perm filename VIEW1[ESS,JMC] blob sn#166625 filedate 1973-05-15 generic text, type T, neo UTF8





                 VIDEO DISPLAY REQUIREMENTS


     Introduction


     The USC/Information Sciences Institute is interested in

purchasing  a  CRT terminal system to be used in conjunction

with the ARPA computer network.  The terminals will be  part

of  the  user's  office  environment and will be used as any

other tool (e.g.  telephone) by the staff in the performance

of their duties.  Most of the offices are in close proximity

to a communication processor (which  is  interfaced  to  the

ARPANET)  in  a  clustered  environment;  however,  a remote

capability is required.


     The basic terminal should consist of a high quality  TV

monitor  and  keyboard  with  required  control  logic.  The

predominant  use  of  the  terminal   will   be   for   text

(alphanumeric)  communication with TENEX: however, a quality

graphics capability is also required.   The  problem,  which

should  dictate  the  architecture of this display system is

how to provide high quality graphics to a limited number  of

terminal  users  without prohibitively taxing, in dollars or

capabilities, the text-only users.  The graphics requirement

has  two aspects: a l)mat%d !nd tL`i
)ted n1mBdr of vector3,

Hf e!mNo)icaLlq f%asible, all dhsplay controllers should  be

provided  with  a limited graphics capability.  The graphics

requirement assumes compatibility with a  variety  of  input

devices  (e.g.  light, pen, tablet, mouse,etc.) which can be


                                                    Page   2



added to the terminal as required.


     Impiled  in  the   statements   of   requirements   and

performance  of the display system is knowledge of the state

of the art of graphics systems.  This should not  deter  the

vendor from suggestions for improving performance.


     Consideration of response to  this  RFP  will  only  be

given  to  digital  systems of a high resolution raster scan

display.   The  raster  scan  is  required   to   insure   a

flicker-free   display   without  concern  for  the  display

content.  The resolution of the system must display  a  full

page  of  text  (typed,  single  space,  approximately 4,000

characters).  The high resolution of  the  display  is  also

needed  for the quality of vectors desired.  The stipulation

of an all digital system is consistent  with  a  requirement

for  maintainability  and  reliability.   It is also assumed

that a  quantized  video  display  produces  better  images,

simplifies the video distribution system and the TV monitor,

takes advantage of current  digital  technology,  and  makes

more  feasible  an  all solid-state approach, simplifies the

registration  problems  with  input  devices,  and  is  more

compatible with a desired modular building blook approach.


     An additional goal for the  display  system  design  is

production   of  a  terminal  that  minimizes  the  required

centralized  equipment.   This  results  in  minimizing  the

differential  per  unit cost of single and multiple terminal


                                                    Page   3



clusters.  With a minimum of required centralized equipment,

the goal of terminal remoteness can better be realized.  For

the most part, the required terminal configuration  will  be

in   close   proximity   to  the  interfacing  communication

processor.  It is expected that economic considerations  may

dictate  packaging  some of the components in a central unit

or multiplexing some of the logic.  This economic  advantage

should  not  compromise the display terminal architecture in

such a way that the stand-alone  unit  cannot  be  assembled

from the same set of building blocks.  The control commands,

character and vector order codes shall be identical for both

the local and remote teminals.


     The computer terminal system developed as a  result  of

this  procurement  will  be  a high quality state of the art

instrument for  the  computer's  user  environment.   It  is

within  the charter of this institute to assist in providing

improved products for general use throughout  the  industry.

Therefore,  in  selecting  a  vendor to produce this display

system, consideration will be given to the vendor's  ability

not  only  to produce this prototype system, but also to the

survivability of the product  should  it  be  in  demand  by

others.


             VIDEO TERMINAL SYSTEM REQUIREMENTS


     The clustered video terminal system is perceived  as  a

collection  of  building blocks, all available on demand and


                                                    Page   4



shared by the users via  automatic  control.   These  blocks

consist  of  the  TV  monitors, character generators, vector

generators, refresh memories  and  interface  controls  (see

Fig.   1).   The  TV  monitor  shall have a raster format of

1,280 points per line and 864  visible  lines.   The  raster

shall  be 2 to 1 interlaced and operate with composite video

(separate sync may be considered) with EIA  sync  standards.

The  monitor shall operate with either black or white video,

with  the  predominant  use  to  be  black  on  white.   The

generators  are interfaced to the computer system with up to

19.2K bits/sec teletype-like (EIA RS-232C)  channel.   These

ports  will  be provided by a communications processor to be

interfaced  to  the  ARPA  network.   The   generators   are

dynamically  tied to the terminal through a video switch and

video distribution system as  required  by  the  user.   The

raster  refresh  memory is also an on-demand resource and is

only required for the full graphics user.


