peripheral performance reports sought

[Ross Harvey]

I am about to order a new 750 system with some late-model CDC
peripherals for use with 4.2BSD.  I would appreciate hearing
from sites with relevant experience using these peripherals.

The proposed configuration is:

	Emulex SC7000		CDC 9715-500 disk drives (qty 2)
	Emulex TC7000		CDC 92185-02 tape transport
	Emulex CS21/F (16 line DMF clone, asynchronous ports only)

The 9715 is a 516 MB fixed 9" drive with thin-film heads. It measures
only 10.2x8.5x24.  The tape transport is a 6250 BPI streamer with a
128K buffer. The disk drives mount side-by-side underneath the
horizontally mounted tape transport...this is over 1 GB of disk storage
and 6250 BPI tape, all in a cabinet smaller than the 750 CPU.

My main concern is the MTBF for the 9715. CDC claims 11,250 hours
now but admits to an 8,200 hour figure for the first year of production.

The other concern is the streamer. Does it stream under 4.2BSD?
I prefer the vacuum column technology but the new technology
seems to be going into streamers. Also, I would like to get
all the peripherals from one manufacturer that happens to do
VAX maintenance, and it turns out that a 6250 BPI vacuum column
tape drive apparently costs $300/month for contract maintenance
and is initially rather more expensive as well. There are many
unbuffered 9218x tape units in use. (The TU80 and TU81 use these
transports.) They are slow, the -02 version is new, it has the
128K buffer, and presumably it can stream. (For those who don't
know, a streamer that doesn't stream is hopeless.)

Of course, I am also interested in experience with basic functionality
and level of emulation. I have seen the problem reports on the TC7000.
Thanks in advance...

Ross Harvey

decvax!frog!aphasia!ross ulysses!aphasia!ross lcc!pdc750!aphasia!ross