T H E U N I V E R S IT Y OF M I C H I G A N Memorandum COMPARATIVE EVALUATION OF DIGITAL EQUIPMENT CORPORATION'S 340 AND 330 DISPLAY CONTROLS Stephen F. Lundstrom F. H. Westervelt, Project Director ORA Project 07449 supported by: DEPARTMENT OF DEFENSE ADVANCED RESEARCH PROJECTS AGENCY WASHINGTON, D. C. CONTRACT NO. DA-49-083 OSA-3050 ARPA ORDER NO. 716 administered through: OFFICE OF RESEARCH ADMINISTRATION ANN ARBOR June 1966

This evaluation was compiled during the development of the display specifications for one of the remote display consoles at The University of Michigan. The DEC 330 Display is the name given the DEC 338 Buffered Display when it is supplied without the PDP-8. For purposes of this evaluation, the 330 and 340 are configured with standard options to have, as much as possible, the same capabilities. The evaluation is divided into three basic sections. The first is a cost comparison. The second is a comparison of the execution time and instruction size for the basic operations causing display of information. The final section, which comprises the bulk of the evaluation, compares the equivalent instructions in each display. The 330 Display Control is clearly the best display on an economic and technical basis. When these displays are compared in the environment of a PDP-7, one more factor should be noted. The 340 Display has a fair amount of software support on the PDP-7. The 330 Display can use the same display programs as the 338, but the control programs must be translated to the PDP-7 from the PDP-8. When the 330 Display is used on the PDP-7, only the low order 12 bits of the 18 bit word are used for display programs. This fact allows the display structure to be imbedded in a higher order data structure which could use the high order 6 bits for other information pertinent to the data structure. Thus, the 330 Display is probably the best display to connect to the PDP-7 in a research environment. In a production environment, more weight will probably have to be given to the software support of the 340. 1

Cost 340 Display 330 Display Item Subtotal Item Subtotal Display $25,800 $25,800 Subroutine Interface 3,358 29,158 $37,000 $37,000 Light Pen 1,625 30,783 Pushbutton Box NA Character Generator 11,600 42,383 6,000 43,000 10,000 $53,000 (DEC Interface) Interface to PDP-7 900 435283* or 1,000 $44,000 (U of M Interface) *Note: If the $5,000 cost of an additional pushbutton box on the 330 Display is used as an estimate for a pushbutton box on the 340 Display, the total 340 Display cost is $48,283.

TIMING AND INSTRUCTION SIZE (Display Instructions) Speed (~isec) Display No. of Core Accesses Mode Condition Nonintensified Intensified Speed per 541-0 330 540 330 540 330 Points close 2 1 or 2 36.8 6.5 36.8-71.6 Point together (including graph) Points far apart2 1 or 2 56.8 ss~s 56.8-7l,6 5. apart 5. 3. Short (7 bits) (4 bits) vector 1 1 Vector Vector and (7 bits) (10 bits) vector con- 1 20 1.2 tinue Increment 1/4 1/2 2.25 0.25 2.25 1.2 Character Character 1/5 1/2 + 5 355 -8 -40 350 Character

340 330 POINT I O1 1 2 3 4 51 6 1 7 1 8 9 10 11 121131141151 16117 #1 o 1 21 3 141 51 6 7 8 9 10 11 PLOT,, m l IP ),D 0 0 CL ~ PI4CD c- 'r - I I o cF CD SD H cF Fct - 0 M M HD ctct T -C ~ 0 ' HF 0 3 o -2 ') 2 3 4 6 7 8 9 CD 0 c'- 0 c O P O X or 0 (D _I ~~0' o C NOTES: NOTES: Requires two words if both coordinates are to change. Requires two words, even if only one coordinate Mode of the next instruction must be specified. changes. Next instruction assumed to be a point plot, unless the escape bit is set. TI2ING: TIMING: Nonintensified = 36.8 psec. Nonintensified-same as intensified Intensified = 36.8 - 71.6 prsec. Intensified, close to last C 6.5 psec. (regardless of position relative to the last point) Intensified, far from last 35,5 psec.

