Questions tagged [memory-hardware]
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Same Address and Write signal for two block of RAM?
I don't know if I asked the question in correct way but I will try to explain what's the thing I am not getting. I am currently reading book titled "Code: The Hidden Language of Computer Hardware ...
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If the register size and the address bus are equal so do we need those segementation register to segment our memory?
In 8086, as i know we need those segementation register to segment our memory because the address bus is 20 bit and register size is 16. So, If the register size and the address bus are equal and we ...
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Memory Address Block diagram
Given A memory chip that has 4-addresses and each address location holds 8-bits is denoted as (4×8) RAM chip.
I want to draw a block-diagram showing the memory address that the first 3 chips will hold ...
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Understanding the Relationship Between CPU Registers Amounts and Maximum RAM in 32-bit Architectures
To my knowledge,
The number of CPU registers can tell us the maximum RAM we can have. I am only talking about physical memory, no virtual memory or virtualization in my question.
A 32-bit CPU ...
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At what precision are GPT's parameters stored?
OpenAI's technical paper on GPT-3 says that GPT-3 has 175 billion parameters. Several sites (here, here) claim that these parameters are stored as single-precision floating-point numbers and so ...
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Physical memory address space
When you address physical memory, in the kernel, is it just another value like 0xf78f9 just like virtual addresses (and the only thing that is different is that the ...
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Disk addressing
I am wondering how disk addresses are accessed from a program. From my understanding, the two main facilities are programmed I/O (instructions) and memory-mapped I/O (simply loads and stores). The ...
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Log-Structured Filesystem -- why do we need an explicit, scattered inode map?
From OSTEP Chp. 43:
The imap is a structure that takes an inode number
as input and produces the disk address of the most recent version of the inode
This makes sense to me as a solution to the ...
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How does non-DMA transfers really work?
I recently discussed DMA and non-DMA with my OS professor. Here is my current understanding:
disk controller has its own CPU, maybe own ISA, tiny program that simply handles reading from the disk (...
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How are memory busses and capacity determined?
If m = Ram quantity in GB, b = bus width in bits, and n = a nonnegative integer, it appears that b = m•2^n and or m = w/2^n, what do the variables represent physically? I.e., what physically changes ...
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DMA mode: burst or cycle stealing -- how to know and set? What is blocked?
What component and mechanism determines which DMA transfer mode is used?
How can be identified what DMA mode is used by a device, let's say on Linux?
Let's consider a contemporary AMD or Intel x86-64 ...
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Memory test that discovers any PCB error
I'm questioning whether the typical walking bit in data bus together with the typical address test where in each address we write a data equal to the address would be able to discover any PCB ...
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k-compact vectored I/O
I have a practical programming problem that I am struggling to find an optimal algorithm for, in part because I don't know what to call it. The problem concerns vectored I/O (scatter/gather).
Consider ...
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How is the memory address structured when the number of blocks per cache set is not a power of 2?
When it comes to defining the memory address structure given the RAM size, cache size, and other parameters such as the cache block size..., we can have the following generalization:
$$Address = TAG|...
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Why does a 32 bit address only contain 1 byte, when 32 bits = 4 bytes?
I am really confused about it. I think 32 bits = 4 bytes but 32 bit address is only 1 bit.
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Does the OS come in the hard drive?
This might be a a simple and for some a silly question as well.
If I buy two hard drives and have windows in one and Ubuntu in the other, can I work with both two systems(one at a time).
Example, I ...
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Is there any reason why you cannot use flash memory for a hard disk?
Is there a reason why you cannot use flash memory as a HD? Less moving parts and more affordable. Whats not to like?
Why dont we see Pci-express cards with a couple of terrabytes of flash memory that ...
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How many bits are needed to reference physical vs virtual addresses?
I trying to learn about virtual memory at the moment and one of the explanations I've look at has a diagram like below. You can see that 32 bit virtual addresses are used so the virtual address space ...
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Are variables stored again in RAM?
Assuming this set of instructions:
declare variable 'A' which has value 5
declare variable 'B' which has value 2
From what I've understood, those instructions are loaded into RAM an then read by CPU,...
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Memory Hierarchy Mappings to real world
This article from IBM (link) talks about Memory hierarchy in its actual hardware parts.
NUMA
While operating systems present memory to the running applications as a unified space, modern large ...
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How can computers tell where the beginning and end of file/packet/frame headers are?
I'd like to know how a computer can determine the beginning and end of certain file components (attributes, headers, frame/packet/segment headers etc.) when these components can be omitted or added in ...
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How hardware write a byte in memory?
I want to know how hardwares write a byte in memory?
If there is difference between writing process in RAM and ROM I would like to know as well.
Specially I want to know:
Is hardware writes values ...
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Are all CPU computations done using registers?
From my understanding, a CPU register is a temporary storage or working location built into the CPU itself. The CPU includes some functional units such as the ALU (which is part of the chip, as far as ...
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Single port register file
I have a test that asks to build a register file using only a single port.
The register file should also output 2 values, the read values, and be able to write one.
I tried to build it, but ,simply ...
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Is it possible to directly access permanently deleted data from SSD without recovering it using recovery program?
