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architecture basic

Hi All,

I wish to know that whether we have anything like 32-bit or 64-bit machine concept in Linux / Solaris as well, or not ?
If Yes, then how can we check that ?
If not then what is the alternative for that we have here ?

Could anybody please help me with this.

Thanks in advance,
Kapil.

32 bit and 64 bit processors are a hardware concept, they are not implemented in software. If you are asking if Unix systems support 64 bit hardware, then yes, for a very long time now.

Hi MS3FGX,

Thank you for the reply.
I have a RHEL5 machine here at my workplace, and I had been told that it is a 64-bit machine. I don't know how can I check that. Also, which one of them, in partivcular, is more prominent in current IT usage ?
Like in Windows, we can check these things easily, then how can we check the same thing in Linux ?

Thank You,
Kapil.

You can tell all of the information available to the kernel about the CPU with the command:

Code:

cat /proc/cpuinfo

From there you can easily figure out what CPU you have and what it can do. As for the prevalence in the marketplace, there are billions of 32 bit machines out there still, and will be the majority for a very long time. That said, new machines are almost all 64 bits, and any server hardware almost certainly will be 64 bit at this point. 64 bit processors are much better at computationally intensive tasks, and can support larger amounts of memory, so they are an obvious advantage on any server.

Hi MS3FGX,

Thank You very much for the clear reply.

Thanks,
Kapil.

Quote:

Originally Posted by MS3FGX (Post 3682664)

64 bit processors are much better at computationally intensive tasks, and can support larger amounts of memory, so they are an obvious advantage on any server.

As long as you can get 64-bit versions of the apps you want to take advantage of 64-bit!

Quote:

Originally Posted by kapilbajpai88 (Post 3682642)

I have a RHEL5 machine here at my workplace, and I had been told that it is a 64-bit machine. I don't know how can I check that.

To check whether RHEL5 is running in 64 bit mode use the command

Code:

uname -a

When I do that I get

Code:

XXXXXX 2.6.18-128.1.10.el5 #1 SMP Thu May 7 10:35:59 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

The x86_64 means it is running 64 bit mode. If it were running 32 bit mode that might say various things such as i686 or i386.

If your system is running 64 bit, end of question.

But if it is running 32 bit, you may want to know whether the cpu is able to run 64 bit (whether it could run 64bit if you had a different copy of RHEL5). To get that type

Code:

grep lm /proc/cpuinfo

A 64 bit capable CPU should give one or more lines similar to:

Code:

flags          : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm pni monitor ds_cpl cid xtpr

while a non 64 bit capable CPU would probably give no output at all and certainly no lines beginning with the word flags.

Quote:

Originally Posted by MS3FGX (Post 3682664)

You can tell all of the information available to the kernel about the CPU with the command:

But you need to know how to read it. The lm on the flags line indicates 64 bit capable.

Quote:

new machines are almost all 64 bits, and any server hardware almost certainly will be 64 bit at this point.

True. But lots of people run 32 bit OS's on 64 processors, in some cases for good reason.

Quote:

64 bit processors are much better at computationally intensive tasks, and can support larger amounts of memory, so they are an obvious advantage on any server.

I'm sure you can find lots of exceptional cases where a server would be better off running a 32 bit Linux. I think the OP's question is more about what RHEL is actually running vs. what could run.

What you say about the processor rather than the Linux, is primarily true because all the high performance x86 CPUs are 64 bit capable. So if you were buying a CPU for a 32 bit Linux server, you would almost certainly get a 64 bit CPU.