34
votes
How does a computer know which device is connected to the usb port?
Yes. USB, aka Universal Serial Bus is a connection of 4 ports. VCC, Data+, Data- and Ground, where newer specifications will have more bandwidth and power transmission.
When you connect a USB device ...
- 61.5k
28
votes
Why are most of the common processors' bit counts powers of 2?
8-bit bytes
Much of this grows out of the adoption of the 8-bit byte. That became popular with the introduction of the IBM 360 family of computers in 1964. In an issue that year of the IBM Technical ...
- 510
21
votes
How does a computer know which device is connected to the usb port?
Do each usb device send some unique information about them to the computer to be recognized by the computer?
Yes.
Basically USB devices have a class number (which isn't super unique across devices ...
- 74k
17
votes
How does a computer know which device is connected to the usb port?
A good source of information on USB is the www.usb.org, more on that later. I admit that it can be difficult to understand where to start, so I try to give a short introduction below.
Firstly, there ...
- 313
16
votes
Why are most of the common processors' bit counts powers of 2?
Having 2ⁿ bit registers, allows bits in the registers to be addressed with an integer number of bits:
Addressing a bit in an 8 bit register will need 3 bits. Addressing a bit in a 16 bit register will ...
- 2,391
13
votes
Why are there so many pins on a SATA power connector?
I am not sure this has been sufficiently answered.
I don't have an answer per-se, but I can share what I've learned in search of an answer:
The best, given answer- and really the only actual answer is ...
- 317
12
votes
Accepted
X86 Address Space Controller?
It's all inside the CPU these days, ever since CPUs started integrating the memory controller on-die. The "system agent" built into the CPU's memory hierarchy maps physical addresses to either the ...
- 5,920
11
votes
Accepted
How is microcode loaded to processor?
I read that microcode is loaded in the processor on each reboot.
The BIOS can issue a microcode update during boot. So can the operating system.
Frequently these updates are required, especially ...
- 74k
10
votes
Why are most of the common processors' bit counts powers of 2?
The most common reason is because computers use the binary system, where
a bit can be either a zero or one.
If computers used ternary values for the bits, then we'd have everything in powers of 3.
As ...
- 481k
9
votes
How does a computer know which device is connected to the usb port?
Do each USB device send some unique information about them to the
computer to be recognized by the computer?
Yes, it is called "device descriptor(s)".
There is a process in USB framework ...
- 12.7k
8
votes
Is there any existing CPU implementation which uses one's complement?
Unisys 1100/2200 legacy systems use 1's complement arithmetic, and this continues in the newer Dorado series.
Rather than there "perhaps" being some still in use, they are being actively developed ...
- 170
8
votes
Why are most of the common processors' bit counts powers of 2?
As RonJohn wrote, "computer industry, pushed by IBM, standardized on 8-bit bytes for General Purpose computers".
After that, there are internal advantages with using powers of 2 multiples of ...
- 181
8
votes
Difference between Arm/Amd/aarch/armf?
Architecture
32-bit
64-bit
Intel x86 (PCs)
x86, i386, i486 … i686
x86_64, amd64
ARM (mobile devices)
armhf, armv7h
arm64, aarch64
"aarch64" and "arm64" are the same thing. ...
- 454k
8
votes
How do Spectre patches work?
There are various techniques to mitigate Spectre-style vulnerabilities in software without patching microcode or changing hardware, but they do incur some performance cost. I'm not familiar with how ...
- 181
7
votes
What does it mean (to decode) in the execution cycle
Assembly instructions, besides an opcode, often have bit fields that indicate registers and addressing modes (absolute, relative, auto-increment and more).
Decoding is the cycle that interprets the ...
- 819
7
votes
Accepted
GPU cores vs. CPU cores
A CPU is a much more general purpose machine than a GPU. We might talk about using a GPU as a "general purpose" GPU, but they have different strengths.
CPU cores are capable of a wide variety of ...
- 92.7k
7
votes
How does a computer know which device is connected to the usb port?
(Shorter reference from FTDI)
Keyboards and mice are slightly special in USB. While they do have a vendor and product ID, you don't want a situation where a new keyboard manufacturer is unable to work ...
- 6,071
6
votes
What does it mean (to decode) in the execution cycle
Instructions and adressing modes are what is decoded. Instructions + addressing modes consist of an opcode and any immediate data (operands) following the opcode.
If so, why it is encoded then?
...
- 74k
6
votes
How to check my RAM configuration (Windows 7)?
You can use Powershell and get WMI Object, like the wmic command in CMD, except you can output it to a table using GridView.
Lots of information too, and no need to download/install any software!
...
6
votes
How is microcode loaded to processor?
The microcode update is a patch only to the existing CPU microcode which is burned into ROM permanently. The CPU has a permanent ROM and a patch RAM which can contain new code. There is also a table ...
- 6,121
6
votes
Are computers still being limited by the RAM frequency?
all the components of a computer have to run on the same frequency
That's simply not true. Your computer would run at 60 Hz - that's the refresh rate of your monitor.
CPUs have internal cache which ...
- 57k
6
votes
How does a motherboard become an open circuit after shutdown of PC/laptop?
Modern computers are not like typical electrical appliances. They never truly turn 100% off. There are reason for this, but that is outside the scope of the question, but this is done to accommodate ...
- 73.3k
6
votes
How does a motherboard become an open circuit after shutdown of PC/laptop?
The Power Switch is not an off/switch.
When you press it a circuit is completed and send a signal. It has a spring under it so when it is released the circuit is open again.
So a very short signal is ...
- 157k
5
votes
How is microcode loaded to processor?
The question is ill-formulated. There are many "microcodes" in modern x86/IA64 CPU, and there is a difference between "microcode patch" and microcode.
The microcode in its classic understanding (as ...
- 12.7k
5
votes
Accepted
Literal white noise
Increased power draw doesn't just mean that the power draw goes up from one steady value to another. In reality, the power drawn by the computer and monitor are spiky, often with repeating patterns. ...
- 669
5
votes
what exactly is VGA
It's not exactly a specific piece of hardware; it's multiple "standards" that were introduced by the IBM "PS/2 Display Adapter" graphics card – it could mean any of these depending ...
- 454k
4
votes
Relationship between the size of CPU registers and main memory
each of which can hold up to 2^32 data
No. A 32 bit register can hold 32 bits of data. One possible use of that would be for an integer that can range from 0 to (2^32)-1, i.e. 0 through 4,294,967,295,...
- 23.6k
4
votes
Accepted
what is the the reason CPU utilization gets high?
Short answer, as people have written whole books about this topic:
Cycles are usually expressed with the terminology "CPU time". A process is allocated a certain number of 'quantums' on the CPU. Keep ...
- 16.9k
4
votes
Accepted
Can one use 4-bit, 8-bit, 16-bit, or 32-bit sized pointers on a 64-bit machine?
A pointer points to contains an absolute address.
If you need to add a value before you use the pointer, what you have is an offset, not a real pointer.
In C, a void pointer can be a function ...
- 74k
4
votes
If two bit-identical computers perform the same actions but in different orders, will they remain bit-identical?
Two computers doing absolutely the same thing as each other have absolutely no guarantee of being bit identical, let alone doing the same thing in different orders. In fact there is almost no way for ...
- 92.7k
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