STANFORD UNIVERSITY
                     Stanford, California 94305


COMPUTER SCIENCE DEPARTMENT                    Telephone 415-321-2300
                                                       extension 4202
                             May 7, 1973


Defense Supply Service - Washington
Room 1D-245
The Pentagon
Washington, D. C. 20310


Attention:  Mr. Eugene Stubbs, Contracting Officer

Subject:  Computer Equipment Purchase (SD-183 Capital Equipment)

Reference:

1.  Letter to Eugene Stubbs (DSS-W) from Lester Earnest (Stanford),
    27 March 1973.


Gentlemen:


This  letter  supplements  my  earlier  communication  (Reference  1)

regarding the  proposed purchase of  capital equipment in  support of

our  research  program.   Each  of the  six  items  described  in the

Reference is needed to perform the contract (SD-183);  the particular

functions for which they are needed was described there.  Sole-source

procurement is appropriate based on the following considerations.
Defense Supply Service - Washington                            Page 2


SOLE SOURCE


For  visual information  processing,  we need  a device  that  can do

spatial  filtering and  similar  signal processing  at a  rate  of 10

microseconds per picture  element or less.   This device must  have a

changable program  store, so  that it can  switch tasks  quickly.  As

indicated in Table 1 of Reference 1, the SPS-41 Signal Processor more

than meets the performance requirement.  We have made a survey of the

market and  find that  it is the  only commercially  available device

that meets these requirements.


For operation  and control, the  SPS-41 is must  be connected  to the

Unibus of  a Digital Equipment  Corperation PDP-11 processor.   For a

processor  of  the  PDP-11  class  to  control  two  mechanical  arms

concurrently, as  we plan  to do,  it must  execute something  over 1

million instructions  per second.  Of  the various models  of PDP-11,

only the PDP-11/45 is sufficiently fast.  Hence it is uniquely suited

to this application.


As shown in Figure 1  of Reference 1, the needed 3*65K*16  bit memory

is to be connected to the Unibus, the PDP-11/45 memory bus,  the SPS-

41, and the  Video I/O System.   Thus it is  to have four  ports.  In

order to keep the processors  running at full speed, the  memory must

have a cycle time of 500 nanoseconds or less.  In order to be able to

digitize and display  television images, the  memory must be  able to
Defense Supply Service - Washington                            Page 3


sustain  a bandwidth  of 120  million bits  per second  or  more.  We

require a memory system,  completely wired, although we can  do minor

interfacing if needed.


Based on a  rather extensive study of  the market, there  are several

memory  systems  available  that  could  be  configured  to  meet our

performance requirements, but that greatly exceed the amount  that we

can spend under our budget (about 1 cent per bit).  There is only one

memory system available that is satisfactory in all  respects, namely

an Intel system based on their CU-10 and MU-10 modules.


The Video I/O and  PDP-10 Interface systems (see Figure  1, Reference

1) are unique devices  that are not available from  any manufacturer.

Consequently, we propose to fabricate them from available components.


Principal considerations in  the selection of portable  terminals are

portablility   (low   weight   and   compactness),   low   noise  (in

consideration  of office  and home  environments where  they  will be

used),  and keyboard/character  set compatibility  with  our existing

system.  We  have 64  display stations connected  to our  computer at

present and would like to minimize confusion that would be  caused by

departures from our standard keyboard layout.


On the basis of portability requirements, there appear to be just two

acceptable devices  on the  market: the Execuport  310 and  the Texas
Defense Supply Service - Washington                            Page 4


Instruments 725.  Two considerations dictate the selection of  the TI

device: the noise level of the Execuport exceeds our requirements and

its keyboard layout is  different from our standard.  Thus  we choose

the Texas Instruments 725.


LEASE/PURCHASE


Of  the  various  devices  under  consideration,  only  the  portable

terminals are available for lease.


We expect to use the  portable terminals for at least four  years and

they should be expected to have  some value at the end of  that time.

The TI 725 leases for $111 per month (not including  maintenance) and

sells for $2,895.  On this basis, the breakeven point is just over 26

months.  Thus, it is more economical to purchase.


I hope that  this provides sufficient  information for the  review of

our request.


Sincerely,



Lester D. Earnest
Executive Officer
Stanford Artificial Intelligence Laboratory



cc:  J. Ducey, ONR
     A. Blue, S. Crocker, L. Roberts, ARPA