Jerome Fine replies: I have been using these magneto optical media for about 10 years, on and off - mostly OFF since I first set up a system for a customer in 1990. At that time, there were the newest system available and had just managed to shift to RW media as opposed to WORM media that I had used a few years before that. The Sony EXTERNAL version is the Sony SMO S-501. Over the years, larger and still larger drives and media have become available with media that now holds about 5 GBytes. I can't remember the media part numbers, but as Roger stated, there are two types - 512 byte per sector media and 1024 byte per sector media. MOST of the time, I use ONLY the 512 byte per sector media since I always have in mind that I want the media to be readable on both my real DEC PDP-11 hardware (CQD 220/TM host adapter) plus using a PC with Windows 98 SE and Ersatz-11 with BOTH systems running RT-11 (what else with an RT-11 addict use?). BUT, while the software and firmware on the PDP-11 is unable to read the 1024 byte per sector media, on the PC that was not a problem the last time I tried it with Ersatz-11. But since my experience is EXTREMELY limited with the 1024 byte per sector media, I can't say for sure that it will always work. The key seems to be that under Ersatz-11, I am able to use the 1024 byte per sector media as if it is actually 512 bytes per sector, but exactly how that is managed I have NO idea. I just did a few copies this week, so my Sony SMO S-501 seems up and running. On eBay, the Sony SMO S-501 drives seems to be available only rarely. When they are available, the price is rarely over $ US 10, so the shipping will cost you more. http://search.ebay.com/search/search.dll?MfcISAPICommand=GetResult&ht=1… The REO-650 uses a Sony C-501 controller and Sony D-501 drive, but the SCSI cable connection at the back does not daisy chain correctly, so more than one drive is usually not possible. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2745657616&categ… The Sony D-501 drive by itself requires the Sony C-501 controller between the D-501 drive and the 50 pin connection to the host adapter. In addition, the shipping charges also include hidden handling charges. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2746152827&categ… Are these going to be the ONLY time you will be using the magneto optical media? If so, buying a magneto optical drive and getting it to work might be more difficult than having someone recover the files for you. How many of the magneto optical media do you have? Which operating system was used to write the files? Sincerely yours, Jerome Fine -- If you attempted to send a reply and the original e-mail address has been discontinued due a high volume of junk e-mail, then the semi-permanent e-mail address can be obtained by replacing the four characters preceding the 'at' with the four digits of the current year.