Method and apparatus for transferring coordinate data between a host computer and display device

• US 5,274,794 A
• Filed: 01/22/1991
• Issued: 12/28/1993
• Est. Priority Date: 01/22/1991
• Status: Expired due to Fees

• Current Assignee: Tatung Company
• Original Assignee: GraphOn Corporation
• Inventors: Eckert, William A., Ewing, Bland
• Primary Examiner(s): Harrell, Robert B.
• Assistant Examiner(s): Coleman, Eric
• Application Number:
  US07/643,738
• Time in Patent Office: 1,071 Days
• Field of Search: 395/500, 395/200, 358/11
• US Class Current: 345/428
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

The method and apparatus for efficiently storing or transmitting related sets of data such as X, Y coordinate data determines the resolution of a display device and the transmission limitations of a communication channel to the display device and encodes a selected portion of the bitmap for display with associated offsets and additional information as a complex number according to a variable-radix polynomial, where the number is segmented into selected bytes for transmission within the operating limitations of the communication channel for decoding and restoration of offsets by the display device.

Claims

1. A method for transferring a set of data whose members (A'"'"', B'"'"' . . . n'"'"') have selected independent ranges of values between a host computer and a remote device along a communication channel, comprising the steps of:

for each member (A'"'"', B'"'"' . . . n'"'"') of the set of data, determining a range of values the member may take on, each range having a magnitude (AMag, BMag, . . . , nMag) indicating the size of the range;

for each member (A'"'"', B'"'"' . . . n'"'"') of the set of data, selecting an offset value (AOffs, Boffs, . . . , nOffs) associated with said member;

transferring to the remote device information regarding the magnitudes (AMag, BMag, . . . nMag) of the ranges and the offsets (AOffs, BOffs, . . . , nOffs) associated with the members of the set of data;

deriving a set of translated data (A, B, . . . , n) by subtracting from each member (A'"'"', B'"'"' . . . n'"'"') of the data set the offset (AOffs, BOffs, . . . , nOffs) value associated with said member; and

converting the set of translated data (A, B, . . . n) to a single number (V) in accordance with the equation;

##EQU4##

2. The method of claim 1 wherein the communication channel includes operating limitations, the method comprising the additional step of:

determining a number of data words required to communicate the set of data to the remote device along the communication channel in accordance with a first logical combination which multiplies the magnitudes (AMag, BMag, . . . nMag) of the ranges with each other to produce a multiplied range magnitude, and which successively divides a number of times the multiplied range magnitude by a number (R) of available different values that can be transferred in a data word along the communication channel to yield zero quotient, said number of times constituting the number of data words required to communicate said set of data.

3. The method according to claim 2 comprising the additional steps of:

communicating the number (R) of available different values to the remote device along the communication channel; and

determining the values of the data words to send to said remote device in accordance with a second logical combination which successively divides the value (V) by the number (R) to yield remainder quantities for transfer to the remote device along the communication channel.

4. The method according to claim 3 for transferring the values of the data words along a communication channel operable on a set of ASCII codes, the method comprising the additional steps:

modifying the values of the data words in accordance with a third logical combination which adds 32 to the value of each data word to produce an altered value of data word, and which adds 33 to any altered value of data word greater than 126; and

supplying the modified data words to the remote device.

5. The method according to claim 3 comprising the additional steps of:

accumulating in the remote device a plurality of remainder quantities in sequence;

retrieving the accumulated remainder quantities in reverse sequence for reproducing the value (V) in accordance with the inverse of said second logical combination;

forming the set of translated data (A, B, . . . , n) from the reproduced value of (V) in accordance with the inverse of said equation; and

restoring each member (A'"'"', B'"'"', . . . n'"'"') of the set of data by adding to each member of the set of translated data (A, B, . . . , n) a corresponding offset value (AOffs, BOffs, . . . , nOffs).

6. Apparatus for transferring a set of data whose members (A'"'"', B'"'"' . . . n'"'"') have selected independent ranges of values between a host computer and a remote device, comprising:

means for determining, for each member (A'"'"', B'"'"', . . . n'"'"') of the set of data, a range of values the member may take on, each range having a magnitude (AMag, Bmag, . . . , nMag) indicating the size of the range;

means for selecting, for each member (A'"'"', B'"'"' . . . n'"'"') of the set of data, an offset value (AOffs, BOffs, . . . nOffs) associated with said member;

a communication channel connected for transferring to the remote device information regarding the magnitudes (AMag, BMag, . . . , nMag) of the ranges and the offsets (AOffs, BOffs, . . . , nOffs) associated with the members of the set of data;

deriving means for deriving a set of translated data (A, B, . . . n) by subtracting from each member (A'"'"', B'"'"', . . . n'"'"') of the set of data the offset (AOffs, BOffs, . . . , nOffs) value associated with said member; and

means for converting the set of translated data (A, B, . . . n) to a single number (V) in accordance with the equation;

##EQU5##

7. Apparatus according to claim 6 wherein the communication channel includes operating limitations, further comprising:

means for determining a number of data words required to communicate the set of data to the remote device along the communication channel in accordance with a first logical combination which multiplies the magnitudes (AMag, BMag, . . . nMag) of the ranges with each other to produce a multiplied range magnitude, and which successively divides a number of times the multiplied range magnitude by a number (R) of available different values that can be transferred in a data word along the communication channel to yield zero quotient, wherein said number of times constituting the number of data words required to communicate said set of data.

8. Apparatus according to claim 7 further comprising:

means for communicating the number (R) of available different values to the remote device along the communication channel; and

means for determining the values of the data words to send to said remote device in accordance with a second logical combination which successively divides the value (V) by the number (R) to yield remainder quantities for transfer to the remote device along the communication channel.

9. Apparatus according to claim 8 for transferring the values of the data words along a communication channel operable on a set of ASCII codes, the apparatus further comprising:

means for modifying the values of the data words in accordance with a third logical combination which adds 32 to the value of each data word to produce an altered value of data word, and which adds 33 to any altered value of data word greater than 126.

10. Apparatus according to claim 8 further comprising:

means in the remote device for accumulating a plurality of remainder quantities in sequence;

means for retrieving the accumulated remainder quantities in reverse sequence for reproducing the value (V) in accordance with the inverse of said second logical combination;

means for forming the set of translated data (A, B, . . . , n) from the reproduced value of (V) in accordance with the inverse of said equation; and

means for restoring each member of the set of data (A'"'"', B'"'"', . . . , n'"'"') by adding to each member of the set of translated data (A, B, . . . , n) a corresponding offset value (AOffs, BOffs, . . . , nOffs).