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Master Buffer for Image System Work Station of Communication Network

IP.com Disclosure Number: IPCOM000079341D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 57K

Publishing Venue

IBM

Related People

Audretsch, LM: AUTHOR [+5]

Abstract

Fig. 1 shows a block diagram of a work station in a communication network including image processing capability.

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At least one non-text object (such as an image or picture) has been suppressed.
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Master Buffer for Image System Work Station of Communication Network

Fig. 1 shows a block diagram of a work station in a communication network including image processing capability.

The Master Buffer provides 256K bytes of shared random-access memory, which is utilized for all random-access memory functions in the work station, thus effecting savings in memory cost.

The Master Buffer provides the following: approx. 184,000 bytes - Image Raster Refresh Buffer (for 8 1/2'' x 12'', 120 lpi. image)

2,700 bytes - A/N (Alpha-numeric) Dictionary of

character matrices.

6,120 bytes - A/N Record Buffer for keyed-in characters.

1,300 bytes - Data Transmission buffers (four 256-byte

messages) approx. 50,000 bytes - Program and Table Storage for the Controller which functions as a

miniprocessor.

Fig. 2 shows the Master Buffer space allocation for the above.

Fig. 3 shows a timing chart which illustrates the scheduling of the various accesses to the shared Master Buffer.

The DCE - Display Control Element - accesses the Master Buffer to obtain a 128-byte image raster line. It does this 722 times, at 22 mu sec intervals, pauses while the vertical retrace is performed and then repeats the 722 line accesses.

The Communication Logic accesses the Master Buffer up to 4 times every 22 mu sec to fill and/or empty the 256-byte message buffers.

The controller - a miniprocessor - accesses lower memory - 0 to 64K - to perform conventional program instructions, store data, manipulate tables, lists, etc.

The controller also accesses memory on each key-stroke.
1) To place the EBCDIC code for the keyed-in character into

the A/N record buffer.
2) To obtain, from the A/N dictionary, the 140-bit (10 x 4

character matrix) raster image representation of the keyed-in

character.

The controller next accesses upper memory - the image raster refresh buffer - to place the 140-bit character matrix into the appropriate character position in the 8 1/2'' x 12'' image.

Since the controller has an address space of only 64K bytes (16 lines), it utilizes a base register in the buffer control unit to shift its address up into the 2nd, 3rd or 4th quadrant of the buffer address space. This register is set by the controller program via a...