i.e., on start it will show, e.g. "Mon 31 Oct 2011 09:17:15 GMT" (en_GB format), and stay that way for 45 seconds, then show "Mon 31 Oct 2011 09:18:00 GMT" for a minute, etc.
It redraws to show the correct time, including seconds, when the window is resized. Window manager is Unity, version as of oneric-updates: 4.24.0-0ubuntu2b1 0.
ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: x11-apps 7.6+4ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 1.23-0ubuntu3
Architecture: amd64
CheckboxSubmission: b0d31efda01870980e2e5a89390b685c
CheckboxSystem: 6ce041aeed0a2c17b3343b66d157175d
Date: Mon Oct 31 09:11:52 2011
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
ProcEnviron:
PATH=(custom, user)
LANG=en_GB.UTF-8
SHELL=/bin/zsh
SourcePackage: x11-apps
UpgradeStatus: Upgraded to oneiric on 2011-05-03 (181 days ago)
At least on 12.04 and later there is an "-update" option to set the number of seconds for updating. Therefore digital works fine when you run:
xclock -digital -update 1
So while the default of 60 seconds is odd in digital mode, it works as described in the man pages.