laptop at launches

Slide rules are shockingly powerful tools in trained hands. Do not poo poo slide rules. Rocketry problems are particularly slide rule compatile.

Jerry

On Wed, 01 Oct 2003 13:27:13 GMT, Jerry Irvine is alleged to have written:

Agreed, 100%.

One thing I absolutely *love* about slide rules is that they force the user to think about, and account for, orders of magnitude and significant figures. Too many people nowadays simply plug numbers blindly (and often incorrectly) into their calculators, and come up with wildly wrong answers, and insanely precisely specified answers.

Silly (but common) example: calculating the surface area of a triangle. Dimensions given: height = 21.2 inches, width of base =

11.3 inches. OK.... A = 1/2 * W * H, so, plugging into my calculator, and missing one of the decimal points, I get 1192.15, which the idiots will call "the answer". It's wrong, for several reasons.

First of all, it's off by an order of magnitude. Half of 20-ish times

10-ish should be 100-ish, not 1000-ish. If I'd been using a slide rule, I would have thought about this, and wouldn't have flubbed the decimals.

Secondly, it's way too precise. I only have 3 significant figures in my measurements, so I CANNOT have more than 3 significant figures in my answer. I just *do* *not* *know* the answer to that degree of precision. Accuracy is irrelevant beyond the precision of your measurements.

Using a slide rule, I'll see *immdiately* that I only have three significant figures in each of my measurements, so my answer can only have 3 significant figures, as well. With a good slide rule, coming up with the right answer is easy:

Line up 1 on the slide rail with 1.13 on the fixed rail. Multiply by

2.12 by moving the line on the slider to the 2.12 mark on the slide rail. Divide by 2 by moving the 2 mark on the slide rail to line up with the line on the slider. Read the answer off the fixed rail under the one on the slide rail. You should have 1.19, which, taking into account the magnitude of the numbers involved, translates to 119 square inches, the correct answer.

Simple, faster than punching the numbers into a calculator, and easier to get the *correct* answer. I just wish that schools today would teach the use of slide rules, as they would help prevent some of the rampant innumeracy out there....

- Rick "Too young to be an old codger, damnit!" Dickinson

So . . .

This should be in the FAQ.

Another good idea! Thanks

da rmr plumber Gary R Goldenbaum NAR #73669 L1 Northwest Florida remove 'nichspam' to reply

Done. Thanks, Chris

da rmr plumber Gary R Goldenbaum NAR #73669 L1 Northwest Florida remove 'nichspam' to reply

one more thing. for easy "changes" to this kind of system. go on ebay. for $30-$50 depending on ebay mood get a ENclosure for 2.5" hard drives (I suggest Firewire but they have usb and usb2 as well)

then you can yank the drive pop it in the enclosure and plug into you main laptop or desktop and transfer information quickly and effeciently both ways.

USB 2 is faster than firewire.

Don't use USB 1

comparisons: USB 1: 1.5 mb/s USB 2: 60 mb/s firewire: 50 mb/s

I have full size hot swap trays on USB 2 in a couple machines... can't imagine how anyone gets along without it. I can do an EIDE hot-swapping RAID 0 (mirror) because of this, without using serial ATA OR SCSI.

~Duane Phillips.

Indeed, usb 2.0 is FAST. I used a usb 2.0 60 gig hd to backup my system. Using native w2k Veritas backup it takes about 59 minutes for

35 gigs. No compression though. Just love the speed.

It would be cool if there's such a thing as a usb 2.0 to firewire adapter. From what I can tell that's just not possible unless someone knows of a way.

Ted Novak TRA#5512

Isn't this machine a 486? USB2 or Firewire on a 486??

Very interesting, and y'all are very knowledgeable... but...

Laptop... Rockets... Launch... Software...... Focus?

For HPR... G-wiz, R-Das, GPSFlight, APRS, ALT4, Rocksim, FinSim, AeroCFD, TurboCad, Excel, Word, Ulead, Aiptek (and other camera download software), an Eprom burner along with some floppies, an internet connection with links to the National Weather Services, findu, etc.

For 'park flyers'... all of the above and the PDF files for all available Model Rocket Kit plans, tips for quick repairs, suggestions to prevent common launch problems, lists of Range box contents (including 'quick repairs', glass, epoxy, tape, EXTRA igniters), a List of things to bring to a Launch (sunblock, water, fire extinguisher, tarp)...

Etc. etc... the lists are still being compiled. No ones' got it perfect yet.

Hell, man... bring along a printer and print out your stuff and REALLY impress 'em and draw 'em into the sport!

1.5mb per second ain't fast enough?!? Ya can't PRINT stuff that fast!!!

yes. Hard to do on an old laptop, but there are PCI adapters add-in cards for USB 2.0 on an AT case (provided your old 486 board has PCI slots...). Most common boards did not add PCI until the Pentium era.

~Duane Phillips.

1.5 mb/s is only a tad faster than a 3.5 floppy disk drive speed... maybe twice the speed... but still, no, it ain't fast enough. Maybe for the purposes of a range computer... but having to work with PC's every day, I do everything I can to "spruce" them up.

~Duane Phillips.

Saw something like this at Microcenter today;

It might be a stretch if it would work on that 486 laptop.

Ted Novak TRA#5512

Checked it out... I noticed they are comparing it to USB 1... 1394 is slower than USB 2.

But could still be a nice PCMCIA card if you have something to hook up to it... USB 2 seems to have won in the majority of the marketplace.

~Duane Phillips.

For the exception of digital camcorders :(

I really wish there was a adapter to go from usb 2.0 to firewire.

Ted Novak TRA#5512

Are you sure belkin doesn't have one? How about a drive body as a converter? Put an ATAPI dongle on the drive hardware. Hot pluggable converter.

Jerry

not really. actually throughput on firewire ends up be faster than usb2

usb2 has a technical speck that is faster. it has not yet been realized (google some comparisons)

firewire is peer to peer.

usb requires a host. hence more overhead and it actually ends up slightly slower than firewire >

no firewire on the desktop jacked into a 2.5" hard drive cradle.

he can then "yank" the drive from the laptop and place in cradle.

Very effecient means of backup and new software addition of the laptop is lacking a CD drive.