Both commands can be used, and the output can be interpreted like the following:
Cisco Internetwork Operating System Software
IOS ™ 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 when, for example, if given a special version of software to try out a bug fix, it will say experimental version.
Major: Major version number, which (in theory) whenever has major feature additions and changes to the softare.
Minor: Minor version number, which counts smaller but still signficant feature added.
Release: Increment of 1, 2, 3, 4… for each maintenance release of released software for every compile in some other places.
Interim: Increment on every build of the release tree in software control, 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, which has “fc 1” or similar for released software.
Desc: Additional description.
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, 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.
demo.cisco.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.
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.
Configuration register is 0x102
Lastly, the “configuration register”, which may be set via software in recent release.