Let’s take a look how to find out all interesting information about hardware and software (Solaris OS) on your SUN box.
We can start with the uname command. The most interesting options are uname -a and uname -X.

$ uname -a
SunOS test1 5.8 Generic_108528-26 sun4u sparc SUNW,Sun-Fire-880
$

Output above is telling me that my SUN box has SunOS operating system with test1 as nodename. The release of the operating system is 5.8 ( Solaris 8 ) and its
version is Generic_108528-26. The machine hardware class is sun4u, it has sparc processor type and the SUNW,Sun-Fire-880 platform.

If you need just one specific information you can filter it by using other uname options (see man uname). I prefer to use uname -a because here I see all information at once.

Other interesting option of the uname command is uname -X.

$ uname -X
System = SunOS
Node = test1
Release = 5.8
KernelID = Generic_108528-26
Machine = sun4u
BusType =
Serial =
Users =
OEM# = 0
Origin# = 1
NumCPU = 4

As you can see from the output we got almost the same amount of information as before plus we see some new lines. BusType, Serial, Users, OEM#, Origin# are set to default values and are not too interesting. On the other hand NumCPU is telling as that our SUN box has four CPUs.

We can see list of available CPUs by issuing following command as root.

# psrinfo
0 on-line since 04/19/09 12:30:36
1 on-line since 04/20/10 10:15:18
2 on-line since 04/20/10 16:15:25
3 on-line since 04/20/10 16:15:25
#

For some details about each CPU including frequency of the CPU and uptime we can use psrinfo -v:

# psrinfo -v
Status of processor 0 as of: 05/11/10 07:48:17
Processor has been on-line since 04/19/09 12:30:36.
The sparcv9 processor operates at 900 MHz,
and has a sparcv9 floating point processor.

Status of processor 1 as of: 05/11/10 07:48:17
Processor has been on-line since 04/20/10 10:15:18.
The sparcv9 processor operates at 900 MHz,
and has a sparcv9 floating point processor.

Status of processor 2 as of: 05/11/10 07:48:17
Processor has been on-line since 04/20/10 16:15:25.
The sparcv9 processor operates at 900 MHz,
and has a sparcv9 floating point processor.

Status of processor 3 as of: 05/11/10 07:48:17
Processor has been on-line since 04/20/10 16:15:25.
The sparcv9 processor operates at 900 MHz,
and has a sparcv9 floating point processor.
#

There is possibility how to change uname -a output should you for whatever reason need it. I know about two methods that can do the trick. It could be done using sloggi kernel module for Solaris 8, Solaris 9, Solaris 10, Solaris Express, OpenSolaris, and other distributions based on that code. Sloggi can be used in Solaris for SPARC and Solaris for x86.
In Solaris 10 you can also use dtrace for this purpose but obviously that does not work in previous Solaris releases.

For detailed procedure, please refer to following webpage

There is one more file you should be familiar with. It is /etc/release. This file is created automatically during OS installation and contain details about release installed on your SUN box.

$ cat /etc/release
Solaris 8 10/00 s28s_u2wos_11b SPARC
Copyright 2000 Sun Microsystems, Inc. All Rights Reserved.
Assembled 31 August 2000

You can compare output from your /etc/release with SUN Solaris release naming matrix on the following webpage