From: utzoo!decvax!cca!CAULKINS@USC-ECL@sri-unix Newsgroups: net.works Title: CPU-per-user architectures Article-I.D.: sri-unix.1477 Posted: Sun May 16 22:52:22 1982 Received: Mon May 17 04:20:24 1982 Here's a series of exchanges concerning my suggestion of CPU-per-user architectures in WORKS Digest V2 #151. My apologies for repeating some stuff from earlier digests, but I don't believe the trains of thought would be clear otherwise. Date: 5 May 1982 2250-PDT From: CAULKINS at USC-ECL Subject: Re: WORKS Digest V2 #51 To: Deutsch at PARC-MAXC cc: CAULKINS In response to your message sent 4 May 1982 16:42 PDT Any interactive workstation is going to need "case, keyboard, CRT, and other non-computer elements". So the savings is strictly in (1) the extra packaging not required for the processors and memories, and (2) the sharing of the disk. I don't see that making the difference between "less than $2K" and $5K. What did I miss? [Several points: 1) The manufacturing wizards at my company tell me that the cost of all non- silicon parts of a workstation type device (case, power supply, et al) is 30 - 50% of the total cost of the device. These things are not rapidly cost-declining technology like the silicon parts. 2) The workstation folks have not gotten nearly as far up on the economy of scale curves as the terminal manufacturers - I can get a very respectable terminal for $450 today; about 10% of the $5K workstation price. Until and unless a lot of shaking out takes place the workstation manufacturers are unlikely to achieve terminal-like scale economies. 3) Two important workstation/CPU-per-user architecture parts - hard disks and power supplies - have decidedly convex cost-per-unit-resource curves; $/amp and $/megabyte decrease markedly as the capacity of the PS or disk drive goes up. The CPU-per-user wins here because many users share bigger disks and power supplies. Conclusion - cost/effectiveness favors an architecture taking full advantage of economies of scale in terminals, disks, and power supplies; and one with a maximum amount of value in silicon as opposed to plastic, iron, and copper. Dave C] ------- Date: 6 May 1982 09:20 PDT From: Deutsch at PARC-MAXC Subject: Re: WORKS Digest V2 #51 In-reply-to: Your message of 5 May 1982 2250-PDT To: CAULKINS at USC-ECL Hm. What you say about workstations and terminals may be true for the current generation of character-display terminals. It certainly isn't true (at least not yet) for bitmap displays. The price of $450 for a character-display terminal (including an interface to some kind of shared bus, Ethernet, or serial line) seems low to me, and the price of $5K for a workstation is much too high if it doesn't include a disk. I.e. I think you need to distinguish the disk-sharing part of your argument (which I basically agree with) from the power-supply part (which I am less sure about) and the processor/memory part (which I think is more complex than you make it out to be). Date: 6 May 1982 09:24 PDT From: Deutsch at PARC-MAXC Subject: P.S. Re: WORKS Digest V2 #51 In-reply-to: Your message of 5 May 1982 2250-PDT To: CAULKINS at USC-ECL It seems to me that your statement that "the cost of all non- silicon parts of a workstation type device (case, power supply, et al) is 30 - 50% of the total cost of the device. These things are not rapidly cost-declining technology like the silicon parts." actually suggests the opposite conclusion from the one you want to draw. If the case, keyboard, and CRT cost essentially the same for a workstation or a terminal (which they do) and they represent a growing fraction of the device cost (which you assert they do, i.e. their cost is declining slower than that of memory and logic), then as time goes on it becomes LESS important to share those parts of the device (the processor and memory) whose cost is dropping. 16 May 82 I (Dave Caulkins) finally get some time to continue this discussion: One thing I think we've learned about the economics of modest (under $5,000) computing equipment is that it is very price-elastic, and in a non-linear way. The success of Apple, Sinclair, Tandy, etc. seems to indicate that when the price for a particular unit of computational capability is lowered by N% (where N is 10 - 50), the market for this particular unit grows by much more than N%. This suggests to me that it makes more sense (from a marketing point of view) to lower cost than it does to expand capability, given that a particular computational capability can be made available for a lower cost. I'll apply some crude cost rules-of-thumb to illustrate: Assumptions: 1) The ratio between the packaging (case/keyboard/CRT/power supply) cost and the total cost (the packaging plus the electronic (ICs/PC board/disk) parts) of a workstation (WS) type device is 0.4; i.e. (total cost)*0.4 ~= packaging cost 2) The retail price of a workstation type device ~= 4 *(total cost). 3) A reasonable non-bit-mapped terminal has a current retail price of $500, quantity 1. My entire case is based on non-bit-mapped systems; it is not clear to me that bit-mapped displays contribute that much to the value of a workstation. This is, of course, a highly subjective judgement. Using these numbers and a workstation price of $5000, then: 5000/4 = 1250, WS cost 1250 * 0.4 = 500, WS packaging cost 1250 - 500 = 750, WS electronics cost 750 * 4 = 3000, WS electronics price 3000 + 500 = $3500, WS electronics plus terminal price, the approximate price per user for a CPU-per-user architecture. This represents a 30% savings over the ordinary WS price, quite substantial enough to induce the non-linear price elasticity mentioned above. -------