Memory Management Flashcards
what is a source module?
a program written in a symbolic language like C or Assembly
what is an object module?
machine language output from the compiler
what is a load module?
a program that is ready to be loaded into main memory and executed
an object model is the input to the __________
linker
what is the difference between static and dynamic program relocation?
static binds all logical addresses to physical addresses prior to execution. dynamic delays this until the thing is needed during execution
what does the 50% rule imply?
that 1/3 of all memory partitions are holes…importantly it makes no distinction about memory utilization only the holes
what is memory compaction?
shifting of modules in memory to consolidate and reduce fragmentation. normally this is done by just shifting all memory in one direction
for each process, pages are numbered consecutively starting with ____
0
the OS maintains ______________ for each logical space
separate page table
what is a memory segment?
a variable sized block of logical address space identified by a single number, the segment number
how are pages and segments different?
segments are dynamically sized
what is the translation lookaside buffer?
a fast associative memory buffer that maintains recent translations of logical address to frames (a cache)
in the LRU, what is the referenced bit? (r-bit)
a bit associated with a page that is set automatically by the hardware whenever the page is referenced
in the LRU, what is the aging register?
the page is shifted to the right by 1 bit over time to “age” it
what is the second-chance page replacement algorithm?
a coarse-grain approximation of the LRU. Uses the r-bit to divide all pages into to categories: recently used and not recently used
