Though Avid doesn’t officially support this, it is entirely possible to connect your ISIS5000 < 4.6 using the respective ISIS client to your Mac on OS X 10.9, which currently only supports ISIS7000. Update: As of ISIS v4.6 this article is partially obsolete (see Avid KB).
To make it work, you need to have a Mac on which the ISIS client software that corresponds to your ISIS 5000 is installed. From there, copy the following items to a USB stick or network location, ideally you mimic the folder structure of your Mac HD in order to put everything in its appropriate place:
/Applications/AvidISIS (entire folder)
(executable; use Cmd-Shift-G to go to folder)
Next, copy the files to your 10.9 machine’s system drive. You will need to enter admin credentials when modifying the /Library, /sbin, and /System folders.
Next, fire up Terminal to modify the permissions to certain files and folders, because those will very likely be “damaged” during the copying process off the original computer. You will need to enter your admin credentials when doing the following:
sudo chmod -R 0755 /System/Library/Extensions/AvidUnityISIS.kext
sudo chown -R root:wheel /System/Library/Extensions/AvidUnityISIS.kext
sudo chmod -R 0755 /sbin/mount_AvidUnityISIS
sudo chown -R root:wheel /sbin/mount_AvidUnityISIS
sudo chmod -R 0755 /Library/StartupItems/AvidUnityISIS
sudo chown -R root:wheel /Library/StartupItems/AvidUnityISIS
This will set the files and folders to the proper permissions. However, I strongly recommend verifying your permissions with Apple’s Disc Utility, because on one machine where I did this there was one admin user who couldn’t mount any of the ISIS workspaces (some error on the /Volumes folder), after repairing permissions everything was fine. And it is vital to perform these steps in this exact order, if you leave them out it won’t work.
Reboot your Mac, then you should be able to launch the ISIS client, and after properly setting up your connections you should be able to mount workspaces as usual.
Please keep in mind that this is a hack; Avid does not provide support for any problem that might occur because of this, neither do I. You’re doing this at your own risk. Make a backup copy before working on critical data or projects.