Dynamic Mental Representations	Freyd Dynamics Lab File Saving and Sharing in the Lab	Betrayal Trauma

The dynamics lab has lots of computers -- Macs, PCs, and a linux file server (dynamic.uoregon.edu). That means there are lots of ways to share files. Here are a few:

General Notes

Reasons for file saving

• You MUST back up your data. Don't ever leave the only copy of your research on a computer in the lab or the dynamic "share" directory -- someone is sure to delete it accidentally, or Straub will burn down or something.
• You often need to share your data with Jennifer or with other lab members.
• You may want to move your data between lab and home.
• You need to archive your data when your experiment is done. Plan to give Jennifer a copy of all datasets generated in the lab before you graduate, including documentation. Check with her to find out exactly what she wants; if your data includes sensitive personal information it may be necessary to sanitize it before archival.

It's essential that you back up all experimental data to at least 2 places. That should include putting one copy on dynamic as well as maintaining your own backup on floppy or CD or a flash drive.

File sizes

To give you a rough idea of the typical amount of space various kinds of file take (all numbers are in MB i.e. megabytes):

As a general rule, simple text (including raw data) takes very little space. Images, executable programs, and some specialized file formats take a lot. A scanned document takes much more space than a PDF file created by the publisher from editable text.

Different storage media have different limits:

Using ZIP drives

We still have a few old 100MB Iomega ZIP drives. Those are the blue boxes next to the computers. You can use a ZIP disk for backup or for file transfer. Just insert it into the drive, and an icon for it will appear on the desktop. ZIP drives are obsolete technology. We keep them around to be able to read ZIP disks from the 1990s.

We also have a few other obsolete technologies. If you need to retrieve data from some odd media, check with JQ.

Using floppy drives

Most of our computers have floppy drives, so you can move files between them on floppies. On the other hand, floppies are an even older technology than ZIP disks, and each floppy holds much less data -- about 1.4MB.

Issues with floppies are similar to those with ZIP disks. Modern computers are increasingly being sold without floppy drives, etc. However, floppies are a more reliable technology than ZIP disks. Floppies are not a very good choice for backup any more since they don't hold much data and are becoming increasingly hard to keep track of. If you do use a floppy for backup, make very sure to label it!

Floppies are an ok choice for moving small files between computers, either in the lab or between lab and home (unless you have a modern computer at home that lacks a floppy drive). If you create a floppy on a Mac for use on a PC, make sure you format it as a PC disk. That's "DOS 1.4MB" or somesuch.

Using CD-RW disks

A couple of the computers in the lab (currently in 456 and 457) have CD drives that can write CDs. You may also have a CD-RW drive on your own PC. It's a good choice for making backup copies of large data sets. A single CD can hold up to about 700 MB of data. Writable CDs come in a variety of formats, including CD-R (write-once), and CD-RW (erasable, re-recordable).

Once concern with CD-RW disks is that the lifetime of such CDs is probably fairly short -- perhaps less than 5 years -- particularly if they are exposed to heat or direct sunlight. So don't plan on using CD-RW for long term storage. CD-R disks are likely to last longer, but still only 10 to 25 years. And 25 years from now it will be as hard to find a computer with a CD drive as it is today to find a computer with a ZIP or tape drive.

We currently recommend that when you are finished with an experiment you burn a copy of all of the experimental materials to CD, carefully label the CD, and keep it as one of your multiple backup copies.

Many modern computers can read and write DVDs, which hold much more data, but have similar lifetimes to CDs. We're not currently using DVDs for data storage in the dynamics lab.

Using USB Flash drives

USB flash drives (sometimes called "keychain" drives or "thumb" drives) are becoming very popular. Just plug it into a USB port on your computer and use it like a floppy drive. When you're done, click the

USB flash drives hold between 16MB and 4GB depending on cost. These days you can buy a 256MB flash drive for under $20.

USB flash drives are quite durable; for instance, I've accidentally washed mine in the laundry several times. However, they. have a limited number of "writes", probably in the 100,000 range.

Using dynamic.uoregon.edu

You can use dynamic either for file backup or for sharing files with other people in the lab. You can reasonably store up to about 1,000 MB of files on dynamic; if you need to store more than that contact JQ.

When you log in to a lab PC, you should automatically have 2 “disks” listed in your My Computer folder that are really parts of dynamic --   a personal disk (H:) that corresponds to your dynamic home directory, and a “share” disk (S:) that is shared by everyone in the lab.  If you don’t see these disks, try using “Run” on the Start menu and typing “\\dynamic”.  Once you’re connected to dynamic you can then drag and drop files from your PC to the dynamic disk.

You can manage your personal disk however you want, and can expect that it is fairly secure. The "share" disk is quite public -- anyone in the lab can view or change it. So use it for data exchange, but don't trust it as a place to back up your data or a place to store confidential subject information.

You can transfer files to and from Dynamic using SFTP rather than windows shares. This should work from your own Mac or PC as well as from lab machines. On a PC, the program will typically be found on the Start menu and called "SSH Secure File Tranfer Client." On a Mac you'll typically use Fugu, Fetch, or Cyberduck. You can get file transfer programs from the DuckWare CD.

Using E-mail

Perhaps the simplest way to back up files is to e-mail them as attachments. You're limited in the amount of disk space you have for your inbox, and antivirus software will sometimes block or change suspicious email. But otherwise it's often a convenient way to make a backup copy of important files.

last update 10-Mar-2007 jqj@darkwing.uoregon.edu