Top 10 List of Week 04

1. Operating System - Memory Management
   Memory management is this week main topic. This site explains every single basic concepts you need to know about Memory management. Memory management is the functionality of an operating system which handles or manages primary memory and moves processes back and forth between main memory and disk during execution. As we continue to learn everyday, understanding basic concepts is a must.

2. Logical vs. Physical Address Space
   This video explains differences between logical address space & physical address space. The set of all logical addresses generated by a program is referred to as a logical address space. The set of all physical addresses corresponding to these logical addresses is referred to as a physical address space. The video is short but the content is good. With some catchy Indian accent, this video is worth to watch.

3. Paging in Operating System
   First heard the word “paging” in Wednesday Zoom session, kinda understand it a little. After class I read the OSC chap 9 to understand it more. When I tried to GSGS I found this article to cross-check my understanding. Paging is a memory management scheme that eliminates the need for contiguous allocation of physical memory. This scheme permits the physical address space of a process to be non – contiguous.

4. Little and Big Endian Mystery
   Little and big endian are two ways of storing multibyte data-types ( int, float, etc). In little endian machines, last byte of binary representation of the multibyte data-type is stored first. On the other hand, in big endian machines, first byte of binary representation of the multibyte data-type is stored first. I first know about this Little Endian - Big Endian thingy back in 2nd semester’s PSD class, and always meet them when talks about memory storing in PSD, POK, and now OS class.

5. Memory Management Unit
   A memory management unit (MMU) is a computer hardware component that handles all memory and caching operations associated with the processor. In other words, the MMU is responsible for all aspects of memory management. It is usually integrated into the processor, although in some systems it occupies a separate IC (integrated circuit) chip. First heard of this, when I watch some videos about memory management. I think it’s one of the most important part in computer.

6. What is Main Memory in a Computer?
   The main memory in a computer is called Random Access Memory. It is also known as RAM. This is the part of the computer that stores operating system software, software applications and other information for the central processing unit (CPU) to have fast and direct access when needed to perform tasks. As someone who uses computer everyday, I need to know the components of my computer.

7. Hashed Page Tables
   Hashed page table is one of the most common techniques for structuring the page table. In hashed page tables, the virtual page number in the virtual address is hashed into the hash table. They are used to handle address spaces higher than 32 bits. I learned about “hashing” in 3rd semester during SDA class. Thing paging method is the one got my interest.

8. Swapping in Operating System
   Swapping is a memory management scheme in which any process can be temporarily swapped from main memory to secondary memory so that the main memory can be made available for other processes. It is used to improve main memory utilization. In secondary memory, the place where the swapped-out process is stored is called swap space. An interesting concept in this week material (in my opinion), I put it here cause I think it’s important.

9. ARM Architecture vs x86 architecture
   ARM is a RISC (Reduced Instruction Set Computing) architecture while x86 is a CISC (Complex Instruction Set Computing) one. The core difference between those in this aspect is that ARM instructions operate only on registers with a few instructions for loading and saving data from / to memory while x86 can operate directly on memory as well. The last page of OSC chapter 9 tells me very little about ARM architecture (dominant mobile platform architecture), as someone who uses smartphone a lot, I need to know more about it.

10. C - Pointers
    A pointer is a variable whose value is the address of another variable, i.e., direct address of the memory location. Like any variable or constant, you must declare a pointer before using it to store any variable address. One of this week demos is 04-pointers-of-pointers-of-pointers.c it was kinda annoying program (What kind of person, mad enough to create such program). This article helps me understand more about pointer in C.