                                                    Page   5



                *********************************      *
        *       *                               *    *
PDP-10  *       *       INTERFACE MESSAGE       *   *  ARPA
        *<----->*                               ****
TENEX   *       *           PROCESSOR           *   * NETWORK
        *       *                               *    *
                *********************************      *
                              / * 
                                *
                                *
                               * /
                *********************************
                *                               *
                *       COMMUNTICATIONS         *
                *          PROCESSOR            *
                *                               *
                *********************************
                      / *               * 
                        * 20 19.2 KBIT  *
                        *    PORTS      *
                        *               * /
     *  *************************************************
      * *       .       .       .       .       .       * 20 CHAR GEN
*********       .       RASTER GENERATORS       .       * 20 VECT GEN
*     * *       .       .       .       .       .       * 4 RASTER BUF
*    *  *************************************************
*               *                               *
*               *       VIDEO OUT - 20 LINES    *               
*               *                               *
*              *                                * /
*       *************************************************
*       *                                               *
*       *       VIDEO SWITCHES     (20 X 40)            *
*       *                                               *
*       *************************************************
*               *                               *
*               *                               *
*            *                                     *
*       *******                                   *******  
*       *     *                                   *     *
*       *     *                                   *     *
*********     *         40 TERMINALS              *     *       
        *.....*.    .    .    .    .    .    .    *.....*
        *******                                   *******

         FIGURE 1:  BLOCK DIAGRAM OF A VIDEO DISPLAY SYSTEM - CLUSTERED

                                                    Page   6



                    CHARACTER GENERATORS


     Twenty  character  generators  consisting  of  a   font

memory,   character  buffer,  and  control  logic  shall  be

provided.   The  operation  of  these  generators   produces

characters  "on  the  fly" in synchronism with the raster of

the TV monitor.


     The character generator shall produce 80 characters  of

fixed  spacing  per  line,  and 54 lines of text.  The total

addressable  raster  (for  16  x  16  bit  characters)   is,

therefore  1,280  x  864 points.  The font memory shall have

256  symbol  descriptions   simultaneously   available   for

character  generation.   These memories shall be writable at

speeds compatible with the  communications  interface.   The

font  memory  shall consist of a 16 x 16 bit matrix for each

symbol which includes character spacing, line  spacing,  and

an  addressable  point  for every point in the raster matrix

for a given character position.  This is necessary  so  that

symbols  can  be constructed with multiple characters (e.g.,

straight lines appear continuous  from  character  space  to

character   space).    Flexibility  in  character  fonts  is

required, and any one of a number  of  known  techniques  to

implement this is acceptable.


     The aspect ratio of the character  shall  be  2  to  1,

length  to  width,  so  that  the density of the addressable

display points is also 2 to  1.   These  bit  densities  are


                                                    Page   7



required  to  produce the required fonts as well as minimize

the  calculations  for  vector  generation.   The  character

buffer  shall  store the 8-bit ASCII characters at a rate up

to 19.2K bits, per second,  as  required  by  the  interface

logic.  The buffer capacity shall be 4,320 8-bit words.


                     VECTOR GENERATORS


     Vector generators shall be of two  types:  limited  and

unlimited  capacity.   Twenty  limited vector generators are

required.  The limited vector generator shall be capable  of

presenting  128  vectors  per  display frame time (60 Hz) in

synchronism with the  interleaved  raster  display.   Vector

order  codes,  specifying  end  points in X and Y , shall be

received unordered at rates up to 19.2K bits per second  and

stored  in  vector  buffers.   The  vector  generator  shall

generate video, as required, to depict the line to the  best

fit of the addressable points.  Vector length for the entire

diagonal of the display  area  shall  be  allowed.   Vectors

shall  be  selcetively  erased  by  removal  from the vector

buffer.   It  is  desirable  that  vectors,  or  strings  of

vectors,  carry  tags  for  identifying  the  vectors  to be

erased.


     The unlimited vector generator shall employ the  vector

generator  described  above  as a component, with additional

components to increase the vector capacity to at least 4,000

vectors.   If  vector length is a sensitive parameter in the


                                                    Page   8



design  of  the  vector  generator,  the  vectors  shall  be

considered to be one inch.  The use of raster storage (1,280

x 864) is one way of achieving unlimited vector  capability.

Four unlimited generators shall be required with the ability

to  switch  the  generator  to  any  of  the  40  terminals.

Techniques  using  increased  vector  buffers in combination

with  vector  generators  are  also  acceptable  to  achieve

unlimited  vector  capability.   In  the  latter  case,  the

quantity of generators required will be dictated by economic

factors.


