Pinboard: bookmarks for raphman tagged 'howto'

System Encryption with LUKS - ArchWiki

Solid state disk users should be aware that by default, Linux's full-disk encryption mechanisms will not forward TRIM commands from the filesystem to the underlying disk. The device-mapper maintainers have made it clear that TRIM support will never be enabled by default on dm-crypt devices because of the potential security implications; if TRIM support were enabled, an attacker may be able to tell which blocks have been used, how many blocks have been used, and other information that is exposed directly to the device when a TRIM is issued.

It may be possible to determine the filesystem utilized by your encrypted device through the data that is leaked by TRIM. Furthermore, any information that may be derived by a profile of block usage may be exposed by enabling TRIM support on an encrypted device.

As of linux version 3.1, support for dm-crypt TRIM pass-through can be toggled upon device creation or mount with dmsetup. Support for this option also exists in cryptsetup version 1.4.0 and up. To add support during boot, you will need to add ":allow-discards" to the
cryptdevice option. The option should look like this:
cryptdevice=/dev/mapper/root:root:allow-discards

For more information, including specific commands and details on dm-crypt TRIM pass-through, see these mailing list threads:
* http://article.gmane.org/gmane.linux.kernel.device-mapper.devel/14134
* http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/5166

linux encryption ssd howto tips
11 weeks ago by raphman

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All Mouse Buttons Working - ArchWiki

This article is for users that have a mouse with more than 7 mouse buttons and want to be able to use all of them. Logitech makes several of these (if you have a Logitech Marble® Mouse you can also look at this page), and Microsoft makes a few as well. If you have one of these mice, read on!

wiki linux mouse input howto
december 2011 by raphman

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Laughton Electronics | the KimKlone: a radical 6502 redesign

The KimKlone represents an architectural extension of the 65C02. The most striking improvement is efficient linear access to a 16 Mbyte Address Space. Also on the short list is hardware acceleration for the Forth programming language, including a one-byte NEXT instruction and a new, stack-savvy addressing mode. To exploit these and other capabilities, the programmer has access to new instructions and new registers. (See the programming model, left.)

6502 microcontroller hardware electronics howto history
october 2011 by raphman

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