From: d...@alice.att.com (Dennis Ritchie)
Subject: Pike patent claims
Date: 5 Mar 91 08:37:40 GMT
Organization: AT&T Bell Laboratories, Murray Hill NJ
To forstall misunderstanding, I typed in the abstract and claims
of the famous patent. It is US Patent 4,555,775, inventor
Robert C. Pike, assigned to AT&T Bell Laboratories, filed Oct 7, 1982,
effective Nov 26, 1985. All typos are mine.
Dynamic generation and overlaying of graphic windows for multiple
active storage areas
A graphic terminal is disclosed using bitmaps to represent plural
overlapping displays. Graphics software is also disclosed in which
the overlapping asynchronous windows or layers are manipulated
by manipulating bitmaps. With this software, the physical screen
becomes several logical screens (layers) all running simultaneously,
any one of which may be interacted with at any time.
What is claimed is:
1. A computer terminal display system comprising
a display surface,
means for simultaneously displaying a plurality of overlapping
rectangular graphic layers on said surface, wherein
each of said graphic layers comprises an autonomous
level of graphical information,
means for associating each of said graphic layers with an independent
means for storing a complete bitmap for each of said graphic layers, and
means responsive to the associated one of said independent computer
programs for continuously updating each of said bitmaps.
2. The display system according to claim 1 wherein said bitmaps
for all partially obscured ones of said graphic layers comprise
a plurality of partial bitmaps of obscured layers linked together.
3. The display system according to claim 2 wherein said interactive
means includes a keyboard.
4. The display system according to claim 1 further comprising means
for selectively interacting with any one of said graphic layers.
5. The display system according to claim 4 wherein said interacting
means comprises a graphical cursor device.
6. The display system according to claim 1 further comprising
means for selectively displaying any one of said graphic layers
in the topmost unobscured position.
7. A graphics terminal comprising
a graphics control device, and
programmed apparatus for controlling said terminal, said
means responsive to said control device for creating a plurality
of overlapping display layers on said display, wherein each of
said display layers comprises an autonomous level of graphical
means for associating each of said display layers with an independent
computer program, and
means responsive to said keyboard for interacting with any selected
one of said display layers to create, execute, and display
the output of and independent computer program.
8. The graphics terminal according to claim 7 further comprising
means for creating a bitmap corresponding to each of said
display layers, and
means for maintaining each said bitmap current in response to said
9. The graphics terminal according to claim 8 further comprising
means for creating a separate partial bitmap for each obscured
portion of all said layers except the top layer, and
means for maintaining an obscured bitmap list of all such
partial bitmaps for each said layer.
10. The graphics terminal according to claim 9 wherein each said
obscured bitmap list includes a specification of the size and
position of the associated one of such layers.
11. The graphics terminal according to claim 7 where said means for
creating, executing, and displaying the output of independent
computer programs includes a digital computer remote from said
graphics terminal, and
means for communicating between said graphics terminal and
and said remote digital computer.
12. The method of supporting a plurality of virtual computer graphical
terminals on a single physical terminal including a display screen
comprising the steps of
identifying a plurality of overlapping working areas on said screen,
associating each said working area with an independent computer program,
selectively communicating data to each said program through its
associated working area, and
continually displaying the output from each said computer program
on its associated working area.
13. The method according to claim 12 further comprising the step of
maintaining full bitmaps of each of said working areas,
including both visible portions and portions obscured by others
of said working areas, and
utilizing said obscured area bitmaps to record corresponding portions
of the output of said associated programs.
14. The method according to claim 13 further including the step of
maintaining a list of all the obscured area bitmaps associated
with each of said working areas.
15. The method according to claim 14 further including the step of
selectively bringing any one of said working areas to full visibility
by assembling said obscured area bitmaps.
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