jr@oglvee.UUCP (Jim Rosenberg) (09/07/88)
I've been asked for a recommendation for a hard disk for a HazMat team to haul around in their truck. They need something like 60M - 80M, but power is *not* a particular problem -- they have a generator in their truck that is plenty beefy enough for any computer. Hard drives cause enough grief just sitting on desktops; the thought of one bouncing around in a truck that has to tear off to the hills to respond to some derailment or truck accident sends shivers up my spine. I've told them that a standard off-the-shelf hard disk probably isn't rugged enough. Alas, most portables with hard disks come in at 40M or less. Does anybody have any recommendations for a rugged hard disk with this capacity? Is there something perhaps made for the military that would work? Is there a way of ruggedizing a standard hard disk with say voice coil -- and would that work? Anybody actually have experience with hard disks in trucks? [Calling all geologists ...] The thought just occurs to me that the most interesting idea here might be a WORM -- except that I don't know if their budget will withstand this, & I don't know if the software they need to run will run on a WORM. Any help appreciated. -- Jim Rosenberg pitt Oglevee Computer Systems >--!amanue!oglvee!jr 151 Oglevee Lane cgh Connellsville, PA 15425 #include <disclaimer.h>
u-dmfloy%sunset.utah.edu@utah-cs.UUCP (Daniel M Floyd) (09/08/88)
In article <277@oglvee.UUCP> jr@oglvee.UUCP (Jim Rosenberg) writes: >... need something like 60M - 80M ... [ disk for a truck]... >Does anybody have any recommendations for a rugged hard disk with this >capacity? Is there something perhaps made for the military that would work? A TRUCK?! Forget the hard disk! It wouldn't live through the first mile. Ok. I may be exaggerating, but I seriously doubt that a hard disk would do well for more than a couple trips. There are places that you can buy "industrial pcs". I've seen one demonstrated at a place here i Utah. The cards are literally mounted on shocks (litter rubber pads). These pcs are tanks when it comes to abuse, even the hard disks. I don't think even these disks are tough enough for a truck though. I suppose I could ask. The military uses bubble memory in their stuff. I don't know how much it costs, but it can be purchased for pcs. Bubble memory can take it. The military puts it in stuff that's going to be shot at (with missles and rockets). I've seen some stuff that's still being built with iron core for the military too. Don't bother looking to buy it for a pc nor the truck. A slightly cheaper alternative would be a bernouli box with 3 or 4 cartriges. I don't know if they make the cartriges in larger than 20M. A bernouli I think could take it too. Hope this helps.
richard@neabbs.UUCP (RICHARD RONTELTAP) (09/09/88)
You can try Tandon computers with removable 30 MB datapacks. I was on a computer show once, and a Tandon saleman confidently dropped such a harddisk from about 1.5 meters on hardboard floor!! Afterwards I checked the disk myself, and everything still worked. Richard (...!mcvax!neabbs!richard)
jamesa@amadeus.LA.TEK.COM (James Akiyama) (09/09/88)
Trying to use a hard disk in a truck would be a very challenging task. There are a few points you'll want to keep in mind. First, the standard shock mounts on a hard disk (the rubber isolator between the hard disk chassis and media chamber) are "tuned" for normal computer environments. This "tuning" involves increasing its resistant to higher frequency (above about 20 Hz) vibration. You will find that these shock mounts generally decrease the hard disk's immunity to lower frequency shock. This is the reason most hard disks come packed in relatively snug fitting containers. These containers are designed to purposely defeat the standard shock mounts. If the standard shock mounts were not disabled, large displacement waves would cause the media platter to "crash" into the chassis as the mounts run into their maximum displacement. The shock energy would then be dissipated in a very short time (at the point of impact) rather than spread out over a longer period. Because of this, it will be necessary to mount the fixed disk in a shock absorbing enclosure. This enclosure should be tuned to dampen low frequency vibrations. The design is a complex interaction between the existing shock mount and mass of the hard disk media chamber, and overall mass of the hard disk (including chassis). Alternately one could design a system where the manufacturer's shock mounts were disabled (or removed). This would void their warranty (although I think your application would void their warranty anyway). This would simplify the design considerably by removing one of the potential resonant sources. You will want to also use a 3 1/2" drive since these tend to offer better shake and shock figures. You would also want to consider using a plated media disk drive. A voice coil system with auto park and auto-lock would help if the drive is powered down while the truck is moving. Be sure the drive does lock--some use a spring tension to pull the heads off the data surfaces. These are much more likely to come out of the parked position under high shock. If the drive will be powered up during this time, a stepper design may be preferred. The "cogging" effects of the stepper will help minimize sideways movement of the head assembly. A voice coil design offers very little resistance to such side-ways movement while powered up. When the system is in place you'll want to monitor the number of times the computer re-calibrates the drive while running. Excessive re-calibration while running is a good sign that the drive is being subject to excessive shock while running. As far as drive recommendations, I would seriously look at the CDC (Control Data Corporation) series of drives. Best would be the CDC "Swift" 80 Meg drive (although I'm not sure its available yet). Unfortunately this drive is not plated media--CDC doesn't use plated media except on their very high capacity drives (> 100 Megs). The drive is voice coil with a very fast (16.5 mS) average access time. Note that the 80 MEG drive is currently the "bottom of the line" in this series of drive (CDC tends to only come out with "high-end" drives--at a price higher than most). CDC also has a well-earned reputation of meeting their specifications in a real-world environment as opposed to many other manufacturers who only meet published specifications in their "laboratory-controlled environment." Hope this helps, and good luck. James E. Akiyama jamesa@amadeus.LA.TEK.COM UUCP: ....!tektronix!amadeus!jamesa ARPA: jamesa%amadeus.LA.TEK.COM@RELAY.CS.NET DISCLAIMER: These view are my own and may not reflect those of Tektronix or and affiliates.
danl@intelca.intel.com (Dan Lau) (09/09/88)
Depending on whether the hard disk must be running on the truck or not, the Tandon Data Pac (removable winchester drive in a plastic package) may be the answer. I don't know the maximum capacity, but I have seen a drive dropped onto carpeted concrete at Comdex/Las Vegas last year and it functioned perfectly after that. The catch here is that the disk must not be spinning when it happens.
jcmorris@mitre-bedford.ARPA (Joseph C. Morris) (09/11/88)
In article <277@oglvee.UUCP> jr@oglvee.UUCP (Jim Rosenberg) writes: >I've been asked for a recommendation for a hard disk for a HazMat team to haul >around in their truck. Is there a requirement that the drive be *running* while the truck is in motion? If not, you could probably use any drive with a solid self-parking mechanism. Since hard disks are routinely shipped through the mail with only infrequent damage, you might be successful by installing one with good shock mounts. Call the disk manufacturers and ask for their specs on non-energized acceleration and vibration limits. On the other hand, if you've got to be able to use the disk while in motion (checking a data base for recommended first-in responses to a particular HazMat type incident, for example), you may have to go to a military-type unit to get the necessary degree of reliability. You might also consider the possibility of a CD-ROM or WORM. If the data base isn't updated too frequently (and interim updates can be posed in a hardcopy binder) this would get away from the fragile disk technology. The same idea could be used for PDR or other similar emergency-service data bases.
eli@spdcc.COM (Steve Elias) (09/11/88)
if you are looking for the most beat-proof hard disk around, buy a CDC Wren 2 drive. they take a licking and keep on spinning.