Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: nyu notesfiles V1.1 4/1/84; site rna.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!zehntel!hplabs!hpda!fortune!amdcad!decwrl!decvax!bellcore!allegra!mit-eddie!godot!harvard!seismo!cmcl2!rna!dan From: dan@rna.UUCP Newsgroups: net.periphs Subject: Re: 6250 tape drive experience ?? Message-ID: <9900003@rna.UUCP> Date: Thu, 17-Jan-85 17:27:00 EST Article-I.D.: rna.9900003 Posted: Thu Jan 17 17:27:00 1985 Date-Received: Tue, 22-Jan-85 03:49:08 EST References: <177@hsi.UUCP> Lines: 70 Nf-ID: #R:hsi:-17700:rna:9900003:000:4275 Nf-From: rna!dan Jan 16 17:27:00 1985 > We're looking for a modestly priced ($10K - $20K) 6250 bpi tape system. > Talking to Emulex they have the Cipher M990/M991 CacheTape which streams > at 125 ips with a 128 Kbyte cache for around $13K. They also have the > Kennedy 9400 which is a standard Kennedy start/stop at 45 ips for > 6250 or 75 ips at 800/1600 for around $17K. Both will interface through > the Emulex TC7000 Massbus controller to our 11/785 under 4.2 BSD. > (The prices above include the TC7000.) > > My questions are: has anyone had any experience with either of these ?? > Any other recommendations ?? Do you really think that the Cipher > with 128 Kbytes of cache will ever stream on a 785 ?? (We don't want to > make any kernel changes to have the drive stream.) Thanks. > We have two Kennedy 9400's, and are (somewhat) aware of the rest of the market, including the Cipher M991 and the STC2920 (there are also drives manufactured by Telex and CDC that I know less about, but they're quite new). The Kennedy now performs quite well. I couldn't say that six months ago. They had a lot of initial problems with that product. However it is now quite solid. One problem which few people know about is that the Kennedy as it comes does not include enough buffer RAM to allow DMA's of greater than about 15kbytes (that is no tape records larger than 15kb). One can add more RAM buffer easily to allow the maximum the Unibus controllers support (65kb). A tiny additional advantage of the Kennedy is that it also includes 800bpi. The STC2920 was a more reliable product from the start, had earlier deliveries and costs a full $2000 less than the Kennedy. It also uses VLSI and more state of the art technology which is quite impressive. However, last I heard, the STC was only available with the STC tape interface, not with the more prevalent Pertec interface. This fact then limits the controllers which can operate the STC. I believe currently the Wesper TDIII (and IV), the Aviv and System Industries are the controllers which can operate the STC. STC did promise to later produce a Pertec interface for their drive. Secondly, of course, STC is not doing well, financially. Also, only a few vendors are willing to service this drive, including Aviv and SI. Many more service vendors are willing to service the Kennedy, including DEC (who services our drive). The Cipher is a very new product. Delivery times are not good and there are reportedly a few bugs which remain in the drive. I have a Cipher M891 which I reluctantly got because of price. I simple hate the autoloading mechanism of the drive. In addition, some of the mechanics are a bit fragile and we have had to replace a particular plastic part in the drive which undergoes much stress. I believe the M991 to be very similar to the M891 and would only recommend it because its price is quite good. I haven't gotten it to stream continuously, but it should be possible (perhaps with the newer dump and double buffered programs that have recently been posted). If you shop around, you should be able to get a Kennedy 9400 with controller for less than $13K (instead of your quote of $17K). The Cipher should be less than $10K including controller. (Let me know if you want specific vendors to call for such prices). One contributing factor to Emulex's higher price is that they are specifying a TC7000. I believe it to be unnecessary to use the TC7000 unless you are definitely planning to upgrade your drive to a $30K 6250bpi 125ip tape drive (e.g. STC or Telex). If you have no such plans, a Unibus controller is quite adequate, costs less and is more flexible (works on any Unibus). The TC7000 is a CMI bus controller capable of higher bandwidths but costs more and won't be good for anything other than a CMI bus, such as that on a 750 or provided by an Emulex V-master for the 780, which costs an additional $3K. In short, I would recommend a Kennedy 9400 with a Unibus controller, either a Dilog DU132 or an Emulex TC13. I would recommend the Dilog DU132. It is an older, proven product which even DEC buys for its TU80. Either configuration should cost under $13K. Cheers, Dan Ts'o Dept. Neurobiology Rockefeller Univ. 1230 York Ave. NY, NY 10021 212-570-7671 ...cmcl2!rna!dan