|Format 1 (7 bits for character (CH) selection):|
|123||Move the beam to (x.y)|
|124||Enter Format #2 mode at (x,y)|
|125||Draw a line to (x,y)|
|126||Advance film 1 frame|
|127||Display a point at (x,y)|
|2 bits for character size control|
|1 bit for intensity control (bright or normal)|
|1 bit for orientation (erect or rotated 90 degrees CCW)|
|1 bit to select a focus level (sharp or fuzzy)|
|10 bits for the x coordinate|
|10 bits for the y coordinate|
|Format 2 (The Typewriter Mode):|
|1 bit for intensity control|
|7 bits to choose a character; CHi = 0 to 122, where i = 1 to 4|
|Note: Device stays in Format 2 until CH1 is 123 or higher|
|Display a point at (x,y)||4 microseconds|
|Draw a line to (x,y)||6 to 42 microseconds|
|Draw a character||9 microseconds|
|Frame advance||about 30 milliseconds|
|IGRAPH (i,j,k)||Initialize the display and allocate j words starting at i for display buffer memory. k = minimum buffer size used for a naned picture part.
Later, if i is not zero, then the display is active and j = unused buffer size
|NAME (A,N)||Designate a picture part named A with light pen value n|
|CLEAR(A)||Clear a picture part A|
|IN (A)||Enter the picture part A into the display list|
|OUT (A)||Remove the picture part A from the display list|
|RUN (M)||Turn the Display on continuously if M = 0, if M < 0 run the display for M cycles|
|trACK (X,Y, N)`||Display the tracking cross at (X,Y). If it sees display light set n=1; update (X,Y)|
|NtrACK||Stop following the Light Pen|
|LPEN (N, X, Y)||The Light Pen value N was seen by the Light Pen at (X,Y)|
|STOREC(i1,C1,i2,C2,i3,C3,I4,C4)||Construct text and add it to the current picture part|
|STORE (construct a
|Construct one display word and add it in the current picture part. The structure of a display word was given earlier|
Click on an image to view it at full size.
The dd-80 direct view CRT in between two dd-50s. Each dd-50 was associated with a CDC 6600 system; the one on the left, and the red leather chair came with serial #1 of the 6600. A manager (naturally) appropriated the chair for his office--rank has its privileges. ./images/dd80-1.jpg
This is a view of the dd-80, serial #1, with the camera unit in the left background. The dd-80, when first delivered, was first interfaced to an IBM 709, then to an IBM 7090, and finally to the 7094. On the left of the 7094 console is a card reader able to read 150 cards per minute. At the extreme left of the picture is an IBM line printer; rated at 150 lines per minute. In front of the dd-80 camera unit are two I/O engineering consoles because we had two channels. The dd-80 was interfaced through one of the I/O channels to a special unit that provided a 36-bit data item to the dd-80 every 6 microseconds. Also visible in the center background are the two core memory units for the 7094. Each housed 16k of 36-bit words.
This is an interesting and amusing picture of the dd80's 5" CRT along with the Flight Research 30 fps camera. The spots on the face of the CRT are permanent magnets glued to its face. Instead of expensive and slow electronics ordinarily used to compensate for barreling and pin cushioning in the display raster, these magnets accomplished all that was needed to remove these aberrations, and at no cost. The engineer, Bob Mann merely used the pattern generator pictured on the top of the CRT housing to display the four lines that defined the edges of the displayable area and placed the magnets so that the lines were as straight as possible. Simple, elegant, and effective.
A view of our second dd-80, this one interfaced to a CDC 6600, showing the camera unit mounted on a solid, 2-inch thick table of aluminum. A rough analysis indicated that no unwanted vibrations would bother the camera. I thought it was a mistake not to mount the CRT on the same table as the camera. However, it never seemed to matter; vibrations were not a problem
Another view of the dd-800 installation on the CDC6600. Note that the manager, by this time, had appropriated the red leather chair for his office, leaving some decidedly lower quality chairs for those who needed to sit at these consoles. Actually, people hardly ever had the luxury of sitting and working at these stations, but to complete the story, we (in good jest) often escorted certain visitors to the manager's office to see the red leather chair. He never gave any explanation other than that the chair was too good to be left in a computer room.
The dd-80 was fast. Norman Hardy produced a simple demonstration of a 2-dimensional hydrodynamics program for presentation on the direct-view console. The version shown used an 8 x 8 mesh to show the responses to a variety of forces applied on all four sides. Most of the parameters needed could be adjusted by program. If one wished to make a movie of the calculation, a 15 x 15 zone version of the problem ran at the speed of the camera; 30 frames per second. With suitably adjusted densities and equations of state, the mesh vibrated like a piece of gelatin, and this name stuck to the demonstration. Aside from being amusing, the computation was helpful for new employees in visualizing phenomena like elasticity or computational instabilities.