The Linux ABI is a patch to the Linux kernel that allows a linux system to run foreign binaries. It was developed as a follow-on to the iBCS/iBCS2 project for the older 2.2 kernel. It supports binaries from SCO OpenServer, SCO OpenDesktop, SCO Unix 3.x, SCO Xenix 386, SCO Xenix 286 (with userspace x286 emulation), SCO UnixWare 7, Caldera OpenUnix 8, SUN Solaris 2, System V Release 3 (SVR3), System V Release 4 (SVR4), Wyse V/386, and ISC Interactive Unix. Only the Intel i386 platform is currently supported
Compressed caching is the introduction of a new level into the virtual memory hierarchy. Specifically, RAM is used to store both an uncompressed cache of pages in their natural encoding, and a compressed cache of pages in some compressed format. By using RAM to store some number of compressed pages, the effective size of RAM is increased, and so the number of page faults that must be serviced by very slow hard disks is decreased. The main goal is to implement this compressed caching in Linux 2.4 (2.5).
Linux FreeS/WAN provides IPSEC (IP Security, which is both encryption and authentication) kernel extensions and an IKE (Internet Key Exchange, keying and encrypted routing daemon) as well as various rc scripts and documentation. It is known to interoperate with other IPSEC and IKE system already deployed by other vendors such as OpenBSD, Cisco, or CheckPoint. It also features Opportunistic Encryption, subnet extrusion, and with the appropriate patches interops nicely with Microsoft Windows XP/2000 using X.509 certificates.
The Linux Intrusion Detection System (LIDS) is a patch which enhances the kernel's security by implementing a reference monitor and Mandatory Access Control (MAC). When it is in effect, chosen file access, all system/network administration operations, any capability use, raw device, memory, and I/O access can be made impossible even for root. You can define which programs can access specific files. It uses and extends the system capabilities bounding set to control the whole system and adds some network and filesystem security features to the kernel to enhance the security. You can finely tune the security protections online, hide sensitive processes, receive security alerts through the network, and more.
Linux Kernel "make xconfig" Enhancement Patch is a patch to the Linux kernel that enhances the search dialog of "make xconfig" by providing case-sensitivity and a choice of keyword search, regular expression search, and substring search. It was done in a modular way by enhancing the kernel C configuration API.