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At the University of Pennsylvania Cancer Center Flow Cytometry and Cell
Sorter Shared Resource, we have had the opportunity to realize great
benefit from archiving our data to CD-ROM. Below, I hope you will find
a useful, brief description of pertinent facts. Please feel free to
respond with any questions or comments.
On a monthly basis, we backup all data that was generated on the
table-top machines and sorters. We make backups to a 1GB hard drive
through the course of the month, and cut CDs at the end of each month.
Obviously, the number of CDs that you will need will depend mostly on
the volume of data generated per month. For what it's worth, each CD
can hold either 550MB or 650 MB. The slower you write the CD, the more
you can fit on it.
We have a Pinnacle MICRO RCD-5040. The current price for one (in the
United States) is around $1300. It has a 4x/2x-read/write which allows
you to save a little time when it comes to cutting CDs. Remember, a CD
can hold a maximum of 74 minutes of real-time audio. In other words, it
takes 74 min to cut a whole CD, start to finish. 2x speed, literally,
reduces this time in one-half and results in 37 minutes of writing. For
the benefit of higher speeds, you must pay the price of lower volume -
hence, the 550MB and 650MB formats for the same CD. At a cost of
approx. US$8/blank CD, the medium seems to be the most cost-effective,
reliable, and phsyically smallest available. With the popularity of
CD-ROM readers bundled with modern machines, the CD-ROM eliminates the
worries of having to archive on a medium which is easy to support.
Software tends to be bundled with the CD-wrting mechanism, so additional
purchases are not necessary. The CD has a couple of distinct
disadvantages, however, which I would like to briefly point out.
* The computer that has the CD-writing mechanism will have to be
dedicated to the task of writing CDs. You cannot do anything else for
~1 hour.
* There is quite a bit of preparation required along the lines of hard
drive maintenance: defragmenting, optimization, etc...but this is a
once-a-month process.
Comparisons to other machines:
MAGNETO-OPTICALS - were decided against in our facility primarily based
on cost reasons as well as the issue of utility. That is, if we are the
only ones who own a magneto-optical drive, we might find ourselves doing
more work than we bargained for; whereas, with a CD, we can just hand
someone the CD and ask them to please return it (for safety precautions,
we do have a hermetically sealed OFFICE copy). There is no practical
need for such large volumes on each individual disk.
HARD DRIVES (RAID, etc.) - were avoided because one of the primary goals
was to avoid the infinitely-fallible magnetic media. The magnetic media
can be trusted for a while, but with repeated use, accidents (are
accidents really accidents?) happen. Certainly, for a fixed volume of
non-removable media, the hard drives (especially the newer Iomega and
SyQuest media) are cheap. But, you can never worry too much about those
!@#$# crashes. The slower media (tape, DAT, etc.) were not considered
due to speed, bullk, and cost reasons.
OTHER CD-ROM writers - were considered. I don't really want to turn
this into an advertisement for these drives. Suffice it to say that
there are quite a few available on the market. The reviews in Macintosh
magazines tend to be right-on-target...and we've been happy enough with
the one we have. Considerations should include: price, service,
software bundles, and even manufacturer's reputation...
Hope this helps! Best of luck.
Sincerely,
Seong-Joo Jeong
Phone: 215-898-3528
FAX: 215-898-4227
email: sjjeong@mail.med.upenn.edu
University of Pennsylvania Cancer Center
Flow Cytometry and Cell Sorter Shared Resource
297 John Morgan Building
3620 Hamilton Walk
Philadelphia, PA 19104-6082
(flowcyto@mail.med.upenn.edu, http://mail.med.upenn.edu/~flowcyto -
under construction)
Jonni S. Moore, Ph. D., Director
C. H. (Hank) Pletcher, Jr., M. C. I., Technical Director
Seong-Joo Jeong, Technician
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CD-ROM Vol 3 was produced by Monica M. Shively and other staff at the
Purdue University Cytometry Laboratories and distributed free of charge
as an educational service to the cytometry community.
If you have any comments please direct them to
Dr. J. Paul Robinson, Professor & Director,
PUCL, Purdue University, West Lafayette, IN 47907.
Phone: (765)-494-0757;
FAX(765) 494-0517;
Web