00100	.require "good.pub" source_file;
00200	.LTR Defense Supply Service - Washington
00300	Room 1D-245
00400	The Pentagon
00500	Washington, D. C. 20310
00600	
00700	
00800	Attention:  Mr. Eugene Stubbs, Contracting Officer
00900	
01000	Subject:  Computer Equipment Purchase (SD-183 Capital Equipment)
01100	
01200	Reference:
01250	
01300	1.  Letter to Eugene Stubbs (DSS-W) from Lester Earnest (Stanford),
01400	    27 March 1973.
01500	
01600	
01700	Gentlemen:
01800	.fac
01900	This letter supplements my earlier communication (Reference 1) regarding the
02000	proposed purchase of capital equipment in support of our research
02100	program.  Each of the six items described in the
02200	Reference is needed to perform the contract (SD-183); the particular
02300	functions for which they are needed was described there.  Sole-source
02400	procurement is appropriate based on the
02500	following considerations.
02600	
02650	.next page
02700	SOLE SOURCE
02800	
02900	For visual information processing, we need a device that can do spatial
03000	filtering and similar signal processing at a rate of 10 microseconds
03100	per picture element or less.  This device must have a changable
03150	program store, so that it can switch tasks quickly.  As indicated in Table 1 of Reference 1,
03200	the SPS-41 Signal Processor more than meets the performance requirement.  We
03250	have made a survey of the market and find that it is
03300	the only commercially available device that meets these requirements.
03400	
03500	For operation and control, the SPS-41 is must be connected to the
03600	Unibus of a Digital Equipment Corperation PDP-11 processor.  For a processor
03700	of the PDP-11 class to control two mechanical arms concurrently, as
03800	we plan to do, it must execute something over 1 million instructions
03900	per second.  Of the various models of PDP-11, only the PDP-11/45
04000	is sufficiently fast.  Hence it is uniquely suited to this application.
04100	
04200	As shown in Figure 1 of Reference 1, the needed 3*65K*16 bit memory
04300	is to be connected to the Unibus, the PDP-11/45 memory bus, the
04400	SPS-41, and the Video I/O System.  Thus it is to have four ports.
04500	In order to keep the processors running at full speed, the memory
04600	must have a cycle time of 500 nanoseconds or less.  In order to be
04700	able to digitize and display television images, the memory must be
04800	able to sustain a bandwidth of 120 million bits per second or more.
04900	We require a memory system, completely wired, although we can do
05000	minor interfacing if needed.
05100	
05150	Based on a rather extensive study of the market,
05162	there are several memory systems available that could be configured
05175	to meet our performance requirements, but that greatly exceed the
05187	amount that we can spend under our budget (about 1 cent per bit).
05200	There is only one memory system available that is satisfactory in all respects, namely
05400	an Intel system based on their CU-10 and MU-10 modules.
05800	
05900	The Video I/O and PDP-10 Interface systems (see Figure 1, Reference 1)
06000	are unique devices that are not available from any manufacturer.
06100	Consequently, we propose to fabricate them from available components.
06200	
06300	Principal considerations in the selection of portable terminals are
06400	portablility (low weight and compactness), low noise (in consideration
06500	of office and home environments where they will be used), and
06600	keyboard/character set compatibility with our existing system.
06700	We have 64 display stations connected to our computer at present
06800	and would like to minimize confusion that would be caused by departures
06900	from our standard keyboard layout.
07000	
07100	On the basis of portability requirements, there appear to be just
07200	two acceptable devices on the market: the Execuport 310 and the
07300	Texas Instruments 725.  Two considerations dictate the selection
07400	of the TI device:  the noise level of the Execuport exceeds our requirements
07500	and its keyboard layout is different
07600	from our standard.
07800	Thus we choose the Texas Instruments 725.
07900	
08000	LEASE/PURCHASE
08100	
08200	Of the various devices under consideration, only the portable
08300	terminals are available for lease.
08350	
08375	We expect to use the portable
08400	terminals for at least four years and they should be expected to have
08500	some value at the end of that time.
08700	The TI 725 leases for $111 per month (not including maintenance)
08800	and sells for $2,895.  On this basis, the breakeven point is just
08900	over 26 months.  Thus, it is more economical to purchase.
09000	
09100	I hope that this provides sufficient information for the review
09200	of our request.
09300	
09400	.lde
09500	.begin verbatim
09600	
09650	
09675	
09700	cc:  J. Ducey, ONR
09800	     A. Blue, S. Crocker, L. Roberts, ARPA
09900	.end