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Let me add a few comments on the subject:
I have used SCSI drives and controllers for a few years now. Had no
installation problems,
and never had a disk related problem.
One aspect that has not been considered here, is the influence of the
operating system
on the performance.
Bus Mastering has nothing to do with Concurrent IO. Bus Mastering refers to
disk IO
operations that require less microprocessor intervention and supervision
(the microprocessor
just starts the request and is being informed when the request has been
performed).
Concurrent IO operations refer to multitasking operating system in which
different applications
request Disk read or write operations at the same time. A SCSI drive can
schedule its own
operations and deal with multiple requests at the same time in a form that
will result in fastest
total response time.
Windows 3.1, and 95 are NOT true multitasking operating systems and
therefore do NOT gain
much by using SCSI drives. On the other hand, Windows NT makes use of the
Concurrent IO
capabilities of SCSI drives. Not only that but, NT does NOT use the faster
modes of E(IDE)
and reverts to the very basic slowest mode of IDE IO. (that was true for NT
3.5 and I have
not seen anything stating that this has been improved in the latest
versions).
In the case of TS that almost continuously writes data to disk this makes a
big difference!
The bottom line, booting and starting TS under NT operating system with SCSI
drives,
is way faster then doing the same with E(IDE) drives!
If you are going to run SCSI drives and NT, use (E)IDE for your DC ROM and
such drives,
and have NO IDE hard disks, otherwise the boot partition will have to be on
the IDE disk.
Lastly, NT's built in compression actually speeds thing further since the
compression/decompression
take less time that the physical access to the hard disk (even at 7mS access
time and 7500 or 10,000RPM),
and reading/writing 50% of data files (because of compression) takes less
time.
Joseph Biran
________________________________________________
-----Original Message-----
From: Earl Adamy [mailto:eadamy@xxxxxxxxxx]
Sent: Monday, July 27, 1998 5:57 AM
To: omega-list@xxxxxxxxxx
Subject: Re: SCSI vs IDE
I've been custom building my PC's for around 10 years and I've always keyed
in
on quality and performance. There was a time when SCSI had a very clear
advantage over IDE, however SCSI has always required a rather expensive
separate
controller and, at least until recently, has been difficult to configure and
install. While not typical, I had the unfortunate experience of having an
Adaptec SCSI controller I installed fry a circuit on a motherboard -
something
I've never had happen with hundreds of other boards I've installed. SCSI's
advantage was speed and the ability to run concurrent IO operations -
referred
to as bus mastering. The hardware geeks held forth in great detail on the
superiority of SCSI over (E)IDE and, for a while, they had me convinced
enough
to give it a run. However, their claims have not held up in practical
_workstation_ application with the advent of advanced EIDE and bus mastering
motherboards. The bottom line is that a well-configured machine will yield
more
than adequate workstation performance with either SCSI or EIDE and there is
little reason for workstation users to undergo the pain and cost of dealing
with
SCSI. For network servers, there is no question that SCSI is a superior
solution.
I do agree wholeheartedly that disk performance is critical to system
performance. So how to you get great disk performance using EIDE? Buy a fast
EIDE disk - Quantum offers big EIDE drives in 9 millisecond range - I run
one as
my primary drive and it screams. Put the OS pagefile on a second (EIDE) disk
drive and make sure that the page file is allocated at the beginning of the
disk - the page file is the workhorse on many computer systems - the second
drive can also be used for archival and other low access use without
impairing
performance of the page file. Install plenty of memory so that the OS can
cache
files efficiently - the cache is the racehorse and it must have adequate
room to
keep actively used files, indexes, and OS functions in memory - with memory
prices so low there is no reason not to have 64 meg on every workstation.
Make
sure that your motherboard includes Bus Mastering (now standard on most
motherboards) and that it is enabled. Use an industrial strength OS and in
the
world of windows operating systems there is only one - Windows NT - it's
built
from the ground up to manage and cache disk space far more efficiently than
WinXX.
