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[120]
  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.

boot commands

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.