I'm considering a hack somewhat like the Tatra G4... Put a desktop Mac in a car.
The only hangup is storage. I'm worried that a hard drive based system won't be able to stand up to the road conditions and may suffer physical damage.
Does anyone have any suggestions for shock-proof or shock-resistant storage? High capacity is a definite must. I already thought about flash RAM like CF, but there's not enough capacity there. Would a laptop HD be better suited to use under high acceleration?
What kind of G-forces can a traditional HD withstand? Sustained G-forces and instantaneous G-forces are things to be concerned about. Sustained acceleration would probably never get higher than 2 Gs (I should hope!!! I'm not flying an F-16, anyway, and my Sunfire doesn't have much torque). Instantaneous - that's anyone's guess...
Suggestions welcome.
Peace,
Drew
Well, I just looked up a random drive on wdc.com (Western Digital) which turned out to be a 7200 RPM 180 GB drive. It said it could handle 20 G whilst operating and 200 G whilst parked. Most websites have these specs for all their drives. Look up the one you're looking at and see what it says.
Unless you're going to drive the thing over cliffs, I doubt this is likely to be a major problem. If it's really a worry, get a laptop drive, and mount it with those little rubberized things they often mount laptop drives with.
I really think vibration is more of an issue than absolute G force.., but some sort of shock mounting goes a long way.
If you're really worried about movement of the drive, build a shock enclosure that suspends the drive with elastic. Remember the "build a box that will keep an egg from breaking when dropped out the 2nd story window" experiment in high school science class? Think along those lines.
Thanks for your advice, both of you.
Ok, if acceleration isn't likely to be a problem (20Gs is probably unlikely - 9 or 10 at most when going over a nasty pothole at 70MPH), what about conservation of angular momentum?
When cornering, might the spindle servo be a little overlabored? Can any damage occur to the drive mechanisms (not the digital electronics) by turning the car quickly? (Note that I don't actually expect to drive the car so fast that I'd spin down the disk, but...).
Really, I'm not a dangerous driver! I just want to be sure a hard drive won't be damaged. Not that 4GB drives are all that expensive these days... So what the heck am I worried about?!
Peace,
Drew
One solution to this problem I have thought of is tape. If you are mostly wanting to listen to music you could have software that reads the next few songs into a RAM disk. Though it with low cost of small hard drives it might not be as practical as it was 4 years ago. Prehappes with some intelligent software you could load stuff into memory and spin down the drive.
On a hard drive I would for sure a laptop hard drive. The smaller platters would have a lower moment of inertia so the effects from changing of the drives position would not be as severe.
I might be thinking too far into this but the conservation of angular momentum is going to have quite an effect on the drive. The drive will have movement along a 3 axes while driving from turning pot holes and what not. This would cause the spinning platters to induce a torque on the whole drive along all 3 axes. I am kind of worried that this would place additional loads on the motor bearings and cause them to fail prematurely.
If you use a fairly new laptop drive, I wouldn't really worry about it. Unless you are driving on unpaved roads all the time you're probably not going to damage the drive. When I was working on F-15's, the data units that held the flight plans and what not were removeable hard drives. If they can stand up to that, they will survive in your trunk. I would be more worried about heat. I know my trunk gets pretty warm in the summer time, it's not really insulated from the exhaust. In the winter it can get well below zero.
What sort of chores have you in mind for this Suntra-Tatbird-mobile-thingy? What sort of storage capacity do you expect you'll need?
Why a use a desktop and not a PowerBook? Seems like a 'Book would be a better basis for an automobile-computer than a bulky desktop.
In any case, laptop drives are designed with the sort of shock resistance needed.
Dan K
Hi Dan!
(I think I might call it a "PontiMac" ... But that doesn't roll off the toungue very well, does it...)
Well, now that I've got a SGRAM SO-DIMM socket on the way, I've got a spare _working_ beige G3 motherboard and need something to do with it.
I agree that a laptop is a better platform, though.
All that I require the system to do is play QuickTime movies and MP3s. Extra wants include AirPort (actual AirPort - NOT 3rd party wireless) and DVD playback. Unfortunately, those aren't really possible for the beige G3. (A G4 would be better, but I haven't got any of those yet.)
Anyway, I've also got a whole heap of small-ish (2 - 8 GB) IDE drives. I could stick two of them in the box with the beige G3 board...
