🚀 go-pugleaf

+---- In article <109@hobbes.UUCP>, I wrote: ----
| ( Paraphrased from an article in the Capital Times, March 1987)
| more than 1,000 optical disks ... to give 2 Tera Bytes of storage.
| (For comparison shopping, note that this is equivalent to
| 40,000,000 9-Track tapes, 4,000,000,000 Floppy Disks, a stack of paper ....
+----
+---- Philip Kos responded in <1067@osiris.UUCP> ----
| I can't speak for the stack of paper, but according to my calculations,
| 2T/40,000,000 is about 54976 and 2T/4,000,000,000 is about 550.  Now, if
| they're talking *paper* tape, then maybe I can figure the 54976, but hell,
| even an RX01 holds more than 550 bytes!!  Either I'm off by an order of
| magnitude (or three) or somebody else is.
| 
| John, did you seriously mistype these numbers or is this really what was
| in the article?  I could say something here about using marketing numbers
| without independent verification, but I had probably better shut up... :-)
+----
+---- David desJardins also responded in <3220@jade.BERKELEY.EDU> ----
|    Come on now.  Please at least think about what you are saying before
| you post it to the whole world.  If 2 x 10^12 bytes were the equal of 4 x 10^9
| floppy disks, then that would mean 500 bytes on each disk.  Somehow I think
| our technology has advanced slightly beyond that.
+----

  OK, so I didn't verify the numbers printed in the newspaper (I assumed... :-)
The exact quote:
	    "The system will eventually store as much as two terabytes on
	more than 1,000 optical disks, the equivalent of six copies of
	the 1980 U.S. Census or a stack of paper three times the size of
	Mount Everest, Thompson said.
	    Each disk stores the amount of data that would be held on 40,000
	reel-to-reel magnetic tapes or 4 million floppy disks."

    The first paragraph was comparing to the complete 1000 disk system,
the second was comparing to ONE DISK, so

	4,000,000 Floppies * 1,000 Optical disks = 4,000,000,000 Floppy disks
	   40,000 Tapes    * 1,000 Optical disks =    40,000,000 Tapes

Some simple stuff I *should* have done before posting:
	media per optical disk     bytes per media        bytes per optical disk
	----------------------     ---------------        ----------------------
	4,000,000 floppy disks *   360 Kbytes per floppy = 1,440,000 Mbytes
	   40,000 Tapes        *    40 Mbytes per tape   = 1,600,000 Mbytes
	
Compare with:   2 Tbytes       /   1,000 Optical disks   =     2,000 Mbytes

The second paragraph SHOULD be refering to the *complete* system.


The 'correct' numbers would be:
	2T / 360K = 5,425,347 Floppy Disks	("4 million floppy disks")
	2T /  40M =    48,828 Tapes		("40,000 reel-to-reel...")

Mea Culpa...  (That's why the paper is known locally as the "Crap Times")

-- 
 John Plocher		UUCP: <backbone>!uwvax!uwmacc!hobbes!plocher
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