Memory Map, Programming Language, and Windows

1
Memory Map, Programming Language, and Windows

• Dr. Harold D. Camp
• IT 212 002
• 15 February 2007

2
PC Memory

• PC computer memory is divided into segments,
• 64 kilobytes each (65,536 bytes, to be exact)
• Segment register in microprocessor indicates
  segment is to be accessed
• Segment 0
• Contains memory pointers, device drivers,
  buffers, input/output ports, and other essential
  information required by the computer and its
  operating system
• Segment 0 contains 65,536 memory addresses
• Figures on next pages show how different portions
  of memory are allocated

3
PC Memory

• Figure 1 displays the entire contents of the 64K
  memory block that makes up Segment 0
• Each pixel represents the contents of one memory
  location
• Each horizontal row in the display represents one
  256 byte page

4
PC Memory

• The numerical values (in decimal) indicated by
  the different colors are shown in Figure 2
• Blue areas indicated contain lots of zeros
  alternating with small numbers
• Memory set aside that has not yet been put to use
• 8 colored blocks located between H4100 and H8000
  are probably associated with the 32 buffers that
  are indicated to be located there
• The areas with random color patterns relate to
  device drivers and hardware extensions, which are
  actually computer programs
• Areas of memory that are white are likely bits of
  unused memory that still contain the default
  hexadecimal value of FF (255 in decimal).

5
PC Memory

• Figures 3 and 4
• Each colored line contains the mean value of one
  256 byte page of memory
• Colored bands make it easier to see how different
  portions are allocated for different uses
• For instance, the blue-green and green blocks
  appear to be for data storage, since the buffers
  are located there
• Gray areas correspond to the areas where machine
  code is located
• The dotted lines in the gray zones that resulted
  from conversion from bitmap to gif format

6
PC Memory

• Figures 3 and 4
• Each colored line contains the mean value of one
  256 byte page of memory
• Colored bands make it easier to see how different
  portions are allocated for different uses
• For instance, the blue-green and green blocks
  appear to be for data storage, since the buffers
  are located there
• Gray areas correspond to the areas where machine
  code is located
• The dotted lines in the gray zones that resulted
  from conversion from bitmap to gif format

7
PC Memory
8
Memory Map
9
Machine Instructions/Programming Languages

• In Class Tutorial
• Be prepared to take notes

10
How do Operating Systems Work?

• http//www.howstuffworks.com/operating-system.htm

Windows in particular
11
API (Application Programming Interface)

• http//www.winprog.org/tutorial/apivsmfc.html

12
So, How does API work?

• http//www.relisoft.com/win32/index.htm

13
Homework 4

• Two page report on Intel Pentium instruction set
  architecture
• Instructions
• Addresses
• Memory Map