stevens@hsi.UUCP (01/15/85)
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.
Richard Stevens
Health Systems International, New Haven, CT
ihnp4 ! hsi ! stevensmuller@sdcc3.UUCP (Keith Muller) (01/17/85)
> 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. > > Richard Stevens > Health Systems International, New Haven, CT > ihnp4 ! hsi ! stevens I have 5 Kennedy 9400 tape drives, 3 connected to vaxes and 2 connected to pyramid 90x's. I have had no difficulty at all with them. How good your tape drive works depends a lot on the coupler (the 9400 has a formatter built in). You will have to make a small mod to the vax device driver if you want software control for all three densities. If you can live with just two (you can have either 6250/1600 or 1600/800) then no mods are required. I have a tc13 coupler on the vaxes which is truely the wrong coupler as the microcode emulates a ts11. Thus on the vaxes I have no software control of the density. To switch denisty you have to select the correct one on the kennedy in the local mode. If I had any say, I would have purchased the TC7000 also. Keith Muller University of California Academic Computer Center
dan@rna.UUCP (01/18/85)
> 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
ed@mtxinu.UUCP (Ed Gould) (01/19/85)
> We're looking for a modestly priced ($10K - $20K) 6250 bpi tape system. > ... > 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. I don't have any experience with the Cipher 6250 drive, but I've used their 800/1600 CacheTape (M891). It has a 64K cache, and it works quite well. It really does stream much of the time; the software won't see the difference when it doesn't. Among the things that Cipher did right in their CacheTape is EOT handling. The problem is that you don't want data stored in the cache when the EOT marker goes by - the system should know about end of tape at the right time. What Cipher did is monitor how much tape is left on the supply reel, and when it gets below some (small) threshold, they start reducing the effective size of the cache until nothing is cached at all just before EOT. Of course, the drive runs start-stop for the last several feet, but who cares? -- Ed Gould mt Xinu, 739 Allston Way, Berkeley, CA 94710 USA {ucbvax,decvax}!mtxinu!ed +1 415 644 0146