hotplug - Dynamic Hardware Configuration

Posted on July 30th, 2008 in Basics, Hardware by admin

Hotplug is a system for managing devices that can be dynamically attached to and removed from the system while it’s running. The most obvious use for this system is handling USB and firewire devices, though it also handles PCI (32-bit PCMCIA - or CardBus - devices are really PCI in disguise), tape drives, SCSI devices, devices requiring firmware to be loaded into them, input devices, and more. It consists of a kernel part and a userland part. I’ll only cover the userland part in any depth, as users should not ever have to dive into the kernel half.

The problem hotplug tries to solve is a very difficult one, especially for the land of Unix where hardware is accessed through device nodes and includes real permission checking. Device nodes themselves are special little files in /dev that are referenced through static major and minor numbers which must be registered somewhere. They must also be given owners and groups, as well as permissions for access. For static devices like an internal hard disk or a sound card, this system works fairly well.

The /etc/exports Configuration File

Posted on July 30th, 2008 in Basics, Networking by admin

The /etc/exports file controls which file systems are exported to remote hosts and specifies options. Blank lines are ignored, comments can be made by starting a line with the hash mark (#), and long lines can be wrapped with a backslash (\). Each exported file system should be on its own individual line, and any lists of authorized hosts placed after an exported file system must be separated by space characters. Options for each of the hosts must be placed in parentheses directly after the host identifier, without any spaces separating the host and the first parenthesis. Valid host types are gss/krb5gss/krb5i and gss/krb5p.

A reminder about the proper way to invoke root in Ubuntu

Posted on July 26th, 2008 in Ubuntu by admin

I’ve been answering a lot of support threads lately wherein users have said they are unable to empty the trash can because a file in there is owned by root or they cannot get a Firefox setting change to stick (and it turns out their Firefox settings folder is owned by root).

Do you know where this comes from, why this is happening?

Bad advice. It all comes from bad advice.

The follow hopes to counter that.

Guide to faster Ubuntu

Posted on July 20th, 2008 in Ubuntu by admin

Ubuntu is already pretty speedy compared to some bloated OSes out there, but here’s a way to make it a bit faster.

The chage command

Posted on July 17th, 2008 in Basics, Commandline Tools, Security by admin

chage changes the number of days between password changes and the date of the last password change. This information is used by the system to determine when a user must change her password. The chage command is restricted to the root user, except for the -l option, which may be used by an unprivileged user to determine when her password or account is due to expire.

A nice conky file, for all

Posted on July 17th, 2008 in Applications, Tweaks by admin

Screenshot here, config file below:

Have a nice customized .bashrc file

Posted on July 16th, 2008 in Applications, Commandline Tools, Tweaks by admin

Screenshot

Right Click the file below and save it to your home folder.

Backup your current bash profile by  “mv .bashrc .bashrc.bak

then mv bashrc.txt .bashrc

File: bashrc

Kudos goes to ayoli for this.

Installing & Using Gnome-Do

Posted on July 14th, 2008 in Applications, Gnome by admin

GNOME Do (Do) is an intelligent launcher tool that makes performing common tasks on your computer simple and efficient. Do not only allows you to search for items in your desktop environment (e.g. applications, contacts, bookmarks, files, music), it also allows you to specify actions to perform on search results (e.g. run, open, email, chat, play). Want to send an email to mom? Simply type “email mom.” Want to listen to some music? Simply type “play beatles.” Do provides instantaneous, action-oriented desktop search results that adapt to reflect your habits and preferences. For example, if you use Firefox web browser often, typing “f” in Do will launch it. Or, if you visit The New York Times webpage often, Do will open it if you simply type “nyt.” Unlike other search tools that present search results as flat, homogeneous lists, Do provides familiar graphical depictions of search results that assure you that your intent is being realized correctly; searching for “mom” will show a picture of mom, and searching for “beatles” will show a Beatles album cover. Do has many more powerful and exciting capabilities that must be seen to be appreciated.

Installing & Using TimeVault in Ubuntu/Debian

Posted on July 14th, 2008 in Applications, Debian, Ubuntu by admin

TimeVault is a simple front-end for making snapshots of a set of directories. Snapshots are a copy of a directory structure or file at a certain point in time. Restore functionality is integrated into Nautilus - previous versions of a file or directory that has a snapshot can be accessed by examining the properties and selecting the ‘Previous Versions’ tab.

Snapshots are protected from accidental deletion or modification since they are read-only by default. The super-user can delete intermediate snapshots to save space, but files and directories that existed before or after the deletion will still be accessible.

A snapshot is a copy of a directory at a certain point in time. Snapshots don’t use space for the files that haven’t changed but instead simply increment the link count for them. On Linux, when a file is deleted, the link count is decremented, but it isn’t actually removed until the link count hits zero.

Only files are hard-linked this way. Directories have to be recreated for technical reasons (since a hard-link is actually the file it points to, you would find yourself in a completely different path if directories were hard-linked).

How to turn off Firefox 3’s “awesome bar”

Posted on July 13th, 2008 in Applications by admin

In Firefox 3, the Location Bar received a number of improvements. Among those improvements was the move to a XUL richlistbox widget for the auto-complete dropdown. This allowed styled URL/title information, favicons, and highlighted match information. This preference determines how many entries should appear (at most) in the dropdown.  Many find Firefox 3’s “awesome bar” quite annoying.  Luckily  this is easy to disable.

First, in the address bar type:   “about:config”  (without the quotes).

In the about:config search bar type:  Browser.urlbar.maxRichResults

The default value is set to 12.  If you set this interger to 0, nothing will display in the “awesome bar” any longer.

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