OS chapter 4 Flashcards
Intel 386 and up use what are called ______________ to add a certain value to each virtual address to produce a physical address.
relocation registers
The process of assigning memory addresses to program instructions and data is called ____________.
address binding
What is the primary downside to utilizing “virtual memory”?
Keeping memory processes filled so the computer can run at peak efficiency.
When does a multitasking operating system bind addresses for programs?
As the program is run.
DOS was designed to address approximately ________ of memory.
1 MB
In DOS, the part beyond 1 Mb is called _________ memory.
extended
The ____________ is the hardware portion of DOS and contains subroutines such as memory check and other start up routines that do not change from version to version of DOS.
ROM BIOS
____________ are essentially a translator between the O.S. and the hardware.
Device drivers
Where are device drivers typically loaded and configured?
config.sys
What is the term for assigning memory addresses to program instructions and data?
address binding
What is binding?
When a program is loaded into a fixed memory location in memory.
When is an .exe file bound?
As it is loaded.
When can binding occur?
During compilation, loading or running.
When does a multitasking OS bind addresses?
As a program is run.
What problems need to be overcome to use memory efficiently?
When there is either too much or too little memory.
What problem does having too little memory cause?
There is not enough space to handle all the necessary processes, this can be overcome by handling processes as needed.
What problem does having too much memory cause?
If the memory isn’t filled with processes, the computer isn’t running at peak efficiency.
What is the Logical Memory Address?
An offset of the actual physical memory used to locate the actual physical memory address.
What is a device driver?
a computer program that operates or controls a
particular type of device that is attached to a computer. Essentially a translator between the OS and the hardware.
Drivers are essentially _______ between the O.S. and the hardware.
translators
What are Terminate and Stay Resident Programs.
programs that run and then stay in memory after
they finish running
What drivers are needed to use memory management in DOS?
himem.sys (high memory) and emm386.exe
What is the first 640 kb of memory called?
user or conventional memory.
What is the portion of memory between 640 Kb and 1 Mb?
upper memory
What is the term for memory beyond 1 Mb?
extended memory.
What is the term for the first 64 Kb of extended memory?
high memory.
Where is DOS loaded?
All of DOS is loaded in conventional memory with all but the transient portion of command.com in low memory
Where do programs run in the DOS Memory Map?
in the first segment above the
resident portion of command.com and can
overwrite the transient portion of
command.com.
