Typing ``show version'' or ``show hardware'' yields a response like:

        prospect-gw.near.net>sh version
        Cisco Internetwork Operating System Software 
        IOS (tm) GS Software (GS7), Experimental Version 10.2(11829) [pst 113]

System-type (imagename) Version major.minor(release.interim)[who] Desc

System-type:  type of system the software is designed to run on.
imagename:  The name of the image.  This is different (slightly) for
        run-from-rom, run-from-flash, and run-from-ram images, and also
        for subset images which both were and will be more common.
"Version": text changes slightly.  For example, if an engineer gives you
        a special version of software to try out a bug fix, this will say
        experimental version.
Major: Major version number.  Changes (in theory) when there have been
        major feature additions and  changes to the softare.
Minor: minor version number.  Smaller but still signficant feature added.
        (in reality, cisco is not very sure what the difference between
         "major" and "minor" is, and sometimes politics gets in the way,
        but either of these "incrementing" indicates feature additions.)
        EXCEPT: 9.14, 9.17, and 9.1 are all somewhat similar.  9.1 is
        the base, 9.14 adds specical feature for low end systems, 9.17
        added special features specific the high end (cisco-7000)  This
        was an experiment that we are trying not to repeat.
release: increments (1 2 3 4 ...) for each maintenance release of released
        software.  Increments for every compile in some other places.
interim: increments on every build of the "release tree", which happens
        weekly for each release, but is only made into a generically
        shipping maintenance release every 7 to 8 weeks or so.
[who]:  who built it.  Has "fc 1" or similar for released software.
        has something like [billw 101] for test software built Bill
        Westfield (billw@cisco.com).
Desc:   additional description.

The idea is that the image name and version number UNIQUELY identify
a set of sources and debugging information somewhere back at cisco,
should anything go wrong.

        Copyright (c) 1986-1995 by cisco Systems, Inc.
        Compiled Thu 09-Mar-95 23:54 by tli
        Image text-base: 0x00001000, data-base: 0x00463EB0

Copyright, compilation date (and by whom), as well as the
starting address of the image.
           
        ROM: System Bootstrap, Version 5.0(7), RELEASE SOFTWARE
        ROM: GS Software (GS7), Version 10.0(7), RELEASE SOFTWARE (fc1)

The version of ROM bootstrap software, and the version of IOS
in ROM.
           
        prospect-gw.near.net uptime is 2 weeks, 4 days, 18 hours, 38 minutes
        System restarted by reload

How long the router has been up, and why it restarted.

        System image file is "sse-current", booted via flash

How the router was booted.
           
        RP (68040) processor with 16384K bytes of memory.

Type of processor.

        G.703/E1 software, Version 1.0.
        X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.
        Bridging software.
        ISDN software, Version 1.0.

Various software options compiled in.

        1 Silicon Switch Processor.
        2 EIP controllers (8 Ethernet).
        2 FSIP controllers (16 Serial).
        1 MIP controller (1 T1).
        8 Ethernet/IEEE 802.3 interfaces.
        16 Serial network interfaces.
        128K bytes of non-volatile configuration memory.
        4096K bytes of flash memory sized on embedded flash.

Hardware configuration.
           
        Configuration register is 0x102

Lastly, the "configuration register", which may be set via
software in current releases...