Hi,
thank to all who sent me an advice. As I didn't point to problem but
need advice, I think that the best way to summary is to copy relevant
advisees. Sorry if the mail is a little bit longer, but according me,
this is the best way to pass all opinions to community.
thanks and regards,
Denis Salihagic
Original message:
-------------------------
We want to buy a Personal Workstation 500au ( Tru64 UNIX ) and need a
big disks ( 18 Gb ).
Few days ago we received prices for disks:
1. SN-PBXRW-TA 18.2 GB UltraSCSI wide disk drive 7200 RPM -
about $3000
2. SN-PBXRW-WA 18.2 GB Ultra2 LVD Wide SCSI 10K RPM - about
$2300
Why 2, is cheaper than 1. ? Or its just some miss typing ( not mine)?
Any advice about choosing a disk? PW we need for MonteCarlo simulation
with no so big in/ouput.
----------------------
Doug Johnson :
I recently bought some Seagate ST118273 18 G-byte drives from
ADS in NY. I paid $825/each for them. These are too big to put in the
disk holder of a DPW if there is another drive there, but you can mount
them in the front near the CD-ROM and floppy.
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alan_at_nabeth.cxo.dec.com:
The easy reason is that one is 7200 RPM and the other is
10,000 RPM. One is also Ultra2 capable (bus clock rate
of 40 Mhz), where the other is Ultra (20 Mhz). What's
not obvious is why the more recent one is less expensive.
My guess is pricing history. At each new technology point
disk prices seem to go down. The 7200 RPM disk is the
older technology and thus was probably more expensive when
it was released. The 10,000 RPM disk is newer and thus
less expensive.
At each new device release we've tended not to go back and
reprise all the old devices to bring them into line with
new device pricing. In part, probably because of the extra
work involved. I suspect the bigger part of the reason
though is that our price for buying drives from the original
vendor hasn't changed.
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John Francini:
Option 1 is the easiest way to go in your case. Just install it and
go.
Option 2 will require more work. The term LVD in the description means
Low
Voltage Differential Wide SCSI. The 500au has Wide (Single-Ended) SCSI.
(Generally, single-ended SCSI is the most common type, and is therefore
not
specifically called out in short descriptions like the one you gave.)
The LVD drive won't work on your box without an adapter between the two
types
of buses. You can cause significant harm to the new drive, your old
drives,
and your motherboard if you mix differential and single-ended SCSI
together.
If you want to use Option #2, you also need to buy an Ultra2 Low-Voltage
Differential Wide SCSI card to add to your PCI bus, with appropriate
cables.
Just my opinion....
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Mandell Degerness:
The reason is right there. The part number SN-PBXRW-TA is UltraSCSI.
The
part number SN-PBXRW-WA is Wide SCSI. UltraSCSI has significantly more
bandwidth than Wide SCSI. You may not get better performance of the one
drive, but aggregate performance of many UltraSCSI drives on one bus is
likely to be better.
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Received on Tue Feb 16 1999 - 10:58:45 NZDT