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PC Workstations |
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Modern high-end computer drafting packages and 3-dimensional drawing, animation and rendering programs place significant demands on the personal computers typically used by the engineering profession. Due to the rapid pace of change in the computer industry, it is very difficult to recommend the "best" computer configuration. Intel's fastest workstation capable CPU can become an "entry level" model within the span of a few months. It is possible, however, to establish some basic criteria which will aid in choosing equipment which will be useful for a few flavor of the month cycles.
[NOTE: Although the following statistics refer to nearly "ancient" computer components, the point about
increased CPU speed is still relevant.]
The 90-Mhz Pentium chip from Intel was one of the fastest processors available in late
1994. According to Intel's literature, the Pentium or "P5" chip is capable of executing floating-point
instructions approximately 5 to 10 times faster than a 33-MHz 486DX. This statistic is important
because the majority of calculations which are performed by CAD and 3D Graphics packages are
floating point calculations. Thus, a complex AutoCAD drawing regeneration which takes 50 minutes
on a 486 can be completed in 10 minutes or less on a Pentium machine. This amounts to a time
savings of nearly three quarters of an hour. Intel also describes the performance of a 90-MHz
Pentium by providing "iCOMP" values. These values represent a simplified measure of relative
Intel microprocessor performance. A 66-MHz 486DX2 has an iCOMP value of 297 and a
90-MHz Pentium has a value of 735. In general, a fast CPU provides the opportunity to
replace non-productive, costly "down time" with profit producing work.
The type of hard disk which should be installed in a system is determined by examining
two basic issues. First, the appropriate drive interface, IDE or SCSI, must be chosen, and second,
the required capacity must be calculated.
The Integrated Drive Electronics (IDE) interface is characterized by the fact that the drive
electronics are built directly into the hard disk. The controller card for the IDE drive simply
serves to provide a link between the hard disk and the motherboard. IDE drives are popular
because they are fairly fast, reliable, easy to install, and relatively inexpensive. IDE drives have
two major drawbacks. First, they can not address a single disk or partition greater that 528-Mb,
and second, no more than two IDE drives can be installed in a system. Finally, most large capacity
drives are "modified" IDE drives. These drives are known as Enhanced IDE drives (EIDE)
and are capable of exceeding the limits created by the IDE standard.
The second type of popular drive interface is the Small Computer System Interface
(SCSI). This drive interface is designed to support capacities of up to three gigabytes or more,
and it has the capability of supporting multiple devices such as additional hard disks or CD-ROM
drives. Typical multiple device support allows a user to daisy-chain or link up to seven devices.
Finally, standard SCSI is much faster than standard IDE drives. The main problem with SCSI
devices is that they are more expensive than comparable IDE drives and the installation process is
more complicated. In general, SCSI interfaces are best suited for computers, such as file servers,
which require massive amounts of hard disk space.
The issue of required drive capacity can be resolved rather simply. A user should
purchase that largest capacity drive which is economically feasible. Modern programs have a
tendency to require larger amounts of disk space with each revision. The current version of
WordPerfect for Windows, for example, requires nearly 33 megabytes of disk space. This is a
large amount of disk space for a program which used to be a simple word processor! Additional
programs and data files can eat up file space quickly. The best solution to this never ending "real
estate" problem consists of a large capacity hard drive and good file management. As a last
resort, a user can use disk compression software to squeeze added space from a filled drive.
Central Processing Unit (CPU)
The corner stone of a quality system is the CPU. When this article was orginally written, the
fastest x86 based CPU was Intel's 90-Mhz Pentium or P5 chip. Since that time, Intel has released
100-Mhz, 120-Mhz, and 133-Mhz versions of the chip. In addition to the ever increasing clock
speeds, Intel is already introducing its next generation P6 or "Pentium Pro."Graphics Card
The graphics card is another important component because it is the link which
transforms the numerical data into a comprehensible image. Since a graphics card is optimized to
deal with "graphics instructions," it is capable of handling tasks such as drawing polygons and
executing "raster" operations faster than the CPU. Furthermore, the card serves to reduce the
"load" on the CPU by moving a block of calculations to a separate processor. When choosing
a graphics card two important area must be considered. First, the amount and type of memory
(ie. DRAM, VRAM, WRAM) the card contains will affect the number of supported video modes
and the speed of the display. DRAM memory is typically the slowest of the three type since
it can only read or write data in one operation. VRAM and WRAM are capable of
reading and writing data simultaneously. WRAM is supposed to be cheaper
to manufacture than VRAM. VRAM is a solid performer which is used on a number of
top of the line cards. The second consideration is the bandwidth of the card. A 64-bit card
is capable of transfering more data than a 32-bit card.System Memory
The system's RAM and hard disk capacity form the final building block. These pieces of
hardware basically store the data which is processed by the CPU. If a program cannot
temporarily store the needed set of data in RAM, then it will store it on a hard disk. Since
accessing data from RAM is faster than accessing it from the hard disk, it is advantageous to have
as much RAM as possible. The savings in data access times will lead to a dramatic improvement
in overall system performance.Hard Disk
Finally, the system requires sufficient hard disk capacity to permanently store the operating system,
programs, data files, and various temporary files which are created by executing programs. This
free space becomes critical for when dealing with graphics packages. For example, an AutoCAD
rule of thumb suggests that a hard disk should have an amount of free space which is equal to
4 times the size of the original drawing file. Thus, a 25 Mb drawing would require 100 Mb of free
disk space. Another rule of thumb states that you'll never have enough hard disk space. A 1 Gb
hard can become filled in a very short period of time. This is usually due to a combination of
factors such bloated application programs, poor file management, and file systems such
as FAT which waste disk space.Conclusion
This basic criteria leads to the following system configuration:
This concludes the basic coverage. Once you merge this basic criteria with your specific
requirements, you should be able to create your master specification list. Research the market
and find the best equipment which meets your needs. (The Computer Hardware section
of the Useful Links area should help you get started). Finally, DON'T go out and buy
equipment based SOLELY on price. You'll regret it in the long run.
Marco J. Shmerykowsky.
Last updated on: 15 February 1997