Beer and nuts..... Always a good combination... Although it is only 8:00am here, it is always "Happy Hour" somewhere, and we are an international group! Cheers!

David> Kind of off the wall, but the issue came up in a discussion David> here, and want to get some solid numbers... David> June 2004 Disk Capacity [IDE 5.25] = 250 Gig [approx] June David> 2004 Disk Surface Area (total) = ??? Sq inches Average David> Capacity per Sq Inch = ??? Today's drives are usually 3.5 inch enclosure size. The generation that goes up to 250 GB has about 80 GB per platter; coming up any day now is 120 or so GB/platter. I'm not sure about the platter size. Call it 3 inch diameter for a rough guess, that makes perhaps 10 square inches once you take the hub out. So that means 8 GB per square inch. David> RP06 Disk Capacity = ??? [100+ MB] RP06 Disk Surface Area David> (total) = ??? Sq inches Average Capacity per Sq Inch = ??? RP06: 176 MB, 19 surfaces, 14 inch diameter, so maybe 100 square inches per surface, so about 0.1 MM per square inch. David> The above numbers would yield a hypothetical capacity for a David> disk (pack) this size (and number of platter) of an RP06..... David> This was brought up in part by seeing a row of 8 RP-06 drives David> and marveling at the size [floor space] required for just David> about 1 Gig of disk.... Sure, and the RP06 was pretty impressive in its day. Go back a bit more to the RK05: 2 surfaces, somewhat bigger than the RP06 (smaller hub) -- but let's ignore that. 2.4 MB capacity. So that gives 12 kB per square inch. Back a bit further... the CDC 6603 (early 1960s). 100 MB per cabinet. (This is a fixed media, moving head drive.) 32 surfaces, so that's 3 MB per surface. Not sure how big those platters are -- 25 inches perhaps? If yes, that would make about 400 square inches per platter, so about 7.5 kB per square inch. Hm, not much less than the RK05. The 6603 is also MUCH faster because it records data 12 bits parallel (using 12 heads simultaneously) for a transfer time per sector of about 500 microseconds. That's about 1 MB/s (322 12-bit words per sector) -- compare with RK05 at 6 microseconds per byte if I remember right, so 1/6th the speed about 8 to 10 years later than the 6603... Then again, in fairness, the 6603 looks like a 6 foot high by perhaps 8 feet wide rack... and probably cost 20x to 50x an RK05/RK11 combo. paul

Tom, I am well aware that there are significant reasons why this is a "non-real-world" comparision [I worked at Veeco Instruments for a numver of years developing IBE/IBD tools for the manufacturer of disk drive heads]. It is just an "interesting" comparision. A wall of RP06's is less than 0.5% the capacity of a single IDE/ATA hard drive. You can now create tera-byre arrays in a single 4u rack slot. The ironic part is that I keep filling up the darn things faster and faster. I remember when all of my work fit on a few DECTapes! David.

If you are going to compare yesterdays disk's with today's, you should probably use IBM DASDs rather than the RP06. For many years IBM was the big cheese in the disk world. William Donzelli aw288(a)osfn.org

Tom> Areal comparisons don't hold, thermal expansion alone prevents Tom> just increasing capacity physically. It's not a coincidence the Tom> bigger drives are physically smaller. I'm not sure why thermal expansion would matter; the servo can track that trivially. to spin faster while maintaining acceptable size spindle motors, and of course to reduce the seek distances. Access times for high end disk drives are in the single milliseconds now -- that includes BOTH an "average" seek and the time for 1/2 rotation. Apparently, 15,000 rpm drives (high end fibre channel drives) have lower capacity than slower drives not just because the areal density is less, but also because the platter is smaller. You're getting what is effectively a 2.5 inch drive packaged into a 3.5 inch chassis. The reason the platter is that small is that you can't spin a 3.5 inch sized platter at 15k rpm with acceptable motor power. All this means that the modern way to large capacity is to combine lots of (physically) small drives -- in other words, RAID. That also gives you fault tolerance, and increased performance by putting more heads to work. Tom> Encoding for modern data densities has long abandoned the Tom> simplistic schemes used in the deep past, too, and require tons Tom> of logic and software support to pull off. Yes, and this is all packaged in just a small handful of hairy ASICs. Modern data encode/decode schemes involve complex digital signal processing at very uncivilized speeds... paul

I'm looking for the windows software for the Transtronics/Intronics Pocket Programmer 2 EPROM Programmer. I've lost my installation disk and I had to reformat my system, so I need to re-install the software. Transtronics wonderful [sic] customer service declared that I must re-purchase the software for $49. This is insane - it's not like I might be trying to steal their software to use on another device... It's propriatery to the hardware. If someone has a disk image of the installation they could send me, that would be great, or if someone knows the password that's needed to unlock the downloadable version, that would be just as good. I paid enough money for this device, and it's something I use only maybe once or twice a year to burn a couple of EPROMs, so I really detest their customer service policy of having to pay $49 to get the software again. Thanks for any help... - Bob

Antonio> We ship plenty of FC drives at work - the "lower capacity" Antonio> here means (typically) 130GB instead of 250GB. They cost Antonio> more too! Those are the 10,000 rpm ones. The 15,000 rpm ones are smaller still. paul