Path: utzoo!utgpu!cunews!bnrgate!bigsur!bnr-rsc!bcarh185!schow
From: schow@bcarh185.bnr.ca (Stanley T.H. Chow)
Newsgroups: comp.lang.misc
Subject: Re: Sorting
Message-ID: <3717@bnr-rsc.UUCP>
Date: 19 Nov 90 18:27:38 GMT
References: <11628@alice.att.com>
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Reply-To: bcarh185!schow@bnr-rsc.UUCP (Stanley T.H. Chow)
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In article <11628@alice.att.com> dmr@alice.att.com (Dennis Ritchie) writes:
>This group has turned into a sewer, as bad as talk.origins
>(even the people I might politically agree with are acting dumb).
>
>But I do have a serious question.  I've got a boxcar with 10,000 8-mm tapes,
>each containing 10,000,000 100-byte binary records
>without any substructure.  I need to get these records sorted.
>Can someone quote me a cost and expected delivery time?

Ordinarily, I avoid topics like this. Seeing that it is Dennis Ritchie, just
my be I can get rich on this after all, so here is my proposal. :-)

Assumptions: Input - you hand me a boxcar of tapes, (figuratively speaking)
	     Output - I throw you 10,000 tapes back; in sequence, one tape
		      at a time (hope you have a good catching glove).
		      (Each output tape has 10,000,000 records exactly).
             Sort Key - is the entire 100-byte record, duplicates are
			allowed.

Observations:
	     1) Key space is 2 ** 800 (roughly 6 * 10 **240)
	     2) total "file" size = 10,000 * 10,000,000 * 100 bytes
				  = 10 ** 13 bytes.
             3) Companies like SyncSort Inc. (and others) make their money
		soving problems like this. 
                             
I will give you two quotes:

  1) Minimum turn-around time.

     I will need a bunch of tape drives along with a bunch of disk drives
     connected by a network. Stuf an input tape into each tape drive, read
     the records and throw each record into a disk. Unload the input tapes,
     load blank output tapes, and copy 10,000,000 records onto each tapes.

     Elapse time: approximately two times R/W time of a single tape.

     Cost: option a: you provide the hardware
		     I charge 1% of the hardware cost for processing.

           option b: I provide the hardware
		     Sorry, I want to get paid in my life time, so I can't
		     wait for the delivery of all that hardware.


  2) Minimum hardware cost.

     I will buy a really cheap CPU (Commodore 64 comes to mind), hook up a
     single tape drive.

     [I will skip the gory details of how. If you really want to know how,
     look up any sort program on the mainframes - SyncSort is a good example.
     They will tell you how to do it will three drives, cutting down to a 
     single drive is simple, but tedious]

     Elapse time: approximately the expected life time of the universe.

     Cost: option a: Total payment up front - $10K (negotiable)

	   option b: pay as you go: nothing down,
                                    $10 a month for the duration. (negotiatable).


>
>This is just the start of a burgeoning business; next week
>I expect a full trainload of 100 such boxcars.
>What will this cost and how long will it take your company
>to handle it?

By a remarkable coincidence (and extreme lazyness), my quotes for this problem
are exactly the same as the previous smaller problem. This conclusively
demonstrates the advantage of dealing with a service-oriented compnay like
us - "The same price for all your problems". 

Stanley Chow        BitNet:  schow@BNR.CA
BNR		    UUCP:    ..!uunet!bnrgate!bcarh185!schow
(613) 763-2831               ..!psuvax1!BNR.CA.bitnet!schow
Me? Represent other people? Don't make them laugh so hard.