Today I read (some of) Digital Tools I Wish Existed. I didn’t read the whole thing but I did find myself agreeing with the bits I read. I tried creating a reading database for myself but it quickly got clogged and unmanageable then fell into disuse. I think it’s a good idea but I haven’t found a workable solution to the problem yet… presently my notes and reading are strewn out all over the place.
Tag Archives: management
Codd’s 12 rules
Today in my travels I came across Codd’s 12 rules. They are rules for what qualifies as a relational database. Apparently these rules are discussed in RELATIONAL MODEL DATABASE MANAGEMENT 2 but as that is $486 I will not have a copy any time soon…
Gallery of Processor Cache Effects, MMUs, CPUID, etc.
Found Gallery of Processor Cache Effects… also of interest CPU cache, Memory Management Unit, and CPUID on Wikipedia.
Ubuntu/Linux/Unix user and group account management
To disable a user login:
$ sudo passwd -l username
To unlock a disabled user login:
$ sudo passwd -u username
To specify all the secondary groups a user should be in (if they’re already in a group not in this list they will be removed from it) you use:
$ sudo usermod -G grp_a,grp_b username
To append to the list of secondary groups:
$ sudo usermod -a -G grp_c username
To show what users are in a group:
$ grep ^group: /etc/group
E.g. to show which users are in the sudo group:
$ grep ^sudo: /etc/group
You also need to check primary groups by grepping for the gid in the passwd file. For instance the gid for the sudo group is 27, so to see who’s in sudo you also have to:
$ grep 27 /etc/passwd
Of course you should take all of the above with a grain of salt because there are a thousand caveats.