It looks like the reason you can't find it under the Spectra Logic umbrella is that on March 8, 1999
Spectra Logic sold their backup software and business to Sterling. Then, Sterling Software was acquired by
Computer Associates in March 2000.
Performing a search on CA's site for "Alexandria", shows a number of links refering to their
BrightStor Enterprise Backup v 10.5 product. Interestingly enough, one of the meta keywords in the page source is "Alexandria"
<meta NAME="KEYWORDS" CONTENT="Alexandria..."
So I'm guessing that BrightStor Enterprise Backup is either a replacment for or a rebranding of Alexandria. Call Computer Associates' sales department. I'm sure they'd be happy to talk to you.
Cheers,
Keith