340 330 GRAPH #I 0 I 2 13 4 T 5 |6 7 8] 9 |0I 1 PLOT Not Available I CD H Rr s o wr O H e NOTES: Requires one word. Next instruction assumed to be a graph. plot unless the escape bit is set. TIMING: Nonintensified = 0.3 isec Intensified close to last = 6.5 usec Intensified-far from last =35.5,sec O~~~~~~~3. YY s e c

340 330 VECTOR #1 o 1 21 31 4 151 6 7 8 1 9 10111 112 113114115116117 #1 O 2 3 4 5 6 7 8 910 11 and VECTOR M H )+ +) F' CONTINUE + CD ' C+ 1O~ -1 0\ x D N t =" Inesfe0. sc 0 c+ NOTES: NOTES: On times one scale, maximum vector size is 1/8 of raster size. On times one scale, maximum vector size is the full Only one core word required. raster size. Mode of next same unless escape. Two core words required. Mode of next is same unless escape. TIMING (per point): Nonintensified or intensified = 1.5 Lsec. TIMING (per point): Nonintensified = 0.25 psec. Intensified = 1.2 [isec.

340 330 SHORT Not Available!o 12 31415 16171 8 9 011 I1 VECTOR (Use Vector) T I H |+ w to 1+ X CD tD 0a 5D C F CNOTES: On times one scale, maximum vector size is 1/64 raster size, Requires only one word of core. TIMING (per point): Nonintensified = 0.25 Lsec. Intensified = 1.2 psec.

340 330 INCREMENT O I 2 3 4 1 5 6 7 1 8 1 9 110 111 121131141151161171 O 2 3 4 5 6 7 8 9 10 I ~ r I I I I I I TJ N H NOT S:N H 0m o of nr ts i o o CD ID b (C (0 p i t Noninte nsi f D Dd o N0 tCD Oy the m i m o o o i CD t _ t (D directions for each increment instruction, primary directions. Four instructions are packed per word. Two instructions are packed per word. Mode of next same unless escape. Mode of next same unless escape. TOIING (per point): TIMING (per point): Nonintensified or intensified = 2.25 Plsec. Nonintensified = 0.25 psec. Intensified = 1.2 zsec.

340 330 CHARACTER 0 112 3 4 5 176 7 18 19 1101111312113114115116117 012 314151617181 910111 (Optional) t La 0 W pj ro ~~~~~~~~~~~~~ o t C) 0 co c) 0 0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~0 C+ ~~~~~~~~Ct- Ct Ct (D ~ ~ ~ ~ ~~( (D C NOTES: NOTES: Character generator is e fixed character set. Characters are 6 bit code specifies an address in a dispatch drawn by moves around a 5 x 7 matrix, table. The dispatch table holds pointers by display sequences describing the characters in increment or short vector instructions. TIMING (per character): TIMING (per character): Variable - average time 35-40 Psec. Variable - average time 35-40 alsec.

bo F Intensity ~ -- JJ 4,, o _O - Enable Intensity S e t I -- Light Pen Enable Status d O ~(0 I - Enable Light Pen Status Set P4 A O) _ 0 o _ Scale ao d o Id O r() - Enable Scale Set k _-h ) 0 a.o o 0 (Control State op Code for Parameters) t m Intensity L) Enable Intensity Change - Scale _J - - Enable Scale Change Not Used D0 _ n ItruStops Display and Generate an Interrupt (or not) (_ - Light Pen Enable Status LO - Inhibit Change of Light Pen Status Mode of next instruction Not used o J w aC 10

-- Intensify 0 - Light Pen Activate 0 _ -- Set Unit 1 I 0 - Intensify - - Light Pen Activate 43 O D - Set Unit O 1 -_ - - i Slave Group Number rw' - (1) o _ c (O) o o 4o) (Control state op code for set slaves) 43 _- - Intensify (D - Light Pen Activate Unit 4 U) - Set Slave Unit 4 - Light Pen Activate Unit 3 - Intensify 0 - Light Pen Activate Unit 2 0) - Set Slave Unit 2 OD - Intensify - Light Pen Activate Unit 2 CD - Set Slave Unit 1 _I - Not Used Mode of next instruction - I Slave Group Number Oo W, O 0 _J c 0 11