As for laptops, I've got a spare Wallstreet, but I don't really want to stick it in my car. A 3400c board would be better, but I don't have any of those either. The only other spare boards I've got are 5300-series, and they just don't have the horsepower I need. The only spare laptop drives I've got are 500 MB. Wrangling the power, space, and video requirements would be a LOT easier for a PowerBook.
Storage capacity doesn't have to be huge, but it does have to be at least 2 GB to make room for a decent library of MP3s.
Anyway, I'm only in the "thinking stage" of this hack.
Peace,
Drew
The angular force info is also available. Just go to wdc.com and look up the drive specs. That should give you the info you need.
OK, I'm intrigued now . . .
Music? Movies? DVD playback? MP3s on a CD-ROM?
You have an idea for an interface yet? LCD part of the mix? KB? Pointing device? Control from driver's seat or just accessable to passengers, or while stationary?
Hmm, in fact, having an entire bootable OS + files on a CD-R or DVD-R is an intriguing idea . . . rather like the olden days where one's entire MacOS 3.2, apps and docs could reside on one 400K floppy. :coolmac:
Set up the environment based on what you want to do, complete with scripts etc. Insert DVD, boot and it does what it does. Need another function? Just reboot to a different DVD.
Might not work too good though if jostled/bumped while reading data . . .
OK, how about this . . . Lombard with expansion bay HD modules, each bootable with whatever needed. Hmmmmm, not exactly the cheap route though, unless one has a Lombard and S-loads of HD EBMs hanging around.
OK, how about using those caddy things sold for mounting into desktop drive bays, allow 3.5" drives to be pulled and swapped and stuff. I forget what they're called, but widely available.
Dan K (too much thinking for now)
Yep, all of the above.
Actually, I wanted to use the beige G3 or a PowerBook because of the video-out on them - they can do composite video just fine with no scan converters needed. Car-bourne LCDs are cheap and widely available (Audiovox makes several for car DVD players in the ~$100 range. The previous owner of our new house left a PSOne portable LCD sreen behind. Sadly, it doesn't work - I took it apart and the innards are quite corroded. It looks like it drowned to death.) and take composite input. As for the software interface, I was thinking of a customized install of Mac OS with QuickTime, AirPort, AppleScript, Navigation Services, and some other goodies. The Finder would be replaced with an app I'd write in REALbasic (dead easy, actually) that would let me play MP3s, movies, and do some other odds & ends from a streamlined full-screen interface optimized for a 4" screen.
(The Finder is just an application. Rename any app to "Finder", change the type & creator codes appropriately, and place it in the System Folder... Presto - Finder replacement! That's a good trick for increasing the speed of Vitual PC, by the way. The downside is that the Finder isn't running. So you can't manipulate files, you can't launch other programs, etc. Whatever you need to do has to be handled in the code of your custom program.)
I thought about that, too. But the speed would be pretty slow. It might be possible, though. I was toying with that idea for a 6360-based car MP3 player a few years ago, actually.
Well that brings up an interesting idea. Can a USB-bootable Mac (like the Lombard?) be booted from a USB CF card reader? A whole bunch of interchangeable CF cards might work. The 256MB cards were $41 the last time I went to Costco. But even if it's not bootable from USB, you could put a CF card in the PC Card slot of a Wallstreet (Lombard and higher aren't bootable from PC Cards, IIRC... maybe...) and a FireWire or USB card, then on the end of the FireWire or USB cable attach a DVD/CD-ROM drive, some sort of controller (maybe one of those gamepad thingies), and a CF card reader for the "cartridges" of MP3s or QT movies, etc.
But that's starting to sound expensive.
Good suggestions and great food for thought!
Peace,
Drew
I'd expect that the kind of problems you'll run into will be not with the HD, but with cards and connectors working loose. This can especially be a problem with the PERCH personality cards.
Perhaps you could have small blocks of neoprene rubber mounted so that they apply a restraining force on the cards, RAM, etc, while still giving a little. I would suggest wrapping the case in some neoprene (aka wetsuit rubber), or any other kind of foam you can obtain, as well.
Just use high temp hot glue. The digital pic frame I built survived a fall from the wall after bouncing off a table. Everything was glued together, the frame broke and the glass had a smear of plastic from hitting the coffie maker. The little laptop was still running! Just have to get a new picture frame to put it in and a little more sturdy case and all will be good again.