Is any technique present in this technical world regarding accessing data directly from any type of storing device without recovery it. For example if I deleted permanently data and then want to ...
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Why place of MA in MB then copy from MB to IR rather than going straight from MA to IR
During the fetch stage of the fetch-execute cycle, why are the contents of the cell whose address is in the MA (memory address register) placed in MB (memory buffer) then copied to IR (instruction ...
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Max RAM capacity on modern cpus
I am wondering why modern consumer cpu usually has 128GB memory limit when server cpu supports terabytes. 128GB is really not that much.
Do they really can't handle more RAM? How wide is their address ...
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Why PRAM and not PROM?
I read:
NVRAM is the updated Mac terminology for PRAM and is short for
Non-Volatile RAM.
Plus, I know that there are 2 types of main memory RAM and ROM while the first is Volatile the second isn't.
...
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Logical vs physical address program loaded into RAM, how re-mapping done?
What are common primary mechanisms to "re-map" between physical memory in RAM, and the addresses used in a program before it is loaded into RAM? In image below for example, the LOAD 12 ...
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Calculate memory size given address and its value
Given the address 00011001111011101111101011011111 and it save a value
0x1FA0CBB7. Calculate the memory size in KB
What i try: the address has 32 bits so the memory size is 2^32 = 4294967296 bytes ...
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Are sample memory access traces/dumps available, and where?
I am looking for a realistic physical memory access trace/dump of significant, but not insane, length (on the order of 1M accesses) for the purpose of cache simulation. Preferably for a 16-bit or 32-...
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What is the nature of the two bits of data held in a computer memory cell?
I hope this question doesn't offend anyone. I start off by saying that I have and always had difficulty understand the language used in computer science so I have to interpret everything into the ...
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How LRU is used without special hardware?
I had been curious as to which page replacement algorithm is used in OSes like Windows and Linux. I could find that most information on the internet pointed at LRU(Least Recently Used) Algorithm.
But ...
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How does software prefetching work with in order processors?
From prof. Onut Mutlu's slides on prefetching, this example has been shown as software prefetching:
...
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Are the number of entries in the TLB(Translation Lookaside Buffer) limited?
If not, then why aren't all the pages loaded into the TLB so that TLB misses never happen.
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Assembly Language Step By Step: Why deviate from the norm and design computers where the presence of voltage encodes a 0 bit?
That the presence of voltage across a switch encodes 12 is purely arbitrary... Jeff Duntemann's book mentions:
We could as well have said that the lack of voltage indicates a binary
1 and vice versa (...
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Is RAM always volatile? [closed]
I understand that computer memory in typical modern computing systems (such as the laptop I am asking this question from) is generally involatile but in some exceptions, such as RAM, the memory is ...
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can a computer be totally made up of SRAM?
can a computer be totally made up of SRAM with no DRAM but with secondary memory and run an opreating system properly?
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What does "Memory of 128K by 9" means?
This is probably a very stupid question but I couldn't find an answer anywhere. I'm reading the Technical Reference book of the IBM PC XT and it says that "The system board also has from 128K by ...
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How can computer memory remember after the computer runs out of battery?
According to my fragile knowledge of computer hardware the way computers store information is by electric circuits. If there is current the bit is 1 if there isnt its 0. My question is after a ...
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A doubt on best media for a time capsule
So, I have some data to a time capsule project of mine. But the thing is, I need to know the best media on long-time scale to use as storage unity. The time range is 120 years. Now, I've been thinking ...
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Formula to see where a memory address can be depicted in cache?
I've been trying to find a formula that helps us identify where an address can be depicted in cache. I remember my professor talking about some kind of division but I can't find it in my textbook nor ...
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How do I compute the address of the next element?
I have to work on something , but I am making an error that I can not identify. Propably, it is going to sound simple to you but it's my first course on computer architecture and there is nothing in ...
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Is ROM primary memory or secondary memory?
According to this picture ROM is classified under Main Memory , but isn’t ROM a secondary storage because it’s external and non volatile ?
Any clarification with reference links will be highly ...
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Number of hardware page tables and page directories kept in the MMU
How many hardware page tables (physical) and page directories are kept in the memory management unit?
If a cpu has a 32 bit virtual address, the upper 10 bits are used for the page directory, the ...
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Segmented address / normal virtual address
In a cpu with segmented memory, can an address only be accessed with a segmented address, or can a normal virtual address also be used?
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How are programs split up into pages in Memory Paging?
I am a bit confused about how the logical addresses are generated in a paging memory architecture and where and when a program is split up into pages.
I understand how logical addresses are translated ...
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Connection of different buses to memory
The address bus(of cpu) is connected to a digital decoder inside the memory which sets 1 pin logic high and activates the read/write operation of the memory let's say DRAM. Is the data bus(of cpu) ...
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Is it reasonable to assume modern computers can do hardware math with integers up to 2^64?
I was writing up an algorithm that involved knowing the size of integers my hardware can manage without having to resort to software implementations of math operations and the additional computational ...
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Reading process memory of computer A on computer B?
So I was wondering if there is a way of reading process memory of one device on another. So lets say a process is running on computer A, I then use some form of connection lan, pcie etc. Once the two ...
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