340 330 SUBROUTINE 01 2 3 14 15 6 7 1 8 19 1101111121131141151171 *1 0 1 2 3 4 5 6 78190111 MODE (JUMP) I-it ' LY C TI - T__J td0 o~~~~~~~~~~~~~~~ 'd (R~~~~~~0W n - 0 M A.~~~~~~~~~~~~~~~~~oh 5 " I CI 00H CD Q H a5 H eD 'I C+ 0 > ( ~~~~~A ~ ~ ~ ~ ~pCo+ I O II I2 t4 Cd t4 0~~~~~~~~~~~~~~~~~~~~~~~~ 4 M 0~~~~~~~~~~~~~~~~~~~~ 0 0 CD O CDC+:3 ctm M I 5 02~~~~~~~~~~~~~C CD ( C+-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~C 2; v~~~~~~~~~~~~~~ 00 Not Used 2 0H1 2 0'4WI.60 01 Stored the number in the address save register as a jump instruction with Y that number as address in the address specified PIr\ 10 Display Jump (simple control Cump) 0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ M 0' O ~~~~~~~~~~~~~~~~~~~~~~~~~CD4 01 Display tump and save the address of this instruction plus one in the__ address save register. NOTES: NOTES:: No provision for saving display status on subroutine entry. Requires 2 words. The total jump address size is 15 bits. The push saves the (current address plus one), light pen status, scale, mode, and intensity on a pushdown list.

340 330 POP Not Available ol0 1 2 3 4 5 6 7 8 9 10|11 1" —rI i T I I I I N M N W H F N o H W m X e p cF c & M CT c+ Ct Ci CF 5 0 0 t O as et t0 n i s oc o Scale and Light Pen Setting overrides the inhibits. entry on the pushdown list.

- Not Used -- Not Used, - Up (O), Down (1) 3O - Count Intensity - Up (0), Down (.1) D -- ~ Count Scale _n (1) (1) r (0) (Control State Op Code) CM (o) (1) 0 Z - O W Z o -J O z > O O 00 z - Enter Data State H I- = U) < Z 07 Clear Coordinate Bits (low order 10 bits ofI _ ~ 13 bit display address) Clear Sector Bits (high order 3 bits of _ 13 bit display address) o Display State Mode ~ ( J H Enable Displayta State Mode Set - Clear Display address).4 - Stop Display (& Generate Processor Interrupt) _- - 1 (A Control State Op Code) o J 1 o

O) Value of PBO-5 or PB6-11 to be tested L-) - O-PBO-5; 1-PB6-11 _ (0) O)0 0 r) (a) 0 (O) ) - Control State OP Code (1) r0) 0 (1 N)1() as 0 O mW O- L- C. sH 0n <rl - O0 00 H_ - - PB5 or PBll Z - PB4 or PB1 -PB3 orPB9 - PB2 or PB8 r- - PB1 or PB7 _O - PBO or PB6 I) - Complement Selected Bits After Successful Test - Clear Selected Bits After Test 10 _ro -- Sense of Test 0-test for O's, 1-test for l's - Test PBO-51 Control State OP Code O a _ 4 0 a o 3C) o y 15

INSTRUCTIONS AVAILABLE ON THE 330 (NOT AVAILABLE ON THE 340) SKIP ON 101 I123 1 4151 61 7 18 9 10111 AUTOMATIC SCISSORING The capability of automatic scissoring H H o o o I I I I I and specification of "paper" size is FLAGS k H CI CDi C c2 c2 provided with the 13 bit X and Y adF-.GS C~.~,1,1 M 0 dress registers. 'd ~-~ 'd ' P C aJ }, iff g ~] UC H C1- i v m m m~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~_ - o 0 iF-u 'i a ~o Q Mopo o H+ PI PI-O o r~~~~~~~~~~~C aF-\J1 Ct oo H G\ a o (D c+ 4Pi a H 0 a pD maU PI~~~~~~a 0-0 0 0 0 Cj CD

IOT INSTRUCTIONS (PDP-7 to Display) 340 330 1. Read display address counter 1. Read display address counter 2. Skip on edge violation 2. Skip on edge flag 3. Display resume 3. Display resume 4. Skip on stop interrupt 4. Ski- on stop flag 5. Clear display address counter 6. Load display address counter (display start) 7. Skip on light pen flag 5. Load display address counter (start display) 3. Read display coordii-nes (9 high order bits 6. Skip on light pen flag only) 7. Read X coordinates 9. Clear flags 3. Read Y coordinates (read status 2 for high order X & Y bits) 9. Read push down pointer 10. Read status 1 11. Read status 2 12. Read status 3 13. Read status 4 Not Available 14. Read status 5 15. Set push down pointer 16. Set initial conditions 17. Skip on slave light pen 18. Load break field, 6 pushbutton, stop display 19. Special options 20. Skip on manual interrups

UNIVERSITY OF MICHIGAN 11 11011 JJ1115 032 112111 11111 3 9015 03023 7112