Quiz submission record for quiz2-1-1 at Mon Jun 28 00:35:56 2004:

Your Answer for Question 1:
Statement B is true. A successful call to malloc may reduce the number of free blocks, but does not necessarily do so always.  For example, when malloc is called the free list is searched for a big-enough block; if the block is too large then it is split and the sufficient size is returned to the user while the rest remains in the free block list.  Essentially, it is possible to simply "break off" a piece of an existing free block, resulting in no net change of the total number of free blocks.

Your Answer for Question 2:
Statements B and D are true.  B is true because a newly freed block may be adjacent to another free block, in which case the two blocks are combined and there is no net change in the number of free blocks.  Similarly, if a newly freed block fits exactly between two adjacent blocks, then all three are combined, resulting in a net decrease of 2 in the total number of free blocks.

Your Answer for Question 3:
In Java, dynamic variables are "the anonymous objects the programmer creates using new."  

Automatic memory allocation is not possible in C because the language allows pointers to addresses (or, as the PH notes call them, "containers") - meaning that a storage location of local variables may be reused unless explicitly set aside.

In the C language, it is (in principle) impossible to determine automatically that a particular piece of memory is no longer needed and may be recycled; once C allocates a chunk of memory, it will not touch it until explicitly requested.  Moreover, the facts that "programs may cast the pointers returned by dynamic allocation to/from sufficiently large integer types" and that "programs may cast void pointers... to and from pointers of any type with a compatible size and alignment" also prevent an automatic memory allocation/deallocation system.

Your Answer for Question 4:
This structure can be reclaimed using the reference count method since there exists one structure that does not have pointers to itself (essentially, the structure is not quite a circular structure).

Likewise, this structure could also be reclaimed using the mark and sweep method since the structure is unreachable; nothing points to it but rather it points to other objects within itself.

Your Answer for Question 5:
The diagrams in the PH notes were particularly confusing and unclear.  I would read the captions and still be unable to figure out how certain parts related to the image.

I was also a little confused by what the reading means exactly when it discusses "roots" and the pointers associated with them - a visual, perhaps, would greatly assist me.


Your unique submission ID is quiz2-1-1-cs61c-ax-1088408156-2615.