From: underdog@leland.Stanford.EDU (Dwight Joe)
Subject: Buying a Multi-user Computer System with a Unix Operating System
Organization: Miners for a Heart of Gold
Date: Thu, 31 Dec 92 04:04:49 GMT

I thought perhaps that you people might find the following to be interesting.
I wrote it as a final report in one my classes.  Please note that it was
intended to be neither (1) scholarly nor (2) exhaustive but that its purpose
was to provide some reference points for future purchases of computer hardware.
(I did pass the class.)

If you have an opinion, then please send e-mail.  Thanks.  Enjoy!
(You are free to reference this in any of _your_ reports, provided
that you make a reference to me.)

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(c) 1992,1993

             Buying a Multi-user Computer System
                 with a Unix Operating System
                        by Dwight Joe
I.  Introduction
     In purchasing a multi-user computer system, we must 
consider the components that form the total system; they include 
the operating system, the interconnecting network, the mass-
storage system, the printer, and the personal computer or 
workstation.  Our focus in this report is the Unix operating 
system, off-the-shelf cards and devices for interconnecting the 
network and for providing mass storage, a laser printer, and the 
80x86 workstations (where I refer only to 80x86 machines with "x 
> 2").  Although 80x86-based computers are commonly known as 
personal computers, later generations of such machines using the 
80386 or 80486 offer the same speed and memory addressability as 
traditional workstations; the 80386 and its successors are full 
32-bit microprocessors.  Furthermore, compared to more 
traditional workstations, machines based on the 80486 tend to be 
much cheaper and enable financially strapped institutions like 
universities to increase the computing resources per student to 
an extent beyond what the university could afford for 
traditional high-priced workstations.
II.  Operating System
     Unlike traditional workstations, 80x86 workstations 
predominantly run the Microsoft Disk Operating System (MS-DOS), 
and few run any variant of Unix.  Nevertheless, many companies 
produce a Unix OS for 80x86 machines; examples are Next, SCO, 
SunSoft, and Univel (USL in collaboration with Novell).  With 
the exception of USL's Unix, SVR4.2, each variant of Unix 
produced by these companies are incompatible with most other 
major Unix OS's on the market.
     So, which Unix OS should we select?  The decision rests on 
two important criteria:  (1) compatibility with other Unix OS's 
to ensure that our selected Unix OS can run many future Unix 
applications in the event that it does not become the de facto 
industry standard and (2) relatively low cost.  One important 
but less significant criterion is the incorporation of the X-
Window System, which is widely used in the engineering 
community.
     Among Unix implementations, SVR4.2 (which is sold as 
UnixWare by Novell) best meets these criteria.  It is compatible 
with seven major Unix OS's; among these are SunOS/Solaris, 
SVR3.2, BSD, and Xenix.  The X-Window System is included, and so 
is TCP/IP networking in the base version of SVR4.2.  The base 
version supports only the vital functions expected in a Unix 
implementation; in this way, the size and cost are reduced.  The 
base version requires only a minimum configuration of 4 MB of 
memory and a 60-MB hard drive and is expected to cost in the 
range of $100-$150.[1]
III.  Interconnecting Network
     The Unix OS provides networking capability that requires 
communication boards and cable to link the 80x86 workstations 
into a network.  For our purposes, we assume a network of 8 
computers among which we wish to share data and programs.
     So, what type of network should be select?  The most 
important criteria are that the selected network can be serviced 
at many repair sites and that the amortized cost per workstation 
be relatively low.  The presence of many repair companies 
fosters competition in terms of price and speed of service.  
When data is shared among many users across many computers, we 
must try to minimize the down time of a network in order to 
avoid the ire of the users, so the speed of service is 
important.  If one repair site proves unreliable, we can easily 
switch to another repair site simply because there are many 
repair sites due to the popularity of the selected network.
     In terms of popularity, the best local area network is 
Ethernet.  The typical price of an Ethernet set, including 
communication cards and cables for an 8-computer network plus a 
fileserver, should be approximately $2800; the amortized cost 
per workstation (including the fileserver) is about $300 
dollars, which is relatively inexpensive compared to the cost of 
the workstation itself.  The price is virtually invariant with 
