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178 lines
6.6 KiB
Plaintext
178 lines
6.6 KiB
Plaintext
.\" Copyright (c) 1983 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)equip.ms 6.2 (Berkeley) 4/16/91
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.\"
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.ds RH Equipment
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.NH
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Equipment
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.PP
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Various combinations of the three manufacturers disk controllers,
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and two pairs of Winchester disk drives were tested on both
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VAX 11/780 and VAX 11/750 CPUs. The Emulex and Systems Industries
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disk controllers were interfaced to Fujitsu 2351A
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``Eagle''
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404 Megabyte disk drives.
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The DEC UDA50 disk controller was interfaced to two DEC RA81
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456 Megabyte Winchester disk drives.
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All three controllers were tested on the VAX 780 although
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only the Emulex and DEC controllers were benchmarked on the VAX 11/750.
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Systems Industries makes a VAX 11/750 CMI interface for
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their controller, but we did not have time to test this device.
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In addition, not all the storage systems were tested for
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two drive throughput.
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Each of the controllers and disk drives used in the benchmarks
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is described briefly below.
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.NH 2
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DEC UDA50 disk controller
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.PP
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This is a new controller design which is part of a larger, long range
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storage architecture referred to as
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``DSA''
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or \fBD\fRigital \fBS\fRtorage \fBA\fRrchetecture.
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An important aspect of DSA is migrating a large part
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of the storage management previously handled in the operating
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system to the storage system. Thus, the UDA50 is a much more
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intelligent controller than previous interfaces like the RH750 or
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RH780.
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The UDA50 handles all error correction.
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It also deals with most of the physical storage parameters.
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Typically, system software requests a logical block or
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sequence of blocks.
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The physical locations of these blocks,
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their head, track, and cylinder indices,
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are determined by the controller.
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The UDA50 also orders disk requests to maximize throughput
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where possible, minimizing total seek and rotational delays.
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Where multiple drives are attached to a single controller,
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the UDA50 can interleave
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simultaneous
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data transfers from multiple drives.
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.PP
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The UDA50 is a UNIBUS implementation of a DSA controller.
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It contains 52 sectors of internal buffering to minimize
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the effects of a slow UNIBUS such as the one on the VAX-11/780.
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This buffering also minimizes the effects of contention with
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other UNIBUS peripherals.
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.NH 2
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Emulex SC750/SC780 disk controllers
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.PP
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These two models of the same controller interface to the CMI bus
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of a VAX 11/750 and the SBI bus of a 11/VAX 780, respectively.
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To the operating system, they emulate either an RH750 or
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and RH780.
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The controllers install in the
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MASSBUS
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locations in the CPU cabinets and operate from the
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VAX power suplies.
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They provide an
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``SMD''
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or \fBS\fRtorage \fBM\fRodule \fBD\fRrive
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interface to the disk drives.
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Although a large number of disk drives use this interface, we tested
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the controller exclusively connected to Fujitsu 2351A disks.
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.PP
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The controller ws first implemented for the VAX-11/750 as the SC750
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model several years ago. Although the SC780 was introduced more
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recently, both are stable products with no bugs known to us.
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.NH 2
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System Industries 9900 disk controller
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.PP
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This controller is an evolution of the S.I. 9400 first introduced
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as a UNIBUS SMD interface.
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The 9900 has been enhanced to include an interface to the VAX 11/780 native
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bus, the SBI.
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It has also been upgraded to operate with higher data rate drives such
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as the Fujitsu 2351As we used in this test.
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The controller is contained in its own rack-mounted drawer with an integral
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power supply.
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The interface to the SMD is a four module set which mounts in a
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CPU cabinet slot normally occupied by an RH780.
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The SBI interface derives power from the VAX CPU cabinet power
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supplies.
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.NH 2
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DEC RA81 disk drives
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.PP
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The RA81 is a rack-mountable 456 Megabyte (formatted) Winchester
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disk drive manufactured by DEC.
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It includes a great deal of technology which is an integral part
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of the DEC \fBDSA\fR scheme.
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The novel technology includes a serial packet based communications
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protocol with the controller over a pair of mini-coaxial cables.
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The physical characteristics of the RA81 are shown in the
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table below:
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.DS
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.TS
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box,center;
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c s
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l l.
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DEC RA81 Disk Drive Characteristics
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_
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Peak Transfer Rate 2.2 Mbytes/sec.
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Rotational Speed 3,600 RPM
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Data Sectors/Track 51
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Logical Cylinders 1,248
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Logical Data Heads 14
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Data Capacity 456 Mbytes
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Minimum Seek Time 6 milliseconds
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Average Seek Time 28 milliseconds
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Maximum Seek Time 52 milliseconds
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.TE
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.DE
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.NH 2
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Fujitsu 2351A disk drives
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.PP
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The Fujitsu 2351A disk drive is a Winchester disk drive
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with an SMD controller interface.
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Fujitsu has developed a very good reputation for
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reliable storage products over the last several years.
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The 2351A has the following physical characteristics:
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.DS
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.TS
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box,center;
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c s
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l l.
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Fujitsu 2351A Disk Drive Characteristics
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_
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Peak Transfer Rate 1.859 Mbytes/sec.
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Rotational Speed 3,961 RPM
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Data Sectors/Track 48
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Cylinders 842
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Data Heads 20
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Data Capacity 404 Mbytes
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Minimum Seek Time 5 milliseconds
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Average Seek Time 18 milliseconds
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Maximum Seek Time 35 milliseconds
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.TE
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.DE
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.ds RH Methodology
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.bp
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