# Tagged Questions

Questions about the organization and design of computer hardware.

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### Calculate the number of instructions replaced ?

I was studying a cs book for computer architecture(computer organization and design) and I found this exercise: ...
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### On a semiconductor chip, what state (on/off or read/write) corresponds to conducting or insulating behavior?

My textbook has a brief explanation of how semiconductors are used in modern computer chips because they can be made to conduct (by applying enough voltage to excite electrons across the band gap) or ...
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### How to see how efficient a branch predictor is after designing one?

I want to design a branch predictor and then test it to see how efficient it is. The question is: how to test them? Are there data sets available?
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### Number of cycles that arithmetic instruction takes for 25% improvement in performance?

The program has the following proportion of instructions: Arithmetic: 70% Load/Store: 10% Branch: 20% The question is to ...
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### How does the CPU receive, process and output information?

I was studying the I/O process of a PC...and I think I understood it..but not very much so I will type what I understood giving an example..and I hope that I got it right e.g. typing with a keyboard ...
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### Can't understand this division algorithm in Computer Architecture

So, I'm preparing for an exam where I have solve divisions using this division algorithm: While I understand the theory (image above), I couldn't understand this example below: My problem is ...
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### Difference between cordic algorithm and table based methods for elementary functions computation

In this book both Table Based methods and Cordic iterations are explained. computationally speaking i suppose the Table based is usually faster, even though it probably requires more resource, while ...
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### What factors influence machine epsilon?

I was wondering what factors effect a machine's epsilon value. I was thinking about how modern computers can calculate expressions to higher accuracy then their predecessors, but what hardware and ...
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### Given a program which when executed spawns two concurrent processes : semaphore X : = 0 ; Is it possible for process P1 and P2 to starve?

Given below is a program which when executed spawns two concurrent processes: ...
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### Fundamental idea of this memory denial of service simulation using array copy?

I am just watching this lecture Computer Organization - Introduction And Basics where the lecturer mentions about using a simple code to demonstrate how memory denial of service can be simulated in ...
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### Which combination of the following features will suffice to characterize an OS as a multi-programmed OS

Which combination of the following features will suffice to characterize an OS as a multi-programmed OS? More than one program may be loaded into main memory at the same time for execution. If a ...
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### A multi-user, multi-processing operating system cannot be implemented on hardware that does not support

A multi-user, multi-processing operating system cannot be implemented on hardware that does not support Address translation DMA for disk transfer At least two modes of CPU execution (privileged and ...
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### Why the Smallest Operable Data Type in Most Programming Languages Is One-Byte Sized? [duplicate]

Why the smallest operable data type in most programming languages is one-byte sized? Is it possible that to operate with a single bit? If it is possible, how to do it in practical?
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### Would removing the branch delay slots change the instructions set architecture?

I am trying to study for an exam and I noticed a lot of the questions follow the idea of "Changing the ISA". From my understanding the ISA dictates the structure and format of instructions, so ...
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### Advice on using DRAMSimm2 or other DRAM simulation tools

As part of my PhD research I am currently building a simulation of a 256 core NoC and really want to model its interaction with the memory system. My supervisor has suggested using the University of ...
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### RISC machines have register renaming?

I know that one of the techniques used by RISC machines to improve the pipeline is the delayed branch, but what other techniques do they employ, namely, can they use register renaming? I know that ...
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### What does the number of bit of microprocessor mean?

Intel 8085 is a 8 bit processor whereas 8086 is a 16 bit processor,what does the number of bit specify?
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### Pros and Cons of Average Memory Access Time When Increasing Cache Block Size

Assuming we have a single-level (L1) cache and main memory, what are some of the advantages and disadvantages of having a larger cache block size (considering average memory access time). The only ...
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### If my computer is a 32 bit system,it has a 32 bit address right?But when i print any memory address in C why do i get a short value? [closed]

For example printf("%u",&a); gives me output 65524
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### What exactly (and precisely) is “offset”?

Just like my previous question concerning 'hash'; what exactly is an (or the) "offset?" Is it a value or data type? Or is it an address location? I have heard it used in different contexts within the ...
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What is the trend over time for the size of registers of x86 CPUs? I know that we have today 512-bit registers, but is there a kind of Moore's Law to predict the size of registers in the future? ...
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### How Is a Computer Able to Store and Quickly Manipulate All the Data Required For A Computer Display?

I did some quick math on how much data is contained on a screen at any given instant and I ended up with a number well beyond what I thought was possible. 256 colors for Red, Green, and Blue each ...
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### Is it possible to construct 3-dimensional microchips?

In our daily computer, the microchips in it are 2-dimensional, but could it be possible to produce 3-dimensional ones, in some way similar to the brain structure?
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### Convert non-integer decimal to octal

I follow a course in Computer Architecture and I'm making exercises on number conversions. Now one of the questions asks me to convert 251.5625 to octal and hexdecimal base. No further info is given. ...
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### In instruction pipelining, can we forward an operand more than one clock cycle?

Most operand forwarding examples that use the standard 5-stage MIPS pipeline forward operands from EX or MEM by ONE clock cyle to a later instruction. Is it possible to do so for more than one (from ...
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### How did early computers handle variable word length?