                         TERMINALS


     The current  requirement  is  for  40  terminals.   The

terminals   consisting  of  high  quality  TV  monitors  and

electronic keyboards, shall be packaged suitable for  office

installation.  Although the specifics of the display quality

are not being detailed, the quality of the TV monitor is  of

extreme  importance.   The  specifications  of  the  display

surface, light output,  spot  size,  distrotion,  etc.   are

expected  with  the  response  to  this  RFP.   The terminal

design, appearance, and human factors consideration must  be

approved   by  the  Institute.   The  TV  monitor  shall  be

primarily used in  black  on  a  white  background.   It  is

desirable  to have a switch for white on black display.  The

digital video does not require gray levels.


                                                    Page   9



     The  keyboard  shall  include   the   completee   ASCII

character  set,  the  keyboard  shall  provide  some type of

tactile  feedback  when  striking  keys.    Feedback   shall

indicate  a  keystroke  has  occurred.   Some  form  of  key

contention  roll-over  is  required.   N-key  roll  over  is

desirable.  


     Terminal  mobility  shall  be  provided  by  use  of  a

wheel-type  typewriter  stand  or a wheeled integral base if

necessary.


     The  vendor's  proposed  design  should  consider   the

ability  to  use  these  same  building blocks with a remote

stand-alone terminal.  This configuration shall require  the

EIA  RS 232C type interface at a switchable rate from 300 to

19.2K baud.


     Additional   elements   required   in   the   suggested

configuration  are  video switches.  The video connection to

the terminal is not part of this RFP.


     The video switch is required to dynamically connect  20

generators   to  40  video  output  jacks.   The  switch  is

controlled by terminal demand and whenever an assignment  is

made,  the  selected  switch  shall  remain  until  the user

becomes inactive (logged out).  The switch must function  in

much  the  same  manner  as  a  line finder, as in telephone

terminology.   This  means  responding  to  the   terminal's


                                                    Page  10



request  for  service  by  providing  one  of  the  20 video

generators.  The requesting signal may be a  tone,  keyboard

input,  continuous  polling,  a  D.C.  level change, etc.  A

busy response of a tone or light shall be provided when  all

video  generators  are in use.  The 20 generators shall also

be available via another switch to the 4  refresh  memories.

The output of the 4 refresh memories shall be made available

to any of the  40  video  output  jacks  of  the  switch  in

response  to  a  terminal  request.   Refresh  memories  are

synonymous with unlimited vector generators.


     The video drivers must be capable of driving 300' of RG

59/U  and  producing  a signal compatible with the monitors'

input requirements and display quality.


     The communication interface shall use  the  full  ASCII

character  set, full duplex, 8-bit bytes, asynchronous up to

a 19.2K bits/sec rate.  An  alternative  of  variable  input

rates  for  the  keyboard,  of 300 to 2,400 bits/sec, may be

considered.


                    DESIRABLE ATTRIBUTES


     The  performance  requirements  of  the  terminals,  as

stated  above,  can  be  improved  in  a  variety  of  ways,

depending on economic considerations.  There  are,  however,

additional  highly  desirable attributes for the Institute's

applications which could be included in the proposal.  These


                                                    Page  11



are:


            * The 40 terminals and 20 generators required at

     the  present time may soon be insufficient.  The system

     should be open-ended to allow for growth of  additional

     terminals   or   generators,  without  making  existing

     hardware obsolete.


            * A  two-page  display  of  approximately  8,000

     characters on a single screen.


            * Variable character spacing up to a maximum  of

     100 characters per line.


            * Consideration of future expansion of character

     capacity  up  to  twice  the  present  size.  These 256

     character descriptions will be performed  with  a  full

     8-bit ASCII character set.


            * Line width control, rather than gray level  or

     color for video modifiers.


            *  A  monitor  switch  for  compatibility   with

     standard commercial video (525 line).  


            * If separate sync for the computer  display  is

     proposed,  the standard TV mode switch shall also solve

     the sync problem for the 525 line display.


                       DOCUMENTATION


                                                    Page  12



The procurement of the terminal system  shall  also  include

documentation   sufficient   for   maintenance   and  future

expansion   or   modifications   of   capabilities.     This

documentation  shall include a verbal description, logic and

schematic diagrams, and specifications  and/or  vendor  part

numbers  for all the elements and sub-assemblies used in the

fabrication of  the  terminal  systems.   The  documentation

shall  be  of  commercial  quality with consistent logic and

flow diagram symbology.


(Figure 2.)


                                                    Page  13



        *************************************************
        *                       *                       *
        *                       *                       *
        *   CHARACTER/          *       TERMINAL        *
 SERIAL *       VECTOR          *                       *
 DATA   *         GENERATOR     *                       *
********                        *                       *
  300 - *                       *************************
  19.2K *                       *                       *
  BITS  *                       *                       *
        *************************************************

  FIGURE 2:  BLOCK DIAGRAM OF STAND ALONE TERMINAL