What for stands 32 and 64bit?

WHT

I cant figure it out what for stands 32bit and 64bit on operating systems?

mosan7763

what is a google

WHT

@mosan7763 said:
what is a google

Same as yahoo you smart ass. Am asking for simplified answer.

mike0000

OnraHost_Zack

32 bit and 64 bit stands for the instruction set of the processor. The bits means the size of the data types that it handles, and the size of its registry. The main difference (other than speed) is that 32 bit processors (and, as a result, 32 bit OS's) can only use up to 4GB memory, whereas the memory limit is in the billions of gigabytes for 64 bit.

WHT

@OnraHost_Zack said:
32 bit and 64 bit stands for the instruction set of the processor. The bits means the size of the data types that it handles, and the size of its registry. The main difference (other than speed) is that 32 bit processors (and, as a result, 32 bit OS's) can only use up to 4GB memory, whereas the memory limit is in the billions of gigabytes for 64 bit.

Then why do still exists 32bits if 64bits its better/faster? Any advantages for 32bits?

Jorbox

64bit sends 2 32bit in the same time

WHT

Ow ok I got it.
Now my question: if I run a VPS with 8GB ram in a 32bit os, I can only use 4GB?

ricardo

It really depends on the programs written.

One spurious example when you're running a 32 bit system, all pointers to memory addresses are 32 bits rather than 64, which clearly will result in lower memory usage because they take up half as much space.

mustafaramadhan

@WHT said:
Ow ok I got it.
Now my question: if I run a VPS with 8GB ram in a 32bit os, I can only use 4GB?

Use kernel with PAE if you want 8GB in 32bit OS. Max 12GB RAM in PAE.

OnraHost_Zack

@WHT said:
Then why do still exists 32bits if 64bits its better/faster? Any advantages for 32bits?

Realistically speaking, it's only around for backwards compatibility with old programs (and I'm sure a few very very very specific other examples). Operating systems are slowly phasing out 32 bit (CentOS 7 and Windows 2008 R2 just to name a few examples).

ceibaNet

most software now is built for 64 bit systems, 32 is mostly kept for older software so 64 is almost always recommended, really depends what you're planing to use it for. Some things work best on a 32 bit os

Neoon

globalRegisters

My own general guidelines:

System memory greater than 2GB -> Use 64 bit

System memory less than 2GB -> Use 32 bit

So on a low end VPS use a 32bit OS and save that precious memory.

rm_

There's more to "64-bit" than just the higher memory support limit. Due to a coincidence of sorts, going 64-bit on x86 also doubles the number of available registers (extremely fast temporary storage area) that the CPU operates with. And this is potentially a huge benefit for performance (and it is, in some apps).

https://en.wikipedia.org/wiki/X86-64#Architectural_features

Additional registers

In addition to increasing the size of the general-purpose registers, the number of named general-purpose registers is increased from eight (i.e. eax, ebx, ecx, edx, ebp, esp, esi, edi) in x86 to 16 (i.e. rax, rbx, rcx, rdx, rbp, rsp, rsi, rdi, r8, r9, r10, r11, r12, r13, r14, r15). It is therefore possible to keep more local variables in registers rather than on the stack, and to let registers hold frequently accessed constants; arguments for small and fast subroutines may also be passed in registers to a greater extent.

Additional XMM (SSE) registers

Similarly, the number of 128-bit XMM registers (used for Streaming SIMD instructions) is also increased from 8 to 16.

Always go 64-bit wherever you can, except maybe on 128 MB of RAM or less.

afterSt0rm

rm_ said: also doubles the number of available registers

In a nutshell, having more registers has benefits on speed because a well designed software has more room to operate inside that registers, reducing the need to push or pull values from the stack (slow), memory (slower) or even storage media like a HDD (slow as hell).

Sometimes programmers don't have that level of control over the processor because of the programming language chosen, or because the language has poor optimization. In this case, and when you are running a 32-bits app on a 64-bits OS, the software will not directly benefit from this improvement. Of course, you still can be a dumb developer and write bad code.

Another important thing is that 32-bits programs running on a 64-bits OS will have access to a maximum of 4GB of RAM per process (depends on the OS architecture), even if you have a huge ton of memory available.

namhuy

@Neoon said:

i used to like that dude, then most of his newer mvs are just show off / advertising and not much information like before. unsubscribed.