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We advise our VARs to exercise extreme caution in their selection of PC hosts for Strobe's line of Co-processors. Strobe suggests the use of only top-line PC's -- those marketed specifically for use as file servers, for instance.
Several of Strobe's VARs (and even Strobe itself) have recently fallen victim to the poor design or indifferent quality of some of the PC products and sub-assembly components which find their way to consumers taking advantage of the current ultra competitive nature of the PC marketplace.
For example, even name brand PCs, including some from highly respected Digital Equipment Corporation, are being equipped with non-parity dynamic random access memory, only. Many of the current crop of inexpensive PC motherboards in the marketplace cannot even support parity checking of the DRAM.
While we at Strobe readily acknowledge that the overall reliability of DRAM has improved quite dramatically over the years, these DRAMs are still subject to random soft errors, however infrequent.
Strobe's Co-processor/PC end-users do not wish to belatedly discover in June that their data may have been totally corrupted as a result of a rare, undetected DRAM error which may have occurred in May! Without PC memory parity checking one can never know for sure what might have caused the data corruption or when it occurred. It is exactly for this reason that all Strobe Co- processor products with DRAM have memory parity checking capability.
Many inexpensive PC's currently in the marketplace seem to be "bare-bones" designs with relatively inexpensive supporting chipsets, presumably for the home user market. Within the past few months we have encountered three seemingly reliable motherboards which caused major failures in Strobe's Co-processor environment. Two of these turned out to have serious design flaws which prevented proper operation of our products.
One PC design did not properly handle 8 bit ISA bus transfers. The UniBus adapter for the Osprey requires 8 bit ISA bus support to set up the UniBus mapping function.
Another failure occurred with a Digital* PC motherboard which aborted an ISA bus hold state rather than queue or delay a second memory refresh cycle.
We recently experienced yet another failure mode in another Digital PC model running an Osprey. This failure appeared to be the result of signal crosstalk on the motherboard riser/extender card.
Strobe has long held the opinion that low profile desktop PCs requiring the use of ISA bus riser cards for "side mounted" add-in cards provide marginally sufficient cooling for just a base Pentium configuration. Therefore we cautioned against the use of these PCs as a Co-processor host. We now have clear evidence that this riser card approach may be flawed.
We wish to emphasize that the design flaws we have encountered in no way diminish the PC systems' functionality in the market they are targeted for -- home computing. But, because of the complex nature of our co-processor products, we require PC motherboards to adhere to the traditional published standards. It is those motherboards which do not meet those published standards that are the potential trouble makers.
Strobe's VARs, OEMs, and end-user customers must be aware that in the overall world of PC applications, Strobe's Co-processor series represents something of an anomaly. Strobe's Co-processor products alone consume significantly more power than the average PC add-in card or device. The Hawk three card set, when equipped with the LTX DSP/Array processor consumes almost thirty watts. A single card Osprey, with the Digital DCJ and FPJ components operating at a clock rate of 18 Mhz, consumes almost twenty watts.
The unusual nature of the overall Co-processor environment (RS232 multiplexers, additional PC main memory for RAMDISKS and disk caching, high performance disk drives, etc.) means that both cooling and power consumption issues must be seriously thought out and considered.
Careful selection of the PC power supply is highly recommended. In addition, Strobe has always recommended host PCs housed in the larger floor-standing tower chassis. Obviously, in a large metal chassis, more internal heat will be carried away through the conductive surfaces.
There is a reason why Intel, AMD, and Cyrix all require fans mounted directly on their CPUs. The basic PC chassis design has not changed since the advent of the 6 Mhz 80286 in the early 1980's. Is anyone paying attention to the fact that these CPU mounted fans only move the heat away from the DEVICE, not OUT OF THE BOX?!
Strobe strongly recommends that any PC chassis housing a 486 or Pentium class processor with a Strobe Co-processor have at least TWO 50 CFM fans located far enough apart to create dispersing air flow through the chassis. Please be aware that a forced air inlet fan and a separate forced air outlet fan do not meet this requirement.
Return to Strobe Data Inc's home page*Compaq and/or Digital Equipment Corporation claim 'Digital' as a mark. Strobe Data is a separate company from Compaq and Digital Equipment Corporation.
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