respect to the type of 80x86 computer that we choose to buy 
because almost all IBM-PC compatible machines are 100% 
compatible with IBM, and hence, a card that plugs into one PC 
clone can also be plugged into another PC clone.  Also, because 
of the intense competition in the PC clone market and the 
related peripherals market, the prices of all PC hardware is 
continuously declining at least for the immediate future[2].
IV.  Storage
     To service the mass-storage needs of the 8 computers on our 
network, we need at least 1 file server.  We can choose from a 
number of different fileservers:  AcerFrame 1000, ALR PowerPro, 
AST Premium SE 4/50, Compaq Systempro/Lt, DECpc 450ST, Dell 
450SE/2, Everex Step 486DX2/50 EISA Tower, Gateway 50-MHz 486DX2 
EISA, IBM PS/2 Model 95 XP 486, NCR 3447, Northgate 486 EISA 
DX2, Tangent MultiServer, etc.
     Which fileserver should we select?  The two most important 
criteria are (1) relatively low cost and (2) saturation 
behavior.  The prices of the fileservers can range from about 
$5000 to $20,000.  With regards to the second criterion, network 
saturation occurs as a result of file access requests that 
become bottlenecked at the fileserver.  Network saturation is 
important because once a network reaches saturation, the 
throughput per workstation decreases as the number of 
workstations added to the network increases.
     Fortunately, for our 8-computer network, none of the above 
fileservers reach saturation in benchmarks performed by the 
staff at Byte.  It recommends Compaq Systempro/LT and NCR 3447 
as the overall best fileservers running Unix; also, the Tangent 
MuiltiServer is recommended for those on a tighter budget.  
Since our chosen Unix OS is SVR4.2 and since only the NCR 3447 
runs that implementation, we choose the NCR 3447.  The NCR 
fileserver costs about $11,000, which puts it in the middle of 
the field.  For that price, we get 1.34 Gbytes of storage, and 
an additional 10 hard drives, each having 0.67 Gbyte of storage, 
can be added.[3]
     A relatively inexpensive tape-backup system is also needed 
in our network.  Such a system can be obtained for a relatively 
inexpensive price of $299.95.[2]
V.  Printer
    Of course, we also wish to print the data and other results 
produced by our multi-user computer system.  For about $1500, we 
can attach a high-quality laser printer to the network.[2]
VI.  Workstations
     Finally, the core of our computer network is the computing 
nodes:  80x86 workstations.  Due to intense price competition in 
the PC market, the 80x86 machines have been virtually turned 
into commodity products with profit margins that are razor thin.  
The result is that we can buy a 80486 workstation for about 
$3500.  Most of the IBM-PC's and clones are reliable and cost 
effective.
     Further, there are few differences among them.  The main 
criterion in selecting one brand over another is the long term 
prospects of the company selling the machine.  Buying one from a 
company that collapses before the warranty has expired might 
leave us with very expensive repair bills in the event that the 
workstation breaks down.  
     One good machine is the Compaq Deskpro 4/33i with a 33-Mhz 
80486.  This workstation is comparable in speed to a 
Sparcstation 1+ but costs only about $3500; the Sparcstation 
costs at least $5000.[4]
VII.  Conclusion
     Therefore, our selected multi-user computer system has the 
following costs:
                       1 Unix OS =    $150
               network equipment =   $2800
                    1 fileserver = $11,000
          8 workstations @ $3500 = $28,000
                 1 laser printer =   $1500
Thus, the total cost is approximately $43,450 for a cluster of 8 
Compaq Deskpro 4/33i workstations connected via Ethernet, a NCR 
3447 fileserver, a laser-printer, an Ethernet network, and USL's 
SVR4.2 Unix OS.  For an even higher performance system, we can 
substitute Compaq Deskpro 50M workstations for the Compaq 
Deskpro 4/33i workstations. The former is comparable in speed to 
a Sparcstation 2 but costs about $7000; a Sparcstation 2 costs 
about $20,000.[5]  So the total cost of the system with Compaq 
Deskpro 50M workstations becomes $71,450.












                        References
[1] Yager, Tom and Ben Smith.  "Is Unix Dead?"  Byte. September, 
1992.  Pages 134-146.
[2] Radio Shack catalogue for 1993, Pages 155-164.
[3] Platt, Stephen, Tadesse Giorgis, Leslie Reisz, and Steve 
Apiki.  "Fast 486 File Servers"  Byte. October 1992.  Pages 212-
220.
[4] Eglowstein, Howard and Stan Wszola.  "486 Systems for a 
Graphical World"  Byte. November 1992.  Pages 209-236.
[5] Smith, Ben and Raymond Ga Cote.  "Stalking the Ultimate 
Workstation"  Byte. November 1992.  Pages 192-108.

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Copyright 1992, 1993    Disclaimer:  1 + 1 = 3                    |
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