popular, etc.


F. Christian Thompson
Systematic Entomology Lab., USDA
Smithsonian Institution
Washington, D. C. 20560
(202) 382-1800 voice
(202) 786-9422 FAX
cthompso at sel.barc.usda.gov