When the ACE product was first acquired I think that the software was version 2.0.0. They quickly produced Version 3.0.0 and then started to number minor releases with the sequence A1.
Thus, we had 3.0.0-A1_1, 3.0.0-A1_2 and so on. For some reason this became known as the A1 release. Because now we have the A2 release. See the module output below:
Software loader: Version 12.2 system: Version A2(1.1a) [build 3.0(0)A2(1.1a) adbuild_22:19:41-2008/07/21_/au to/adbu-rel3/rel_a2_1_1_throttle/REL_3_0_0_A2_1_1A] system image file: [LCP] disk0:c6ace-t1k9-mz.A2_1_1a.bin installed license: no feature license is installed
This ACE is running A2.1.1a NOT Version 3.0.0 as you might think.
The documentation now refers, vaguely, to the version on the title page as
Software Version 3.0(0)A1(2) April 2006
but the newer version.
Software Version A2(1.0) March 2008
Confusing eh. _grin_
So, in “Cisco speak” Version 3.0 is NOT NEWER than A2.1, it Version 3.0 nearly always means that A1.x version and you don’t want anything to do with that.
Don’t use Version A1
Frankly, the A1 version was flaky and had almost no features. It was also prone to crashing, and various pieces of weird behaviour. Today, you should proceed immediately to Version A2.1.2.
So when you see something like this, quite confusing, boot syntax you will know what is going on.
boot system image:c6ace-t1k9-mz.A2_1_1a.bin
boot system image:c6ace-t1k9-mz.3.0.0_A1_6_3a.bin
And yes, it IS perfectly obvious.