Earl
-----Original Message-----
From: steinbr@xxxxxxxxxxxx <steinbr@xxxxxxxxxxxx>
To: omega-list@xxxxxxxxxx <omega-list@xxxxxxxxxx>
Date: Sunday, July 26, 1998 6:31 PM
Subject: SCSI vs IDE
>I have built three machines for Win95 platforms earlier this year. I used
>a Hot Shuttle 569 Motherboard and a Diamond Fireport 40 UW SCSI Card with
>an IBM UW SCSI HD. I use the EIDE controller built into the motherboard
>for CD players only since they are typically slow and benefit little from
>SCSI with one notable exceptiion: my CD recorder and my ZIP drive.
>
>At the time, I looked at a Pentium 2 as my preferred chip but the
>additional cost did not justify it. I chose a Pentium 233 MMX. I came to
>the realization that all of us rarely use the computing horsepower of the
>current CPU chips. Performance issues are based largely upon a slow
>peripheral interface: 33 - 66 mhz versus the speed of memory. I put my
>money in the area where it could try to fix the problem -- in a higher
>speed connection to the HD since every PROGRAM must access the HD. (With
>the TS server, this is particularly true since accessing the database
>almost always requires you to access the HD. ) I went from a 11-12 ns
>EIDE drive to a 8.5 ns SCSI HD. In terms of access time, this is a 20%
>performance boost that will be there with whatever the CPU chip. When Bus
>speeds get to 100+ mhz we will see the next performance boost similar from
>going from a 486 to a Pentium.
>
>I have three CD player connected to the EIDE controller and have never had
>a problem. The SCSI controller and HD were seamless to install and only
>one interrupt for all those SCSI devices!!
>
>Once you go to SCSI, you wont go back.
>
>Any Comments for Hardware Geeks ?
>
>Chuck Kaucher
>
>>From: "JL" <fastgroup@xxxxxxxxxx>
>>
>>Personally I like SCSI more than IDE. I find it easier to setup, supports
>>more devices and faster. I have had more problems with my IDE drives then
>>my SCSI drives.
>>
>>SCSI is more expensive because of the added hardware on each device.
>>Someone gave a good explanation of how SCSI is controlled. But with this
>>extra hardware it makes the drives more efficient. For instance, if you
>>compared an IDE and SCSI drive (theoretically running at the same transfer
>>rate such as 20MB/sec) the SCSI drive would have a faster throughput.
>>
>>JL
>>fastgroup@xxxxxxxxxx
>> Manana is often the busiest day of the week.
>> -Spanish Proverb
>>-----Original Message-----
>>From: Ron Augustine <RonAug@xxxxxxxx>
>>To: omega-list@xxxxxxxxxxxxxx <omega-list@xxxxxxxxxxxxxx>
>>Date: Friday, July 24, 1998 8:31 PM
>>Subject: Re: SCSI vs IDE
>>
>>
>>>
>>>SCSI has a lot of problems working comfortably and efficiently in a
>>>DOS/Windows environment but it is faster. Installing and integrating is
>>not
>>>trivial and --in my opinion-- not worth the aggravation. IDE is
generally
>>>sufficient for almost any set of normal applications and the Pentium II
>>data
>>>bus is 66Mhz (twice that of a regular Pentium), so that alone improves
the
>>>throughput.
>>>
>>>A case for SCSI could be made if you have a heavy-duty server application
>>>with multiple hard-drives, but you better have a SCSI Geek on staff and
>>>sleeping in the back room to keep the thing running.
>>>_____________________________________
>>>At 12:01 PM 7/24/98 -0700, you wrote:
>>>>Hi folks,
>>>>
>>>>Did anyone notice any significant improvement after switching to SCSI.
>>>>
>>>>Looks like DOS boxes were not meant for it, and we might have just
another
>>>>vulnerable link in terms of reliability and compatibility.
>>>>
>>>>This "graphics" stuff we use in TS is not that heavy duty from the long
>>>>time DTP apps user point of view.
>>>
>>>
>>>
>
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