gert@ttds.UUCP (Gert Svensson) (12/31/83)
We are just going to buy our first VAX 11/750. Currently we are using a PDP11/45 and an Altos 68000. We have two main alternatives (both including a 11/750 CPU and 4 Mb of memory): Alt 1: DEC RP07 disc DEC TU77 tape DEC RH750 MBA Alt 2: Fujitsu "Eagle" (M2351A) disc 414 Mb Emulex SC750 disc controller Cipher M891 tape drive (1600/3200 BPI) Emulex TC12 tape controller Would anybody like to comment ! Is the DEC RA81 a better choice compared to the RP07 ? Has anyone tested the Cipher tape drive ? Does anyone know about any reliable 6250 BPI tape station (TU78 ? streamers ? ) ? Is there any cheap 6250 stations ? Gert Svensson ..mcvax!enea!ttds!gert
kermit%brl-vgr@sri-unix.UUCP (01/06/84)
From: Chuck Kennedy <kermit@brl-vgr> Personnally, I would never buy an RP07. They seem to break quite often. There is an RP07 on a VAX 780 downstairs that is always causing problems. The Fujitsu Eagle is a very nice drive which is what I would recommend. I would also take the Eagle over the RA81 if you could only connect the RA81 through the UDA50. The problem is that the UDA50 eats about half the Unibus and with only one drive you won't get much performance. It is fairly obvious that if you connect to the CMI you should higher bandwidth than connecting through the Unibus, no matter what the salesman says. Digital has announced the Digital Storage Architecture (DSA) which utilizes their nifty new HSC50. The connection to the HSC50 is via the Computer Interconnect (CI) bus which has a 70Mbit/sec bandwidth. The HSC50 has some really neat features such as disk shadowing (all your disk operation are written to a tape drive which is also attached to the HSC50) so that you have a continuously updated copy of what your system has done (great for error recovery). I only have two problems with the HSC50: 1) If you don't run VMS (i.e. UNIX), you will have to write DSA code to run the HSC50. This is probably more complicated than your average driver. Besides, you have to yank teeth to find out all the information from DEC. 2) I don't know if it's available for use with the 750 yet. As for tapes, I would recommend one of the triple density (800/1600/6250 bpi), 125 ips tape STC drives available from somebody like Systems Industries connected to your choice of either a Unibus or CMI interface. The tape drive is fast! The only problem is the cost (see your local representative). I'm sure that Emulex also offers the same type of equipment. Hope this information proves useful and happy hunting! Cheers, -Chuck Kennedy <kermit @ brl>