1
vote
1answer
133 views

How BIOS extensions (option ROMs) work?

How do BIOS extensions (option ROMs) work? I understand that an installed device may have it's own BIOS that adds features to the system but I'm not sure of how they are set up. I keep reading the ...
2
votes
1answer
196 views

PCI BAR memory addresses

Quick question, I was reading the OSDev Wiki page regarding PCI and it says the following - Base address Registers (or BARs) can be used to hold memory addresses used by the device, or offsets for ...
4
votes
1answer
171 views

Whats the difference between physical and virtual cache?

I am having trouble understanding what virtual cache actually is. I understand virtual memory. If the CPU wants to access memory, as far as I understand, it sends a virtual address to the MMU which, ...
2
votes
1answer
138 views

How are reserved and ACPI NVS memory sizes counted?

My PC has 8GB of memory installed and is running Win 7 64-bit. I ran a tool named fwmemmap that shows the firmware memory map for the system but it's showing around 60MB more than is physically ...
0
votes
1answer
93 views

What is the difference between the terms “memory”, “main memory”, “RAM”, “Memory bank” and “Memory Module”

What is the difference in the followoing words? They seem to all be interchangable. Memory, Main memory, RAM, Memory bank, Memory Module. Correct me if I'm wrong but my understanding is memory is a ...
0
votes
0answers
78 views

Instruction cache vs data cache with reguards to size

In the context of cache for a CPU, I understand some are divided between instructions and for data. How exactly are they divided? Is one physical unit partitioned into two or are there two units ...
2
votes
1answer
156 views

Why is this memory range on the PCI bus?

Why is the following memory address range on the PCI bus? The image is from my Netbook that uses shared video memory with no dedicated video memory so I am unsure as to why the VGA memory range ...
1
vote
1answer
52 views

How shared graphics memory works?

How does shared graphics memory work? It is my understanding that when you set how much system memory to share with the graphics controller in the BIOS, this then becomes invisible to the OS, So ...
0
votes
3answers
449 views

Do I really need 1 GB Ram for a graphic card if i'm going to use only for HPC? [closed]

I have a Nvidia GT640 with 2GB memory and it requirements says that my computer must have at least 1 GB RAM. My computer can't have the enough needed ram (Could be a Raspberry Pi, CubieBoard, 86 Duino ...
3
votes
1answer
983 views

Difference between port mapped and memory mapped access?

Can anyone explain what's the difference between port mapping and memory mapping, and what having both accomplishes? Why is there port mapped, how does it differ in structure from memory maps, and is ...
1
vote
1answer
131 views

What is the actual data transfer rate for the magnetic disk with the given specifications?

I saw the question bellow in a Computer Organization Practice Book for University exams. Its given that, a magnetic disk has the following specifications: Number of tracks = 1024Number of ...
288
votes
18answers
102k views

If 32-bit machines can only handle numbers up to 2^32, why can I write 1000000000000 (trillion) without my machine crashing?

32 bit computers can only store signed integers up to 232 - 1. This is why we have run out of ipv4 addresses and have entered the 64 bit era. However, the number 232 - 1 (2,147,483,647) is not as ...
10
votes
2answers
316 views

On x86 architecture, why are there fewer bits for virtual address space than physical?

I was reading this article on 64 bit computing, and it mentions: For example, the AMD64 architecture as of 2011 allowed 52 bits for physical memory and 48 bits for virtual memory I would think ...
18
votes
3answers
10k views

How to check my RAM configuration (Windows 7)?

I would like to check my RAM configuration. I know it is easy to check the total RAM installed on a computer (eg 32 GB), but is there an easy way to check in Windows if the RAM is e.g. 2x16 GB, 4x8 ...
0
votes
1answer
2k views

How does copy and paste for large files work

I am curious to know how computers execute "copy" and "paste" of large folders. I've read that copy and paste of text between different processes or same process is achieved by saving the content into ...
0
votes
2answers
84 views

How does playstation work with 256M RAM? [closed]

The 200$ phone I have in my pocket has more RAM than that. I realize that it has a very fast processor. But wouldn't the entire time be spent in transferring the data from secondary storage to RAM? ...
4
votes
2answers
581 views

Atomic operation. How does it guarantee consistency from hardware perspective?

Atomic operation. How does it guarantee consistency from hardware perspective ? How is it implemented in HW ? As far as I know, atomic instruction makes sure that when it is executed, no other ...
1
vote
2answers
6k views

Front Side Bus and RAM speed

We encouted an odd question during a Cisco IT Esstenials course which didn't make sense. Which memory module has a front side bus speed of 200 MHz Possible choices were DDR-333 DDR-400 ...
5
votes
4answers
570 views

Why can't memory clock speeds be as fast as the CPU speed?

I was reading that in old i386 based systems, the ram bus used to be the same speed as the CPU but when CPU frequencies increased, it became too hard to make RAM the same speed. Why can't we have 2GHz ...
2
votes
2answers
1k views

Virtual memory vs. Virtual address space

I know virtual memory is a paging file that computer uses to store a part of RAM on hard disk for a running process. But how different is Virtual address space? is it the RAM or hard disk or both?
2
votes
2answers
9k views

what differences and relations are between logical and virtual memory?

I was wondering what differences and relations are between logical and virtual memory? How do their purposes differ? Are the relations and differences the same for logical and virtual addresses?
4
votes
4answers
3k views

Understanding “Flat memory model” and “Segmented memory model”

I am trying to understand Flat memory model and Segmented memory model. Are Flat memory model and Segmented memory model determined by CPU architecture or OS or both? Or are they not determined by ...
9
votes
2answers
4k views

How do I interpret the specification of memory (RAM)?

When looking at memory there are a few specifications that I don't understand and was hoping to have clarification on. What do these terms mean, and how do they affect the systems performance? Feel ...
6
votes
3answers
365 views

If the size of the (accessible) RAM is limited, why isn't the hard disk?

When the number of possible RAM adresses is limited by the computer architecture (32/64 bit), why isn't the size of the hard disk limited? Or is it limited? If yes, what would be the highest possible ...
1
vote
1answer
158 views

What is the SMMA flag?

I'm new to computer architecture. What is the full form of the SMMA flag? Where is it used? Please help me understand it with a brief description.
10
votes
2answers
4k views

Why does RAM need to be installed in pairs?

Why does RAM need to be installed in pairs? What's the reason behind this?
0
votes
3answers
255 views

Learning about BIOS memory, instructions and code origins

I'm learning about the BIOS and have a few questions. What is meant by, "This is the last 16 bytes of memory at the end of the first megabyte of memory"? The first instruction of BIOS is jump, which ...
2
votes
4answers
2k views

What is the maximum addressable memory?

I just started learning assembly. My laptop specification says: Microprocessor: Intel Core Duo processor T2300 Microprocessor Cache: 2MB L2 Cache Memory Max: 2048MB Memory: ...
27
votes
9answers
122k views

How can I enable PAE on Windows 7 (32-bit) to support more than 3.5 GB of RAM?

I know that Windows XP 32-bit can be configured, through PAE, to support more than 3.5 GB of RAM. Is there a good tutorial to do this with Windows 7 32-bit? As to why I don't simply use 64-bit ...
7
votes
2answers
5k views

How does the CPU write infomation to ram?

My question is, how does the CPU write data to ram? From what I understand, modern CPU's use different levels of cache to speed up ram access. The RAM gets a command for information and then sends a ...