So quoting from the book: A History of Modern Computing (History of Computing) The introduction of reliable core memory made it practical to fetch data in sets of bits, rather than one bit at a ...
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### D - Latch or D Flip Flop?

I have a diagram (http://imgur.com/cET8Q14) where it is either a D Latch or D Flip Flop. I am trying to figure out which one it is and why. If it is a D Flip Flip, I also need to know which input is ...
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### Depth of a pipeline in a CPU's architecture

I follow a course on CPU architectures and I'm making exercises at the moment. Now I encountered the word "depth of a pipeline" in one of the exercises, but I don't know what's meant by the depth of a ...
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### How likely is it that a computer miscalculates 1+1? [closed]

Of course, normally a fully-functional computer will calculate 1+1=2. However, the physics governing the behavior of a chip is quantum mechanical. So in principle there is a certain probability that ...
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### What does it mean that a core supports 2 threads?

I understand that a process may have multiple threads, and that a processor may have multiple cores to run processes in parallel. But I can't understand how a core may allow multiple threads, what ...
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### how to track a uop's flag in microprocessor?

Lots of processor renaming their register to achieve the goal of out-of-order,but how to track the instruction's flag,such as carry flag,overflow flag,etc?
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### CPU and GPU differences

What is the difference between a single processing unit of CPU and single processing unit of GPU?  Most places I've come along on the internet cover the high level differences between the two. I want ...
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### Is this Von Neumann Architecture Diagram Correct?

I am preparing for an Exam and would like to know whether this diagram of the Von Neumann Architecture is correct or not. The full form of the acronyms (on the diagram) are as follows: PC: Program ...
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### How to show potential pipeline hazards

Based on following table, I have to show if there is any potential pipeline hazard in the following code segments: X = R2 + Y, R4 = R2 + X R1 = R2 + X, X = R3 + Y, Z = R1 + X. I've been a ...
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### Miss penalty for Write request in a Write-Back style system

If the processor is trying to write a word to a certain memory location, and the system uses a write-back style architecture, what happens in case of a miss? I'm assuming that the system would first ...
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### How does CPU actually retrieve data from memory when you call a variable in a programming language?

As I have understood from all the internet sources I can get to, when you declare and initialize a variable in java, you are allocating this data, say an 8-byte float, in a particular memory cell in ...
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### Draw the Logic Diagram using Half-Adders to implement a ripple-carry addition for the increment

Draw the Logic Diagram using Half-Adders to implement a ripple-carry addition for the increment.(Designing the incrementer circuit for the picture below) Having a tough time drawing out this logic ...
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### Is it possible to figure out cache size and associativity using the length of offset, index, tag fields?

I have a question where I am asked to find the size of a cache. I am given the following info: a) the length of a memory address b) the number of bits for offset, index, and tag fields. I know I ...
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### Is emulation and/or virtualization faster when the host and guest systems are more similar?

Is emulation and/ or virtualization performance faster when the guest and host OS are similar? If yes, how big, relatively speaking, is the difference? And whether the answer is yes or no, why is it ...
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### Computing the hit and miss ratio of a cache organized as either direct mapped or two-way associative

This is an example problem in a computer organization and architecture course that's giving me some trouble. It goes as follows: Consider a cache of 4 lines of 16 bytes each. Main memory is ...
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### How does RAID-5 algorithm locate the right device?

Please consider the following diagram of a RAID-5 array (Ignore the gray background): Now, given a logical address, how can one return the device number (0-3)? For example, DeviceByLogicalSector(50)...
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### How is parallel tag checking achieved in associative Mapping?

I originally posted this question on stack overflow and then realised it was better suited to computer science . In the book on computer organization and architecture by William stallings , in the ...
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### How do computers keep track of time?

How are computers able to tell the exactly correct time and date every time I switch it on? Whenever I close the computer (shut it down) all connections and processes inside stop. How is it that ...
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### Lazy way of comparing ISA on code length

I hope this is not too broad. I need to evaluate about 8 different ISA targets for about 12 specs. The only metric I'm intersted in is size of the output bytecode. Moreover, I'm only interested in ...
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### Mano base computer and the FGO flag

I have a question about the Mano base computer. The state diagram, shown below, implies that the output device will set the FGO flag to "1" after the job is done to continue the output activity from ...
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### For what $N$ does $2^N$ overflow?

Consider the following computation: 2^N (TWO TO THE POWER OF ‘N’, for Int. N>0), being executed on a processor with 32 bit internal, user and ALU registers. The registers rightmost bit is bit 0 and ...
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### Difference between capacity miss and conflict miss

Premise: Two types of cache miss: capacity miss, conflict miss\ Cache contains only 2 sets, SET 1 and SET 2 Problem: If data A maps to SET 1 and it doesn't exist in SET 1 while SET 1 is fully ...
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### Is there a CPU architecture which allows early register access?

In Intel's x86 architecture, imul (integer multiply) usually has latency of a few clock cycles. Those CPUs are very smart in filling the time (e.g., pipelining or out-of-order execution), but do any ...