dan@rna.UUCP (Dan Ts'o) (01/11/90)
What is the current feeling and experience about erasable optical ? It seems that Sony has the most market visibility. What are people's experience with it, particularly on MVAX/Ultrix and SUN ? Is it solid, reliable, not too slow ? Other comments positive and negative ? Thanks. Please email responses. Cheers, Dan Ts'o 212-570-7671 Dept. Neurobiology dan@rna.rockefeller.edu Rockefeller Univ. ...cmcl2!rna!dan 1230 York Ave. rna!dan@nyu.edu NY, NY 10021 tso@rockefeller.arpa tso@rockvax.bitnet PS: We've had good luck with WORM drives and the TenX-OCU, which makes a WORM look like a R/W disk. At $100 for 800Mb, its pretty good. Cheap, too (< $3500).
dan@rna.UUCP (Dan Ts'o) (01/12/90)
In article <970@rna.UUCP> dan@rna.UUCP (Dan Ts'o) writes: >> >> What is the current feeling and experience about erasable optical ? >>It seems that Sony has the most market visibility. What are people's >>experience with it, particularly on MVAX/Ultrix and SUN ? Is it solid, >>reliable, not too slow ? Other comments positive and negative ? >> Thanks. Please email responses. >>PS: We've had good luck with WORM drives and the TenX-OCU, which makes a >>WORM look like a R/W disk. At $100 for 800Mb, its pretty good. Cheap, too >>(< $3500). > >What worm drive do you use? Whats a TenX-OCU? > >I am looking into getting a WORM drive for storing data, and am leaning >toward delta microsystems. Are you really interested in WORM or perhaps optical R/W (MO) ? My current (probably incomplete) analysis follows (I'm open to new opinions and information...): The obvious: WORM is write-once, MO is read-write, like a regular disk. The goodness/badness of this major difference is highly application dependent. For us, the major use of the optical drive is primarily archival, but requiring rapid random access (magtape need not apply...). For this application, write-once is perfectly fine and even slightly preferable. Beyond this point, WORM has several (potential) advantages: - Cheaper media. A Maxtor RXT-800S (we have one) uses 800Mb cartridges that cost $100. I believe Sony MO 600Mb cartridges cost $250. - Cheaper drives. I believe WORM drives usually cost 50% less than MO drives. (no?) - Potentially longer written media life. I think WORM data is certified for > 10 years. BTW, is MO affected by magnetic fields ? - Although at the 5 1/4" form factor, the capacities are similar, at least presently, if you're willing to spend for the 12" form factor ($15-20K), WORM offers higher capacity (>2Gb per cartridge). I'm sure this will change. A major disadvantage of WORM has been that its write-once properties usally makes it incompatible with existing disk device drivers. Usually either a special device driver that either makes the WORM look like a tape (YUCK!) or have a special internal format to support R/W operations, or special programs to archive (copy in/out) from the WORM (thus, not allowing standard OS file manipulation). HOWEVER, this is where the TenX-OCU comes in. It is a hardware (SCSI) box that replaces the need for a special device driver by sitting in between the WORM drive and the host SCSI adapter and allowing the host to think that a real R/W drive is out there. It does do this by creating a special internal filesystem (actually sector-system) format on the media. It includes a cache to prevent too many useless (and wasteful) sector writing and does data compression to reclaim more virtual free space. Of course it cannot ultimately hide the fact that a write-once device is out there. But it is very good (don't try using the TenX/WORM for swap space, though). End of ad: you can reach TenX at 800-922-9050 or 512-346-8360. Another semi-advantage of MO would appear to be market stability. It (to me) looks like MO is here to stay because most people really want R/W disks. The need for archival storage that is random access appears to be a much smaller market. I don't recall much about Delta microsystem's optical drives. But if you really want WORM, I personally would stay away from special software and device drivers. I think for WORM, running on UNIX (or DOS), this means something like the TenX OCU... Cheers, Dan Ts'o 212-570-7671 Dept. Neurobiology dan@rna.rockefeller.edu Rockefeller Univ. ...cmcl2!rna!dan 1230 York Ave. rna!dan@nyu.edu NY, NY 10021 tso@rockefeller.arpa tso@rockvax.bitnet