km@mathcs.emory.edu (Ken Mandelberg) (02/02/91)
The price of reasonably fast SCSI drives has really come down. 1.2GB
drives are well under $3K. However, the preferred drive interface on
Sun's 490 servers is IPI-2, and on that platform the IPI driver and
interface is much higher in performance than Sun's scsi.
So far, I haven't seen any IPI drives that compete in cost with the SCSI.
The Seagate 8" Saber drives which Sun uses cost twice as much as the low
cost 5.25" SCSI's. These Sabers come in IPI,SCSI, and SMD versions all of
which are expensive.
Has anyone seen any sign of lower cost IPI-2 drives that I missed? In
particular are there any 5.25" IPI-2 drives?
--
Ken Mandelberg | km@mathcs.emory.edu PREFERRED
Emory University | {rutgers,gatech}!emory!km UUCP
Dept of Math and CS | km@emory.bitnet NON-DOMAIN BITNET
Atlanta, GA 30322 | Phone: Voice (404) 727-7963, FAX 727-5611pfh@craycos.com (Peter Hill) (02/02/91)
> Has anyone seen any sign of lower cost IPI-2 drives that I missed? In > particular are there any 5.25" IPI-2 drives? Seagate has one in their current catalog. I don't know about price or availability. It is the ST41201K Elite 1, which is a 1200 Mbyte (unformatted) 5.25" full-height drive with dual-port IPI-2 interface. You don't have to have a Sun-4/400 series machine to use IPI disks, by the way. We have a Xylogics SV7890 dual-channel controller in a Sun-4/280S with 12 (soon 16) Seagate two-head-parallel 8" Sabres. So far, so good. (Caution: the SV7890 doesn't support full IPI cable length spec. We had to get an extra set of short cables to stay within their 50' limitation.) -- ___________________________________________________________________________ Peter Hill pfh@craycos.com +1 719 540 4259 Cray Computer Corporation, 1110 Bayfield Drive, Colorado Springs, CO 80906
billbr@xstor.UUCP (Bill Brothers) (02/03/91)
In article <1991Feb1.113445@mathcs.emory.edu> km@mathcs.emory.edu (Ken Mandelberg) writes:
] The price of reasonably fast SCSI drives has really come down. 1.2GB
] drives are well under $3K. However, the preferred drive interface on
] Sun's 490 servers is IPI-2, and on that platform the IPI driver and
] interface is much higher in performance than Sun's scsi.
]
] So far, I haven't seen any IPI drives that compete in cost with the SCSI.
] The Seagate 8" Saber drives which Sun uses cost twice as much as the low
] cost 5.25" SCSI's. These Sabers come in IPI,SCSI, and SMD versions all of
] which are expensive.
]
] Has anyone seen any sign of lower cost IPI-2 drives that I missed? In
] particular are there any 5.25" IPI-2 drives?
The Seagate Elite drives are available in the 5.25 inch form-factor.
However, they are still expensive. You don't get IPI-2 performance
from a drive for nothing. The tolerences are closer, the parts more
expensive, and the engineering more exacting to be able to push
5-20 Mbytes/s off of a drive. SCSI drives (the low end) have come
down in price because of the quantity built and sold.
Bill Brothers
Engineering Mgr.
Storage Dimensions, Inc.
uunet!xstor!billbryuping@auspex.auspex.com (YuPing Cheng) (02/05/91)
In article <248@xstor.UUCP> billbr@xstor.UUCP (Bill Brothers) writes: >In article <1991Feb1.113445@mathcs.emory.edu> km@mathcs.emory.edu (Ken Mandelberg) writes: >] The price of reasonably fast SCSI drives has really come down. 1.2GB >] drives are well under $3K. However, .... > >The Seagate Elite drives are available in the 5.25 inch form-factor. >However, they are still expensive. You don't get IPI-2 performance >from a drive for nothing....... > Bill Brothers Engineering Mgr. Storage Dimensions, Inc. With the exception of 8" IPI drives, most 5 1/4" IPI drives are built with the same HDA (Head Disk Assembly) as the SCSI drives, therefore, offer exactly the same performance and quality as the SCSI drives. Only the interface electronics are different. The only reason for the IPI drives being expensive is the low volume production. To justify its high price, IPI drive manufacturers double the drive data transfer rate from 3MB per second to 6 MB per second by simply transfering data from two disk recording heads at the same time and claiming higher performance. Naturally, the same game can be played by the SCSI drives too. In addition, IPI drives do not offer many advanced SCSI functions such as track buffering, data read ahead, defect management, zero latency read, and constant density recording, etc. You are better off using SCSI drives. Yu-Ping Cheng, Auspex Systems Inc. ycheng@auspex.com