Questions tagged [memory-management]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
9
votes
4answers
11k views

Word- or byte-addressable? Correct terminology

Seemingly, a byte has established itself to be 8bit (is that correct?). RAM and NOR-flash can be normally accessed on a quite granular level, but it is up to the system architecture to determine if ...
0
votes
0answers
82 views

Is this cache entry a hit or a miss? [duplicate]

The Problem: A CPU produces the following sequence of read addresses in hex. Suppose the cache is empty to begin with and assuming an LRU replacement, determine whether each address produces a hit or ...
2
votes
3answers
69k views

How to work out physical address corresponding to logical address?

I am looking to calculate the physical address corresponding to a logical address in a paging memory management scheme. I just want to make sure I am getting the calculation right, as I fear I could ...
4
votes
2answers
728 views

Why is word-addressable the exception, not the rule?

As stated on Wikipedia: Most modern computers are byte-addressable instead of word-addressable. Why is this case? Since the CPU processes words (of predominantly 64 bits or 8 bytes) now, wouldn't ...
2
votes
2answers
349 views

Characterize an OS as multiprogrammed OS

Which of the following features will characterize an OS as multiprogrammed OS? More than one program may be loaded into main memory at the same time. If a program waits for certain event another ...
1
vote
1answer
2k views

what is the need for valid/invalid bit in paged memory technique?

How is the valid/invalid bit in paged memory useful? I am not able to understand the significance. Is it also somehow used to share the processes among different users.
8
votes
2answers
19k views

Changing from Kernel mode to User mode (and vice versa)

I am reading Operating Systems book by Galvin. Galvin explains, what are kernel & user modes, instruction privileges given for both modes & also about mode-bit. But I am interested to know how ...
3
votes
1answer
2k views

Understanding the basic concepts in memory organisation

(Before actually proceeding to the question, I want to confess that this is a homework question, please do consider it and help me in improving my understanding a bit more.) I have recently started ...
3
votes
1answer
9k views

What's the difference between Clock and Second Chance Page-Replacement Algorithm?

I know that they both have reference bit, but I only understand the Second Chance but not the Clock Page-Replacement algorithm. could anyone help me understand?
0
votes
1answer
1k views

Segmentation and paging

I am given a system with a segmented paging architecture. Both physical and virtual address spaces contain $2^{16}$ bytes each. The virtual address space is divided in $8$ equal size segments. The ...
3
votes
1answer
105 views

When was the terminology *tracing collector* introduced to denote both mark-and-sweep and copy collectors

Automatic storage reclamation, aka garbage collection, comes in two main families, sometimes cooperating: the reference count collectors and the tracing collectors. I may develop specifics of each ...
1
vote
2answers
32k views

Size of address spaces (logical and physical)

Suppose a system in which addresses (physical and logical) occupy 32 bits, page size is 1024 bytes (210), and physical memory is of size 32MB. How many frames are in physical memory? Is the logical ...
7
votes
1answer
122 views

Page management in OS kernels

I looked at some old OS theory books of mine and noticed that one glaring omission in all of these OS books is how to actually keep track of physical pages that are free (i.e. algorithms for actually ...
2
votes
6answers
2k views

How can a CPU access more memory locations than 2^wordsize?

I noticed that CPU's like the 8086 and especially the 8080 have the ability to access more memory than what one would normally assume. The 8080, for example, has an 8-bit word size but can use a 16-...
0
votes
1answer
125 views

Virtual Memory: “Page Table or Page Tables?”

I am having a bit of a tough time grasping whether a computer system contains several page tables or just one page table. Some sources speak of page tables in plural others in singular. ...